Catalytic-ultrasonic synergistic treatment process and system for targeted degradation of formaldehyde in wastewater

Abstract

The invention relates to the technical field of industrial wastewater treatment, in particular to a catalysis-ultrasonic synergistic treatment process and system for targeted degradation of formaldehyde in wastewater, and is used for solving the problems of no selectivity, high energy consumption, weak impact resistance and poor long-period stability of high-concentration formaldehyde wastewater treatment in related technologies. The system comprises a reactor main body, a catalyst unit, an array ultrasonic unit, an intelligent regulation and control unit and an auxiliary unit, and all the units form a full-closed-loop integrated processing system of data acquisition, prediction calculation, instruction execution and feedback correction through structural assembly linkage and signal transmission cooperation. The technical problems of unstable formaldehyde degradation efficiency, high energy consumption, weak impact resistance and poor adaptation to extreme working conditions in the prior art can be solved in modes of two-dimensional partition adaptation, dual-drive cavitation coordination, intelligent closed-loop regulation and unit integrated coordination.

Description

Technical Field

[0001] This application relates to the technical field of industrial wastewater treatment, and in particular to a catalytic-ultrasonic synergistic treatment process and system for targeted degradation of formaldehyde in wastewater. Background Technology

[0002] Industrial production processes generate large amounts of formaldehyde-containing wastewater. Formaldehyde is highly toxic and carcinogenic; direct discharge can cause serious harm to the ecological environment and human health. Therefore, the efficient degradation and treatment of formaldehyde in wastewater is an important research direction in the field of industrial wastewater treatment. Currently, catalytic-ultrasound synergistic technology has become one of the mainstream technologies for formaldehyde wastewater treatment due to its advantages such as high degradation efficiency and no secondary pollution, and is widely used in various industrial wastewater treatment scenarios.

[0003] In existing technologies, catalytic-ultrasound synergistic treatment schemes for formaldehyde wastewater mostly employ a single-dimensional zoning design. Cavitation nests are primarily in a passive acoustic response mode, and the control system relies mainly on simple feedback control. Furthermore, the various units of the treatment system are often distributed and combined. In practical applications, these schemes typically use fixed ultrasonic parameters and focal lengths to drive the degradation reaction, and energy distribution is controlled holistically without dynamic adaptation for different concentration zones.

[0004] However, existing technologies have several drawbacks: First, the single-dimensional partition design cannot accurately adapt to the concentration gradient distribution of formaldehyde in wastewater, resulting in insufficient local degradation or redundant energy waste; second, the passive cavitation response mode has a narrow frequency range and low cavitation efficiency, making it difficult to achieve targeted degradation of formaldehyde; third, the control system has a lag in response and weak shock resistance, making it unable to cope with sudden changes in industrial wastewater concentration; fourth, there is a lack of effective adaptation measures for extreme conditions such as high salinity and long-term operation, resulting in poor treatment stability; and fifth, the system units have poor coordination, making it difficult to ensure efficient process implementation and adapt to complex industrial wastewater with large fluctuations in formaldehyde concentration and salinity, ultimately leading to unstable formaldehyde degradation efficiency, high energy consumption, and limited applicability. Summary of the Invention

[0005] This application provides a catalytic-ultrasonic synergistic treatment process and system for targeted degradation of formaldehyde in wastewater. It can solve the technical problems of unstable formaldehyde degradation efficiency, high energy consumption, weak impact resistance, and poor adaptability to extreme working conditions in the prior art by means of two-dimensional partition adaptation, dual-drive cavitation synergy, intelligent closed-loop control and unit integration synergy.

[0006] In a first aspect, this application provides a catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater, employing the following technical solution:

[0007] A catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater includes a reactor body, a catalyst unit, an array-type ultrasonic unit, an intelligent control unit, and an auxiliary unit. The units are linked through structural assembly and signal transmission to form a fully closed-loop integrated treatment system of "data acquisition-predictive calculation-instruction execution-feedback correction".

[0008] The catalyst unit comprises a 3×2 dual-dimensional partitioned catalyst tube array and a 3×2 dual-dimensional partitioned acoustic focusing catalyst module, which are coaxially assembled and integrated. The 3×2 dual-dimensional partitioned acoustic focusing catalyst module is nested inside the 3×2 dual-dimensional partitioned catalyst tube array. The 3×2 dual-dimensional partitions are divided into 3 axial partitions and 2 radial partitions. The axial partitions are divided into a lower high-concentration zone, a middle transition zone, and an upper low-concentration zone in a height ratio of 1:1:1. The radial partitions are divided into a central zone and an edge zone in a radius ratio of 3:2, forming six independent catalyst units. Each partition is isolated by a fluororubber micro-sealing ring with a thickness of less than 0.5 mm.

[0009] Each partition of the 3×2 dual-dimensional acoustic focusing catalyst module is equipped with an independent micro piezoelectric drive mechanism and a catalytic coating. The catalytic coating consists of an active catalyst sub-coating, an acoustic metamaterial nested layer, and a salt-resistant acoustic transmission coating from the inside out. The active catalyst sub-coating contains multi-level pore size cavitation nests, Pt active sites, and microcapsule-type self-healing agents. The multi-level pore size cavitation nests are a PMMA-PNIPAM-PZT composite system with a pore size distribution of 1-2μm:2-4μm:4-5μm=1:2:1.

[0010] The array-type ultrasonic unit consists of an ultrasonic generator and an array-type transducer. The array-type transducer adopts a bottom coupling installation method and corresponds one-to-one with the 3×2 dual-dimensional partitioned catalyst tube. It can realize independent frequency and power modulation of each partition, with a frequency modulation range of 20-1000kHz and a power modulation range of 0.2-1W / mL.

[0011] The intelligent control unit is based on a PLC controller and is equipped with no less than 16 multi-channel interfaces, which are respectively connected to 6 dual-dimensional partitioned spectral sensors, micro electric field control module, LSTM prediction algorithm module and energy optimization algorithm module.

[0012] The auxiliary unit includes a circulating cooling water temperature control module, an enhanced backwashing module, and a fault diagnosis module. The circulating cooling water temperature control module has a temperature control range of 40-70℃ and a temperature control accuracy of ±0.5℃. The enhanced backwashing module has a backwashing pressure of 0.5-0.7MPa and a backwashing duration of 4-6min.

[0013] By adopting the above technical solution, the specific division method and structural design of the two-dimensional partition were clarified, the uniformity of the concentration distribution of the partition was improved, and the fluororubber micro sealing ring ensured the independence of the partition and avoided fluid movement from affecting the degradation effect, providing a stable partition basis for subsequent precise control and targeted degradation.

[0014] The multi-level pore size distribution and composite material design realize the dual-drive mode of passive acoustic response adaptation and active electrical regulation correction of the cavitation nest, expanding the frequency adaptation range; the co-location setting of the cavitation nest and Pt active sites enhances the synergistic effect of cavitation and catalysis, and improves the formaldehyde degradation rate.

[0015] Each unit of the system is precisely adapted to the process. The two-dimensional partition design of the reactor body provides basic structural support for process implementation. The two-dimensional partitioned acoustic focusing catalyst module and array-type ultrasonic unit ensure the realization of dual-drive cavitation and precise focusing. The intelligent control unit realizes four-dimensional linkage intelligent control of the process. The auxiliary unit ensures the temperature stability, long-cycle clean operation and fault monitoring of the process. The coordinated cooperation of each unit ensures the efficient implementation and stable operation of the process.

[0016] Optionally, the outer wall of the 3×2 dual-dimensional partitioned catalyst tube is wound with a spiral microelectrode with a pitch of 4-6 mm and a wire diameter of 0.08-0.12 mm. The electrode voltage is adjustable within a range of 5-10 V and the power is less than 1 W. It shares a 12 V power supply circuit with the micro piezoelectric drive mechanism and is controlled by a PLC branch circuit. A closed electric field circuit is formed between the microelectrode and the active catalyst coating on the inner wall of the catalyst tube. The PZT nanocrystals in the coating serve as the electric field response medium, and the expansion and contraction of the PZT nanocrystals are controlled by the voltage change of the electrode.

[0017] Optionally, the micro piezoelectric drive mechanism of the 3×2 dual-dimensional partitioned acoustic focusing catalyst module has a power of less than 3W and a telescopic stroke of 0-4mm. It can drive the elastic deformation of the transition structure surface to achieve continuous adjustment of the focal length within the range of 6-10mm. The transition structure surface is made of flexible metal film or composite material. The acoustic metamaterial nesting layer is fixed to the transition structure surface and adopts a titanium alloy micro-pillar array structure with a column diameter of 5-20μm and a height of less than 40μm. The alignment accuracy with the cavitation nest focus is ≤±0.2mm.

[0018] By adopting the above technical solution, independent and precise control of the focal length of each zone and radial compensation are achieved. The self-calibration mechanism ensures the stability of the focal length during long-term operation, ensuring that the ultrasonic energy is accurately focused on the active sites of each zone, improving energy utilization efficiency, and further enhancing the targeted degradation effect.

[0019] Optionally, the microcapsule-type self-healing agent of the active catalyst coating has a particle size of 0.8-1.2 μm, the wall material is polyurea formaldehyde, and the core material is a mixed solution of tetrabutyl titanate and tetraethyl orthosilicate in a ratio of 1:2; the Pt active sites are loaded by an equal-volume impregnation method, with the Pt loading on the inner wall of the cavitation nest being 1.2-1.6 wt%, the Pt loading on the edge region being 0.7-1.1 wt%, and the average Pt loading of the entire coating being 0.8-1.2 wt%.

[0020] Optionally, the carrier of the active catalyst coating is processed with a parabolic surface, with a polishing precision of Ra=0.15-0.20μm and a focal length reference value of 7-9mm.

[0021] Optionally, the anti-salt acoustic transmission coating is made by mixing fluorine-modified silicone rubber and nano-zirconia in a weight ratio of 6:4-8:2, adding 0.4-0.6% PVP dispersant, and curing at 115-125℃ for 25-35 minutes to form a thickness of less than 20μm and a salt adhesion amount of <3mg / cm².

[0022] Optionally, the dual-dimensional partitioned spectral sensor has a response time of less than 3s and a sampling frequency of no more than 1s; the LSTM prediction algorithm module is trained based on no less than 1000 hours of historical data and can predict the concentration change trend 20s in advance with a prediction error of ≤±8%; the micro-electric field control module includes 6 independent branch control units with a response time of ≤3s.

[0023] By adopting the above technical solutions, the prediction model based on the LSTM algorithm has achieved accurate prediction of energy allocation, and the design of energy linkage mode and energy-saving mode has realized the efficient utilization of redundant energy and the reduction of overall energy consumption, further improving the economic efficiency of the process.

[0024] Secondly, this application provides a catalytic-ultrasound synergistic treatment process for targeted degradation of formaldehyde in wastewater, employing the following technical solution:

[0025] A catalytic-ultrasound synergistic treatment process for targeted degradation of formaldehyde in wastewater includes the following four core processes:

[0026] S1: Targeted adsorption and activation. After pretreatment, formaldehyde-containing wastewater flows from bottom to top into the 3×2 dual-dimensional partitioned acoustic focusing catalyst module. Formaldehyde is targeted adsorbed and activated through the Pt active sites of the active catalyst coating, with an adsorption rate of ≥90% and a retention rate of ≥99.3% for other biodegradable COD components.

[0027] S2: Cavitation degradation, the array-type ultrasonic unit is activated, and through the dual driving mechanism of the acoustic and thermal passive response and electric field active correction of the cavitation nest of the PMMA-PNIPAM-PZT composite system, the cavitation nest aperture and ultrasonic frequency are resonantly matched, and the cavitation effect is synergistically triggered to generate ·OH free radicals, which degrade the formaldehyde activation intermediate into CO2 and H2O.

[0028] S3: Intelligent collaborative optimization. The intelligent control unit, based on real-time concentration data from a dual-dimensional partitioned spectral sensor, achieves four-dimensional collaborative optimization of focal length, ultrasonic parameters, and energy distribution through an LSTM prediction algorithm module and an energy optimization algorithm module.

[0029] S4: Temperature control and self-cleaning. The circulating cooling water temperature control module maintains a stable reaction temperature. Combined with the enhanced backwashing module and catalyst self-repair function, it achieves online self-cleaning and ensures that wastewater is discharged in compliance with standards.

[0030] The process employs a two-dimensional partitioned active gradient adaptation design, a cavitation nest acoustic-electric dual-drive synergistic mechanism, ultrasonic-catalytic-electric field multi-field coupling, and dynamic energy redundancy allocation. The core process parameters range as follows: focal length 6-10mm, ultrasonic frequency 20-1000kHz, power density 0.2-1W / mL, reaction temperature 40-70℃, residence time 60-120min, and empty tower flow rate 3-12m / h.

[0031] By adopting the above technical solution, the active gradient adaptation design of 3×2 dual-dimensional partitioning achieves precise matching of formaldehyde concentration gradient; the synergistic effect of piezoelectric-acoustic dual-drive cavitation nest and ultrasonic field improves the targeting and efficiency of cavitation degradation; the intelligent control unit achieves synergistic optimization of multiple parameters, combined with an energy redundancy dynamic allocation mechanism to reduce energy consumption; and the temperature control regulation and enhanced self-cleaning measures ensure stable process operation, thereby effectively solving the problems of unstable degradation efficiency and high energy consumption in existing technologies, and achieving efficient targeted degradation of formaldehyde in wastewater.

[0032] Optionally, the flow parameters for the 3×2 two-dimensional partition are: empty tower velocity of 3-12 m / h and residence time of 60-120 min; different combinations of parameters are used for formaldehyde wastewater of different concentrations.

[0033] (1) High concentration of formaldehyde, with a formaldehyde concentration range of 5000-12000 mg / L, excluding 5000 mg / L, and the parameter combination strategy adopted is focal length 6-7 mm + ultrasonic frequency 20-40 kHz + power density 0.35-0.45 W / mL;

[0034] (2) Medium concentration formaldehyde, with a formaldehyde concentration range of 500-5000 mg / L and no formaldehyde concentration of 500 mg / L. The parameter combination strategy adopted is focal length 7-8 mm + ultrasonic frequency 40-100 kHz + power density 0.4-0.5 W / mL.

[0035] (3) Low concentration formaldehyde, with a formaldehyde concentration range of 30-500 mg / L, and the parameter combination strategy adopted is focal length 9-10 mm + ultrasonic frequency 100-500 kHz + power density 0.55-0.6 W / mL;

[0036] By adopting the above technical solutions and designing process parameter combinations adapted to different concentrations, the precise degradation of formaldehyde wastewater of different concentrations was achieved. While ensuring the degradation rate of high-concentration formaldehyde, deep purification of low-concentration formaldehyde was also achieved, avoiding energy waste and improving the versatility of the process.

[0037] Optionally, under high-salt conditions and TDS of 3-50000 mg / L, a salt-resistant acoustic transmission coating is used for protection, and acoustic metamaterial focusing parameter compensation is applied to ensure that the focusing efficiency is not less than 95% under TDS≤50000 mg / L conditions.

[0038] By adopting the above technical solutions, targeted adaptation measures were designed for extreme operating conditions such as high salt content and long-term operation, which effectively reduced the impact of extreme operating conditions on the degradation effect and improved the operational stability and applicability of the process.

[0039] Optionally, the dual-drive mechanism of the cavitation nest is as follows: under the operating conditions of 20-40kHz, PNIPAM swelling increases the pore size by 10%; under the operating conditions of 40-100kHz, PNIPAM is in a stable swollen state; under the operating conditions of 100-400kHz, PNIPAM is in a stable transition state; under the operating conditions of 400-500kHz, PNIPAM phase transformation shrinkage decreases the pore size by 8%; active fine-tuning is achieved by driving the expansion and contraction of PZT nanocrystals through a 5-10V micro-electric field, with a pore size adjustment accuracy of ±0.01μm and a matching error of <1%.

[0040] Optionally, the four-dimensional linkage and collaborative optimization specifically includes:

[0041] (1) When the concentration fluctuation in the zone is ±10%, the focus length is adjusted by ±0.25-0.3mm and the power is adjusted by ±0.04-0.05W / mL.

[0042] (2) Predict the concentration trend 20 seconds in advance to achieve parameter pre-adjustment; perform feedback fine-tuning with a period of 3 seconds, with a response time ≤ 3 seconds;

[0043] (3) When the influent concentration changes by ±50%, the rapid response procedure is initiated, and the parameters of the entire system are adapted within 8-10 seconds;

[0044] (4) When the energy efficiency ratio deviation between adjacent zones is <5%, the energy linkage mode is activated to transfer 10-12% of the redundant energy in the upper zone to the lower high-concentration zone; when the formaldehyde concentration in the effluent is <8mg / L and remains stable for 25-30s, the energy-saving mode is triggered, and the overall energy consumption is reduced by 8-12%;

[0045] (5) Automatically perform zone focal length self-calibration every 280-320 hours of operation, with a reference value of 8mm and a calibration deviation of ≤±0.1mm.

[0046] By adopting the above technical solutions, the four-dimensional linkage logic combined with the feedforward prediction and feedback fine-tuning mechanism significantly improves the response speed and accuracy of the control system. The rapid response procedure enhances the process's resistance to sudden changes in influent concentration and ensures the stability of effluent concentration.

[0047] Optionally, the self-cleaning is triggered every 180-220 hours or when the pressure drop of the catalyst tube changes abruptly by >0.2 kPa. Backwashing is performed using a combination of reverse flushing and low-power ultrasonic cleaning, with a backwashing pressure of 0.5-0.7 MPa and a backwashing time of 4-6 minutes. When microcracks are generated in the active catalyst coating, the microcapsules rupture to release the core material, which cross-links and solidifies to achieve self-repair, with a repair efficiency of >90%.

[0048] Optionally, the preparation method of the active catalyst coating is as follows:

[0049] Step 1: Carrier pretreatment; Cordierite ceramics are soaked in 1M HNO3 for 10-14 hours, washed with deionized water until neutral, and calcined at 480-520℃ for 2.5-3.5 hours;

[0050] Step 2: Parabolic surface machining. A parabolic surface with a focal length of 7-9mm is machined at one end of the carrier using a five-axis CNC machine, and the surface is polished to Ra=0.15-0.20μm;

[0051] Step 3: Preparation of microcapsule-type self-healing agent; prepared by in-situ polymerization, using polyurea formaldehyde as the wall material and a precursor solution containing Ti-O-Si bonds as the core material, to obtain microcapsules with a particle size of 0.8-1.2μm (preferably 1μm);

[0052] Step 4: PZT nanocrystal dispersion; Add 40-60nm (preferably 50nm) PZT nanocrystals to deionized water and ultrasonically disperse them for 30 minutes (selected within the range of 90-110W) using 100W power to ensure uniform distribution;

[0053] Step 5: Preparation of catalytic slurry; Weigh the following by weight: TiO2 (60-65%), PMMA (10-15%), silica sol (12-18%), deionized water (7-10%), and PVP (1-2%). Add 4-6% of a uniformly dispersed 10% PZT nanocrystal solution to the slurry and ball mill for 22-26 hours. Then add 2-4 wt% of microcapsule-type self-healing agent and ball mill for an additional 10-14 hours to form a uniform slurry.

[0054] Step 6: Coating application; vacuum-assisted impregnation (-0.12~-0.08MPa, 25-35min), gradient drying (40℃±5℃ / 10-14h→60℃±5℃ / 6-10h→80℃±5℃ / 3-5h);

[0055] Step 7: Calcination program; increase to 330-370℃ at 1℃ / min ± 0.2℃ / min (hold for 1.5-2.5h to remove PMMA), then increase to 480-520℃ at 3℃ / min ± 0.5℃ / min (hold for 3-5h to crystallize TiO2).

[0056] Step 8: Pt loading; Equal volume impregnation with 0.08-0.12M chloroplatinic acid / ethanol solution, reduction with H2 / Ar (H2 volume fraction 4-6%) at 380-420℃ for 2.5-3.5h to form 2-3nm highly dispersed Pt nanoparticles with a Pt loading of 0.8-1.2wt%.

[0057] In summary, this application includes at least one of the following beneficial technical effects:

[0058] This application provides a synergistic catalytic-ultrasound co-treatment process and system to achieve efficient and targeted degradation of formaldehyde in wastewater, reduce energy consumption and improve operational stability; dual-dimensional zoning design and precise control improve concentration adaptability and ensure targeted degradation effect; intelligent closed-loop control enhances shock resistance and ensures stable effluent concentration; extreme operating condition adaptation measures expand the process applicability range and extend equipment service life.

[0059] Verified results show that the formaldehyde removal rate is ≥99.8%, the energy consumption per unit of formaldehyde degradation is ≤1.25g / kWh, the system can respond to sudden changes in influent concentration of ±50% within 8-10 seconds, and the overall energy consumption is reduced by 8-12%, providing an efficient and stable solution for industrial wastewater treatment. Attached Figure Description

[0060] The above and other features, advantages, and aspects of the embodiments of this application will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0061] Figure 1A schematic diagram of a catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater is shown in an embodiment of this application. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0064] This application provides a catalytic-ultrasonic synergistic treatment process and system for targeted degradation of formaldehyde in wastewater. It can achieve efficient targeted degradation of formaldehyde, reduce energy consumption, improve shock resistance and operational stability, adapt to extreme working conditions, has a wide range of applications, and ensure that the effluent meets standards.

[0065] Example 1

[0066] This embodiment provides a catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater.

[0067] Figure 1 A schematic diagram of a catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater is shown in an embodiment of this application.

[0068] Reference Figure 1 This system provides an integrated equipment system for the targeted degradation of formaldehyde in wastewater using a catalytic-ultrasonic synergistic treatment process. The core consists of a reactor body, catalyst units, arrayed ultrasonic units, intelligent control units, and auxiliary units. These units are interconnected through signal transmission or structural assembly, jointly supporting the efficient operation of the entire process. The system employs a 3×2 dual-dimensional partitioning design: axially, it is divided into a lower high-concentration zone, a middle transition zone, and an upper low-concentration zone in a 1:1:1 height ratio; radially, it is divided into a central zone and an edge zone in a 3:2 radius ratio, forming six independent catalytic units. The specific structure and function of each core unit are as follows:

[0069] The reactor body, serving as the fundamental load-bearing component of the entire system, is made of stainless steel, possessing excellent corrosion resistance and structural strength. Its height-to-diameter ratio is designed to be 2-3:1, adaptable to ultrasonic field distribution and fluid dynamics characteristics. Furthermore, it is equipped with ladders, inspection ports, and vent pipes for easy internal structural maintenance and troubleshooting. Independent fault inspection ports are provided for the 3 axial × 2 radial zones. The reactor body provides a stable cavity environment for catalytic adsorption and ultrasonic reactions, while also providing fundamental support for the assembly and operation of all core units.

[0070] The catalyst unit, the core reaction unit of the entire system, is located inside the reactor body and comprises two sub-modules: a 3×2 two-dimensional partitioned catalyst tube array and a 3×2 two-dimensional partitioned acoustic focusing catalyst module. These two sub-modules are coaxially integrated. The 3×2 two-dimensional partitioned acoustic focusing catalyst module is nested within the 3×2 two-dimensional partitioned catalyst tube array, synergistically achieving targeted adsorption and degradation of formaldehyde. Each partition is isolated by a fluororubber micro-sealing ring less than 0.5 mm thick to prevent fluid movement between partitions. This sealed isolation design ensures the accuracy of partition concentration monitoring data, providing a reliable data foundation for intelligent control.

[0071] The 3×2 dual-zone catalyst tube inlet is equipped with titanium alloy micro-guide vanes with a 10-20° inclination angle and a thickness of less than 1 mm (preferably 15° inclination angle), which can guide the wastewater to be evenly distributed, control the radial concentration gradient within ±3%, and ensure consistent adsorption efficiency in each zone. The inner diameter of the catalyst tube is 45-55 mm (preferably 50 mm), which is suitable for the hydraulic characteristics of industrial wastewater treatment. The outer wall electrode of the catalyst tube adopts a spiral wound micro-electrode with a pitch of 4-6 mm and a wire diameter of 0.08-0.12 mm (preferably 5 mm pitch and 0.1 mm wire diameter). The micro-electric field generated by the spiral micro-electrode drives the expansion and contraction of PZT nanocrystals in the cavitation nests of the subsequent 3×2 dual-zone acoustic focusing catalyst module, realizing the active adjustment of the cavitation nest pore size. The electrode voltage adjustment range is 5-10V, and the power is less than 1W. It shares a 12V power supply circuit with the zone micro-piezoelectric drive mechanism and is controlled by a PLC branch circuit. Verification has shown that this pitch and wire diameter range can ensure an electrode electric field uniformity of ≥90%, thus guaranteeing the stability of PZT nanocrystal stretching regulation.

[0072] The core reaction component is a 3×2 dual-dimensional acoustic focusing catalyst module, divided into six independent units according to the 3×2 dual-dimensional partitioning. This module is structurally assembled and embedded within the 3×2 dual-dimensional catalyst array of the reactor body, simultaneously forming an energy coupling relationship with the array-type ultrasonic unit to achieve synergistic effects between ultrasonic energy focusing and the catalytic reaction. Each module is equipped with an independent micro-piezoelectric drive mechanism and a catalytic coating; the catalytic coating, from the inside out, consists of an active catalyst layer, an acoustic metamaterial nested layer, and a salt-resistant acoustic transmission coating.

[0073] The active catalyst coating consists of a catalyst support substrate, a catalytic matrix, Pt active sites, hierarchical cavitation nests, and a microcapsule-type self-healing agent. These components synergistically construct a targeted degradation functional structure. Specifically, the hierarchical cavitation nests contain spherical cavities of 2-4 μm (excluding 2 μm, including 4 μm), along with cavities of 1-2 μm (including 2 μm) and 4-5 μm (excluding 4 μm), forming a hierarchical pore size distribution of 1-2 μm:2-4 μm:4-5 μm = 1:2:1, thus enhancing the coverage of the cavitation effect.

[0074] The specific method for preparing the active catalyst coating is as follows:

[0075] Step 1: Carrier Pretreatment

[0076] Objective: To clean the surface of the carrier and optimize its physicochemical properties to enhance the adhesion of subsequent catalytic coatings.

[0077] (1) Acid immersion (1M HNO3, 10-14h): A triple effect is achieved by immersion in medium concentration nitric acid: First, it removes impurities and dissolves metal ions and inorganic salt impurities that may exist on the surface of cordierite honeycomb ceramics during firing or storage; Second, it hydroxylates the surface, where H⁺ in nitric acid reacts with the surface of cordierite (mainly composed of Mg and Al silicates) to generate more silanol groups (Si-OH), laying the foundation for subsequent strengthening by forming strong chemical bonds (Ti-O-Si) with the TiO2 coating; Third, it micro-etches to roughen the surface, where slight corrosion increases the micro-roughness and enhances the mechanical anchoring effect of the coating adhesion.

[0078] (2) Wash with water until neutral: thoroughly remove residual acid and dissolved ions to prevent them from condensing and crystallizing in subsequent high-temperature steps, which could damage the coating uniformity or catalytic activity.

[0079] (3) High-temperature calcination (480-520℃, 2.5-3.5h): First, remove physically adsorbed water and thoroughly dry the carrier; second, solidify the surface hydroxyl groups, so that the surface hydroxyl groups partially dehydrate and condense to form a more stable surface structure, while ensuring that enough active hydroxyl groups remain for bonding; third, stabilize the carrier structure, eliminate internal stress that may be introduced by the previous treatment, and ensure the dimensional and mechanical stability of the carrier in subsequent coating and use processes.

[0080] Step 2: Parabolic Surface Processing

[0081] Objective: To precisely fabricate a macroscopic physical structure for focusing sound waves on a carrier.

[0082] The core significance of polishing precision lies in two aspects: reducing sound wave scattering (rough surfaces cause diffuse reflection and energy dissipation of ultrasonic waves, reducing focusing efficiency); polishing to a mirror-like finish ensures that sound waves are reflected regularly to the focal point, just like light on a mirror; and ensuring coating uniformity (a smooth surface is a prerequisite for obtaining a uniform and defect-free catalytic coating). Ra=0.15-0.20μm is not only an indicator of "smoothness," but also a core requirement for acoustic functionality: firstly, it ensures the regular reflection of ultrasonic waves (surface micro-undulations are much smaller than the wavelength of ultrasonic waves, such as the wavelength of a 40kHz ultrasonic wave in water being approximately 37mm). A smooth surface can reflect sound waves regularly to the preset 7-9mm focal point, forming a strong energy zone, just like a mirror reflects light; secondly, it avoids sound wave scattering, preventing energy dispersion that leads to focusing failure and weakened cavitation effects. If the surface is rough, sound waves will undergo diffuse reflection, energy will be dispersed, leading to focusing failure and a significant reduction in cavitation effects.

[0083] (1) Five-axis CNC machining: Five-axis CNC machine tools are used to complete complex three-dimensional machining of curved surfaces. Based on the parabolic equation z=x² / (4f) (where f=7-9mm focal length), the tool path is generated by programming.

[0084] (2) Tools and precision: Diamond or carbide precision tools are used to ensure that the deviation between the curved surface shape and the theoretical design is less than ±20 micrometers through micro-stepping and high-speed cutting, so as to ensure effective focusing of sound waves.

[0085] (3) Mirror polishing (Ra=0.15-0.20μm): First, perform coarse polishing using diamond grinding wheels or diamond whetstones with a grit size of #400-#800 (corresponding to a grit size of about 40-20μm); then perform medium polishing by applying diamond polishing paste with a grit size of W10-W5 (about 10-5μm) to a soft polyurethane polishing pad or non-woven polishing wheel (the elasticity of the polishing pad helps to adapt to curved surfaces); finally, perform fine polishing using ultrafine diamond polishing paste with a grit size of W1 and below (≤1μm). Fine polishing is performed using stone polishing slurry or colloidal silica polishing slurry (the chemical mechanical polishing effect of colloidal silica can achieve excellent surface quality); finally, cleaning and testing are carried out. After polishing, the surface is first ultrasonically cleaned with organic solvents such as acetone to remove oil stains, and then ultrasonically cleaned with deionized water to ensure that no abrasive particles remain; at least 5 points are randomly selected on the parabolic surface using a surface profilometer or white light interferometer for measurement, and the arithmetic mean deviation Ra value is taken to ensure that all measurement points meet Ra=0.15-0.20μm.

[0086] Step 3: Preparation of Microencapsulated Self-Healing Agent

[0087] Objective: To prepare a self-healing agent with specific particle size and distribution characteristics, which can be precisely applied to areas of the coating that are prone to damage.

[0088] Microcapsules with a particle size of 0.8-1.2 μm (preferably 1 μm) were prepared by in-situ polymerization using polyurea-formaldehyde as the wall material and a precursor solution containing Ti-O-Si bonds as the core material. The polymerization temperature and stirring rate were controlled to obtain the microcapsules. After preparation, the capsules were centrifuged, washed with deionized water until neutral, and vacuum-dried at 60-80℃ for 4-6 hours to ensure the integrity of the microcapsule wall material and a core material encapsulation rate ≥95%. The core material was a mixed solution of tetrabutyl titanate and tetraethyl orthosilicate (1:2), with 5% ethanol added as a diluent. Crosslinking and curing were completed within 30 minutes at a reaction temperature of 50℃ and a humidity of 40-60%, with a cured bond strength ≥2 MPa.

[0089] Step 4: PZT nanocrystal dispersion

[0090] Objective: To ensure that PZT nanocrystals are uniformly dispersed in the subsequent slurry system, thereby guaranteeing the cavitation nest size control function.

[0091] Add 40-60nm (preferably 50nm) PZT nanocrystals to deionized water in a certain proportion to prepare a 10% PZT nanocrystal solution (i.e., 10g of solution contains 10g of PZT nanocrystals and 90g of deionized water). Place the prepared solution in an ultrasonic disperser, adjust the power to 90-110W, and disperse continuously for 25-35 minutes. During the dispersion process, control the solution temperature to not exceed 40℃ (to avoid excessive temperature affecting the stability of the nanocrystals). After dispersion, use a laser particle size analyzer to ensure that there is no obvious agglomeration.

[0092] Step 5: Preparation of Catalytic Slurry

[0093] Objective: To prepare a slurry system with stable dispersion, uniform mixing of components, and precise inclusion of microcapsules and PZT nanocrystals, laying the foundation for the formation of co-localized structures.

[0094] Weigh the following components by weight: TiO2 (60-65%), PMMA (10-15%), silica sol (12-18%), deionized water (7-10%), and PVP (1-2%). Add 4-6% of a uniformly dispersed 10% PZT nanocrystal solution to the slurry and ball mill for 22-26 hours to achieve nanoscale uniform mixing of the basic components. Then add 2-4 wt% of microcapsule-type self-healing agent and ball mill for an additional 10-14 hours to ensure that the microcapsules are uniformly dispersed and precisely distributed only in the areas around the cavitation nests and the edges of the transition structure surfaces that will form later. Control the grinding ball speed and filling rate during ball milling to avoid microcapsule wall material breakage.

[0095] Functional descriptions of each component: TiO2 (60-65%): The main catalytic component, selected as P25 type titanium dioxide (approximately 80%±5% anatase phase, 20%±5% rutile phase). The mixed crystal effect promotes the separation of photogenerated electron-hole pairs, and the nanoscale particle size provides a huge reaction surface area; PMMA microspheres (10-15%): Cavitation nest substrate, which is combined with PNIPAM to form a PMMA-PNIPAM-PZT composite system (PMMA and PNIPAM are mixed at a mass ratio of 6:4~8:2, preferably 7:3; PNIPAM molecular weight is 10000-20000 Da; the thermosensitive phase transition properties of PNIPAM and the piezoelectric effect of PZT are used to construct an acoustic-electric dual-driven response mechanism, with electric field modulation and thermal response working together to ensure pore size expansion and contraction at ultrasonic frequencies of 20-500kHz). The amount reaches 8-10%, and the particle size (2-4μm) determines the size of the cavitation nests in the final coating. During subsequent calcination, it completely decomposes and leaves spherical cavities, which serve as preferential nucleation points for cavitation bubbles; Silica sol (12-18%): Inorganic binder and structural reinforcing agent. After drying and calcining, nano-SiO2 particles form a three-dimensional network, which firmly binds the components and enhances the overall mechanical strength and resistance to ultrasonic cavitation erosion of the coating; Deionized water (7-10%): Dispersion medium, providing a uniformly mixed liquid environment for the components. Combined with the water in the PZT nanocrystalline solution, it ensures that the slurry concentration is appropriate; PVP (1-2%): Dispersant, which prevents component agglomeration through steric hindrance effect and ensures that the slurry remains stable during ball milling; PZT nanocrystalline solution (4-6%): Balancing the control effectiveness and coating pore structure, it is adjusted within this range to optimize the control sensitivity.

[0096] Step Six: Coating Application

[0097] Objective: To uniformly, completely, and firmly load the catalytic slurry onto the prepared parabolic support, ensuring precise distribution of microcapsules and PZT nanocrystals.

[0098] (1) Vacuum-assisted impregnation (-0.12~-0.08MPa, 25-35min): After placing the carrier in the slurry, vacuum is drawn to remove the air in the honeycomb channels of the carrier (to avoid air resistance leading to uneven coating or hollowness); the pressure is maintained for 25-35min to ensure that the slurry fully penetrates all micropores and parabolic surfaces of the carrier under the action of capillary action and pressure difference, while allowing the microcapsules and PZT nanocrystals to be precisely embedded in the preset area.

[0099] (2) Gradient drying (40℃±5℃ / 10-14h→60℃±5℃ / 6-10h→80℃±5℃ / 3-5h): Low temperature start (40℃±5℃) is to slowly evaporate moisture to avoid coating cracking or peeling; gradually increasing the temperature promotes silica sol gelation, PVP slow migration, and at the same time ensures the stability of microcapsule structure, and finally forms a dried embryo with uniform pores, low internal stress and precise distribution of each functional component.

[0100] Step 7: Program roasting

[0101] Objective: To remove organic components, crystallize TiO2, form a stable porous catalytic coating and cavitation nests of the PMMA-PNIPAM-PZT composite system, while ensuring the integrity of the microcapsule wall material.

[0102] (1) Low temperature stage (heating to 330-370℃ at 1℃ / min±0.2℃ / min and holding for 1.5-2.5h): slow heating ensures that PMMA and PVP decompose slowly and completely (without damaging the microcapsule wall material and PZT nanocrystals); after PMMA is completely decomposed, it leaves spherical cavities, which together with PZT nanocrystals form cavitation nests, while microcapsules are evenly distributed around the cavitation nests and at the edges of the transition structure surface.

[0103] (2) High temperature stage (increase to 480-520℃ at 3℃ / min±0.5℃ / min and hold for 3-5h): at around 500℃, the amorphous TiO2 is fully converted into the highly catalytically active anatase crystal form, and the silica sol is converted into the amorphous SiO2 glass phase to achieve solid sintering; this temperature does not exceed the stable range of the microcapsule wall material, which can further stabilize the dispersion state of PZT nanocrystals, so that the coating forms a sintering neck and obtains sufficient mechanical strength to withstand long-term ultrasonic impact.

[0104] Step 8: Pt Load

[0105] Objective: To introduce highly catalytically active Pt sites to achieve co-localization design with cavitation nests and enhance the targeted degradation of formaldehyde.

[0106] (1) Equal volume impregnation: Accurately calculate the total pore volume of the carrier coating and impregnate it with an equal volume of 0.1M chloroplatinic acid ethanol solution to ensure that the Pt precursor solution is completely absorbed by the coating and preferentially penetrates into the inner wall area of ​​the cavitation nest (with no excess solution residue), so that the Pt is evenly distributed and the loading is accurately controllable.

[0107] (2) Drying: The impregnated carrier is placed in an oven at 60-80℃ to dry, so that chloroplatinic acid (H2PtCl6) is evenly distributed on the inner wall of the cavitation nest and other areas of the coating pores, laying the foundation for the formation of the co-positioning structure.

[0108] (3) H2 / Ar reduction (380-420℃, 2.5-3.5h): A mild reducing environment is formed by a mixture of 4-6% H2 and 94-96% Ar to avoid the aggregation of Pt nanoparticles; through the chemical reaction H2PtCl6 + 2H2 → Pt 0 + 6HCl generates highly dispersed Pt nanoparticles of 2-3 nm. Through the pore adsorption effect of the cavitation nest region, Pt is selectively enriched and precisely distributed in the inner wall region of the cavitation nest (loading 1.2-1.6 wt%), the loading in the edge region is 0.7-1.1 wt%, and the overall average Pt loading of the coating is 0.8-1.2 wt%. This forms Pt active sites co-located with the cavitation nest, ensuring that the ·OH free radicals generated by the cavitation effect directly act on the formaldehyde activation intermediate.

[0109] The core characteristics of the active catalyst coating are as follows: Through a precise parabolic macrostructure, the originally diffuse ultrasonic mechanical energy in the system is efficiently captured and focused onto a specific reaction region with a preset focal length of 7-9 mm (preferably 8 mm), increasing the sound pressure and energy density of this region by 3-5 times. The microscopic cavitation nests formed by the decomposition of PMMA microspheres within the active catalyst coating serve as preferential nucleation sites, significantly reducing the cavitation energy barrier and inducing dense and intense cavitation bubble collapse. The synergy between macroscopic focusing and microscopic cavitation results in an unusually large number of hydroxyl radicals (·OH) generated on the catalyst surface for oxidative attack, accompanied by localized shock waves of 100-500 MPa and a physical pulverizing effect of instantaneous high temperature and pressure of 5000-10000 K and 50-100 MPa. Crucially, the high-energy effect is precisely confined to the vicinity of the active sites of the catalyst that have adsorbed and activated formaldehyde molecules, achieving targeted removal of the pollutant. This results in efficient and deep mineralization of formaldehyde at the molecular level, significantly improving energy utilization efficiency and overall system stability.

[0110] The ultrasonic-catalyst synergistic mechanism of active catalyst coating consists of three core stages, as detailed below:

[0111] (1) Energy Convergence and Targeted Adsorption: The parabolic structure of the catalyst concentrates the diffuse ultrasonic energy in the system to a specific area with a preset focal length of 7-9 mm in front of it. The Pt active sites on the surface precisely adsorb and activate formaldehyde molecules, laying the foundation for subsequent degradation. (2) Cavitation Effect and Free Radical Generation: The focused ultrasonic waves create an extreme environment in the focal area, triggering a cavitation effect. The violent collapse of cavitation bubbles simultaneously generates physical effects (ultra-high temperature and pressure, shock waves) and a large number of ·OH free radicals (concentration can reach 10). -4 -10 -3mol / L). (3) Synergistic targeted degradation: The microscopic cavitation nest ensures that the cavitation effect is efficiently excited near the activated formaldehyde intermediate. The high concentration of ·OH and strong physical shock wave carry out in-situ precise degradation of the locked and activated formaldehyde intermediate, and completely mineralize it into CO2 and H2O; at the same time, the shock wave also continuously cleans the catalyst surface to realize the self-regeneration of the catalyst, and the activity recovery rate after regeneration is ≥98%.

[0112] The acoustic metamaterial nested layer adopts a titanium alloy micropillar array structure. The micropillars have a diameter of 5-20μm and a height of less than 40μm. They are manufactured by five-axis CNC machining, and the micropillar size gradient is designed according to the focal length requirements. Its adaptation logic is as follows: for short focal lengths (5-6mm), ultrasonic energy needs to be focused to a small area, so a large-diameter micropillar array is used to enhance the energy focusing ability; for long focal lengths (9-10mm), ultrasonic energy needs to be focused to a large area, so a small-diameter micropillar array is used to expand the energy coverage range, ensuring that the focusing efficiency and coverage area are matched at different focal lengths. A flexible transition structure, with a thickness of less than 5 μm, is fixed to the outer surface of the active catalyst coating using a 5% silica sol binder. The binder layer aligns with the cavitation nest focal point with an accuracy of ≤ ±0.2 mm. The transition structure, made of flexible metal film or composite material, possesses sufficient structural strength to support the micropillar array and can undergo elastic deformation under the drive of a micro-piezoelectric actuator, dynamically changing its surface curvature. This allows for continuous adjustment of the equivalent focal length of the acoustic metamaterial nested layer, serving both to fix the acoustic metamaterial nested layer and assist in ultrasonic field energy focusing, without interfering with the reaction of the active catalyst coating. The titanium alloy micropillar array exhibits excellent resistance to bending fatigue, and combined with the slight curvature changes of the flexible transition structure, it can achieve over a million zoom cycles without breakage. The acoustic metamaterial nested layer is pre-set with strong focusing (6-7 mm, including 7 mm), medium focusing (7-8 mm), and wide focusing (9-10 mm), synergistically adapted to the 7-9 mm core focal length range of the acoustic focusing catalyst.

[0113] Each dual-dimensional partition is equipped with an independent micro piezoelectric drive mechanism with a power of less than 3W (preferably 2.5W) and a telescopic stroke of 0-4mm. It can drive the segmented parabolic extension and retraction of the transition structure surface to achieve continuous adjustment of the focal length within the range of 6-10mm, which can meet the focal length adjustment requirements of acoustic focusing catalysts.

[0114] The salt-resistant acoustic transmission coating is prepared by mixing fluorinated modified silicone rubber and nano-zirconia in a weight ratio of 6:4-8:2 (preferably 7:3), with the addition of 0.4-0.6% (preferably 0.5%) PVP dispersant. The preparation process involves ultrasonic dispersion for 18-22 min (preferably 20 min), followed by coating and curing at 115-125℃ (preferably 120℃) for 25-35 min (preferably 30 min). The coating thickness is less than 20 μm, with an acoustic transmission rate ≥95% and a salt adhesion amount <3 mg / cm². Accelerated testing has verified that in high-salt wastewater with TDS ≤50000 mg / L, long-term operation maintains a salt adhesion amount <5 mg / cm² and an acoustic transmission rate attenuation of less than 3%, effectively ensuring stable transmission and focusing of ultrasonic energy. An additional hydroxyapatite coating can be prepared to achieve a pH range of 5.5-8.5.

[0115] The 3×2 dual-dimensional partitioned acoustic focusing catalyst module has the following functions: Targeted adsorption and activation: Formaldehyde molecules are selectively adsorbed and activated through Pt active sites, with an adsorption rate ≥90%, while retaining other biodegradable COD components to the greatest extent, with a retention rate ≥99.3%; Cavitation degradation enhancement: Cavitation nests are violently destroyed under the action of an ultrasonic field, generating ·OH free radicals. The co-localization design allows free radicals to directly act on the formaldehyde activation intermediates adsorbed on the Pt active sites, significantly reducing the ineffective loss of free radicals; Ultrasonic energy focusing: The acoustic metamaterial nested layer and the parabolic structure of the catalyst itself work together to focus diffused ultrasound waves to the focal area, increasing the energy density of the focal area. Under high concentration conditions, the energy density is 1.2-1.4 times higher than that of a fixed focal length; Self-healing function: When the active catalyst coating develops microcracks due to ultrasonic impact, the microcapsules rupture and release the core material, achieving self-healing through cross-linking and curing at the reaction temperature, with a repair efficiency >90%; Salt resistance protection: The salt-resistant acoustic transmission coating reduces salt ion adsorption and ultrasonic energy attenuation, adapting to TDS. High-salt conditions of 3-50000 mg / L.

[0116] The array-type ultrasonic unit provides ultrasonic energy to the system and consists of an ultrasonic generator and an array of transducers. The ultrasonic generator is skid-mounted next to the reactor body, and the array of transducers is installed using a bottom-coupled method, corresponding one-to-one with the 3×2 two-dimensional partitioned catalyst tubes. This allows for independent frequency and power modulation of each partition, ensuring precise energy distribution. The frequency modulation range is 20-1000kHz, and the power modulation range is 0.2-1W / mL. It is also connected to the intelligent control unit via signal lines to receive control commands and adjust the energy output parameters to adapt to different focusing modes of the acoustic metamaterial and the energy requirements of the acoustic focusing catalyst.

[0117] The array-type ultrasonic unit provides stable ultrasonic energy to the system, inducing cavitation effect and generating ultra-high temperature and high pressure physical effects and ·OH free radical chemical effects, matching the cavitation requirements of the acoustic focusing catalyst; through independent zone control, precise energy distribution is achieved, adapting to the degradation requirements of formaldehyde wastewater with different concentrations and improving energy utilization efficiency.

[0118] The intelligent control unit is the core of the system. It uses a PLC controller as the core component, is skid-mounted next to the reactor body, and is equipped with no less than 16 multi-channel interfaces. It is connected to 6 dual-dimensional partitioned spectral sensors, micro electric field control module, LSTM prediction algorithm module and energy optimization algorithm module through signal lines to construct a fully closed-loop control logic of "data acquisition-prediction calculation-instruction execution-feedback correction".

[0119] The sensing and algorithm module comprises a dual-dimensional zonal spectral sensor, an LSTM prediction algorithm module, and an energy optimization algorithm module. The functions of the sensing and algorithm module are as follows: Real-time monitoring: Accurately collects formaldehyde concentration data for each zone using the dual-dimensional zonal spectral sensor, providing precise input for regulation; Feedforward prediction: Predicts concentration change trends based on real-time concentration data, triggering parameter pre-adjustment to avoid the impact of regulation lag; Energy efficiency optimization: Calculates the energy efficiency ratio of each zone, identifies energy redundancy, and provides a basis for dynamic energy allocation.

[0120] A dual-dimensional partitioned spectral sensor is set for each dual-dimensional unit, synchronously covering the axial and radial regions of the corresponding unit to achieve real-time monitoring of formaldehyde concentration within the dual-dimensional partition. Six dual-dimensional partitioned spectral sensors are installed in six pre-drilled mounting holes on the side wall of the reactor body, collecting partitioned concentration data in real time and transmitting it to the PLC controller. The sensor's response time is less than 3 seconds (preferably 2.5 seconds), and its sampling frequency is no greater than 1 second (preferably 0.8 seconds). It is structurally compatible with the 3×2 dual-dimensional partitioned acoustic focusing catalyst module, providing cavity support for the partitioned treatment of wastewater.

[0121] The LSTM prediction algorithm module is trained on at least 1000 hours (preferably 1200 hours) of historical data and can predict concentration change trends 20 seconds (preferably 18 seconds) in advance, with a prediction error ≤ ±8% (preferably ±6%). The LSTM algorithm input parameters include six dimensions: formaldehyde concentration, ultrasonic power, focal length, reaction temperature, electric field voltage, and wastewater flow rate. The model structure consists of three hidden layers (128 neurons per layer), with 500 iterations and a learning rate of 0.001. The energy optimization algorithm module incorporates energy redundancy identification logic, and the model prediction accuracy is no less than 95%.

[0122] The PLC controller and the micro-electric field control module constitute the execution and control module. The PLC controller also has a self-healing trigger function. By monitoring whether the voltage drop change is greater than 0.2 kPa and the ultrasonic frequency scanning results, it can determine the microcracks in the active catalyst coating and trigger a self-healing environment that temporarily reduces the ultrasonic power by 10% (lasting for 3 minutes).

[0123] The micro-electric field control module includes six independent branch control units (corresponding to six dual-dimensional zones), a 5-10V precise voltage regulation circuit, and a signal conversion interface. It can independently output different voltage parameters with a response time ≤3s (preferably 2.5s). The functions of the micro-electric field control module are as follows: Constructing a control link: Together with the PLC controller, the microelectrode outside the catalyst tube, and the dual-dimensional zone spectral sensor, it forms a control link of "concentration-electric field-cavitation nest pore size." It receives control commands and converts them into dynamic micro-voltages to drive the expansion and contraction of PZT nanocrystals, actively correcting the pore size deviation of the cavitation nests, ensuring that the matching error between the pore size and the ultrasonic frequency is stable at <1%; Four-dimensional linkage control: Establishing a four-dimensional linkage logic of dual-dimensional zone concentration-focal length-ultrasonic parameters-energy distribution. When the zone concentration fluctuates by ±10%, it triggers a focal length adjustment of ±0.25-0.3mm (preferably ±0.25mm) and a power adjustment of ±0.04-0.05W / mL (preferably ±0.04W). / mL); Rapid response: When the influent concentration changes by ±50%, the rapid response program is automatically activated, and the parameters of the entire system are adapted within 8-10s (preferably 8s); Energy optimization allocation: When the energy efficiency ratio deviation between adjacent zones is <5%, the energy linkage mode is activated, transferring 10-12% (preferably 11%) of the redundant energy in the upper zone to the lower high-concentration zone; When the formaldehyde concentration in the effluent is <8mg / L and remains stable for 25-30s (preferably 25s), the energy-saving mode is triggered, and the overall energy consumption is reduced by 8-12% (preferably 10%); Focus self-calibration: Every 280-320 hours of operation, the zone focus self-calibration is automatically performed, with 8mm as the reference, and the calibration deviation is ≤±0.1mm (preferably ±0.05mm).

[0124] Example of the instruction flow sequence of the intelligent control unit: The spectral sensor collects data (0.8s / time) → transmits it to the LSTM prediction module (predicts the concentration after 18s) → the energy optimization module calculates the optimal energy efficiency ratio → the PLC controller generates instructions (response time 2.5s) → outputs them to the ultrasonic unit (adjusting power / frequency), the micro electric field module (adjusting voltage), and the micro piezoelectric mechanism (adjusting focus).

[0125] The auxiliary units provide a guarantee for the stable operation of the system, including a circulating cooling water temperature control module, an enhanced backwashing module, and a fault diagnosis module.

[0126] The circulating cooling water temperature control module is connected to the cooling circuit between the two-dimensional partitioned catalyst tubes in the reactor body through pipelines. It adopts a closed-loop circulation method and the temperature control range is 40-70℃ (temperature control accuracy ±0.5℃), with the preferred reaction temperature being 50℃.

[0127] The enhanced backwashing module is connected to the reactor body and the dual-dimensional zoned acoustic focusing catalyst module through pipelines. The backwashing pressure is 0.5-0.7MPa (preferably 0.6MPa), the backwashing duration is 4-6min (preferably 5min), and the triggering condition is every 180-220h (preferably 200h) or the catalyst tube pressure drop suddenly >0.2kPa.

[0128] The fault diagnosis module is connected to the key components of each core unit through signal lines to monitor the operating status in real time. It also supports self-diagnosis of partition faults and redundancy calibration. When a partition fails, it automatically calls the parameters of adjacent partitions for compensation.

[0129] The auxiliary unit has the following functions: Precise temperature control: Maintains the optimal reaction temperature, avoids temperature fluctuations affecting degradation effect and catalyst life, and prevents excessive temperature from increasing vapor pressure and weakening cavitation effect; Enhanced self-cleaning: Adopts a cleaning method of reverse flushing and ultrasonic synergy, combined with the self-repair capability of microcapsules, to achieve online self-cleaning and activity recovery of the catalyst (recovering to more than 98% of the initial state); Fault protection: Monitors the operating status in real time and ensures long-term stable operation of the system through zoned fault compensation.

[0130] Each unit is assembled into a complete equipment system through structural assembly, and coordinated control is achieved through signal transmission: after the wastewater enters the main body of the reactor through the guide, the intelligent control unit collects data through the dual-dimensional partitioned spectral sensor, and synchronously controls the array-type ultrasonic unit to output appropriate ultrasonic energy, and the dual-dimensional partitioned acoustic focusing catalyst module to adjust the focal length and catalytic state. The auxiliary unit simultaneously ensures temperature stability and equipment cleanliness, and finally forms a closed-loop operation mode of "concentration monitoring-parameter control-reaction execution-operational condition protection", ensuring the smooth realization of the catalytic-ultrasonic synergistic treatment process for targeted degradation of formaldehyde in wastewater.

[0131] Example 2

[0132] This embodiment discloses a catalytic-ultrasonic synergistic treatment process for targeted degradation of formaldehyde in wastewater. Formaldehyde-containing wastewater is pumped into the reactor body through the inlet and flows upward through the catalyst unit inside the reactor body. Within the catalyst unit, formaldehyde molecules are selectively adsorbed and activated. Through a four-stage process of "targeted adsorption and activation - cavitation degradation - intelligent synergistic optimization - temperature control and self-cleaning," targeted and efficient degradation of formaldehyde is achieved while maximizing the preservation of the wastewater's biodegradability.

[0133] The process specifically includes the following steps:

[0134] S1: Targeted adsorption and activation. After pretreatment by diversion, formaldehyde-containing wastewater flows from bottom to top into a two-dimensional partitioned acoustic focusing catalyst module with at least two axial partitions and at least two radial partitions for targeted adsorption and activation.

[0135] In this embodiment, the dual-dimensional partitioned acoustic focusing catalyst module with "3 axial partitions + 2 radial partitions" in the system shown in Example 1 is specifically selected to complete the targeted adsorption and activation of formaldehyde.

[0136] The wastewater to be treated originates from industrial emissions from acrylic acid production enterprises, etc. The initial water quality parameters are formaldehyde concentration of 30-12000 mg / L, COD content of 50000-150000 mg / L, low TDS content and no suspended solids. The core treatment objective is to utilize the Pt active sites of the dual-dimensional partitioned acoustic focusing catalyst module to achieve targeted adsorption and activation of formaldehyde, while retaining other biodegradable COD components to the greatest extent.

[0137] The pretreatment stage employs a combination of a grid and a filter to remove any minute mechanical impurities that may be present in the wastewater, preventing clogging of the subsequent two-dimensional zoned catalyst array. The suspended solids content of the pretreated wastewater is controlled to <1 mg / L to ensure stable water quality entering the catalyst unit. The pretreated wastewater flows upwards through the two-dimensional zoned catalyst module. Key flow parameters are: empty tower velocity 3-12 m / h (preferably 4-5 m / h), which ensures sufficient contact between formaldehyde and the catalyst while avoiding insufficient adsorption due to excessive flow; residence time 60-120 min, preferably 90 min, to ensure full adsorption and activation of formaldehyde molecules.

[0138] The results of this step are as follows: formaldehyde molecules are selectively adsorbed and activated into formaldehyde activation intermediates by Pt active sites, with an adsorption rate of ≥90%; other biodegradable COD components are not adsorbed, with a retention rate of ≥99.3%, and the wastewater still maintains good biodegradability and can be directly connected to subsequent processes.

[0139] S2: Cavitation degradation. The array-type ultrasonic unit is activated. Through the dual-drive mechanism of passive acoustic and thermal response and active electric field correction of the cavitation nest in the PMMA-PNIPAM-PZT composite system, the cavitation nest aperture and ultrasonic frequency are resonantly matched, and the cavitation effect is synergistically triggered to generate ·OH free radicals, which degrade the formaldehyde activation intermediate into CO2 and H2O.

[0140] The array-type ultrasonic unit is activated, and cavitation degradation is induced by the synergistic effect of piezoelectricity and acoustic sensitivity to drive cavitation nests and ultrasonic fields.

[0141] The object to be treated is the formaldehyde activation intermediate wastewater produced by S1. The wastewater has completed the targeted adsorption and activation of formaldehyde molecules, but other biodegradable COD components have not been adsorbed. The core treatment objective is to efficiently degrade the formaldehyde activation intermediate into CO2 and H2O through the synergistic effect of cavitation and catalysis, while not destroying other beneficial COD components.

[0142] The high-frequency sound waves generated by the array-type ultrasonic unit work in synergy with the cavitation nests of the two-dimensional partitioned acoustic focusing catalyst module to achieve dynamic pore size matching through an acoustic-thermal-electric multi-field coupling mechanism: Acoustic-thermal passive response: The PNIPAM component in the cavitation nests has temperature-sensitive characteristics. Utilizing the Joule heating effect (acoustic-thermal effect) generated by ultrasound in the medium, passive pore size adjustment is achieved. Under low-frequency (20-40kHz) conditions, the sound intensity distribution is wide, and the medium temperature rise is relatively gradual. PNIPAM is in a swollen state, and the pore size expands (increasing by 10%) to match the longer wavelength of the low-frequency sound waves, reducing the large cavitation nuclei. Nucleation threshold: In the mid-frequency range (40-100kHz), PNIPAM is in a stable swollen state, and the pore size remains at its initial size. In the mid-to-high frequency range (100-400kHz), PNIPAM is in a stable transition state, and the pore size only needs to be finely adjusted with an electric field to match the frequency. In the high-frequency range (400-500kHz), energy concentration leads to a significant temperature rise in local micro-regions, causing PNIPAM to undergo a phase transition and enter a contraction state. The pore size shrinks (by 8%), forming tiny cavitation nuclei to match the short wavelength of high-frequency sound waves, thereby increasing the oscillation rate and collapse intensity of the cavitation bubbles. Active electric field correction: Based on the acoustic-thermal response, the system drives the PZT nanocrystals to undergo inverse piezoelectric effect through a 5-10V (preferably 6-8V) micro-electric field, resulting in expansion and contraction, and actively fine-tuning the pore size. Through the dual-drive mechanism of coarse acoustic-thermal tuning and fine electric field tuning, the cavitation pore size and ultrasonic frequency are always kept in the resonant matching range (i.e., the pore size is in a specific proportional relationship with half wavelength or quarter wavelength), ensuring that the cavitation efficiency is maximized across the entire frequency range.

[0143] Different parameter combinations were used for formaldehyde wastewater of different concentrations: For high-concentration formaldehyde (formaldehyde concentration range of 5000-12000 mg / L, excluding 5000 mg / L), the parameter combination strategy was an ultrasonic frequency of 20-40 kHz (preferably 30 kHz) + power density of 0.35-0.45 W / mL (preferably 0.4 W / mL), utilizing the strong cavitation bubble collapse power of low-frequency ultrasound to enhance the degradation rate of high-concentration formaldehyde; for medium-concentration formaldehyde (500-5000 mg / L, excluding 500 mg / L), the parameter combination was different. For L) treatment, the parameter combination strategy is an ultrasonic frequency of 40-100kHz (preferably 70kHz) + power density of 0.4-0.5W / mL (preferably 0.45W / mL) to balance cavitation efficiency and energy consumption; for low-concentration formaldehyde (30-500mg / L) treatment, the parameter combination strategy is an ultrasonic frequency of 100-500kHz (preferably 250kHz, with a core preference of 100-400kHz) + power density of 0.55-0.6W / mL (preferably 0.58W / mL). Deep purification is achieved by increasing the production of ·OH free radicals through high-frequency ultrasound; under high-salt conditions (TDS 3-50000mg / L), acoustic metamaterial focusing parameter compensation is used to enhance ultrasonic energy focusing, offsetting the attenuation effect of the high-salt environment on ultrasonic energy, and ensuring a focusing efficiency of no less than 95%.

[0144] Focal length adaptation rules: For high-concentration formaldehyde treatment, use a focal length of 6-7mm (preferably 6.5mm); for medium-concentration formaldehyde treatment, use a focal length of 7-8mm (preferably 7.5mm); for low-concentration formaldehyde treatment, use a focal length of 9-10mm (preferably 9.5mm). Skip the 8-9mm focal length range where performance is substandard (because the acoustic metamaterial has Bragg diffraction loss in the 8-9mm range under a specific lattice arrangement, resulting in energy focusing efficiency of less than 85%, the system logic is set to quickly cross this range and directly switch to the 9-10mm wide-area mode); the focal length deviation between the center area and the edge area is controlled within ±0.05-0.1mm (preferably ±0.08mm).

[0145] The results of this step are as follows: formaldehyde is deeply degraded, with a formaldehyde removal rate of ≥99.8% and an effluent formaldehyde concentration of <10mg / L (meeting the requirements for subsequent biological treatment influent); the removal rate of other biodegradable COD components is ≤0.68%, and the biodegradability remains good.

[0146] S3: Intelligent collaborative optimization. The intelligent control unit, based on real-time concentration data from a dual-dimensional partitioned spectral sensor, achieves four-dimensional collaborative optimization of focal length, ultrasonic parameters, and energy distribution through an LSTM prediction algorithm module and an energy optimization algorithm module.

[0147] The treatment targets are wastewater after cavitation degradation in step S2. At this point, the wastewater has completed the initial degradation of formaldehyde activation intermediates, and the formaldehyde concentration is significantly lower than after S1. However, local concentration unevenness may occur due to fluctuations in influent concentration and differences in reaction conditions between zones. The core objectives are to improve the system's shock resistance, optimize energy consumption, and ensure the uniformity and stability of degradation across the entire system.

[0148] The core equipment relied upon in this step is the intelligent control unit, which establishes a four-dimensional linkage mechanism of "concentration-focal length-ultrasonic parameters-energy distribution," specifically including:

[0149] (1) Parameter linkage response: When the concentration of the zone fluctuates by ±10%, the focal length is adjusted by ±0.3mm (preferably ±0.25mm) and the power is adjusted by ±0.05W / mL (preferably ±0.04W / mL) to ensure that the parameter adjustment responds to the concentration change in a timely manner;

[0150] (2) Feedforward prediction + feedback coordination: Based on real-time data from a dual-dimensional partitioned spectral sensor (sampling frequency ≤ 1s, preferably 0.8s), the concentration trend is predicted 20s (preferably 18s) in advance (prediction error ≤ ±8%, preferably ±6%) through the LSTM prediction algorithm module (training data ≥ 1000h, preferably 1200h), thus achieving parameter pre-tuning; feedback fine-tuning is performed with a period of 3s (preferably 2.5s), with a response time ≤ 3s (preferably 2.5s), thus achieving accurate correction;

[0151] (3) Shock resistance control: When the influent concentration changes by ±50%, a fast response program is started. The focal length and power parameters of the high concentration zone are adjusted first through the PLC controller. The parameters of the whole system are adapted within 8-10s (preferably 8s) to maintain the stability of the effluent concentration.

[0152] (4) Energy optimization allocation: When the energy efficiency ratio deviation between adjacent zones is <5%, the energy linkage mode is activated, and 10-12% (preferably 11%) of the redundant energy in the upper zone is transferred to the lower high-concentration zone through the PLC controller to avoid local energy excess; when the formaldehyde concentration in the effluent is <8mg / L and stable for 25-30s (preferably 25s), the energy-saving mode is triggered, and the overall energy consumption is reduced by 8-12% (preferably 10%).

[0153] (5) Focal length calibration and maintenance: Automatically perform zoned focal length self-calibration every 280-320 hours (reference value 8mm, calibration deviation ≤ ±0.1mm, preferably ±0.05mm).

[0154] The optimization effect of this step is as follows: after the wastewater with uniform concentration and optimized degradation conditions, the formaldehyde concentration difference between different zones is <0.5%, and the formaldehyde concentration fluctuation in the effluent is ≤±1mg / L; it can tolerate the sudden change in influent concentration of ±50%; and the energy consumption per unit of formaldehyde degradation is ≤1.25g / kWh.

[0155] S4: Temperature control and self-cleaning. The circulating cooling water temperature control module maintains a stable reaction temperature, and combined with the enhanced backwashing module and catalyst self-repair function, it achieves online self-cleaning and ensures that wastewater is discharged in compliance with standards.

[0156] After precise temperature control and catalyst-enhanced self-cleaning, the wastewater meets discharge standards or is connected to a subsequent biochemical treatment system.

[0157] The wastewater being treated is the wastewater after the S3 step of co-optimization. This wastewater has achieved efficient formaldehyde degradation through precise matching of focal length, ultrasonic parameters and energy distribution. The problems of uneven local concentration and energy redundancy have been solved. The core treatment objective is to maintain the stability of the reaction system, restore the activity of the catalyst, and ensure that the final effluent meets the standards.

[0158] The core equipment relied upon in this step is the auxiliary unit, which specifically includes:

[0159] (1) Precise temperature control: The reaction temperature is maintained at 40-70℃ (preferably 50℃) by circulating cooling water temperature control module, with a temperature control accuracy of ±0.5℃, to avoid temperature fluctuations weakening the cavitation effect or causing catalyst deactivation;

[0160] (2) Enhanced self-cleaning: Every 180-220 hours (preferably 200 hours) or when the pressure drop of the catalyst tube changes abruptly by >0.2 kPa, the enhanced backwashing module is activated, employing reverse flushing + low-power ultrasonic cleaning (power density ≈0.3 W / mL) (backwashing pressure 0.5-0.7 MPa, preferably 0.6 MPa; backwashing time 4-6 min, preferably 5 min; ultrasonic power density ≈0.3 W / mL), simultaneously linking with the catalyst self-repair function to achieve online self-cleaning and activity recovery (activity restored to the initial state ≥98%). Ultrasonic shock waves are used to assist in the removal of adhering substances. When microcracks develop in the active catalyst coating due to long-term scouring, the crack propagation stress causes the microcapsules to rupture, releasing the core material for repair. This, combined with the self-repairing capability of the dual-dimensional zoned acoustic focusing catalyst module, achieves synergistic cleaning.

[0161] The total residence time of the process is 60-120 min, preferably 90 min. This time range is determined based on the formaldehyde degradation reaction kinetics to ensure that the wastewater has sufficient time to complete the final degradation in the reactor.

[0162] The treatment effect of this step is as follows: the final effluent formaldehyde concentration is ≤10mg / L (preferably ≤8mg / L), which meets the influent requirements of subsequent anaerobic + aerobic biological treatment; the retention rate of other biodegradable COD components is ≥99.3%, and the biodegradability of the wastewater is not damaged; the pH is stable at 5.5-8.5; there are no chemical residues, no sludge generation, and no secondary pollution, and it can be directly connected to the anaerobic + aerobic biological treatment system or discharged directly in accordance with environmental protection requirements.

[0163] This process relies on five core theories to achieve efficient degradation: ① Acoustic focusing theory: 6-10mm continuous focusing increases the energy density of the focal zone in high-concentration conditions by 1.2-1.4 times, improving formaldehyde removal rate by 8-10%; ② Cavitation effect theory: Multi-level cavitation nests (1-2μm:2-4μm:4-5μm=1:2:1) reduce the cavitation energy barrier by 30-40%, increasing ·OH free radical production by more than 30%; ③ Reaction engineering mass transfer theory: Two-dimensional partition design reduces the concentration gradient from ±15% to ±3%, with local reaction rate differences ≤±3%; ④ Piezoelectric effect theory: A 5-10V electric field drives the expansion and contraction of PZT nanocrystals, achieving pore size adjustment accuracy of ±0.01μm, matching error <1%, and improving cavitation efficiency by 15-20%; ⑤ Energy efficiency optimization theory: Redundant energy recovery reduces overall energy consumption by 8-12%.

[0164] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to the embodiments of this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0165] Example 3

[0166] This embodiment verifies the performance of the acoustic focusing catalyst.

[0167] To verify the formaldehyde-targeted degradation performance of the acoustic focusing catalyst and the catalytic-ultrasound synergistic treatment system of this application, the following performance tests were conducted. Details are as follows:

[0168] The core testing items include: 1. Formaldehyde concentration in effluent; 2. Formaldehyde removal rate; 3. Other COD removal rates; 4. Cavitation noise level; 5. Energy efficiency ratio (relative value); 6. Catalyst pressure drop. Among them, the formaldehyde removal rate reflects the core degradation efficiency of the catalyst and ultrasound synergy; the other COD removal rate verifies the target selectivity; the cavitation noise level indirectly characterizes the intensity of the cavitation effect; the energy efficiency ratio reflects the energy utilization efficiency; and the catalyst pressure drop assesses the hydrodynamic suitability.

[0169] The specific testing methods are as follows:

[0170] (1) Core device: A scaled-down prototype of the 3×2 dual-dimensional partitioned catalytic-ultrasonic synergistic processing system described in this application, including an array ultrasonic system (frequency range 20-1000kHz, power range 0.2-1W / mL), an experimental reactor (adapted to catalyst module, including ultrasonic coupling interface, sampling port and temperature / pressure monitoring interface), a constant flow pump (flow accuracy ±1%), and a constant temperature circulating water bath (temperature control accuracy ±0.5℃); the supporting detection equipment includes a gas chromatograph (equipped with an FID detector, detection limit ≤0.01mg / L), a rapid digestion spectrophotometer (RSD≤3%), a precision sound level meter (accuracy ±0.5dB), a precision pressure transmitter (accuracy ±0.01kPa), and a digital pH meter (accuracy ±0.01pH).

[0171] (2) Test materials: The catalyst modules to be tested (8mm focal length, 15mm focal length, 20mm focal length, 30mm focal length acoustic focusing catalysts) and planar comparison catalysts; simulated wastewater (initial formaldehyde concentration ~6000mg / L, total COD ~80000mg / L, pH 6.5~7.5), prepared by analytical grade formaldehyde, anhydrous glucose (simulating non-formaldehyde COD components) and deionized water; formaldehyde standard stock solution (1000mg / L, national standard substance), COD rapid digestion reagent, 1mol / L hydrochloric acid and sodium hydroxide solution.

[0172] (3) Test conditions: The ultrasonic system parameters were fixed at a frequency of 40kHz and a power density of 0.3W / mL; fluid parameters: empty tower flow rate of 5m / h, reaction temperature maintained at 50℃; reaction time of 90min; each focal length catalyst was tested in parallel 3 times to ensure data reliability.

[0173] (4) Specific testing steps

[0174] 1) Pretreatment: Prepare simulated wastewater and adjust the pH to 6.5~7.5. After standing for 30 minutes, measure the formaldehyde concentration and total COD concentration of the influent three times in parallel and take the average value as the initial data. Adjust each device until the parameters are stable. Use the gas chromatograph to plot the standard curve (R²≥0.999) with the formaldehyde standard series (0.1mg / L, 1mg / L, 10mg / L, 100mg / L, 1000mg / L). Use the rapid digestion spectrophotometer to calibrate with the standard quality control sample.

[0175] 2) Setup: Install the catalyst module to be tested, ensuring the reactor is well sealed and leak-free; connect the pressure transmitter to the catalyst inlet and outlet, and place the precision sound level meter on the side wall of the reactor 10cm from the center of the catalyst (at the same height) and fix it in place.

[0176] 3) Reaction operation: Start the constant flow pump to pump in simulated wastewater, and simultaneously turn on the constant temperature circulating water bath; after the wastewater fills the reactor, start the ultrasonic system and start timing. Record the cavitation noise level, reaction temperature and catalyst pressure drop every 15 minutes during the reaction.

[0177] 4) Sample detection: After 90 min of reaction, collect water samples at the reactor outlet (rinse the sampling bottle 3 times before sampling), filter through a 0.45 μm organic phase filter membrane, and determine the formaldehyde concentration in the water using a gas chromatograph (3 parallel tests); take 2 mL of water sample (dilute if necessary) and determine the total COD concentration using a rapid digestion spectrophotometer (3 parallel tests); simultaneously perform a deionized water blank experiment and subtract the blank value.

[0178] 5) Variable testing: After completing the testing of one type of focal length catalyst, backflush the reactor and pipeline three times, replace with the next type of catalyst module, and repeat the above steps until all samples have been tested.

[0179] (5) Data processing methods

[0180] Formaldehyde removal rate (η): η=(C1-C2) / C1×100%. Where C1 is the formaldehyde concentration in the influent (mg / L) and C2 is the formaldehyde concentration in the effluent (mg / L).

[0181] Other COD removal rate (η): η = (influent non-formaldehyde COD - effluent non-formaldehyde COD) / influent non-formaldehyde COD × 100%. Calculate the COD concentration corresponding to formaldehyde based on the formula 1 mg formaldehyde ≈ 1.07 mg COD, and then calculate the non-formaldehyde COD concentration (total COD concentration - COD concentration corresponding to formaldehyde).

[0182] Energy efficiency ratio (relative value): The energy consumption per unit of formaldehyde degradation is calculated (E=P×t / m, where P is the ultrasonic power (kW), t is the reaction time (h), and m is the mass of degraded formaldehyde (kg)). The energy consumption of the planar catalyst is used as the benchmark (1.00). Energy efficiency ratio = benchmark energy consumption / energy consumption of the catalyst to be tested.

[0183] Parallel sample results: Take the average of 3 parallel tests and calculate the relative standard deviation (RSD). The RSD should be ≤5%.

[0184] (6) Test results

[0185] The test results are shown in Table 1.

[0186] Table 1 Performance test results of acoustic focusing catalyst

[0187]

[0188] Table 1 shows that the acoustic focusing catalyst exhibits significantly better targeted formaldehyde degradation performance than the planar catalyst. The 8mm focal length catalyst demonstrates the best performance, achieving an effluent formaldehyde concentration <10mg / L and a formaldehyde removal rate of 99.86%. This indicates that the acoustic focusing catalyst exhibits significant directional focusing performance of ultrasound, greatly enhancing the synergistic effect between the catalyst and ultrasound. Furthermore, shorter focal lengths result in higher formaldehyde removal rates and lower cavitation noise levels, suggesting that shorter focal lengths can enhance ultrasonic energy focusing and improve cavitation effects. This is attributed to the fact that shorter focal lengths can concentrate ultrasonic energy closer to the catalyst surface, generating stronger cavitation noise. The acoustic cavitation effect allows for more efficient degradation of formaldehyde intermediates adsorbed on the catalyst surface. All acoustic focusing catalysts showed removal rates of less than 0.55% for other CODs, significantly lower than planar catalysts, validating the targeted selectivity of this application. The 8mm focal length catalyst had an energy efficiency ratio of 1.11, 11% higher than the planar catalyst, indicating higher energy utilization efficiency. This demonstrates that acoustic focusing significantly improves energy utilization efficiency; the shorter the focal length, the more concentrated the energy and the higher the efficiency. The pressure drop of the acoustic focusing catalyst was slightly higher than that of the planar catalyst, but within an industrially acceptable range, demonstrating practical application feasibility.

[0189] Example 4

[0190] This embodiment verifies the performance of an 8mm focal length acoustic focusing catalyst with different residence times.

[0191] To clarify the degradation efficiency, energy efficiency characteristics, and reaction stage patterns of the 8mm focal length catalyst (optimal focal length) under different residence times, the following residence time performance evaluation experiments were conducted. Details are as follows:

[0192] The core testing items include: 1. Formaldehyde concentration in effluent; 2. Formaldehyde removal rate; 3. Other COD removal rates; 4. Energy efficiency ratio (g formaldehyde / kWh); 5. Reaction stage assessment. Among these, the formaldehyde removal rate and effluent concentration reflect the degradation effect at different residence times; the other COD removal rate verifies the stability of the targeted selectivity; the energy efficiency ratio reflects the energy utilization efficiency at different reaction stages; and the reaction stage assessment provides a basis for optimizing process parameters.

[0193] The specific testing methods are as follows:

[0194] (1) The core device, supporting testing equipment and test materials are consistent with those in Example 3; among them, the catalyst is fixed to be an 8mm focal length acoustic focusing catalyst, and the simulated wastewater composition is: initial formaldehyde concentration ~6000mg / L, total COD ~80000mg / L, and pH adjusted to 7.2.

[0195] (2) Experimental conditions: The ultrasonic system parameters were fixed at a frequency of 40kHz and a power density of 0.3W / mL; the fluid parameters were: empty tower flow rate of 5m / h and reaction temperature maintained at 50℃; the variable was the reaction residence time, which was set at six gradients of 15min, 30min, 60min, 90min, 120min and 150min respectively. Each residence time gradient was measured in parallel 3 times to ensure data reliability.

[0196] (3) Specific detection steps: The pretreatment, device setup, sample detection and variable testing process is the same as that in Example 3; among them, the sampling time should be accurately controlled according to different residence time gradients to ensure that the sampling time is completely matched with the set residence time.

[0197] (4) Data processing methods

[0198] The formaldehyde removal rate and other COD removal rates were consistent with those in Example 3. The energy efficiency ratio (g formaldehyde / kWh) was calculated as the mass of formaldehyde degraded per unit of ultrasonic energy consumption, with a baseline value of 1.0 based on the energy efficiency ratio at a residence time of 15 min.

[0199] (5) Test results

[0200] The test results are shown in Table 2.

[0201] Table 2 Performance test results of acoustic focusing catalyst at different residence times

[0202]

[0203] Table 2 shows that the formaldehyde degradation efficiency of the 8mm focal length catalyst exhibits a pattern of "rapid increase - slowing growth - stabilization" with increasing residence time. During the rapid reaction phase (15-60 min), the formaldehyde removal rate rapidly increases from 85.8% to 99.25%, and the effluent formaldehyde concentration decreases from 850 mg / L to 45 mg / L. In this phase, the cavitation effect and the catalytic active sites work synergistically, resulting in high degradation efficiency. At a residence time of 60 min, the effluent formaldehyde concentration is already low enough to meet the subsequent biological influent conditions, demonstrating initial compliance. When the residence time is extended to 90 min, the formaldehyde removal rate further increases to 99.83%, and the effluent formaldehyde concentration decreases to 10 mg / L. At a concentration of g / L and an energy efficiency ratio (EER) maintained at a relatively high level of 2.3, extending the residence time at this point can significantly improve both the removal rate and energy efficiency, making it the optimal parameter balancing treatment effectiveness and economy. Between 90 and 120 minutes, the formaldehyde removal rate approaches its limit (99.83%~99.87%), but the EER drops from 2.3 to 1.8, indicating that more energy is required to remove trace amounts of formaldehyde at this stage, and economic efficiency begins to decline. When the residence time reaches 150 minutes, the formaldehyde removal rate does not improve significantly, and the removal rate of other CODs rises to 0.68%, slightly higher than that of short residence times, indicating a slight weakening of target selectivity. At the same time, the EER further decreases to 1.4, making further increases in residence time meaningless. In summary, the optimal reaction residence time for the 8mm focal length catalyst is 90 minutes. Under this parameter, the synergistic goals of efficient formaldehyde degradation, optimal energy efficiency, and stable target selectivity can be achieved.

[0204] Example 5

[0205] This embodiment verifies the single-factor and synergistic effects of the core improvement elements in the above-mentioned system and process.

[0206] To verify the independent effects and synergistic mechanisms of the core improvement elements in this application, six sets of comparative experiments were designed using the controlled variable method. The wastewater and reaction parameters were kept consistent, and the core improvement elements were added step by step. The technological value was demonstrated through the stepwise changes in the indicators.

[0207] Experimental Procedure: All experiments maintained the following parameters to ensure the uniqueness of variables: Wastewater parameters: initial formaldehyde concentration 6000 mg / L, total COD 80000 mg / L, pH 7.0, TDS 3000 mg / L; Reaction parameters: empty tower flow rate 5 m / h, residence time 90 min, reaction temperature 45-55℃, ultrasonic power density 0.3 W / mL; Detection cycle: each group of experiments ran continuously for 1000 hours, with key indicators detected every 100 hours; supplementary verification was carried out simultaneously under high salinity conditions (TDS=50000 mg / L) and formaldehyde concentration shock conditions (sudden increase from 3000 mg / L to 10000 mg / L).

[0208] The specific design of the 6 experimental groups is as follows:

[0209] (1) Experiment 1: Existing technical benchmark scheme

[0210] The core of the solution is to use a conventional flat-plate formaldehyde degradation catalyst. The catalyst substrate is an Al2O3 plate with a TiO2 catalyst layer (5μm thick) coated on the surface. It has no dynamic adjustment, multi-stage cavitation and partitioned structure.

[0211] Component composition: It contains only conventional flat plate catalyst (not the 3×2 two-dimensional partitioned catalyst unit of this application), basic ultrasonic generator (simplified array ultrasonic unit, without partitioned frequency modulation function), reactor body (the basic structure of the "reactor body" of this application system, without partitioned maintenance ports and other optimized designs), without the transition structure segmented parabolic surface, piezoelectric-acoustic dual-drive cavitation nest, and two-dimensional partitioned control module of this application system (to realize the two-dimensional partitioning of "3 longitudinal + 2 transverse", and the independent adjustment of the ultrasonic frequency of each partition).

[0212] (2) Experiment 2: Dynamically Adjustable Focal Length Optimization Scheme

[0213] The core of the scheme is to replace the conventional flat plate catalyst with a dynamically adjustable focal length catalyst (corresponding to the core focal length adjustment function module of the "3×2 dual-dimensional zone acoustic focusing catalyst module" in this application system) based on Experiment 1, while the remaining components and parameters are the same as in Experiment 1.

[0214] Improvements (compared to Experiment 1): A new segmented parabolic transition structure (corresponding to the flexible transition structure + parabolic carrier of the "3×2 dual-dimensional zoned acoustic focusing catalyst module" in this application system, with a single-lobed curvature radius of 12mm and a total of 6 lobes spliced ​​together) and a micro piezoelectric drive mechanism (corresponding to the independent micro piezoelectric drive mechanism of the 3×2 dual-dimensional zoned acoustic focusing catalyst module in this application system) are added to achieve dynamic continuous adjustment of the focal length from 6 to 10mm (matching the 6-10mm zoom range of the acoustic focusing catalyst in the system).

[0215] Components: Dynamically adjustable focal length catalyst (including segmented parabolic surface + piezoelectric drive mechanism, corresponding to the core functional module of the acoustic focusing catalyst of the system), basic ultrasonic generator (simplified array ultrasonic unit), reactor body (basic structure of the system reactor body).

[0216] (3) Experiment 3: Multi-level aperture cavitation nest composite scheme

[0217] The core of the scheme is to add a multi-level cavitation nest (corresponding to the multi-level cavitation nest in the active catalyst coating of the 3×2 dual-dimensional acoustic focusing catalyst module in this application system) to the dynamic adjustable focal length catalyst of Experiment 2. The other components and parameters are the same as those of Experiment 2.

[0218] Improvements (compared to Experiment 2): Within the active catalyst coating (TiO2 layer) of the dynamically adjustable focal length catalyst, PMMA-PNIPAM-PZT piezoelectric-acoustic dual-driven cavitation nests are integrated (completely corresponding to the multi-level pore size cavitation nests in the active catalyst coating of the "3×2 dual-dimensional partitioned acoustic focusing catalyst module" system of this application, with consistent pore size distribution). The cavitation nests are distributed in an array (spacing 200 μm), with pore sizes of 1-2 μm:2-4 μm:4-5 μm=1:2:1.

[0219] Components: Catalyst with segmented parabolic lobes and piezoelectric drive mechanism (system acoustic focusing catalyst zoom module), multi-level pore size cavitation nest array (core structure of system acoustic focusing catalyst active catalyst coating), basic ultrasonic generator (simplified array ultrasonic unit), reactor body (basic structure of system reactor body).

[0220] (4) Experiment 4: Two-dimensional partitioning and frequency response scheme

[0221] The core of the solution is to add a two-dimensional partition control module (corresponding to the 3×2 two-dimensional partition control structure of the system in this application, including partition division and independent ultrasonic adjustment function) based on Experiment 3, while the other components and parameters are the same as those in Experiment 3.

[0222] Improvements (compared to Experiment 3): A dual-dimensional partition control module is added (corresponding to the 3×2 dual-dimensional partition design of this application system, including 3 vertical partitions + 2 horizontal partitions, matching the 3×2 dual-dimensional partition structure of the system with 3 axial partitions and 2 radial partitions). Each partition has a built-in independent ultrasonic frequency regulator (adjustment range 15-1000kHz, corresponding to the partition independent frequency tuning function of the "array ultrasonic unit" of this application system), which is linked and fixed with the dynamic focal length catalyst through a mechanical support (matching the assembly linkage relationship of each unit structure of the system).

[0223] Components: Dynamically adjustable focal length catalyst (system acoustic focusing catalyst zoom module), multi-level pore size cavitation nest array (system acoustic focusing catalyst active catalyst coating core structure), dual-dimensional zone control module (system 3×2 dual-dimensional zone + zoned ultrasonic adjustment core structure), basic ultrasonic generator (upgraded to a simplified version of array-type ultrasonic unit with zoned frequency modulation function), reactor body (system reactor body basic structure, adapted to dual-dimensional zone design).

[0224] (5) Experiment 5: Voltage enhancement and energy linkage optimization scheme

[0225] The core of the scheme is to add a micro electric field control module (corresponding to the micro electric field control module of the "intelligent control unit" in this application system) and energy linkage optimization algorithm hardware (corresponding to the energy optimization algorithm module of the "intelligent control unit" in this application system) based on Experiment 4. The remaining components and parameters are the same as those in Experiment 4.

[0226] Improvements (compared to Experiment 4): A micro-electric field control module (completely corresponding to the micro-electric field control module of the "intelligent control unit" in this application system, with an output voltage of 5-10V, an accuracy of ±0.1V, and matching system parameters) and energy linkage optimization algorithm hardware (corresponding to the energy optimization algorithm module of the "intelligent control unit" in this application system, with the core chip model STM32F407) are added. The micro-electric field electrode is connected to the PZT nanocrystals in the cavitation nest through wires (corresponding to the connection and control link between the spiral electrode on the outer wall of the 3×2 dual-dimensional partitioned catalyst tube and the PZT nanocrystals in the cavitation nest in the system). The algorithm hardware communicates with the ultrasonic frequency regulator and the piezoelectric drive mechanism (matching the signal linkage logic between the intelligent control unit and the ultrasonic unit and the catalyst unit in the system).

[0227] Components: Dynamically adjustable focal length catalyst (system acoustic focusing catalyst zoom module), multi-level pore size cavitation nest array (system acoustic focusing catalyst active catalyst coating core structure), dual-dimensional zone control module (system 3×2 dual-dimensional zone + zone ultrasonic adjustment core structure), micro electric field control module (system intelligent control unit core component), energy linkage optimization hardware (system intelligent control unit algorithm module hardware), ultrasonic generator (fully corresponding to the system "array ultrasonic unit", with zone frequency modulation and power modulation function), reactor body (system reactor body basic structure).

[0228] (6) Experiment 6: Complete technical solution of this application

[0229] The core of the solution is to integrate all the core components of this application (completely corresponding to all the core units of the "catalytic-ultrasonic synergistic processing system" of this application), achieve full signal interoperability between components, and ensure that the experimental parameters are consistent with those of Experiments 1-5.

[0230] Improvements (compared to Experiment 5): A new PLC controller (model S7-200 SMART, fully corresponding to the core component PLC controller of the "intelligent control unit" in this application system) and an LSTM prediction algorithm module (integrated in the STM32F407 chip, corresponding to the LSTM prediction algorithm module of the "intelligent control unit" in this application system) are added. The PLC controller is connected to the micro electric field control module, energy linkage optimization hardware, ultrasonic generator, piezoelectric drive mechanism, and zone control module respectively (matching the full-link signal connection logic between the intelligent control unit and each core unit of the system), realizing full-link collaborative control (corresponding to the full closed-loop control logic of "data acquisition-predictive calculation-instruction execution-feedback correction" in this application system).

[0231] Components include: a dynamically adjustable focal length catalyst (segmented parabolic surface + piezoelectric drive, corresponding to the core zoom structure of the 3×2 dual-dimensional zoned acoustic focusing catalyst module in the system), a multi-level aperture cavitation nest array (corresponding to the cavitation nest structure of the active catalyst coating in the acoustic focusing catalyst of the system), a dual-dimensional zoned control module (corresponding to the 3×2 dual-dimensional zoned and zoned ultrasonic adjustment structure in the system), a micro-electric field control module (corresponding to the micro-electric field control component of the intelligent control unit in the system), energy linkage optimization hardware (corresponding to the energy optimization algorithm module of the intelligent control unit in the system), a PLC controller (corresponding to the core of the intelligent control unit in the system), an LSTM prediction algorithm module (corresponding to the prediction algorithm module of the intelligent control unit in the system), an ultrasonic generator (corresponding to the array-type ultrasonic unit in the system), and a reactor body (corresponding to the reactor body of the system in this application, including the assembly structure adapted to each unit); the above components completely cover the reactor body, catalyst unit, array-type ultrasonic unit, and core components of the intelligent control unit of the system in this application, realizing the closed-loop operation of the system with full functionality.

[0232] The specific testing methods are as follows:

[0233] Key testing indicators: formaldehyde removal rate (%), unit energy consumption (g formaldehyde / kWh), effluent concentration fluctuation (mg / L), 1000-hour performance degradation rate (%), formaldehyde removal rate under high salinity conditions (TDS=50000mg / L) (%), and suitable formaldehyde concentration range (mg / L); supplementary testing includes resistance to shock loads (effluent stabilization time after a sudden increase in concentration).

[0234] Detection equipment and methods: Formaldehyde removal rate and effluent concentration: Gas chromatography (FID detector, detection limit ≤0.01mg / L), three parallel tests were performed and the average value was taken; Unit energy consumption: Energy consumption was monitored in real time by a power meter and calculated in combination with the total amount of formaldehyde degraded (unit: g formaldehyde / kWh); Performance degradation rate: (initial removal rate - removal rate at the end of 1000 hours) / initial removal rate × 100%; High salt and shock conditions: The wastewater TDS was adjusted to 50000mg / L or the formaldehyde concentration increased sharply, and the above method was used for testing; Material properties: Only the salt adhesion amount of the PZT nanocrystalline self-healing coating was verified (gravimetric method, unit mg / cm²).

[0235] The test results are shown in Table 3.

[0236] Table 3. Independent Effects and Synergistic Mechanisms of Each Core Improvement Element

[0237]

[0238] Supplementary verification results: Impact load resistance: In Experiment 6, under the sudden change of formaldehyde concentration from 3000 mg / L to 10000 mg / L, the effluent concentration recovery time was ≤10s, which was significantly better than 45s in Experiment 1 and 18s in Experiment 5; Material performance: The salt adhesion amount of the salt-resistant acoustic transmission coating in Experiment 6 was <3mg / cm²; Long-term stability: During 1000 hours of continuous operation, the formaldehyde removal rate of Experiment 6 fluctuated by no more than 0.1% every 100 hours, and its stability was significantly better than that of the previous experiments.

[0239] As shown in Table 3 and the supplementary verification results, compared with Experiment 1, Experiment 2 improved the formaldehyde removal rate by 5.7 percentage points (90.5%→96.2%) and reduced the unit energy consumption by 10% (2.0→1.8g formaldehyde / kWh), proving that the dynamically adjustable focal length of the 3×2 dual-dimensional partitioned acoustic focusing catalyst module of this application system can improve the ultrasonic energy focusing efficiency; compared with Experiment 2, Experiment 3 further improved the removal rate by 2.3 percentage points (96.2%→98.5%), reduced energy consumption by 11.1%, and reduced the attenuation rate from 3.8% to 2.5%, verifying the synergistic effect of the dynamically adjustable focal length and multi-stage cavitation nest in the "3×2 dual-dimensional partitioned acoustic focusing catalyst module" of this application system; compared with Experiment 3, Experiment 4 reduced the effluent fluctuation from ±0.8mg / L to ±0.4mg / L, and broadened the suitable concentration to 100-11000mg / L, indicating that the "3×2 dual-dimensional partitioned" of this application system... The "regulation structure" and "array-type ultrasonic unit zonal frequency modulation function" can improve the uniformity of treatment across the entire domain. Compared with Experiment 4, Experiment 5 showed a removal rate approaching 99.7%, energy consumption reduced to 1.3g formaldehyde / kWh, and attenuation rate of 0.8%, indicating that the micro-electric field voltage enhancement and energy linkage optimization function of the "intelligent regulation unit" in this application system can achieve a precise balance between energy consumption and effect. Experiment 6 achieved full-link synergy, with a removal rate of 99.95% (+9.45 percentage points from the baseline), energy consumption reduced to 1.25g formaldehyde / kWh (-37.5%), attenuation rate of 0.3%, removal rate of 97.2% under high-salt conditions, adaptable concentration of 30-12000mg / L, and excellent shock resistance, indicating that the integration of all core units (reactor body, catalyst unit, array-type ultrasonic unit, and intelligent regulation unit) in this application system can achieve the goals of high efficiency, energy saving, wide adaptability, and long-term stability. In summary, each core element of this application possesses independent technical value and exhibits significant synergistic effects. The integration of all elements achieves a comprehensive breakthrough in technical indicators, surpassing existing technologies and demonstrating strong practicality and advancement.

[0240] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the foregoing disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A catalytic-ultrasonic synergistic treatment system for targeted degradation of formaldehyde in wastewater, characterized in that, It includes a reactor body, a catalyst unit, an array-type ultrasonic unit, an intelligent control unit, and an auxiliary unit. Each unit is linked through structural assembly and coordinated through signal transmission to form a fully closed-loop integrated processing system of "data acquisition - predictive calculation - command execution - feedback correction". The catalyst unit comprises a 3×2 dual-dimensional partitioned catalyst tube array and a 3×2 dual-dimensional partitioned acoustic focusing catalyst module, which are coaxially assembled and integrated. The 3×2 dual-dimensional partitioned acoustic focusing catalyst module is nested inside the 3×2 dual-dimensional partitioned catalyst tube array. The 3×2 dual-dimensional partitions are divided into 3 axial partitions and 2 radial partitions. The axial partitions are divided into a lower high-concentration zone, a middle transition zone, and an upper low-concentration zone in a height ratio of 1:1:

1. The radial partitions are divided into a central zone and an edge zone in a radius ratio of 3:2, forming six independent catalyst units. Each partition is isolated by a fluororubber micro-sealing ring with a thickness of less than 0.5 mm. Each partition of the 3×2 dual-dimensional acoustic focusing catalyst module is equipped with an independent micro piezoelectric drive mechanism and a catalytic coating. The catalytic coating consists of an active catalyst sub-coating, an acoustic metamaterial nested layer, and a salt-resistant acoustic transmission coating from the inside out. The active catalyst sub-coating contains multi-level pore size cavitation nests, Pt active sites, and microcapsule-type self-healing agents. The multi-level pore size cavitation nests are a PMMA-PNIPAM-PZT composite system with a pore size distribution of 1-2μm:2-4μm:4-5μm=1:2:

1. The array-type ultrasonic unit consists of an ultrasonic generator and an array-type transducer. The array-type transducer adopts a bottom coupling installation method and corresponds one-to-one with the 3×2 dual-dimensional partitioned catalyst tube. It can realize independent frequency and power modulation of each partition, with a frequency modulation range of 20-1000kHz and a power modulation range of 0.2-1W / mL. The intelligent control unit is based on a PLC controller and is equipped with no less than 16 multi-channel interfaces, which are respectively connected to 6 dual-dimensional partitioned spectral sensors, micro electric field control module, LSTM prediction algorithm module and energy optimization algorithm module. The auxiliary unit includes a circulating cooling water temperature control module, an enhanced backwashing module, and a fault diagnosis module. The circulating cooling water temperature control module has a temperature control range of 40-70℃ and a temperature control accuracy of ±0.5℃. The enhanced backwashing module has a backwashing pressure of 0.5-0.7MPa and a backwashing duration of 4-6min.

2. The system according to claim 1, characterized in that, The outer wall of the 3×2 dual-dimensional partitioned catalyst tube is wound with a spiral microelectrode with a pitch of 4-6 mm and a wire diameter of 0.08-0.12 mm. The electrode voltage is adjustable from 5-10V and the power is less than 1W. It shares a 12V power supply circuit with the micro piezoelectric drive mechanism and is controlled by a PLC branch circuit. A closed electric field circuit is formed between the microelectrode and the active catalyst coating on the inner wall of the catalyst tube. The PZT nanocrystals in the coating act as the electric field response medium, and the expansion and contraction of the PZT nanocrystals are controlled by the voltage change of the electrode.

3. The system according to claim 1, characterized in that, The micro piezoelectric drive mechanism of the 3×2 dual-dimensional partitioned acoustic focusing catalyst module has a power of less than 3W and a telescopic stroke of 0-4mm. It can drive the elastic deformation of the transition structure surface to achieve continuous adjustment of the focal length within the range of 6-10mm. The transition structure surface is made of flexible metal film or composite material. The acoustic metamaterial nesting layer is fixed to the transition structure surface and adopts a titanium alloy micro-pillar array structure with a column diameter of 5-20μm and a height of less than 40μm. The alignment accuracy with the cavitation nest focus is ≤±0.2mm.

4. The system according to claim 1, characterized in that, The microcapsule-type self-healing agent in the active catalyst coating has a particle size of 0.8-1.2 μm, with polyurea formaldehyde as the wall material and a mixed solution of tetrabutyl titanate and tetraethyl orthosilicate in a 1:2 ratio as the core material. Pt active sites are loaded using an equal-volume impregnation method, with a Pt loading of 1.2-1.6 wt% on the inner wall of the cavitation nests, 0.7-1.1 wt% on the edge region, and an overall average Pt loading of 0.8-1.2 wt% for the coating. Optionally, the carrier of the active catalyst coating is processed with a parabolic surface, with a polishing precision of Ra=0.15-0.20μm and a focal length reference value of 7-9mm.

5. The system according to claim 1, characterized in that, The anti-salt acoustic transmission coating is made by mixing fluorine-modified silicone rubber and nano-zirconia in a weight ratio of 6:4-8:2, adding 0.4-0.6% PVP dispersant, and curing at 115-125℃ for 25-35 minutes. The thickness is less than 20μm and the salt adhesion amount is <3mg / cm².

6. The system according to claim 1, characterized in that, The dual-dimensional partitioned spectral sensor has a response time of less than 3 seconds and a sampling frequency of no more than 1 second; the LSTM prediction algorithm module is trained based on no less than 1,000 hours of historical data and can predict the concentration change trend 20 seconds in advance with a prediction error of ≤ ±8%; the micro-electric field control module contains 6 independent branch control units with a response time of ≤ 3 seconds.

7. A catalytic-ultrasonic synergistic treatment process for targeted degradation of formaldehyde in wastewater, characterized in that, The system described in any one of claims 1-6 comprises the following four core processes: S1: Targeted adsorption and activation. After pretreatment, formaldehyde-containing wastewater flows from bottom to top into the 3×2 dual-dimensional partitioned acoustic focusing catalyst module. Formaldehyde is targeted adsorbed and activated through the Pt active sites of the active catalyst coating, with an adsorption rate of ≥90% and a retention rate of ≥99.3% for other biodegradable COD components. S2: Cavitation degradation, the array-type ultrasonic unit is activated, and through the dual driving mechanism of the acoustic and thermal passive response and electric field active correction of the cavitation nest of the PMMA-PNIPAM-PZT composite system, the cavitation nest aperture and ultrasonic frequency are resonantly matched, and the cavitation effect is synergistically triggered to generate ·OH free radicals, which degrade the formaldehyde activation intermediate into CO2 and H2O. S3: Intelligent collaborative optimization. The intelligent control unit, based on real-time concentration data from a dual-dimensional partitioned spectral sensor, achieves four-dimensional collaborative optimization of focal length, ultrasonic parameters, and energy distribution through an LSTM prediction algorithm module and an energy optimization algorithm module. S4: Temperature control and self-cleaning. The circulating cooling water temperature control module maintains a stable reaction temperature. Combined with the enhanced backwashing module and catalyst self-repair function, it achieves online self-cleaning and ensures that wastewater is discharged in compliance with standards. The process employs a two-dimensional partitioned active gradient adaptation design, a cavitation nest acoustic-electric dual-drive synergistic mechanism, ultrasonic-catalytic-electric field multi-field coupling, and dynamic energy redundancy allocation. The core process parameters range as follows: focal length 6-10mm, ultrasonic frequency 20-1000kHz, power density 0.2-1W / mL, reaction temperature 40-70℃, residence time 60-120min, and empty tower flow rate 3-12m / h.

8. The process according to claim 7, characterized in that, The flow parameters for the 3×2 two-dimensional partition are: empty tower velocity of 3-12 m / h and residence time of 60-120 min; different parameter combinations are used for formaldehyde wastewater of different concentrations. (1) High concentration of formaldehyde, with a formaldehyde concentration range of 5000-12000 mg / L, excluding 5000 mg / L, and the parameter combination strategy adopted is focal length 6-7 mm + ultrasonic frequency 20-40 kHz + power density 0.35-0.45 W / mL; (2) Medium concentration formaldehyde, with a formaldehyde concentration range of 500-5000 mg / L and no formaldehyde concentration of 500 mg / L. The parameter combination strategy adopted is focal length 7-8 mm + ultrasonic frequency 40-100 kHz + power density 0.4-0.5 W / mL. (3) Low concentration formaldehyde, with a formaldehyde concentration range of 30-500 mg / L, and the parameter combination strategy adopted is focal length 9-10 mm + ultrasonic frequency 100-500 kHz + power density 0.55-0.6 W / mL; Optionally, under high-salt conditions and TDS of 3-50000 mg / L, a salt-resistant acoustic transmission coating is used for protection, and acoustic metamaterial focusing parameter compensation is applied to ensure that the focusing efficiency is not less than 95% under TDS≤50000 mg / L conditions.

9. The process according to claim 7, characterized in that, The dual-drive mechanism of the cavitation nest is as follows: under the operating conditions of 20-40kHz, PNIPAM swelling increases the pore size by 10%; under the operating conditions of 40-100kHz, PNIPAM is in a stable swollen state; under the operating conditions of 100-400kHz, PNIPAM is in a stable transition state; under the operating conditions of 400-500kHz, PNIPAM phase transformation shrinkage reduces the pore size by 8%; active fine-tuning is achieved by driving the expansion and contraction of PZT nanocrystals through a 5-10V micro-electric field, with a pore size adjustment accuracy of ±0.01μm and a matching error of <1%.

10. The process according to claim 7, characterized in that, The four-dimensional linkage and collaborative optimization specifically refers to: (1) When the concentration fluctuation in the zone is ±10%, the focus length is adjusted by ±0.25-0.3mm and the power is adjusted by ±0.04-0.05W / mL. (2) Predict the concentration trend 20 seconds in advance to achieve parameter pre-adjustment; perform feedback fine-tuning with a period of 3 seconds, with a response time ≤ 3 seconds; (3) When the influent concentration changes by ±50%, the rapid response procedure is initiated, and the parameters of the entire system are adapted within 8-10 seconds; (4) When the energy efficiency ratio deviation between adjacent zones is <5%, the energy linkage mode is activated to transfer 10-12% of the redundant energy in the upper zone to the lower high-concentration zone; when the formaldehyde concentration in the effluent is <8mg / L and remains stable for 25-30s, the energy-saving mode is triggered, and the overall energy consumption is reduced by 8-12%; (5) Automatically perform zone focal length self-calibration every 280-320 hours of operation, with a reference value of 8mm and a calibration deviation of ≤±0.1mm; Optionally, the self-cleaning is triggered every 180-220 hours or when the pressure drop of the catalyst tube changes abruptly by >0.2 kPa. Backwashing is performed using a combination of reverse flushing and low-power ultrasonic cleaning, with a backwashing pressure of 0.5-0.7 MPa and a backwashing time of 4-6 minutes. When microcracks are generated in the active catalyst coating, the microcapsules rupture to release the core material, which cross-links and solidifies to achieve self-repair, with a repair efficiency of >90%.

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