Method for adsorbing and purifying wastewater by using modified blue-green algae biochar loaded nano material

Abstract

The invention relates to the technical field of water treatment, and discloses a modified blue-green algae biochar loaded nano material wastewater adsorption purification method, which comprises: placing blue-green algae powder loaded with a nano active material precursor in an inert atmosphere, and carrying out stepped heating pyrolysis, carrying out in-situ pore forming by utilizing instantaneous internal pressure separated by blue-green algae endogenous lipid resolution to generate a graded pore channel structure, and inducing a polysaccharide component to react with the nano active substance to construct a heteroatom doped modification layer; adding the product into a wastewater system, applying a pulsed magnetic field, selectively inhibiting interfering ion competitive adsorption by utilizing the electrical property of the modification layer, generating a micro-vibration shear force by utilizing the asynchronous displacement difference between the nano active substance and the carbonized skeleton, stripping a deposited passivation film on an adsorption interface, and performing adsorption. Accurate exposure and charge recognition of adsorption sites are achieved through functional evolution of endogenous components, the defect of agent passivation is overcome by cooperating with an interface self-cleaning mechanism assisted by a magnetic field, the selective capture performance of target pollutants is improved, and the purification service cycle is prolonged.

Description

Technical Field

[0001] This invention relates to a wastewater adsorption and purification method using modified cyanobacterial biochar-supported nanomaterials, belonging to the field of water treatment technology. Background Technology

[0002] Currently, using biochar as a carrier to load composite materials composed of active nanomaterials is the mainstream technology. The microporous structure of the biochar surface anchors nanoparticles, and removes water pollutants through physical adsorption and chemical reaction. Industrial wastewater usually contains high concentrations of non-target interfering ions such as calcium ions and magnesium ions. Since the functional groups on the surface of biochar lack the ability to electrically recognize ions, interfering ions occupy a large number of adsorption sites. At the same time, organic macromolecules in wastewater tend to form passivation films at the adsorption interface, blocking the hierarchical pores of carbon-based materials and increasing the mass transfer resistance of pollutants to internal active sites.

[0003] To maintain treatment effectiveness, conventional methods typically employ linear improvement pathways such as increasing reagent dosage or performing secondary chemical activation. However, increasing reagent dosage generates a large amount of waste sludge and increases treatment costs. Strong acid or strong alkali activation processes disrupt the confined structure between nanoparticles and the carbon skeleton, causing active components to detach. Under complex operating conditions, existing technologies struggle to simultaneously achieve adsorption selectivity, interfacial passivation resistance, and the physical stability of the support structure. For example, Chinese invention patent CN114105290B discloses a method for preparing modified cyanobacterial biochar-supported nano-zero-valent iron materials and its application. Although supporting nano-zero-valent iron enhances reduction activity and assists in denitrification of the bioelectrochemical system, the adsorption surface is still blocked by non-target components when facing high-salt and colloidal organic conditions.

[0004] Therefore, the technical problem to be solved by this invention is how to perform in-situ modification of the endogenous components of cyanobacterial biomass, solve the competitive adsorption of non-target ions by constructing an interface structure with recognition function, and construct interconnected mass transfer channels by using the endogenous pressure release mechanism to overcome the performance degradation caused by interface passivation. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A wastewater adsorption and purification method using modified cyanobacterial biochar supported on nanomaterials, comprising the following steps:

[0006] Step S101: The cyanobacterial biomass is pulverized to obtain cyanobacterial powder;

[0007] Step S102: Immerse the cyanobacterial powder in a solution containing a precursor of nano-active substances, and perform ultrasonic dispersion and solid-liquid separation to obtain a cyanobacterial matrix loaded with the precursor.

[0008] Step S103: The cyanobacterial matrix loaded with the precursor is placed under an inert atmosphere to perform the following step-by-step pyrolysis procedure: The first stage is... / min to Heating rate of / min to Within this temperature range, the temperature is maintained, and the instantaneous expansion pressure generated by the decomposition of endogenous lipid components in the precursor-loaded cyanobacterial matrix is ​​used to scour and generate a hierarchical pore structure within the carbonized framework; the second stage involves heating to... to The graphitization transformation is performed to induce a thermochemical reaction between the nitrogen-containing polysaccharide components in the carbonized framework and the nano-active materials, thereby generating a heteroatom-doped modification layer in situ on the surface of the hierarchical pore structure.

[0009] In step S104, the pyrolysis products generated in step S103 are added to the wastewater system, and an intermittent pulsed magnetic field is applied using a magnetic field generator. The electrostatic selectivity of the heteroatom-doped modification layer on wastewater ions is used to block non-target interfering ions and guide target heavy metal ions into the hierarchical pore structure. The asynchronous thermal expansion displacement difference between the nano-active material and the carbonized framework under the action of the intermittent pulsed magnetic field generates micro-vibration shear force at the adsorption interface, peeling off the passivation film deposited on the surface of the pyrolysis products.

[0010] Preferably, the stepped heating pyrolysis process executed in step S103 further includes a cooling process after the heat preservation is completed, wherein the cooling process is performed by... / min to Cooling at a rate of / min is used to maintain the geometric stability of the hierarchical pore structure and limit the particle size of the nano-active material.

[0011] Preferably, the precursor of the nano-active material in step S102 includes one or more of zero-valent iron salt, manganese sulfide salt, or nano-metal oxide salt; step S103 limits the distribution density of active sites in the heteroatom doped modification layer by adjusting the molar ratio of nitrogen to nano-active material in the cyanobacterial matrix loaded with the precursor.

[0012] Preferably, the magnetic induction intensity of the intermittent pulsed magnetic field in step S104 is T to T, pulse frequency is Hz to Hz.

[0013] Preferably, the temperature range for the first stage of step S103 is selected by obtaining the thermogravimetric curve of cyanobacterial biomass and setting the peak temperature of the maximum weight loss of lipid component decomposition rate in the thermogravimetric curve as the center temperature of the heat preservation stage.

[0014] Preferably, the heteroatom-doped modification layer includes an electron cloud shift structure formed by co-doping of biogenic nitrogen and phosphorus. The electron cloud shift structure acts as an interface electron donor to slow down the oxidation rate of the nano-active material.

[0015] Preferably, step S101 further includes deashing the cyanobacteria powder with an inorganic acid solution.

[0016] Preferably, in step S104, the conductivity value of the wastewater system is obtained through a monitoring device during the wastewater purification process, and the pulse duty cycle of the magnetic field generator is adjusted according to the rate of change of the conductivity value over time.

[0017] Preferably, the selective adsorption performance of the heteroatom-doped modified layer for target heavy metal ions is measured by the selectivity coefficient. Evaluation, selectivity coefficient Satisfy the following formula: ,in, This represents the equilibrium adsorption capacity of the pyrolysis products for the target heavy metal ions. This represents the equilibrium concentration of the target heavy metal ions in the wastewater. This represents the equilibrium adsorption capacity of the pyrolysis products for interfering ions. This represents the equilibrium concentration of interfering ions in the wastewater.

[0018] Preferably, the pyrolysis products after purification are regenerated after magnetic separation. During the regeneration process, micro-fluid disturbances are induced inside the hierarchical pore structure by intermittent pulsed magnetic field, thereby reconstructing the surface active sites of the nano-active materials.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In wastewater adsorption and purification, the electrochemical interaction between nitrogenous polysaccharides in the cell wall of cyanobacteria and nano-active sites during pyrolysis induces a local dipole moment at the adsorption interface, constructing a polar gating layer with charge recognition function. Based on the difference between ion hydration diameter and charge density, the polar gating layer blocks the physical contact of non-target interfering ions through electrostatic repulsion and induces the target heavy metal ions to migrate directionally into the biochar. This solves the problem of ineffective occupation of adsorption sites by interfering ions in complex water bodies, ensuring high selective capture of target pollutants during the adsorption process without increasing the amount of reagents added.

[0021] 2. By applying an intermittent pulsed electromagnetic field to the wastewater system, the magnetic moment response of the embedded nano-active particles generates instantaneous thermosensitive micro-displacement, creating an asynchronous thermal expansion displacement difference between the nano-active particles and the carbon skeleton. This generates micro-vibration stress inside the pores, mechanically peeling off the colloidal pollutants or physical passivation film wrapped on the surface of biochar. In addition, the local catalytic activity of the nano-active particles is used to degrade interfacial deposits in situ, avoiding the rapid decline in adsorption performance caused by interfacial passivation in conventional processes. This achieves online recovery of purification efficiency and extends the service life of the reagent.

[0022] 3. A stepped heating program is used to guide the non-homogeneous pyrolysis of endogenous components in biomass. The lipid cleavage plateau phase is selected to allow intracellular lipids to graphitize before the carbon skeleton, generating a high-pressure gas flow. The high-pressure gas flow utilizes the instantaneous pressure generated by the in-situ vaporization of biological components to perform micro-area scouring in the dense skeleton formed by cell wall collapse, opening nanoscale interconnected micropore channels that directly reach the internal active sites. This internal pore-forming method eliminates the internal diffusion resistance of deep sites without destroying the anchoring strength of nanoparticles, shortens the mass transfer path of pollutants inside the carbon layer, and fundamentally improves the adsorption kinetics of the system. Attached Figure Description

[0023] Figure 1 This is a flow chart of the stepwise pyrolysis preparation and magnetic field-assisted adsorption purification process of the modified cyanobacterial biochar of the present invention.

[0024] Figure 2 This is a block diagram illustrating the principle of the closed-loop control system for wastewater adsorption and purification using a pulsed magnetic field regulated by conductivity feedback, as described in this invention. Detailed Implementation

[0025] The following embodiments are intended to explain the present invention, and not to limit the scope of protection of the present invention. Those skilled in the art should understand that the following technical features can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

[0026] This invention discloses a wastewater adsorption and purification method using modified cyanobacterial biochar supported on nanomaterials, comprising: cyanobacterial powder pretreatment, nanomaterial precursor loading, step-heat pyrolysis for pore formation and modification, and dynamic adsorption and purification under pulsed magnetic field assistance; utilizing the instantaneous internal pressure released from the decomposition of endogenous lipids in cyanobacteria to generate an in-situ pore-forming effect, and inducing the reaction of nitrogen-containing polysaccharide components with nanomaterials to generate a heteroatom-doped modification layer; suppressing interfering ion competition through interfacial electrical differences, and synergistically using the micro-vibration shear force generated by magnetic field excitation to peel off the deposited passivation film at the adsorption interface; after pulverizing the cyanobacterial biochar to obtain cyanobacterial powder, using a concentration of... to The cyanobacterial powder was deashed with an inorganic acid solution to clear the physical channels for precursor penetration; the cyanobacterial powder was then immersed in a solution containing a nano-active precursor, selected from one or more of zero-valent iron salts, manganese sulfide salts, or nano-metal oxide salts; the mixed system was then subjected to... to The precursor ions are dispersed by ultrasound and the ultrasonic cavitation effect is used to push the precursor ions into the microporous structure of the cyanobacterial cell wall. The precursor-loaded cyanobacterial matrix is ​​obtained by solid-liquid separation.

[0027] The cyanobacterial matrix loaded with precursors was placed under an inert atmosphere and subjected to a stepped temperature-increasing pyrolysis process. The first stage was... to The rate of temperature increase is to The temperature is maintained within this range, which is selected based on the peak temperature of maximum weight loss in the lipid decomposition rate of the cyanobacterial biomass thermogravimetric curve. During this stage, the instantaneous expansion pressure generated by the decomposition of endogenous lipid components in the cyanobacteria is used to scour the carbonized framework and generate a hierarchical pore structure. The temperature is then increased to... to The second stage of pyrolysis was performed to induce graphitization, during which the molar ratio of nitrogen to nano-active materials in the cyanobacterial matrix was adjusted to maintain it at a certain level. to Within a certain range, the nitrogen-containing polysaccharide components in the induced carbonized framework undergo a thermochemical reaction with the nano-active materials, thereby generating a heteroatom-doped modification layer in situ on the surface of the hierarchical pore structure, formed by co-doping of biogenic nitrogen and phosphorus. To address fluctuations in the endogenous components of different batches of cyanobacterial biomass, before the impregnation treatment in step S102, a 10-gram sample of cyanobacterial powder needs to be extracted for elemental analysis to obtain the original percentage mass value of biogenic nitrogen. If the measured percentage of biogenic nitrogen is less than 4%, urea is added to the solution containing the nano-active material precursor at a ratio of 5 grams per liter as nitrogen source compensation to ensure that the molar ratio of nitrogen to nano-active materials in the carbonized framework is locked within a certain range of 1.5:1 to 3:1 when entering the pyrolysis stage in step S103. The heteroatom-doped modification layer contains an electron cloud shift structure, which acts as an interface electron donor to slow down the oxidation rate of the nano-active materials. The pyrolysis products generated above are added to the wastewater system, and a magnetic field generator is used to apply a magnetic induction intensity of [insert value here]. to The pulse frequency is to The intermittent pulsed magnetic field; the heteroatom doped modification layer uses electrostatic selective blocking of non-target interfering ions and guides target heavy metal ions into the hierarchical pores.

[0028] During the purification process, the conductivity of the wastewater system is obtained through monitoring devices. The value, and based on the rate of change of the conductivity value over time. The pulse duty cycle of the magnetic field generator is adjusted; when the rate of conductivity decrease slows down due to the formation of a deposited passivation film at the adsorption interface, the asynchronous thermal expansion displacement difference between the nano-active material and the carbonized framework under the action of an intermittent pulsed magnetic field generates micro-vibration shear force to peel off the passivation film deposited on the surface of the pyrolysis products to restore the exposed area of ​​the adsorption sites; the Lorentz force scouring effect experienced by the magnetic components in the nano-active material under an alternating magnetic field environment, combined with the micro-regional relative displacement caused by the difference in magnetostriction coefficients between the nano-active material and the carbonized framework, makes the micro-vibration shear force inside the hierarchical channels exceed the interfacial binding energy between the passivation film and the carbonized framework in terms of energy level. Based on the asynchronous thermal expansion displacement difference, the reciprocating magnetostriction torque response of the nano-active material inside the hierarchical channels disrupts the geometric continuity of the passivation film and peels it off with the flow field of the wastewater system, realizing the dynamic maintenance of the exposed area of ​​the adsorption sites; the selective adsorption performance of the heteroatom doped modification layer for target heavy metal ions is measured by the selectivity coefficient. Evaluation, selectivity coefficient Satisfy the following formula: ,in, This is the selectivity coefficient; The equilibrium adsorption capacity of the pyrolysis products for the target heavy metal ions is expressed in units of... ; The equilibrium concentration of the target heavy metal ions in the wastewater, in units of ; The equilibrium adsorption capacity of interfering ions by the pyrolysis products is expressed in units of 1. ; The equilibrium concentration of interfering ions in the wastewater, in units of .

[0029] Example 1: In an industrial application scenario for treating coking wastewater, the influent system contains a concentration of... Lead ions and concentrations of Calcium ions, with a mass concentration of [missing information], are present simultaneously. The high salinity and high organic load conditions cause conventional carbon-based adsorbents to fail during operation. The adsorption activity is lost due to the non-specific occupation of calcium ions and the blockage of the surface passivation film. Under this condition, the pyrolysis product prepared in the aforementioned specific embodiment is introduced, and the heteroatom-doped modification layer generates a local dipole moment on the surface of the hierarchical channels. This moment electrostatically repels calcium ions with larger hydrated diameters and guides lead ions with higher charge density to migrate directionally to the internally loaded nano-active material sites. This process balances the adsorption capacity of lead ions. Maintain at And the equilibrium adsorption amount of calcium ions Limited to the following.

[0030] When the monitoring device collects the conductivity of the wastewater system The value was calculated, and the rate of change of that value over time was determined. Below the preset threshold At that time, it was determined that a passivation film was deposited and blocked at the adsorption interface; the magnetic field generating device applied a magnetic induction intensity of And the pulse frequency is The intermittent pulsed magnetic field utilizes the asynchronous physical response between the internally confined nano-active material and the graphitized carbonized framework to generate a micro-region displacement difference. The resulting micro-vibration shear force mechanically peels away the colloidal deposits at the entrance of the hierarchical channels, thus re-exposing the adsorption sites to the wastewater system. After five consecutive adsorption cycles, the effluent lead ion concentration stabilized at [value missing]. The following are the calculated selectivity coefficients. It remains no lower than [a certain value] even under the interference of complex coexisting ions. The system achieves dynamic recovery of adsorption performance through physical field coupling with intrinsic functional structures without the need for additional chemical cleaning agents, maintaining the exposure rate of active sites on the surface of pyrolysis products at their initial state. above.

[0031] Example 2: This verification experiment was conducted in a multi-component heavy metal wastewater system. The experimental platform used a dynamic continuous flow reactor with temperature control and magnetic field regulation functions, wherein the temperature control accuracy was [insert accuracy here]. The conductivity monitor has a resolution of And the sampling frequency is set to ; Target heavy metal ions Pb in the influent system concentration Interfering ions Ca concentration And introduce a concentration of The fulvic acid colloid is used as an interface passivation interference source, and fluid noise generated by flow fluctuations is superimposed in the inlet channel to simulate a real industrial flow field environment; the core parameter settings follow the logic of thermodynamic and physical field response, and the temperature of the first stage of pyrolysis is selected as [temperature value missing]. This value is derived from the peak temperature of maximum weight loss in the lipid component decomposition rate of the cyanobacterial biomass thermogravimetric curve. The heating rate balances the instantaneous internal pressure released from lipid decomposition and the mechanical strength of the carbonized skeleton; the pulse frequency of the intermittent pulsed magnetic field is set to... The frequency was chosen based on the magneto-relaxation frequency of the embedded nano-active material in a viscous fluid environment. When the frequency tends towards... At the lower limit, the generated micro-vibration shear force is insufficient to overcome the van der Waals adsorption energy between the passivation film and the carbon substrate. When the frequency tends towards When the upper limit is reached, the thermal effect generated by the magnetic loss of the system will increase the risk of thermal deactivation of the nano-active materials.

[0032] The experiment compared the purification performance of pyrolysis products obtained under different preparation conditions in the same wastewater environment to evaluate the synergistic effect of hierarchical pore structure, heteroatom doping modification layer, and pulsed magnetic field mechanism. The experiment was divided into the present invention sample group, control group A, control group B, control group C, and control group D. The present invention sample group fully followed the process flow of the aforementioned specific implementation method. Control group A omitted the pore-forming step during the lipid pyrolysis plateau, control group B omitted the heteroatom doping modification layer, and control group C had its second-stage pyrolysis temperature set to [temperature value missing]. That is, exceeding the upper limit temperature specified in this technical solution, control group D does not apply an intermittent pulsed magnetic field during the adsorption process, through operation The key performance data collected afterward are as follows:

[0033] Table of purification performance test data for each sample group (Table #1)

[0034]

[0035] Analysis of the data in Table 1 shows that the selectivity coefficient of the present invention sample group with heteroatom doped modification layer in complex systems is [data missing]. for Compared to control group B The data shows a significant improvement, confirming that the local dipole moment generated at the adsorption interface by the modified layer effectively electrostatically repels interfering ions; control group C showed a similar improvement. equilibrium adsorption capacity Descending to This indicates that pyrolysis temperatures exceeding the upper limit lead to the collapse of the hierarchical pore structure and the encapsulation of active sites; control group D, lacking pulsed magnetic field assistance, exhibits a lower rate of change in conductivity. Attenuation rate as high as The present invention's sample group controls the attenuation rate within a certain range through the micro-vibration shear force generated by physical field coupling. This enables dynamic updating of adsorption sites.

[0036] Example 3: This example combines Figures 1 to 2 This document describes a wastewater adsorption and purification method using modified cyanobacterial biochar-supported nanomaterials, as follows: Figure 1As shown, a wastewater adsorption and purification method using modified cyanobacterial biochar loaded with nanomaterials is proposed, comprising four sequential steps. Step S101 involves pulverizing the cyanobacterial biomass to obtain cyanobacterial powder. Step S102 involves immersing the cyanobacterial powder in a solution containing a precursor of nano-active substances, followed by ultrasonic dispersion and solid-liquid separation to obtain a cyanobacterial matrix loaded with the precursor. Next, step S103 involves step-by-step pyrolysis under an inert atmosphere. This process is divided into a first stage of low-temperature holding to utilize the internal pressure of lipid decomposition to generate a hierarchical pore structure, and a second stage of high-temperature graphitization to induce the formation of a heteroatom-doped modification layer. Finally, in step S104, the product is added to the wastewater system and an intermittent pulsed magnetic field is applied. During this process, the modification layer electrostatically selectively blocks interfering ions and guides target ions into the pores, while the asynchronous thermal expansion displacement difference under the magnetic field generates micro-vibration shear force to peel off the passivation film.

[0037] like Figure 2 As shown, the system consists of a dynamic continuous flow reactor, an online monitoring device, a central control unit, and a magnetic field generator connected in sequence. The dynamic continuous flow reactor contains a modified cyanobacterial biochar and a wastewater system containing heavy metals. Water samples are transported to the online monitoring device, which includes a conductivity monitoring probe, through real-time sampling. The online monitoring device transmits feedback conductivity values ​​to the central control unit. After internally performing conductivity attenuation deviation calculation and pulse duty cycle adjustment mapping, the central control unit issues an adjustment pulse duty cycle command to the magnetic field generator. The magnetic field generator generates an intermittent pulsed magnetic field through a power conversion circuit, ultimately applying a magnetic field with a magnetic induction intensity of 0.1~0.5 Tesla to the dynamic continuous flow reactor to complete the feedback regulation.

[0038] Example 4: In an industrial application for treating wastewater from electronic component cleaning, the influent system contains a concentration of... Lead ions and dynamically fluctuating background salinity, initial conductivity of the influent system Depending on the production shift to The concentration fluctuates within the range, and the system contains a concentration of not less than [amount missing]. Oily organic compounds; to address the uncertainty of pore-forming parameters caused by differences in raw materials, a standardized calibration procedure was performed before preparing the adsorbent, using a thermogravimetric analyzer at a nitrogen flow rate of [missing information]. And the heating rate is Under specific conditions, mass loss data of this batch of cyanobacterial powder was collected. The derivative thermogravimetric curve was obtained by calculating the first derivative of mass with respect to temperature, and the values ​​located in the curve were identified. to The peak value of the maximum weight loss rate was determined, and the corresponding temperature was set as the first stage holding temperature for stepped heating pyrolysis.

[0039] During the operation of this dynamic adsorption process for industrial wastewater, the system uses an online conductivity monitor to collect the conductivity of the wastewater system in real time. The values ​​were calculated, and the normalized conductivity attenuation deviation was used. As a control input; the pulse duty cycle of the magnetic field generator. Based on conductivity attenuation deviation Real-time mapping is performed, and its mapping logic satisfies the following mathematical expression: ,in, The pulse duty cycle of the intermittent pulsed magnetic field; The duty cycle of the reference pulse is set to a value of [value to be filled in]. ; To adjust the gain constant, the value is set to... ; This refers to the deviation in conductivity decay; when the system detects that the decay is due to the formation of a passivation film by oily organic matter at the adsorption interface. The value is from Growth to At that time, the pulse duty cycle output by the formula calculation From the initial Automatically adjusted to This increase in value prolongs the single-cycle conduction time of the power conversion circuit within the magnetic field generator, enhancing the Lorentz force scouring intensity experienced by the nano-active materials within the hierarchical channels. At this point, the mechanical stress generated by the nano-active materials under strong magnetic field oscillation exceeds the interfacial bonding energy between the grease passivation layer and the carbon substrate, causing the passivation film to physically fracture and peel off with the water flow. This restores the lead ion adsorption rate, which was initially reduced due to interfacial barrier, to its initial rated rate. This achieves closed-loop self-healing of drug adsorption efficiency under complex working conditions.

[0040] Example 5: During the on-site deployment of wastewater treatment facilities in an electroplating industrial park, to determine the expected adsorption rate baseline required for the control algorithm, the system executed an adsorption kinetics background calibration procedure. 1.00 g of pyrolysis product was weighed and added to 1000.0 mL of wastewater to be treated. Under conditions of zero magnetic field strength and a constant stirring speed of 200.0 rpm, the conductivity value was recorded for the first 30.0 min. The slope of the conductivity change over time was calculated through linear regression analysis, and the absolute value of this slope was stored in the storage unit as the expected adsorption rate. Initial assignment, conductivity decay deviation The following calculation formula must be satisfied: ,in, The deviation of conductivity decay; The expected adsorption rate is expressed in units of... ; This represents the real-time rate of change of conductivity, in units of... .

[0041] When the system encounters a new operating condition with significant fluctuations in the concentration of colloidal organic matter, it executes a magnetic field response sensitivity calibration procedure, recording the rate of change of conductivity in response to the pulse duty cycle by altering the magnetic induction intensity of the magnetic field generator. The response amplitude, during the calibration process, the magnetic induction intensity is changed from by The step size was increased to Response characteristic curves were established and the critical duty cycle value for the micro-vibration shear force to break through the binding energy of the gel passivation layer was determined, which was then used as the reference pulse duty cycle in the closed-loop control logic. The pulse duty cycle of an intermittent pulsed magnetic field Satisfy the following mathematical expression: ,in, This refers to the duty cycle of the magnetic field pulse. To adjust the gain constant; The reference pulse duty cycle; this process achieves matching between the power conversion frequency output by the magnetic field generator and the physical characteristics of the pollutants; reference pulse duty cycle With adjustment of gain constant The established procedure is: under constant magnetic induction intensity... to Fixed value within Tesla range and with The pulse duty cycle is gradually increased in stages to collect the rate of change in conductivity of the wastewater system. The data is used to determine the critical duty cycle starting point when the rate of change of conductivity changes from a downward trend to a stable or upward trend. The critical duty cycle is then set. to The duty cycle of the reference pulse is 10 times. Deviation in conductivity attenuation Under conditions of step change, adjust the adjustment gain constant. To restore the system adsorption rate to its rated value The above response time is controlled within to A deterministic mapping relationship between the output power of the intermittent pulsed magnetic field and the passivation film formation rate was established over a time interval of minutes.

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wastewater adsorption and purification method using modified cyanobacterial biochar-supported nanomaterials, comprising the following steps: Step S101: The cyanobacterial biomass is pulverized to obtain cyanobacterial powder; Step S102: Immerse the cyanobacterial powder in a solution containing a precursor of nano-active substances, and perform ultrasonic dispersion and solid-liquid separation to obtain a cyanobacterial matrix loaded with the precursor. Step S103: The cyanobacterial matrix loaded with the precursor is placed under an inert atmosphere to perform the following step-by-step pyrolysis procedure: The first stage is... / min to Heating rate of / min to Within this temperature range, the temperature is maintained, and the instantaneous expansion pressure generated by the decomposition of endogenous lipid components in the precursor-loaded cyanobacterial matrix is ​​used to scour and generate a hierarchical pore structure within the carbonized framework; the second stage involves heating to... to The graphitization transformation is performed to induce a thermochemical reaction between the nitrogen-containing polysaccharide components in the carbonized framework and the nano-active materials, thereby generating a heteroatom-doped modification layer in situ on the surface of the hierarchical pore structure. In step S104, the pyrolysis products generated in step S103 are added to the wastewater system, and an intermittent pulsed magnetic field is applied using a magnetic field generator. The electrostatic selectivity of the heteroatom-doped modification layer on wastewater ions is used to block non-target interfering ions and guide target heavy metal ions into the hierarchical pore structure. The asynchronous thermal expansion displacement difference between the nano-active material and the carbonized framework under the action of the intermittent pulsed magnetic field generates micro-vibration shear force at the adsorption interface, peeling off the passivation film deposited on the surface of the pyrolysis products.

2. The wastewater adsorption and purification method according to claim 1, characterized in that, The stepped heating pyrolysis process executed in step S103 also includes a cooling process after the holding period, wherein the cooling process is performed by... / min to Cooling at a rate of / min is used to maintain the geometric stability of the hierarchical pore structure and limit the particle size of the nano-active material.

3. The wastewater adsorption and purification method according to claim 1, characterized in that, The precursor of the nano-active material in step S102 includes one or more of zero-valent iron salt, manganese sulfide salt or nano-metal oxide salt; step S103 limits the distribution density of active sites in the heteroatom doped modification layer by adjusting the molar ratio of nitrogen to nano-active material in the cyanobacterial matrix loaded with precursor.

4. The wastewater adsorption and purification method according to claim 1, characterized in that, The magnetic induction intensity of the intermittent pulsed magnetic field in step S104 is T to T, pulse frequency is Hz to Hz.

5. The wastewater adsorption and purification method according to claim 1, characterized in that, The method for selecting the temperature range in the first stage of step S103 is as follows: obtain the thermogravimetric change curve of cyanobacterial biomass, and set the maximum weight loss peak temperature of the lipid component decomposition rate in the thermogravimetric change curve as the center temperature of the heat preservation stage.

6. The wastewater adsorption and purification method according to claim 1, characterized in that, The heteroatom-doped modification layer includes an electron cloud shift structure formed by co-doping of biogenic nitrogen and phosphorus. The electron cloud shift structure acts as an interface electron donor to slow down the oxidation rate of nano-active materials.

7. The wastewater adsorption and purification method according to claim 1, characterized in that, Step S101 also includes deashing the cyanobacteria powder with an inorganic acid solution.

8. The wastewater adsorption and purification method according to claim 1, characterized in that, In step S104, the conductivity value of the wastewater system is obtained through a monitoring device during the wastewater purification process, and the pulse duty cycle of the magnetic field generator is adjusted according to the rate of change of the conductivity value over time.

9. The wastewater adsorption and purification method according to claim 1, characterized in that, The selective adsorption performance of heteroatom-doped layers for target heavy metal ions is determined by the selectivity coefficient. Evaluation, selectivity coefficient Satisfy the following formula: ,in, This represents the equilibrium adsorption capacity of the pyrolysis products for the target heavy metal ions. This represents the equilibrium concentration of the target heavy metal ions in the wastewater. This represents the equilibrium adsorption capacity of the pyrolysis products for interfering ions. This represents the equilibrium concentration of interfering ions in the wastewater.

10. The wastewater adsorption and purification method according to claim 1, characterized in that, After purification, the pyrolysis products are separated by magnetic separation and then regenerated. During the regeneration process, micro-fluid disturbances are induced inside the hierarchical pore structure by intermittent pulsed magnetic field.

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