227 results about "Zerovalent iron" patented technology

The present invention discloses a sulfurized nano zero-valent iron material, its preparation method and application, including: a core-shell structure sulfurized nano zero-valent iron material and a preparation method, the inner core of the sulfurized nano zero-valent iron is zero-valent iron, and the outer shell is Fe9S 10 , calculated by the mass of the sulfurized nano zero-valent iron, the mass percentage of zero-valent iron is 70-80%, and the mass percentage of the iron sulfide is 20-30%; the preparation method includes: placing iron powder in an H2S gas atmosphere for calcination, after the calcination is completed, cooling to room temperature to obtain the sulfurized nano zero-valent iron material. This material can be used for in-situ remediation of chlorinated hydrocarbon organic pollutants in groundwater. Compared with the prior art, the prepared sulfurized nano zero-valent iron is less likely to be oxidized and can overcome the problem of rapid passivation of nano zero-valent iron during the remediation process.

The invention provides nitrogen / sulfur co-doped charcoal loaded nano zero-valent iron as well as a preparation method and application thereof, and relates to the technical field of sewage treatment. The nitrogen / sulfur co-doped biochar loaded nano zero-valent iron is a composite material prepared by taking nitrogen / sulfur co-doped biochar as a carrier material and loading nano zero-valent iron; the nitrogen / sulfur co-doped biochar is prepared from the following raw materials: melamine, diphenyl disulfide and walnut shells. The nitrogen / sulfur co-doped biochar loaded nano zero-valent iron prepared by the invention combines the porous characteristic of biochar and the high reaction activity of nano zero-valent iron, not only has excellent oxidation resistance and corrosion resistance, but also retains good hydrophilicity and magnetism, can efficiently remove antibiotic pollutants in the environment, and has a good application prospect. And actual operation and recycling are facilitated.

The invention belongs to the technical field of wastewater treatment, and particularly relates to a composite material as well as a preparation method and application thereof. According to the composite material, blended hydrogel of sodium alginate and polyvinyl alcohol is used as a matrix, zeolite molecular sieves, activated charcoal and zero-valent iron particles are embedded into the matrix to form microspheres, sulfate reducing bacteria are immobilized on the surfaces of the microspheres, the composite material is directly added into a mine water anaerobic reactor, the sulfate radical removal rate exceeds 92%, and the sulfate radical removal rate exceeds 92%. Heavy metals such as Cu, Pb and Cr in the mine water can be synchronously precipitated, and the treatment efficiency and stability of the anaerobic system are remarkably improved.

The invention relates to the technical field of environmental pollution control, in particular to application of grass acidified zero-valent iron in in-situ remediation of organic polluted underground water. According to the preparation method, oxalic acid and micron zero-valent iron are evenly mixed and then subjected to ball milling treatment, oxalic acid zero-valent iron of a core-shell structure is obtained through post-treatment, the oxalic acid zero-valent iron has high electron transfer efficiency, Fe < 2 + > / Fe < 3 + > circulation is further regulated and controlled through oxalic acid coordination in the oxalic acid zero-valent iron, interface electron transfer is enhanced, and the preparation method is suitable for industrial production. Peroxyacetic acid is promoted to be activated to generate various active oxygen species, and efficient degradation of organic pollutants is achieved. The invention solves the problems of low zero-valent iron electron transfer efficiency, single active oxygen species, secondary pollution of iron sludge and the like in the process of degrading organic pollutants by using the existing zero-valent iron advanced oxidation technology.

The invention discloses a preparation method and application of phytic acid modified zero-valent iron. The method comprises the following steps: (1) mixing phytate and liquid phytic acid according to a molar ratio of (5: 5)-(8: 2), and preparing a buffer solution with the concentration of 0.05-0.5 mol / L; (2) adding micron or nano zero-valent iron into a buffer solution according to a solid-to-liquid ratio of 1: 10 to 1: 50 (g / mL), and transferring to a polytetrafluoroethylene reaction kettle; (3) under the protection of nitrogen, reacting for 6-48 hours under the conditions that the temperature is 20-80 DEG C and the oscillation rate is 100-1000 rpm, and controlling the pH value to be 3.5-5.5; and (4) after the reaction, carrying out suction filtration, ethanol-water alternate washing and vacuum drying to prepare the modified zero-valent iron with the surface coated with the phytic acid iron complex. A stable chelation layer is formed on the surface of phytic acid molecules and zero-valent iron, the oxidation resistance, dispersity and heavy metal adsorption capacity of the material are remarkably improved, and the material is suitable for efficient repair of industrial wastewater.

The invention belongs to the technical field of water treatment, and particularly relates to a method for regulating and controlling a nanoscale zero-valent iron shell structure to enhance the reaction activity of the nanoscale zero-valent iron shell structure. The carbon-doped nano zero-valent iron is of a core-shell structure; the carbon-doped nanoscale zero-valent iron comprises a nanoscale zero-valent iron core with carbon gradient doping and an iron carbide shell layer located on the surface of the nanoscale zero-valent iron core. By means of collision between grinding balls and material (Fe and C) particles, deformation and crushing of the ground material particles are achieved through friction force, shearing force, tension and the like, an oxidation shell layer of nanoscale zero-valent iron is broken, Fe < 0 > is exposed on the surface of the material and further doped with activated carbon to form an iron carbide shell layer to construct Fe-C double-active sites, the reaction activity of the material is improved, and the service life of the material is prolonged. The reducibility and electron transfer capability of the nZVI are effectively improved, meanwhile, after the nZVI is subjected to the action of mechanical force, the lattice spacing of the nZVI is increased, the material property is changed, and the removal efficiency of the nZVI to pollutants is further improved.

The invention relates to the technical field of wastewater treatment and resource recovery, and discloses an organophosphorus degradation and recovery system based on double-cathode electro-Fenton reaction, comprising: an electrolytic tank for accommodating organophosphorus wastewater to be treated; the anode is arranged in the electrolytic tank and is electrically connected with an anode of a power supply; the oxidizing agent generating cathode is arranged in the electrolytic tank and is used for generating hydrogen peroxide in situ under a power-on condition; the metal reduction cathode is arranged in the electrolytic tank and is used for adsorbing and reducing ferric ions; the metal source is composed of zero-valent iron or iron alloy, is not directly and electrically connected with the power source, and is arranged in an electric field acting area established by the anode and the at least one cathode. Through the design of inductive slow-release iron supply and double-cathode collaborative circulation, a series of problems of uncontrollable iron ion release, high iron sludge yield, low catalyst utilization efficiency, difficulty in resource recovery and the like in the traditional electro-Fenton technology are effectively solved.

According to the red mud-based composite material and the preparation method and application thereof, bentonite, red mud and biomass are mixed in a proper amount of water according to the mass ratio of 1: 1: (1-10), and first suspension liquid is formed; drying the first suspension to obtain a precursor of the red mud-based composite material; the precursor is subjected to a carbon thermal reaction at 300-700 DEG C, ferric oxide in the red mud is converted into zero-valent iron, and the red mud-based composite material is obtained. The red mud is alkaline and promotes manganese ions to form insoluble precipitates, the unique structure and ion exchange capacity of the bentonite can effectively solidify the manganese ions, the biomass has a high specific surface area and a developed pore structure, and the manganese ions are physically adsorbed through Van der Waals' force and pore interception; ferric oxide in the red mud is converted into zero-valent iron in the carbothermal reaction process, and the zero-valent iron can catalytically oxidize ammonia nitrogen, so that the red mud-based composite material synchronously solves the problem of combined pollution of manganese and ammonia nitrogen in the soil.

The invention provides a method for removing nitrate in water by using a modified zero-valent iron aerogel electrocatalyst, which comprises the following steps: preparing a mixed solution of ferrous sulfate and sodium sulfide, preparing a sodium borohydride solution, mixing and magnetically stirring the mixed solution and the sodium borohydride solution to obtain black colloid, and finally obtaining vulcanized zero-valent iron aerogel, dispersing the obtained sulfurized zero-valent iron aerogel and a Nafion solution in absolute ethyl alcohol to prepare a catalyst mixed solution; potassium nitrate and potassium hydroxide are dissolved in a pure water solution to serve as electrolyte, a sulfurized zero-valent iron aerogel electrode is used as a cathode, a platinum sheet is used as an anode, a mercuric oxide electrode is used as a reference electrode, and an electrocatalytic reduction reaction is carried out by using a three-electrode system. The technology not only can improve the efficiency of water nitrate pollution treatment, but also conforms to the concept of green and low-carbon development, and has a wide environment application prospect.

The invention provides a biochar-zero-valent iron enhanced bentonite-based vertical barrier material for combined polluted underground water, which comprises sodium modified calcium bentonite and sandy soil, and also comprises biochar and slow-release zero-valent iron particles, and the slow-release zero-valent iron particles are formed by mixing and stirring micron-sized zero-valent iron and sodium alginate. Related preparation methods and uses are also provided. The anti-seepage performance of the biochar-zero-valent iron enhanced bentonite-based vertical barrier material for combined polluted underground water meets the anti-seepage requirement that the permeability coefficient is lower than 10 <-9 > cm / s under the stress of heavy metal, chlorinated hydrocarbon and micro-plastic combined polluted underground water, heavy metal can be effectively reduced and precipitated, chlorinated hydrocarbon is dechlorinated, and micro-plastic is adsorbed; therefore, the concentration of composite pollutants in underground water is reduced, and the long-acting performance of the vertical barrier material is improved.

The present invention discloses a biochar-supported rhamnolipid-coated nano-zero valent iron modified material, its preparation method and application. The modified nano-zero valent iron material includes biomass carbon, rhamnolipid and nano-zero valent iron. The rhamnolipid is modified on the surface of the nano-zero valent iron and loaded on the biomass carbon. The mass ratio of nano-zero valent iron, rhamnolipid and biochar is 1:0.05-0.2:0.5-2. The preparation method is to mix the rhamnolipid solution with the ferrous sulfate solution, then mix with the biomass carbon, and dropwise add the NaHB4 solution for reaction to obtain the modified nano-zero valent iron material. The biochar-supported rhamnolipid-coated nano-zero valent iron material of the present invention has the advantages of good stability, high reaction activity, strong dispersion performance, etc. It has good removal efficiency for the chlorinated flame retardant dechlorane in the environment and will not cause secondary pollution, and has potential good application value and broad application prospects in the field of organic polluted soil and water treatment.

The invention relates to the technical field of environmental engineering, and particularly discloses an underground water remediation and activity monitoring system based on a zero-valent iron-based nano material, which comprises composite nano particles consisting of a zero-valent iron core, a ferrous sulfide / humic acid dynamic compensation layer and a temperature-sensitive polymer, through a crack self-adaptive regulation and control module driven by a sensor array and a temperature difference driving migration module based on an underground water temperature gradient, the system can realize automatic circulation of selective adsorption, desorption and degradation of pollutants under different temperature conditions through the combined action of a phase change behavior of a temperature-sensitive polymer and a dynamic compensation layer; the stability and the repair efficiency of the nanoparticles are improved; compared with a traditional scheme, the method has the advantages that on-demand response activity adjusting capacity and an accurate injection path guiding mechanism are achieved, the technical bottlenecks that in the groundwater heterogeneous environment, migration of a repairing agent is uncontrollable, and adsorption selectivity is poor are avoided, and good engineering adaptability and practical application prospects are achieved.

The invention discloses a preparation method and application of modified zero-valent iron based on wet ball milling, and the preparation method is characterized by comprising the following steps: pre-mixing commercially available zero-valent iron powder and a transition metal salt solution, introducing into a crowbar type high-energy ball mill for ball milling, and eluting an aqueous solution to obtain the modified zero-valent iron. The transition metal salt is a salt in which a transition metal is a main metal component, such as a Co salt, an Ni salt, or a Cu salt. The concentration in the solution is 0.01-1.00 mol / L according to the amount of substance concentration, and the concentration of the zero-valent iron in the solution is 1-500 g / L according to the solid-to-liquid ratio. The obtained wet ball-milling modified zero-valent iron can be applied to removal of (similar) metal pollutants in industrial wastewater. The prepared zero-valent iron has high reaction activity, compared with traditional zero-valent iron, the rate of removing metal and metalloid pollutants in industrial wastewater can be increased by 30-600 times, and the zero-valent iron has the advantages of being easy and convenient to operate, capable of achieving large-scale production, low in pollutant treatment cost and the like.

The invention discloses a submicron sphere soil remediation material as well as a preparation method and application thereof. The remediation material takes modified silicon dioxide as an inner core, nano zero-valent iron as a middle layer and aluminum oxide as an outer layer; the mass ratio of the inner core to the middle layer to the outer layer is (30-50): (20-40): (10-50). The remediation material synthesized through the method has the advantages of being good in soil compatibility, high in cyclic utilization rate, high in heavy metal removal efficiency and the like, and the target of low-energy-consumption remediation of the heavy metal contaminated soil can be achieved.

The invention discloses an iron-carbon composite material for heavy metal contaminated soil remediation and a preparation method of the iron-carbon composite material, and belongs to the field of heavy metal contaminated soil remediation. The iron-carbon composite material comprises rape straw, hydroxyapatite, zero-valent iron, sulfydryl functionalized magnetic cerium oxide and nitrogen-doped graphene quantum dot-sodium alginate. The sulfydryl-functionalized magnetic cerium oxide is prepared from cerium nitrate and ferric nitrate through precipitation, calcination and sulfhydrylation, and the nitrogen-doped graphene quantum dot-sodium alginate is prepared from citric acid and urea through microwave reaction, dialysis, mixing and freeze drying; the preparation method comprises the following steps: treating straws and hydroxyapatite to obtain ball-milled phosphorus-containing biochar, mixing the ball-milled phosphorus-containing biochar with zero-valent iron and two modifiers, and carrying out molding and high-temperature calcination to obtain the phosphorus-containing biochar-based composite material. The material has a remarkable remediation effect on the heavy metal contaminated soil, can effectively reduce the activity of heavy metals in the soil, has the characteristics of environmental friendliness and high stability, and is suitable for treating the soil compositely contaminated by the heavy metals such as cadmium and lead.

The invention discloses a thickening suspending agent containing modified attapulgite and application of the thickening suspending agent, and belongs to the technical field of thickening suspending agents. After acidification treatment, the content of impurities on the surface of attapulgite is reduced, the surface area and the porous property are increased, the load rate of zero-valent iron can be increased, and the utilization rate of the zero-valent iron is increased. Zero-valent iron is uniformly loaded on tubular pore channels or the surface of attapulgite in the form of nano-particles, so that the surface roughness of the composite powder is increased, stronger steric hindrance can be formed around pesticide particles, and the pesticide particles are prevented from being gathered and enlarged due to collision, so that sedimentation is reduced, and the composite powder has good suspension property and dispersity; the load of zero-valent iron can endow the thickening suspending agent with the heavy metal chelating capability; through two times of intercalation treatment, the modified zero-valent iron composite attapulgite powder can be uniformly loaded between graphene oxide layers, the graphene oxide can assist the dispersion of the attapulgite to avoid agglomeration, and the existence of the graphene oxide can improve the thermal stability of the thickening suspending agent.

The invention relates to a biochar-loaded nano zero-valent iron material as well as a preparation method and application thereof. The biochar loaded nano zero-valent iron material comprises biochar and nano zero-valent iron particles uniformly loaded on the surface and in pore channels of the biochar; the nano zero-valent iron particles have a core-shell structure; the biochar loaded nano zero-valent iron material is prepared by mixing biomass powder and iron mud powder and then pyrolyzing the mixture under a high-temperature condition. The biochar loaded nano zero-valent iron material is mixed with organic contaminated soil in situ, and the mixture is left to stand, so that organic pollutants can be degraded. Compared with the prior art, the biochar-loaded nano zero-valent iron material has the advantages that biomass and treated waste iron mud are subjected to co-pyrolysis reaction, so that the biochar and zero-valent iron are fully combined, and a unique porous structure and a core-shell structure are formed; and finally, in-situ efficient remediation of the new pollutant perfluorinated compound of the soil system is realized.

The invention discloses a preparation method of a granular iron-based biochar material. The preparation method comprises the following steps: a, performing acid pickling on a waste biomass raw material, and performing drying and crushing to obtain biomass raw material powder; b, immersing the biomass raw material powder obtained in the step a into an iron salt solution, filtering and drying to obtain an iron-loaded biomass raw material; c, mixing and granulating the iron-loaded biomass raw material obtained in the step b, an adhesive, an expanding agent and water, and drying to obtain a material precursor; and d, pyrolyzing the material precursor obtained in the step c in an inert atmosphere to prepare the granular iron-based biochar material. According to the granular iron-based biochar material prepared by the method, aggregation of metal nanoparticles can be effectively reduced, effective load of zero-valent iron is improved, the removal rate of chlorinated hydrocarbon is improved, and meanwhile, the granular material solves the problems that a powder material is easy to corrode and passivate and gaps are blocked; the method can be used for repairing the chlorohydrocarbon polluted soil-underground water.

The invention belongs to the technical field of underground water pollution remediation functional catalytic materials and water treatment, and particularly relates to a modified iron heterojunction biomass slow-release material, a preparation method thereof and application of a coupled electric field in underground water organic pollutant remediation. The mushroom biochar is used as a carrier to load the modified zero-valent iron, so that the problem of iron agglomeration is effectively relieved; and the modified zero-valent iron grows in the three-dimensional pore channel of the charcoal in situ, so that the slow release of the iron active component can be realized, and the utilization efficiency of the oxidizing agent is improved. An electric field is built in the iron-carbon structure reinforcing material, so that the problem of slow mass transfer in an underground water medium is solved, and the surface accessibility of an oxidizing agent and pollutants is improved. The material not only can reduce the invalid consumption of an oxidizing agent caused by overhigh local Fe < 2 + > concentration, but also can drive directional electron migration through an electric field, realizes space-time matching and dynamic regulation and control of an electron transfer rate and an iron supply rate, forms an in-situ regeneration closed-loop system, and has a good application prospect in groundwater remediation.

The present invention provides a heavy metal adsorption material in soil and a preparation method thereof. The method comprises the following steps: preparing a nanometer zero-valent iron dispersion; adding PVA to water for swelling; adding the nanometer zero-valent iron dispersion and stirring to obtain an electrospinning solution; performing electrospinning; drying to obtain a nanometer iron skeleton; preparing a NaOH-urea aqueous solution; pre-cooling, adding microcrystalline cellulose and stirring, and then adding a polyether-type gemini surfactant and stirring evenly; centrifuging to obtain a supernatant; taking the nanometer iron skeleton and placing it in a mold, slowly pouring the supernatant until the nanometer iron skeleton is submerged, and gelling reaction; aging, vacuum freeze drying; placing in a carbonization furnace and sintering. The present invention adopts a nanometer iron skeleton, which can form a fully flowing nanochannel in the aerogel after sintering, not only greatly increasing the specific surface area, but also enabling the flowable channels to quickly and more abundantly adsorb heavy metal ions; at the same time, the nanometer iron skeleton can also effectively enhance the frame structure of the aerogel and prevent the collapse of the aerogel.

This invention discloses a method for the simultaneous preparation of micronized and stabilized zero-valent iron (ZVFe) based on ball milling with terephthalic acid, belonging to the field of groundwater pollution remediation materials. The method includes the following steps: 1) incorporating terephthalic acid into micron-sized ZVFe powder and mechanically ball milling it; 2) cleaning the material with a solvent and drying it to obtain micronized and stabilized ZVFe reducing material. This invention simultaneously achieves the micronization and stabilization of ZVFe. This method enhances the reducing activity, internal surface hydrophobicity, and electron selectivity of ZVFe materials, improves their reducing performance and electron selectivity for pollutants such as halogenated hydrocarbons and heavy metals, effectively inhibits the oxidative deactivation of ZVFe materials in the aquatic environment and the hydrogen evolution side reaction with water, enabling ZVFe materials to maintain high reducing activity stably in water for a long period. This invention solves the technical problems of poor stability and difficult storage of micronized ZVFe materials in water, which is beneficial for reducing material replacement frequency and resource consumption.

This invention relates to a modified zero-valent iron / biochar composite material with oxygen-rich vacancies and its application. The modified zero-valent iron / biochar composite material comprises a biochar carrier and zero-valent iron loaded on the biochar carrier. The surface of the zero-valent iron is coated with sulfur-containing iron compounds and / or boron-containing iron compounds, and the surface of the zero-valent iron contains abundant oxygen vacancies. The modified zero-valent iron / biochar composite material is specifically prepared by the following method: dispersing the biochar carrier and zero-valent iron in oxygen-free water and grinding; adding a sulfur source or boron source to the ground suspension, stirring and grinding thoroughly, and drying; subsequently soaking in a reducing solution, followed by high-temperature calcination and cooling to obtain the modified zero-valent iron / biochar composite material. Compared with the prior art, the modified zero-valent iron / biochar composite material prepared by this invention can be used synergistically with compound oxidants to achieve effective remediation of organically contaminated soil.

The present application belongs to the technical field of wastewater treatment, and relates to a method for pretreating coking wastewater by zero-valent iron process combined with ultrasonic-flocculation method, comprising the following steps: 1) the wastewater is subjected to heating and ultrasonic degradation treatment; 2) air is introduced into the wastewater after ultrasonic degradation, and a composite flocculant, iron filings and coal-based acicular coke powder are sequentially added, and ultrasonic stirring and standing and sedimentation are performed to complete the pretreatment. The present application provides a method for pretreating coking wastewater by zero-valent iron process combined with ultrasonic-flocculation method, which effectively removes pollutants in the coking wastewater, improves the subsequent biodegradability of the wastewater, has low implementation cost, and has large-scale popularization and application value.

The utility model discloses a groundwater remediation module based on osmotic oxidation, which belongs to the technical field of environmental remediation and comprises a water-resisting layer, a remediation mechanism is slidably connected to the inner side of the water-resisting layer, and quick release mechanisms are arranged on two sides of the water-resisting layer. The remediation mechanism can be conveniently and independently replaced when the reaction medium zero-valent iron, activated carbon particles and limestone are subjected to performance reduction, failure and the like due to long-time use, the whole remediation module does not need to be disassembled on a large scale, the maintenance cost and difficulty are effectively reduced, continuous and efficient development of underground water remediation work is guaranteed, and the remediation efficiency is improved. When the repair mechanism needs to be integrally overhauled and replaced or parts such as an internal filtering frame need to be deeply maintained, the repair mechanism can be quickly detached from the water-resisting layer through the quick detaching mechanism, so that the time and the labor cost are greatly saved, and the maintainability and the use flexibility of the whole underground water repair module are improved.

The application discloses a Ce2S3@Fe composite material and a preparation method and application thereof, and belongs to the technical field of radioactive wastewater treatment, and the preparation of the Ce2S3@Fe composite material comprises the following steps: under the protection of inert gas, cerium sulfide is added into a ferric iron solution, and then a sodium borohydride solution is slowly added dropwise, so that the ferric iron is reduced to zero-valent iron by using the reducing property of the sodium borohydride solution and is uniformly loaded on the surface of the cerium sulfide, thereby forming the Ce2S3@Fe composite material; and the prepared Ce2S3@Fe composite material is applied to purification of uranium-containing wastewater. 2+ The application adopts the above Ce2S3@Fe composite material, the preparation method and the application thereof, and has the advantages of convenient operation, low cost, environmental friendliness, fast reduction rate, long UO2 stabilization time, all-weather operation, simultaneous consideration of radioactive wastewater treatment and uranium resource recovery.

The invention relates to preparation of graphene-loaded nano zero-valent iron and application of the graphene-loaded nano zero-valent iron in chromium-containing wastewater treatment. The preparation method comprises the following steps: preparing 60mL of a KBH4 solution with the concentration of 0.5 mol / L as a solution A and 60mL of a FeSO4. 7H2O solution with the concentration of 0.1 mol / L as a solution B, adding 0.25 g of a single-layer graphene oxide dispersion liquid into the solution B, stirring for 30 minutes, recording as a solution C, slowly dripping the solution A into the solution C, performing suction filtration separation on powder C, and drying to obtain nZVI-coated GO. The graphene is loaded with nZVI to adsorb chromium in chromium-containing wastewater, and nZVI-GO-Cr formed after wastewater treatment can be used as an auxiliary tanning agent for leather tanning or retanning sections and has good recyclability.

The present invention discloses a method for enhancing methane production and carbon sequestration in anaerobic digestion by zero-valent iron in cooperation with exogenous CO2. The method includes: inoculating sludge in a reactor, adding zero-valent iron thereto, and then adding wastewater. The reaction temperature is maintained at 35 ± 1 °C, and CO2 is injected into the liquid surface at a flow rate of 1.5 L / min for 5 - 50 min / L under stirring. CO2 and zero-valent iron jointly regulate the pH of the system, providing a suitable anaerobic digestion environment for microorganisms. Through the corrosion reaction of zero-valent iron under anaerobic conditions, electrons are released and H2 is generated, stimulating the proliferation of hydrogen-consuming microorganisms, while improving the activity of microorganisms and enzymes, increasing the methane production and rate. In addition, some methanogens in the system utilize H2 and CO2 to produce amorphous carbon, and zero-valent iron and exogenous CO2 are used to regulate the growth of amorphous carbon, strengthening the fixation of CO2 in the system.

The invention belongs to the field of environmental governance materials, and relates to a composite material for repairing heavy metal pollutants as well as a preparation method and application thereof. The technical problems that in the prior art, although modified Schwertmannite can synchronously remove arsenic and cadmium, the cadmium removal capacity is still weak, and a single sulfur modified zero-valent iron-based material is low in reaction activity and selectivity are solved. The invention provides a composite material for repairing heavy metal pollutants, the composite material comprises Schwertmannite and sulfur-doped zero-valent iron, the mass ratio of the Schwertmannite to the sulfur-doped zero-valent iron is (0.05-10): 1, the heavy metal pollutants arsenic, cadmium and lead can be synchronously removed, and the adsorbing capacity of cadmium and lead is increased. The invention further provides a preparation method of the composite material, elemental sulfur and zero-valent iron are subjected to ball milling and mixing, and sulfur-doped zero-valent iron is obtained; the composite material for repairing the heavy metal pollutants is obtained by ball-milling and mixing with the Schwertmannite, and the ball-milling modification method is simple, convenient, feasible, efficient and pollution-free. Meanwhile, the invention further provides application of the composite material for repairing the heavy metal pollutants in repairing an arsenic-cadmium-lead heavy metal polluted environment.

The application discloses a nano zero-valent iron modified hemicellulose biochar composite material and a preparation method and application thereof. The preparation method comprises the following steps: mixing xylan raw materials and iron oxide, performing ball milling treatment, and then performing a carbothermic reduction process in a microwave pyrolysis device under a nitrogen protection atmosphere and a constant temperature condition, so as to obtain the nano zero-valent iron modified hemicellulose biochar material after cooling. The composite material is prepared by using the above preparation method. The composite material is applied to purification treatment of polluted wastewater containing chlorinated hydrocarbons. The composite material has low raw material cost, simple preparation method, can form stable structure pores, has good adsorption performance and catalytic activity, realizes molecular dispersion of zero-valent iron in a hemicellulose biochar matrix, and improves adsorption and reduction capacity of the composite material on chlorinated hydrocarbon pollutants.

The application provides a phosphorus modified zero-valent iron catalytic material, a preparation method, a remediation agent and application. 3‑ The phosphorus modified zero-valent iron catalytic material is obtained, wherein the particle size of the zero-valent iron is micron level. The preparation method of the application can be completed in an air atmosphere, and does not need high temperature, vacuum or addition of toxic chemical reagents. The preparation process only involves physical mixing and mechanical ball milling, the equipment requirement is simple, the operation is convenient, the energy consumption is low, the dual benefits of environmental governance and ecological restoration are combined, and the green and sustainable development environmental governance concept is met.