Environment-friendly membrane material efficient cleaning agent based on environment-degradable material

Abstract

The invention belongs to the technical field of chemical cleaning, and particularly relates to an environment-friendly efficient cleaning agent for a membrane material based on an environment-degradable material, which comprises a stimuli-responsive cleavable surfactant, a biogenic polycarboxylic acid chelating system, an environment-induced degradation accelerator, a modified biopolymer membrane layer protective agent and a permeation enhancement cofactor, the controlled extinguishing of interfacial activity is realized by utilizing the acid-induced fracture characteristic of an acetal bond of a surfactant, and active induced degradation is realized through a microcapsule packaging oxidation catalysis system; while efficient decontamination and membrane protection are realized, the medicament degradation period is remarkably shortened, and the foam impact of waste liquid on a biochemical system is thoroughly eliminated.

Description

Technical Field

[0001] This invention belongs to the field of chemical cleaning technology, specifically an environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials. Background Technology

[0002] Against the backdrop of global water scarcity and industrialization, membrane separation technology occupies an important strategic position in key industries such as seawater desalination and wastewater reuse. Processes such as reverse osmosis and ultrafiltration can effectively remove impurities in water, but in the long run, the membrane interface will experience performance degradation due to organic pollution, biofilm, and inorganic scale accumulation, resulting in decreased membrane flux, increased operating pressure, shortened membrane life and increased operation and maintenance costs. Regular chemical cleaning is a standard procedure in membrane water treatment. Existing mainstream cleaning agents contain strong acids, strong alkalis, EDTA and phosphates. Although they can achieve the descaling effect by complexing scale ions, phosphates can easily lead to eutrophication of water bodies, and EDTA is difficult to be degraded by microorganisms and can easily induce secondary migration of heavy metals, which violates the requirements of stringent environmental protection regulations.

[0003] While environmentally friendly cleaning agents derived from natural sources, such as APG, have advantages in biocompatibility, their discharge can generate secondary foam pollution, interfering with the efficiency of downstream biochemical treatment systems. Furthermore, their degradation process passively depends on environmental factors and is prone to accumulation under extreme conditions. This results in an irreconcilable contradiction between cleaning efficiency and treatment controllability, failing to meet actual industrial needs.

[0004] Therefore, the present invention provides an environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: The present invention provides an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials, comprising 15 to 25 parts of a stimulus-responsive cleavable surfactant, 10 to 20 parts of a bio-derived polycarboxylic acid chelation system, 5 to 10 parts of an environmentally induced degradation accelerator, 3 to 8 parts of a modified biopolymer membrane layer protectant, 2 to 5 parts of a penetration-enhancing auxiliary factor, and the balance being high-purity deionized water.

[0007] The stimulus-responsive cleavable surfactant is an acetal alkyl glycoside derivative with acid-induced cleavage properties, and its molecular structure has an acetal bond linking point between the hydrophobic alkyl chain and the hydrophilic glycoside group. In a neutral or slightly alkaline cleaning environment, the acetal bond maintains high chemical stability and exhibits excellent performance in reducing interfacial tension, emulsifying organic pollutants, and stripping biofilms. When the cleaning process is completed and an acidifying medium is introduced into the waste liquid to lower the pH to the range of 3.5 to 4.5, the acetal bond undergoes rapid hydrolytic breakage, resulting in the physical separation of the hydrophobic and hydrophilic segments of the molecule. This disintegration of the molecular structure directly leads to the disappearance of interfacial activity, eliminating the physical basis for the generation of persistent foam when the subsequent waste liquid enters the biochemical treatment system. The specific synthetic route of the stimulus-responsive cleavable surfactant involves the condensation of a linear fatty alcohol with 12 to 14 carbon atoms and a glucose monomer with an acetal precursor under acid-catalyzed dehydration conditions. Its weight-average molecular weight is distributed between 450 and 650 Daltons, and its surface tension at room temperature is less than 28 millinewtons per meter.

[0008] Preferably, the bio-derived polycarboxylic acid chelation system is a synergistic complexation system composed of tetrasodium L-glutamate diacetate and tetrasodium iminodisuccinate in a mass ratio of 3:1. The system has extremely strong biodegradability, with a biodegradation rate of over 95% in the receiving water body after 28 days. During the cleaning process, the chelation system forms chelates with calcium ions, magnesium ions, and transition metal iron and manganese ions in the inorganic scale on the membrane surface through multiple carboxyl sites on its molecular chain. The complexation stability constant of the tetrasodium L-glutamic acid diacetate for calcium ions is greater than 5.0, which can effectively destroy the crystal lattice structure of calcium carbonate and calcium sulfate crystals and promote the transformation of the inorganic scale layer from a dense state to a loose state. The introduction of tetrasodium iminodisuccinate enhances the system's salt-tolerance capacity under alkaline conditions, prevents secondary precipitation of dissolved metal ions during cleaning fluid circulation, and ensures thorough removal of deep-seated scale inside the membrane pores. Preferably, the environmentally induced degradation accelerator is a slow-release oxidation catalytic system based on microencapsulation technology; Its core components are peroxidase and nano-sized titanium dioxide powder loaded on a porous nano silica carrier, and the outer layer is coated with a pH-sensitive cellulose acetate phthalate material. When the cleaning fluid is in operation, the outer shell material remains intact, and the internal catalytic components are completely isolated from the cleaning environment, without affecting the chemical stability of the cleaning agent. When the cleaning wastewater is discharged and enters the conditioning stage, the pH value is adjusted to trigger the dissolution of the coating layer. The released peroxidase can use the dissolved oxygen in the wastewater to catalyze the decomposition of organic pollutant molecular chains. Under the light of the receiving environment, nano-titanium dioxide generates hydroxyl radicals through photocatalysis, which further mineralizes the residual chain segments after the surfactant is cracked. This accelerated mechanism under artificial intervention allows the natural degradation process, which originally takes several weeks to complete, to reach the mineralization endpoint within 48 hours, significantly reducing the load pressure on the sewage treatment plant.

[0009] Preferably, the modified biopolymer membrane protectant is a carboxymethylated chitosan quaternary ammonium salt, which plays a dual role in the cleaning process; The quaternary ammonium cation groups on its molecular chain can generate weak electrostatic adsorption with the negatively charged membrane surface, forming a transient hydration protective layer with a thickness of nanometers on the membrane material surface. This protective layer can not only buffer the possible chemical erosion of the membrane polyamide layer by the strong cleaning components, but also quickly occupy the active sites on the membrane surface after the pollutants are stripped off, reducing the roughness of the membrane surface, thereby delaying the re-attachment of pollutants in the next operating cycle. Carboxymethyl chitosan has good water solubility and biocompatibility. It can be easily washed away with water after cleaning and will not remain in the membrane pores, thus preventing flux attenuation.

[0010] Preferably, the permeation-enhancing auxiliary factor is a mixture of low molecular weight fatty alcohol polyoxyethylene ether sodium sulfate and isomeric decaol polyoxyethylene ether. This component has extremely high osmotic pressure regulation capability, which enables the cleaning liquid to quickly penetrate into the interior of the dry or highly compressed pollutant filter cake layer, generating a swelling effect at the interface between the pollutant and the membrane material, decomposing large pieces of dirt into tiny suspended particles, and greatly improving the kinetic rate of the cleaning operation.

[0011] Based on the system-level technical solution composed of the above components, the environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials described in this invention follows a strict engineering logic process in practical applications. In the cleaning stage, the cleaning agent is prepared into an aqueous solution with a mass fraction of one to three percent and circulates within the membrane module. Stimulus-responsive cleavable surfactants embed themselves into the organic fouling layer through hydrophobic interactions generated by their long alkyl chains. Simultaneously, a bio-derived polycarboxylic acid chelation system complexes and dissolves the inorganic scale. During this process, a modified biopolymer membrane protectant simultaneously constructs a dynamic protective barrier. After the cleaning cycle is completed, the waste liquid is treated by adding a small amount of organic acid (such as citric acid or formic acid) to the waste liquid through an automatic dosing device to adjust the pH value of the waste liquid to the preset cleavage threshold.

[0012] Under acid triggering, the acetal bonds of the stimulus-responsive cleavable surfactant break instantaneously, and the interfacial tension of the waste liquid rapidly increases from 28 millinewtons per meter to over 60 millinewtons per meter within 30 minutes, resulting in a decrease in foam stability of over 90%. The microcapsules in the environmentally induced degradation accelerator rupture, and the catalytic components enter the waste liquid system. Under natural light irradiation or artificial aeration, the complex organic molecules in the waste liquid are oxidized into low molecular weight organic acids, carbon dioxide, and water.

[0013] By integrating acetal bond cleavage technology and microencapsulation-induced catalysis technology into the field of membrane cleaning, a logically self-consistent closed-loop system was constructed. When performing the cleaning function, all components work synergistically, exhibiting superior cleaning capabilities compared to traditional EDTA formulations, with a flux recovery rate of over 98% of the original state. When performing the degradation function, a simple pH adjustment can trigger a logical transformation of the chemical structure, changing passive natural degradation into active induced degradation.

[0014] The preparation process of an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials includes the following steps: Step 1: Add the preset amount of high-purity deionized water to the reactor, start stirring and heating, and control the water temperature at 40 to 45 degrees Celsius; Step 2: Under the condition of stirring speed of 300 to 500 revolutions per minute, add the bio-derived polycarboxylic acid chelation system and modified biopolymer membrane protectant in sequence, and continue stirring for 30 minutes until the solution becomes transparent and clear. In step two, the bio-derived polycarboxylic acid chelation system is added in batches, with each batch not exceeding five percent of the total mass. Step 3: Adjust the stirring speed to 800 revolutions per minute, slowly add the stimuli-responsive, degradable surfactant, and use shear force to ensure that its molecules are evenly distributed in the aqueous phase. During the addition process, monitor the temperature fluctuation inside the vessel to ensure that it does not exceed 2 degrees Celsius. Step 4: Under constant temperature conditions, add the environmentally induced degradation accelerator and the penetration-enhancing auxiliary factor, and continue to stir at a low speed and steady flow for one hour; The cleaning agent is configured to adjust the pH value to 4.0 by adding citric acid or formic acid to the waste liquid when it enters the waste liquid treatment stage, so as to instantaneously break the acetal bond of the stimulus-responsive degradable surfactant and trigger the microcapsule rupture in the environmentally induced degradation accelerator to release the catalytic component. Step 5: The obtained product is filtered through a precision filter with a filtration accuracy of five micrometers, and then filled after the functional group characteristic peaks are confirmed by online infrared spectroscopy scanning.

[0015] The beneficial effects of this invention are as follows: 1. The present invention discloses an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials. Through the present invention, the interfacial activity is precisely controlled and extinguished. Traditional biodegradable surfactants such as APG, although eventually degradable, still maintain strong interfacial activity for several days before degradation, which causes great trouble to wastewater treatment. The present invention utilizes the acid-induced pyrolysis characteristics of acetal bonds to eliminate interfacial activity within minutes, completely eliminating the risk of foaming in biological treatment tanks and sludge loss.

[0016] 2. The present invention provides an environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials. Through the construction of this invention, a highly efficient synergistic cleaning mechanism is established. The combination of a bio-derived polycarboxylic acid chelation system and a stimulus-responsive surfactant exhibits extremely strong penetration and stripping capabilities against common complex fouling on the surface of reverse osmosis membranes. Experimental data show that when treating biofouled membranes containing high concentrations of extracellular polymers, the cleaning efficiency of the present invention is more than 35% higher than that of conventional alkaline cleaning agents.

[0017] 3. The present invention provides an environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials. Through the introduction of the modified biopolymer membrane layer protectant, the present invention has excellent membrane material protection performance. The introduction of the modified biopolymer membrane layer protectant effectively compensates for the membrane performance damage that may be caused by strong cleaning. By forming a temporary protective film in situ during the cleaning process, the potential fluctuation of the membrane surface is reduced, the rate of increase of transmembrane pressure difference after cleaning is reduced, and the service life of the membrane module is indirectly extended.

[0018] 4. The present invention provides an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials. Through the present invention, the degradation process is fully artificially intervened. The environmentally induced degradation accelerator introduces highly efficient catalytic components into the system through microencapsulation technology, which solves the problem of slow degradation of environmentally friendly agents in low temperature and low microbial abundance environments, and ensures zero chemical impact of the discharged wastewater on the environmental water body.

[0019] 5. The environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials described in this invention has the complete environmental compatibility of chemical components. All raw materials used in the formula are derived from biomass-based raw materials or synthetic intermediates with extremely high degradation rates, and are free of phosphorus and nitrogen. Attached Figure Description

[0020] The invention will now be further described with reference to the accompanying drawings.

[0021] Figure 1 This is a structural block diagram of an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials, as described in this invention. Figure 2 This is a process flow diagram of the preparation process of an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials in this invention. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] like Figure 1-2 As shown in the embodiment of the present invention, an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials includes 15 to 25 parts of a stimulus-responsive cleavable surfactant, 10 to 20 parts of a bio-derived polycarboxylic acid chelation system, 5 to 10 parts of an environmentally induced degradation accelerator, 3 to 8 parts of a modified biopolymer membrane protectant, 2 to 5 parts of a penetration-enhancing auxiliary factor, and the balance being high-purity deionized water as a solvent.

[0024] Furthermore, the stimulus-responsive cleavable surfactant has a unique acid sensitivity in its molecular structure; Specifically, the surfactant is an acetal alkyl glycoside derivative with a finely crafted molecular structure that incorporates an acetal linking point between the hydrophobic linear fatty alcohol (with a carbon chain length between twelve and fourteen) and the hydrophilic glucose monomer. During the cleaning phase, when the reagent environment is neutral to weakly alkaline (e.g., pH 7.5 to 9.5), the acetal bond exhibits extremely strong chemical stability, causing the entire molecule to exhibit typical and highly efficient nonionic surfactant properties. Its surface tension can be stably maintained below 28 millinewtons per meter, which can rapidly reduce the wetting angle of pollutants on the membrane surface and promote the emulsification and peeling of the organic fouling layer. Once the waste liquid is treated, the pH value is adjusted to the trigger range of 3.5 to 4.5 by adding an appropriate amount of acidic medium to the system. The acetal bond will undergo a rapid protonation hydrolysis reaction, causing the original surfactant molecules to be completely broken down into long-chain alcohols and glucose. Since neither of these products has significant surface activity and is easily metabolized by microorganisms, the physical manifestation is the instantaneous dissolution of waste liquid foam and an exponential increase in biodegradability. In actual preparation, the weight-average molecular weight of this component is precisely controlled between 450 and 650 Daltons to ensure its free diffusion capability within the membrane pores.

[0025] Furthermore, the bio-derived polycarboxylic acid chelation system, as the core removal solution for inorganic scaling and metal ion contamination, employs a synergistic combination of tetrasodium L-glutamate diacetate (GLDA) and tetrasodium iminodisuccinate (IDS), with their mass ratio strictly set at three to one. GLDA, as a green chelating agent derived from natural amino acids, exhibits extremely high complexation stability constants (log) for calcium and magnesium ions. K values ​​are typically greater than 5.0, which can effectively capture metal cations in the inorganic lattice through coordination bonds, causing the scale layer of calcium carbonate, calcium sulfate, etc., to collapse. The introduction of IDS mainly utilizes its excellent salt-tolerance capacity under alkaline conditions and its targeted chelation of transition metals (such as iron and manganese), preventing secondary precipitation of metal oxides or hydroxides during the cleaning process. This combination is not only superior to traditional EDTA or DTPA in chemical efficacy, but more importantly, it has extremely high environmental compatibility. Under standard receiving water conditions, the biodegradation rate can stably exceed 95% after 28 days, effectively avoiding the eutrophication problem of receiving water caused by traditional phosphorus chelating agents.

[0026] Furthermore, the environmentally induced degradation accelerator is a key engineered component for achieving controlled degradation in this invention. Structurally, it employs a precisely designed microcapsule encapsulation system. The core of the microcapsule is a porous nano-silica as a carrier with a pore size distribution between 10 and 20 nanometers. The interior is loaded with high-density active peroxidase and anatase titanium dioxide powder with an average particle size of 20 nanometers. To ensure that these catalytic components are not released prematurely during the cleaning phase, the outer layer of the microcapsules is coated with a layer of cellulose acetate phthalate material that is highly sensitive to pH. Under normal cleaning conditions, the coating layer remains dense and insoluble because the pH value is maintained above neutral, perfectly isolating the internal enzymes and catalysts from the cleaning environment. When the waste liquid enters the conditioning tank and is acidified to the trigger threshold, the coating layer dissolves rapidly, and the released peroxidase, with the participation of dissolved oxygen in the waste liquid, performs preliminary oxidative degradation on the stripped organic pollutant molecular chains. When nano-titanium dioxide is excited by natural light (especially the ultraviolet spectrum) in a controlled environment, it generates highly oxidizing hydroxyl radicals, which deeply mineralize the residual components after surfactant pyrolysis, converting them into carbon dioxide and water. This mechanism compresses the originally lengthy natural degradation process to within 48 hours, greatly reducing the load pressure on downstream wastewater treatment facilities.

[0027] Furthermore, the modified biopolymer membrane protectant acts as an in-situ shield for the precise structure of the membrane material during the cleaning process. This component is composed of chitosan quaternary ammonium salt modified by carboxymethylation, and its degree of carboxymethyl substitution is precisely anchored between 0.6 and 0.8. This specific molecular structure endows the component with good solubility and charge neutrality in aqueous solution. During the circulation of the cleaning solution, the quaternary ammonium cationic groups on its molecular chain can preferentially form an ultra-thin dynamic protective layer on the negatively charged polyamide reverse osmosis membrane surface by using electrostatic attraction. This protective layer can not only act as a physical barrier to reduce the potential chemical erosion of the membrane functional layer by strong detergency components, but also form a transient hydration membrane in the micropores on the membrane surface, reducing the probability of secondary adhesion of pollutants. Experimental observations show that after using this protective agent, the zeta potential fluctuation on the membrane surface is significantly reduced, and the slope of the transmembrane pressure difference increase after cleaning is effectively suppressed, thereby significantly extending the overall service life of the membrane module.

[0028] Furthermore, the permeation-enhancing auxiliary factor is composed of low molecular weight fatty alcohol polyoxyethylene ether sodium sulfate and isomeric decayl alcohol polyoxyethylene ether in a 1:1 ratio. This component is designed to overcome the diffusion resistance of the dense fouling cake layer on the membrane surface. The introduction of the isomerized branched structure effectively disrupts the regular hydrogen bond network of water molecules, reduces the dynamic viscosity of the cleaning solution, and enables it to penetrate through the pollutant gaps to the interface between the membrane and the scale layer in a very short time (milliseconds). At this interface, a swelling effect is generated at the microscopic level through osmotic pressure regulation, which mechanically decomposes the originally cohesive contaminants into micron-sized suspended particles. This greatly increases the reaction surface area of ​​the subsequent surfactants and chelating agents, and shortens the cycle time of the entire cleaning operation.

[0029] The preparation process of the environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials described in this invention follows an engineered high-precision compounding principle. First, add a preset amount of high-purity deionized water to a reactor equipped with a double-layer anchor stirrer and a circulating cooling jacket, start stirring and control the speed at 300 revolutions per minute, and at the same time turn on the heating system to raise the water temperature and stabilize it at 42 to 45 degrees Celsius. Slowly add the bio-derived polycarboxylic acid chelation system, ensuring that the amount added in each batch does not exceed 5% of the total amount, in order to prevent precipitation caused by excessively high local concentrations. After the solution becomes clear and transparent, add the modified biopolymer film protectant in sequence. At this time, the stirring frequency needs to be increased to 500 revolutions per minute, and the cycle is continued for 40 minutes to ensure that the polymer molecular chains are fully extended.

[0030] After ensuring the stability of the physical properties of the system, the stirring speed was increased to a high shear state of 800 revolutions per minute, and a stimulus-responsive, degradable surfactant was slowly added dropwise through a metering pump. During this process, it is necessary to closely monitor the temperature changes inside the reactor, and the fluctuations must not exceed two degrees Celsius. High shear force is used to achieve the microscopic homogenization distribution of surfactant molecules in the aqueous phase. After cooling to room temperature, an environmentally induced degradation accelerator and a penetration-enhancing auxiliary factor are added, and low-speed steady-flow stirring is continued for one hour. The final product must be filtered through a precision filter with a filtration accuracy of five micrometers to remove any possible small undissolved substances. Only after online infrared spectroscopy confirms that the characteristic peaks of each functional group meet the standards can aseptic filling be carried out. The entire production process does not require the addition of any phosphorus- or nitrogen-containing (non-biodegradable) additives, and the amount of production waste generated is zero.

[0031] In specific engineering applications, such as the reverse osmosis membrane module for treating a large-scale dyeing and printing wastewater reuse system, the cleaning agent is first diluted to a 2% working condition solution according to the amount of fouling in the system, and then circulated and rinsed in the membrane module for two hours. At this time, the components work together to efficiently remove pollutants and suspend them in the cleaning solution. After cleaning, the waste liquid is discharged into a special conditioning tank. A 10% citric acid solution is added to the conditioning tank by an automatic dosing pump. The pH value is monitored in real time by an online potentiometer. The dosing is stopped when the pH value reaches 4.0. Under these acidic conditions, surfactant molecules begin to break down, and the foaming property of the waste liquid disappears within thirty minutes. By activating the microporous aeration system at the bottom of the pool and introducing oxygen and activating the induced degradation accelerator through light, the chemical oxygen demand (COD) removal rate in the waste liquid can reach more than 85% after 48 hours of intensive treatment. Moreover, it has no inhibitory effect on the nitrifying bacteria in the subsequent biological treatment system, realizing full life cycle management from efficient cleaning to green discharge.

[0032] Under normal temperature and pressure conditions, first add high-purity deionized water to the reactor equipped with an anchor stirrer, start stirring and heat to 40 to 45 degrees Celsius; Add the bio-derived polycarboxylic acid chelation system and the modified biopolymer membrane protectant in sequence according to the preset ratio, keep the speed at 300 to 500 revolutions per minute, and stir for 30 minutes until the solution becomes transparent and clear. Adjust the rotation speed to 800 revolutions per minute and slowly add the stimuli-responsive, degradable surfactant, using shear force to ensure uniform distribution of molecules in the aqueous phase; Under constant temperature conditions, an environmentally induced degradation accelerator and a penetration-enhancing auxiliary factor are added, and the mixture is stirred for one hour. After filtration and inspection, the product is then filled. The entire production process does not generate wastewater, waste gas, or solid waste, and has an extremely high degree of green process.

[0033] Through innovative molecular structure design and deep coupling with system architecture, an intelligent and environmentally friendly cleaning agent solution is provided that can maintain high performance output under complex industrial conditions and achieve self-cleaning logic in the waste stage. This solution not only significantly improves the operational reliability of membrane separation systems, but also provides key technical support for the green upgrading of reagents in the water treatment industry, and has extremely high engineering application value and ecological and environmental benefits. In practical large-scale industrial applications, this cleaning agent demonstrates high universality in dealing with membrane fouling from different sources (such as dyeing and printing wastewater, papermaking wastewater, and seawater desalination), proving the robustness and forward-looking nature of its technical solution. By precisely controlling the chemical interactions between components, this invention successfully integrates four originally mutually exclusive technical indicators—cleaning efficiency, membrane protection, low-foaming treatment, and rapid degradation—into a unified system, representing the highest technological evolution direction in the field of chemical cleaning of membrane materials.

[0034] Furthermore, regarding the chemical properties of the aforementioned stimulus-responsive cleavable surfactant, this invention can achieve hydrophilic-hydrophobic balance adaptation for different membrane materials (such as polyvinylidene fluoride, polyethersulfone, and polyamide) by adjusting the carbon number distribution of the acetal chain segments. When using membranes to treat dyeing and printing wastewater with high pollution loads, increasing the proportion of long-chain alkyl glycosides in the components can significantly enhance the solubilization capacity for complex dye molecules. When dealing with inorganic scale contamination in seawater desalination systems, the descaling speed is improved by increasing the proportion of tetrasodium iminodisuccinate in the bio-based polycarboxylic acid chelation system and utilizing its excellent lattice distortion effect. This flexibility based on modular ratio adjustment allows the cleaning agent of this invention to cover the cleaning needs of the entire membrane treatment industry chain.

[0035] Furthermore, the permeation-enhancing auxiliary factor used in this invention effectively disrupts the hydrogen bond network of water molecules on the membrane surface through its isomerized branched structure, enabling the effective components in the cleaning agent to reach deep into the membrane pores within microseconds. This deep penetration capability, combined with the stripping effect of the stimulus-responsive surfactant, ensures the long-term stability of membrane flux and reduces the accumulation of contaminants caused by incomplete cleaning.

[0036] The implementation of the technical solution described in this invention avoids the irreversible oxidative damage to the polyamide desalination layer caused by the use of strong oxidants (such as sodium hypochlorite) in traditional cleaning agents. By replacing the traditional cleaning agent with a biocatalytic and mild oxidation mechanism, it achieves ultimate protection of the membrane chemical structure without reducing the cleaning intensity. This precise design based on chemical kinetic control ensures that the cleaning agent can quickly return to the carbon-oxygen cycle in nature after completing its functional mission, leaving no lasting environmental footprint and fully reflecting the technological foundation of sustainable development.

[0037] In the specific engineering implementation phase, this invention also provides an online monitoring and closed-loop control logic. By monitoring the changes in conductivity and surface tension of the cleaning waste liquid in real time, the degree of acetal bond cleavage is automatically determined, thereby accurately guiding the dosage of acidification medium. This realizes the intelligent linkage between reagent use and waste liquid treatment. This systematic technical output greatly reduces the dependence on the professional skills of operators and improves the overall automation level and operational safety of the membrane treatment system.

[0038] Furthermore, regarding the molecular construction of the modified biopolymer membrane protectant, the degree of carboxymethylation is precisely controlled between 0.6 and 0.8. This specific range of substitution ensures that the polymer molecule has both good water solubility and retains enough active sites to interact with the amide bonds on the membrane surface. In actual operation, this interaction manifests as a competitive adsorption, where the protective agent molecules prevent small molecule organic pollutants from entering the microporous structure of the membrane material by physically occupying the sites. When the cleaning cycle ends, increasing the shear force of the system or changing the ionic strength of the rinsing solution will cause the protective layer to peel off, ensuring that the membrane's filtration characteristics are not affected by long-term physical factors.

[0039] Furthermore, the peroxidase encapsulated within the environmentally induced degradation accelerator has undergone tolerance screening and can maintain more than 80% of its initial activity within a wide range of pH values ​​from three to nine and temperatures from five to fifty degrees Celsius. This strong environmental adaptability ensures that the induced degradation mechanism described in this invention can function stably in both wastewater treatment plants in frigid regions and seawater desalination plants in tropical regions.

[0040] The cleaning agent described in this invention has also been specially designed in terms of packaging and storage stability. Due to the use of microencapsulation technology and layer stabilization mechanism, the product has a shelf life of up to two years under normal temperature and sealed conditions, and the various active ingredients do not undergo layering, precipitation or reduction in potency.

[0041] At the end of wastewater treatment, the residues produced by the decomposition of stimuli-responsive surfactants are all low-toxicity small-molecule alcohols and sugars. They not only do not inhibit the activity of microorganisms in the biological treatment tank, but can also serve as an additional carbon source for microbial metabolism to a certain extent, promoting the renewal and activity enhancement of the biofilm in the wastewater treatment system. This transformation from pollutant to nutrient source is a redefinition of the environmental behavior of membrane cleaning agents in this invention from the perspective of circular economy.

[0042] Example 1 A cleaning agent with the median proportions of each component was prepared: 20 parts of a stimulus-responsive, cleavable surfactant, 15 parts of a bio-derived polycarboxylic acid chelating system, 8 parts of an environmentally induced degradation accelerator, 5 parts of a modified biopolymer membrane protectant, 3 parts of a penetration-enhancing auxiliary factor, and 49 parts of deionized water.

[0043] Example 2 The formulation was adjusted for environments with high inorganic scale: 15 parts of stimulus-responsive degradable surfactant, 20 parts of bio-derived polycarboxylic acid chelation system, 10 parts of environmentally induced degradation accelerator, 3 parts of modified biopolymer membrane protectant, 5 parts of permeability-enhancing auxiliary factor, and 47 parts of deionized water.

[0044] Example 3 The formula was optimized for working conditions with severe organic pollution: 25 parts of stimuli-responsive degradable surfactant, 10 parts of bio-derived polycarboxylic acid chelation system, 5 parts of environmentally induced degradation accelerator, 8 parts of modified biopolymer membrane protectant, 2 parts of penetration-enhancing auxiliary factor, and 50 parts of deionized water.

[0045] Comparative Example 1 The selected product is a non-degradable chemical cleaning agent with EDTA and traditional sodium alkylbenzene sulfonate (LAS) as its core components, which does not have irritant-responsive properties.

[0046] Comparative Example 2 A cleaning agent based on a single biodegradable surfactant (such as APG) was selected, but no environmentally induced degradation accelerator or modified biopolymer membrane protectant was added.

[0047] For the above embodiments and comparative examples, comparative experiments were conducted under the same reverse osmosis membrane damage model (initial flux reduction of 30%, and contaminant components including calcium carbonate, biofilm, and organic dyes). The experimental test indicators included flux recovery rate, membrane surface potential recovery value after cleaning, waste liquid foaming height (initial and after 30 minutes of acid treatment), and biodegradation rate after 28 days.

[0048] For a detailed comparison of the experimental data, please refer to the table below: Table 1: Comparison of Performance Indicators of Each Embodiment and Comparative Example

[0049] The data in Table 1 clearly shows that the environmentally friendly membrane material cleaning agent based on environmentally degradable materials described in this invention exhibits significant generational advantages in all key technical indicators, especially in terms of flux recovery rate. Examples 1 to 3 all consistently maintain a rate of over 98%, demonstrating the highly efficient synergy between the stimulus-responsive surfactant and the bio-based chelate system at the molecular level. More crucial data lies in the changes in surface tension and foam height after acid treatment. In the embodiments of this invention, under acidification induction, the surface tension rapidly recovers to a state close to that of pure water (over 60 millinewtons per meter), and the foam almost completely dissipates. In contrast, Comparative Examples 1 and 2, lacking a directional molecular bond cleavage mechanism, maintain stable interfacial activity under acidic conditions, which will lead to a large amount of persistent foam in actual wastewater treatment processes.

[0050] In terms of biodegradation performance, this invention achieves a high COD removal rate within 48 hours through the action of an environmentally induced degradation accelerator. This is in stark contrast to the comparative example, which, due to the presence of recalcitrant EDTA and LAS, has a degradation rate of only 42.5% after 28 days. Long-term discharge of these substances will cause cumulative damage to the aquatic ecosystem. The data from this example demonstrate that this invention successfully minimizes the environmental impact of chemical agents through an active induction mechanism.

[0051] Further analysis of the engineering logic of this invention reveals that the effect of the modified biopolymer membrane protectant is fully demonstrated in the Zeta potential recovery rate. The recovery rate in Example 3 reached 97.8%, which means that the chemical state of the membrane surface after cleaning is extremely close to the original uncontaminated state. This stable potential not only means the complete removal of contaminants, but also the reconstruction of the hydrophilicity of the membrane surface. Through the transient hydration layer formed on the membrane surface, the microscopic swelling or oxidative damage of the polyamide layer by the chemical components in the cleaning solution is effectively prevented. This conclusion was confirmed in subsequent membrane service life tracking experiments: the membrane module using the cleaning agent of this invention had an average cleaning cycle that was 40% longer than that of Comparative Example 1.

[0052] Furthermore, for complex industrial conditions with high pollution loads, the environmentally friendly membrane material cleaning agent based on environmentally degradable materials described in this invention exhibits extremely strong robustness. When treating the ultrafiltration membrane module of a paper mill's white water recovery system, due to the large amount of lignin, cellulose degradation products, and various industrial additives in the wastewater, traditional alkaline cleaning agents often fail to completely remove deep-seated biocolloidal contamination. This invention, through the isomerization structure of the penetration-enhancing auxiliary factor, successfully penetrates the highly viscous biocolloidal layer, allowing the stimulus-responsive surfactant to directly act on the membrane-fouling interface. Under these conditions, the cleaning scheme in Example 1 achieved complete flux recovery within just sixty minutes, and the wastewater after cleaning, through on-site acidification-photocatalytic linkage treatment, directly met the standards for entering the subsequent biochemical system.

[0053] By adjusting the carbon number distribution of the hydrophobic alkyl chain, researchers can customize and optimize the spreading ability of the cleaning agent according to the critical surface tension of different membrane materials. For example, for polyvinylidene fluoride (PVDF) membranes with low surface energy, appropriately increasing the proportion of C14 segments in the components can significantly enhance the capillary penetration of the cleaning agent in the membrane pores. When dealing with high-concentration carbonate scale in seawater desalination systems, increasing the proportion of tetrasodium iminodisuccinate in the chelation system can utilize its stronger multidentate coordination ability to achieve rapid pulverization of hard scale layers.

[0054] Regarding quality control in the production and preparation process, the high-shear homogenization process adopted in this invention ensures that the microcapsules in the environmentally induced degradation accelerator are in a uniform suspension state in the system, without sedimentation or aggregation. This stability is of vital importance for long-term storage and long-distance transportation. Experiments show that the cleaning agent described in this invention, after being placed in a high-temperature accelerated aging experiment at 50 degrees Celsius for three months, did not show a significant decrease in its interfacial tension and degradation activity, proving the chemical inertness of the microcapsule coating and the physical strength of the structure.

[0055] Furthermore, the modified biopolymer membrane protectant used in this invention, whose carboxymethyl chitosan quaternary ammonium salt not only has a protective function, can also play a certain flocculation role in the waste liquid treatment stage when the pH value is adjusted to acidic due to the reversal of molecular charge. This unexpected technical gain can help precipitate the suspended organic particles that have been stripped off in the waste liquid, thereby removing some pollutants through simple physical sedimentation before entering the biochemical system, further reducing the operating pressure of environmental protection facilities.

[0056] In summary, this invention constructs a closed-loop cleaning system that is highly integrated in function and highly controlled in terms of environmental impact through a precisely designed stimulus-responsive molecular structure, an efficient bio-based chelation system, a controllable environmentally induced degradation mechanism, and an in-situ membrane protection strategy. The design of each component fully considers the needs of the entire process, from cleaning efficiency and membrane life protection to wastewater end-of-pipe treatment.

[0057] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials, characterized in that, By weight, it includes the following components: 15 to 25 parts of a stimulus-responsive, cleavable surfactant; Ten to twenty parts of a bio-derived polycarboxylic acid chelation system; Five to ten portions of environmentally induced degradation accelerator; Three to eight parts of modified biopolymer film protectant; Two to five parts of penetration-enhancing cofactor; The remainder is high-purity deionized water.

2. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 1, characterized in that, The stimulus-responsive cleavable surfactant is an acetal alkyl glycoside derivative with acid-induced cleavage properties, and its molecular structure has an acetal bond linking point between the hydrophobic alkyl chain and the hydrophilic glycoside group. The stimulus-responsive cleavable surfactant is formed by the condensation of a linear fatty alcohol with twelve to fourteen carbon atoms and a glucose monomer with an acetal precursor under acid-catalyzed dehydration conditions, and its weight-average molecular weight is between 450 and 650 Daltons. The acetal bond is configured to maintain chemical stability in a cleaning environment with a pH value between 7.5 and 9.5, thereby maintaining the effectiveness of the surfactant in reducing interfacial tension, emulsifying organic contaminants, and stripping biofilms. When the pH of the cleaning waste liquid is adjusted to the range of 3.5 to 4.5, the acetal bonds undergo rapid hydrolytic breakage, resulting in the physical separation of the hydrophobic and hydrophilic segments of the molecule. This causes the interfacial tension of the cleaning waste liquid to rise from below 28 millinewtons per meter to above 60 millinewtons per meter within 30 minutes.

3. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 1, characterized in that, The bio-derived polycarboxylic acid chelation system is a synergistic complexation system composed of tetrasodium L-glutamate diacetate and tetrasodium iminodisuccinate in a mass ratio of 3:

1. The tetrasodium L-glutamic acid diacetate has a complexation stability constant for calcium ions with a logarithm greater than 5.0, and is used to disrupt the lattice structure of calcium carbonate and calcium sulfate crystals in the inorganic scale layer on the membrane surface. The tetrasodium iminodisuccinate is used to enhance the salt-tolerance capacity of the system under alkaline conditions and to form chelates with transition metal ions such as iron and manganese ions with high stability constants, preventing the dissolved metal ions from undergoing secondary precipitation during the cleaning solution circulation process. The biodegradation rate of this bio-derived polycarboxylic acid chelation system in the receiving water body exceeds 95% after 28 days.

4. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 2, characterized in that, The environmentally induced degradation accelerator is a slow-release oxidation catalytic system based on microencapsulation technology, comprising: The cellulose acetate phthalate coating layer, which serves as the outer shell of the microcapsule, is pH sensitive and is configured to remain intact in neutral and alkaline environments and to dissolve and release in acidic environments. A porous nano-silica carrier is disposed inside the cellulose acetate phthalate coating layer, and its pore size is distributed between ten and twenty nanometers. Peroxidase, loaded within the pores of the porous nano-silica carrier, is used to catalytically decompose the molecular chains of organic pollutants using dissolved oxygen in the waste liquid. Nanoscale titanium dioxide powder, loaded on the porous nano-silica carrier, with an average particle size of 20 nanometers, is configured to generate hydroxyl radicals under light irradiation in a receiving environment, thereby mineralizing the residual chain segments after surfactant pyrolysis.

5. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 4, characterized in that, The peroxidase has tolerance screening features and is configured to maintain more than 80% of its initial activity in a pH range of 3 to 9 and a temperature range of 5 to 50 degrees Celsius. The environmentally induced degradation accelerator is configured to trigger the dissolution of the cellulose acetate phthalate coating by adjusting the pH value during the conditioning stage after the discharge of the cleaning waste liquid, thereby completing the active induced degradation of organic pollutants and residual surfactant segments within forty-eight hours.

6. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 1, characterized in that, The modified biopolymer film protectant is a chitosan quaternary ammonium salt modified by carboxymethylation, and its degree of carboxymethylation substitution is controlled between 0.6 and 0.

8. The quaternary ammonium cationic groups on the molecular chain of the modified biopolymer membrane protectant are configured to electrostatically adsorb onto the negatively charged membrane surface, forming a transient hydration protective layer with a thickness of nanometers on the membrane material surface, which buffers the chemical erosion of the membrane polyamide layer by the strong cleaning components and occupies the active sites on the membrane surface. The modified biopolymer membrane protectant is washed away by the water flow after cleaning and does not remain in the membrane pores.

7. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 1, characterized in that, The penetration-enhancing auxiliary factor is a mixture of low molecular weight fatty alcohol polyoxyethylene ether sodium sulfate and isomeric decaol polyoxyethylene ether in a 1:1 mass ratio. The isomeric deca-ol polyoxyethylene ether has an isomerized branched structure and is configured to reduce the dynamic viscosity of the cleaning solution by disrupting the hydrogen bond network of water molecules on the membrane surface, allowing the cleaning solution to penetrate to the interface between the contaminant and the membrane material and generate a swelling effect, thereby decomposing the dirt into suspended particles.

8. The environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials according to claim 1, characterized in that, When the high-efficiency cleaning agent is applied to the cleaning of membrane modules, it is prepared as an aqueous solution with a mass fraction of one to three percent. When treating dyeing and printing wastewater for membrane reuse, the proportion of long-chain alkyl glycosides in the components is increased to enhance the solubilization ability of dye molecules. When treating inorganic scale contamination in seawater desalination systems, the mass percentage of tetrasodium iminodisuccinate in the bio-derived polycarboxylic acid chelation system is increased.

9. A preparation process for an environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials, applicable to the environmentally friendly, high-efficiency cleaning agent for membrane materials based on environmentally degradable materials as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Add the preset amount of high-purity deionized water to the reactor, start stirring and heating, and control the water temperature at 40 to 45 degrees Celsius; Step 2: Under the condition of stirring speed of 300 to 500 revolutions per minute, add the bio-derived polycarboxylic acid chelation system and modified biopolymer membrane protectant in sequence, and continue stirring for 30 minutes until the solution becomes transparent and clear. Step 3: Adjust the stirring speed to 800 revolutions per minute, slowly add the stimuli-responsive, degradable surfactant, and use shear force to ensure that its molecules are evenly distributed in the aqueous phase. During the addition process, monitor the temperature fluctuation inside the vessel to ensure that it does not exceed 2 degrees Celsius. Step 4: Under constant temperature conditions, add the environmentally induced degradation accelerator and the penetration-enhancing auxiliary factor, and continue to stir at a low speed and steady flow for one hour; Step 5: The obtained product is filtered through a precision filter with a filtration accuracy of five micrometers, and then filled after the functional group characteristic peaks are confirmed by online infrared spectroscopy scanning.

10. The preparation process of an environmentally friendly membrane material high-efficiency cleaning agent based on environmentally degradable materials according to claim 9, characterized in that, In step two, the bio-derived polycarboxylic acid chelation system is added in batches, with each batch not exceeding five percent of the total mass. After step four, the cleaning agent is configured to adjust the pH to 4.0 by adding citric acid or formic acid to the waste liquid upon entering the waste liquid treatment stage, so as to instantaneously break the acetal bonds of the stimulus-responsive cleavable surfactant and trigger the microcapsule rupture in the environmentally induced degradation accelerator to release the catalytic component.

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