47 results about "Chromium contamination" patented technology

The invention provides a remediation method for hexavalent chromium polluted underground water, and relates to the technical field of water treatment. According to the preparation method, rice hulls are adopted as raw materials and treated through an oxygen-limited pyrolysis-ferric salt dipping composite technology, and the rice hull-based iron-rich biochar material is obtained; loading microorganisms with the rice hull-based iron-rich biochar material to obtain an adsorption material; the adsorption material is used for carrying out adsorption treatment on the hexavalent chromium-containing polluted underground water. Aiming at Cr (VI) polluted underground water, a prepared rice husk-based iron-rich biomass material is adopted to load domesticated soil indigenous microorganisms, and the domesticated soil indigenous microorganisms are added into a nearly neutral Cr (VI) polluted soil / underground water reaction system, so that efficient reductive degradation of Cr (VI) is realized, and the influence mechanism of Fe < 3 + > is explored.

The invention discloses a remediation agent for high-concentration hexavalent chromium polluted soil and a preparation method and a remediation method thereof, and belongs to the technical field of soil pollution remediation. The remediation agent for the high-concentration hexavalent chromium contaminated soil comprises an acidic precursor, an iron-sulfur reducing agent and a synergist, the acidic precursor comprises organic acid and propylene glycol alginate; the iron-sulfur reducing agent comprises an iron-based reducing agent and a sulfur-based reducing agent; the synergist is prepared from sophorolipid and alkyl glucoside. The remediation agent can be used for high-concentration hexavalent chromium contaminated soil, hexavalent chromium in the soil is exposed in a Cr < 6 + > ion form as much as possible by replacing the hexavalent chromium in the soil, then the hexavalent chromium is converted into trivalent chromium by using a reducing agent, and the removal efficiency of the hexavalent chromium reaches up to 99.6%. In addition, the soil remediation agent is simple in use mode, rapid and thorough in reaction and lasting in effect.

The present application provides a remediating agent and a remediation method for hexavalent chromium contaminated soil, which relates to the field of treatment and remediation of contaminated soil. Based on 100% by mass, the raw materials of the remediating agent for hexavalent chromium contaminated soil include: 25%-40% of photoinitiator, 5%-10% of organic acid, and 50%-65% of water; the photoinitiator includes polyethylene glycol. The remediating agent for hexavalent chromium contaminated soil can in-situ reduce hexavalent chromium in the soil to trivalent chromium. The organic acid can reduce the soil pH value, alleviate soil salt damage, improve the soil environment, and promote crop growth; polyethylene glycol and the organic acid can also act as stabilizers to prevent trivalent chromium in the soil from being oxidized to hexavalent chromium. Using this remediating agent to treat chromium contaminated soil has simple equipment requirements, is easy to use, has low costs, high remediation efficiency, low operating costs, does not produce secondary pollution, and has broad prospects for popularization and application.

The present application relates to the technical field of groundwater pollution remediation, and particularly relates to a method and device for in-situ remediation of hexavalent chromium contaminated groundwater, wherein the device comprises a multifunctional well group, a medicament supply system, an aeration system, a monitoring system and a control system; the multifunctional well group comprises a plurality of multifunctional wells; the medicament supply system is used for pretreating medicaments, modified composite reducing agents and composite functional bacteria liquid respectively; the control system is used for receiving monitoring data; the control system is also used for displaying monitoring data and equipment operating states, and setting operating parameters by a user; the control system is also used for automatically adjusting medicament dosing amount, aeration flow and aeration pressure according to monitoring data and operating parameters set by the user. Through the design of the multifunctional well group, the medicament supply system and the aeration system, the hexavalent chromium contaminated groundwater can be simultaneously subjected to chemical reduction, biological reinforcement and adsorption fixation, so that the three processes are coordinated to realize rapid, efficient and long-acting remediation of the hexavalent chromium contaminated groundwater.

The invention provides a chromium-polluted aquifer in-situ layered injection remediation method based on a response curved surface. The method comprises the following steps that a prediction model is constructed based on a response curved surface method, optimal agent parameters are predicted, pilot test verification is conducted based on the predicted optimal agent parameters, and the optimal pilot test agent injection amount is determined; establishing a relational expression between the agent injection concentration and the initial concentration of the underground water Cr (VI) based on the theoretical agent dosage, the adsorption capacity of the water-containing medium to the agent and the model prediction result; the optimal pilot plant test agent injection amount is the total injection amount of all the injection points, and according to the relational expression, the agent injection concentration of all the injection points in the chromium pollution site is determined. The method disclosed by the invention can be used for accurately regulating and controlling medicament parameters in actual engineering application, improving the remediation efficiency, shortening the construction period and saving the capital cost, fully remedying the chromium-polluted aquifer and reducing the risk of'yellowing 'of underground water in the later period, and is suitable for in-situ remediation construction application of the large-scale polluted aquifer.

The three-dimensional electrodynamic force chromium-contaminated soil remediation system based on solar energy storage comprises a remediation area built in situ along chromium-contaminated soil, and an anode electrolysis chamber and a cathode electrolysis chamber are arranged at the two ends of the remediation area correspondingly. Separation plates with holes are arranged between the repairing area and the anode electrolysis chamber and between the repairing area and the cathode electrolysis chamber, graphite felt electrodes are arranged in the anode electrolysis chamber and the cathode electrolysis chamber and connected with a direct-current power supply, and the direct-current power supply is further connected with a solar photovoltaic panel; wherein the remediation area comprises a plurality of soil chambers which are arranged in sequence, and a three-dimensional electrode is arranged in each soil chamber. According to the in-situ remediation device, in-situ remediation operation of the chromium-contaminated soil can be continuously carried out for a long time, meanwhile, the three-dimensional electrode introduced into the soil chamber not only improves the conductivity, but also can effectively weaken the focusing phenomenon, the remediation efficiency is guaranteed, the manual labor requirement for remediation of the chromium-contaminated soil is reduced, and development of soil remediation is facilitated.

The present application relates to the technical field of pollution detection, in particular to a water body heavy metal chromium pollution detection method and system, the method comprising the following steps: obtaining the concentration of water body dissolved organic matter, hydrogen ion concentration, oxidation-reduction potential, temperature and initial hexavalent chromium concentration and normalizing, determining the reduction reaction rate constant according to the temperature and oxidation-reduction potential, predicting the reduction rate of hexavalent chromium, the theoretical reduction amount and the theoretical residual concentration, collecting the online electrochemical concentration and the unmanned aerial vehicle hyperspectral inversion concentration and performing difference verification, respectively correcting the electrochemical concentration and the hyperspectral concentration when there is data contradiction, and fusing the two types of correction results to judge the pollution state. In the present application, by establishing a hexavalent chromium natural evolution reference and combining multi-source observation consistency verification, the electrochemical underestimation caused by organic matter passivation and the hyperspectral overestimation caused by spectral background are identified, compensation correction and background stripping are completed, and the accuracy and reliability of chromium pollution detection in complex water bodies are improved.

The invention relates to a trivalent chromium passivation solution and a preparation method thereof, and belongs to the technical field of passivation solutions. In the trivalent chromium passivation solution, the concentration of trivalent chromium salt is 80 g / L-90 g / L, the concentration of an oxidation accelerant is 65 g / L-75 g / L, the concentration of a coordination agent is 10 g / L-15 g / L, the concentration of a pH buffering agent is 8 g / L-12 g / L, the concentration of an activating agent is 10 g / L-15 g / L, the concentration of a grain refiner is 4 g / L-6 g / L, the concentration of cobalt salt is 60 g / L-75 g / L, the concentration of nickel salt is 220 g / L-240 g / L, and the concentration of an oxidizing agent is 20 g / L-30 g / L; the concentration of the complexing agent is 50 g / L-60 g / L, and the concentration of the nano silica gel is 8 g / L-12 g / L. The problem of hexavalent chromium pollution is eliminated, the problems that a trivalent chromium passivation film is poor in corrosion resistance and uneven in blackness are solved, and the process stability can be improved.

The application provides a chromium-contaminated laterite soil repairing agent and a repairing method thereof, and the method realizes effective repair of the laterite soil through the steps of pretreating the soil, applying the repairing agent I and applying an electric field, adding the repairing agent II for maintenance, and finally connecting biological strains.The method comprises the following steps: removing sundries, plowing the soil, applying the repairing agent I containing a reducing agent, citric acid and other components, and treating under specific electric field conditions.Subsequently, the repairing agent II, such as organic fertilizer, iron oxide, nano zeolite and chitosan derivative, is added.Finally, specific proportions of aspergillus, citrobacter freundii and psychrobacter are connected for biological repair.The method comprehensively considers physical, chemical and biological repair means, aims to efficiently remove chromium pollution in the soil, improve the soil organic carbon content of the laterite soil, and restore the ecological function of the soil.

The invention discloses a method for preparing FeS / FeSn carbon aerogel and repairing hexavalent chromium contaminated soil, which comprises the following steps: preparing SA-Fe < 3 + > by using sodium alginate (SA) as biomass, adding SA-Fe < 3 + > gel into a Na2S solution, stirring, dissolving, standing, transferring the mixed solution into a culture dish, freezing in a refrigerator, transferring into a freeze dryer, and drying to obtain the FeS / FeSn carbon aerogel. And drying, grinding into powder by using a planetary ball mill, putting into a quartz boat, and carrying out constant-temperature pyrolysis in a tubular furnace to prepare the FeS / FeSn carbon aerogel. And uniformly mixing the FeS / FeSn carbon aerogel with the to-be-repaired chromium-polluted soil, adding water to maintain the water content of the soil to be 60-80 wt%, and repairing for 1-4 weeks at normal temperature. The FeS / FeSn carbon aerogel prepared by the method disclosed by the invention has a relatively good removal effect on Cr (VI) under acidic, neutral and alkaline conditions.

The invention discloses a compound microbial fertilizer capable of efficiently reducing chromium pollution of rice and a preparation process of the compound microbial fertilizer, and belongs to the technical field of microbial fertilizer preparation. The preparation method comprises the following steps: stirring and mixing the compound fertilizer and the modified biochar, drying and crushing. The biochar is modified, so that hexavalent chromium ions in soil can be better reduced into trivalent chromium precipitates and adsorbed in a porous structure of the biochar, and the possibility that trivalent chromium is oxidized into hexavalent chromium again is reduced. By adding sodium silicate nonahydrate, the stress resistance of plants is enhanced, and the chromium ion absorption of rice is reduced. The complex microbial inoculants are added, and the fertilizer is wrapped by the biochar, so that too fast degradation of nutrients is avoided. The compound microbial fertilizer has the functions of efficiently reducing chromium pollution of rice and slowly releasing nutrition.

This invention belongs to the field of soil and rock mass pollution remediation technology, and discloses a remediation system and method for hexavalent chromium contaminated soil / fractured rock mass, including a heating unit, a temperature monitoring unit, and a ground barrier unit. The heating unit includes an energy supply system and a heating well, with the energy supply system and the heating well sealed together, using heat conduction heating to heat the soil and fractured rock mass in situ. The temperature monitoring unit includes temperature sensors and monitoring wells, with the temperature sensors spaced along the depth direction of the monitoring wells. The temperature monitoring unit enables real-time temperature monitoring and feeds the data back to the energy supply system. The ground barrier unit is a concrete layer that insulates and seals the surface of the remediation area, preventing heat loss and air ingress into the soil. This invention solves the technical problems of difficult mass transfer of reducing agents, unstable remediation effects, and high difficulty in remediating fractured bedrock in traditional in-situ remediation technologies for Cr(VI) pollution.

The invention discloses a hexavalent chromium polluted underground water green remediation system and application. The hexavalent chromium polluted underground water green remediation system comprises a remediation well body and a non-contact sustainable electron injection system arranged in the remediation well body. The repair well main body comprises a shaft and a through hole formed in the wall of the shaft; the non-contact sustainable electron injection system comprises a medicament chamber and a graphite cathode plate; the medicament chamber is a closed space enclosed by a proton exchange membrane and a sealing plug, and a graphite anode plate and a sodium dithionite solution are accommodated in the medicament chamber; the graphite cathode plate is electrically connected with the graphite anode plate; according to the non-contact sustainable electron injection hexavalent chromium polluted underground water green remediation method, a reducing agent does not need to be added into a water-containing layer, the secondary pollution risk caused by the reducing agent and a product thereof is avoided, and green and efficient hexavalent chromium underground water remediation is achieved.

The present invention discloses a method for solar-coupled electrochemically enhanced mineral remediation of chromium-contaminated soil and / or groundwater, comprising: constructing at least two electrode units and placing them in chromium-contaminated soil and / or groundwater, filling the outside and bottom of the electrode units with a mineral material having hexavalent chromium reduction and fixation capabilities and / or attaching it to the electrodes as an electrode coating; utilizing a solar power source to power an online monitoring and control system, monitoring the temperature, humidity, pH, redox potential, and current and voltage changes of the electrode unit's surrounding environment through the online monitoring and control system, and regulating the current and voltage between the electrodes based on real-time monitoring data, achieving chromium reduction and fixation by electrically driving the migration of chromium-containing pollutants and the migration of reducing ions released by the mineral material, and repairing chromium-contaminated soil and / or groundwater. The present invention provides a simple, green, safe, and highly efficient and synergistic method for effectively treating chromium-contaminated soil and groundwater.

The present application relates to water remediation technical field, especially to a kind of groundwater remediation equipment and system for chromium pollutant.Its technical scheme includes: adsorption conversion piece, the adsorption conversion piece includes track, rack, gear, winding shaft and adsorption thick piece, the track is set four, is evenly fixedly installed in the top inner wall and bottom inner wall of magnetic adsorption tank respectively, the track adopts curved U-shaped structure, the inner wall of the track is slidably connected winding shaft.The present application is moved along track by gear and rack cooperation, so that winding shaft and adsorption thick piece move, when adsorption thick piece moves from the inner curved portion of track to outer curved portion, the contact surface of adsorption thick piece with water is converted, so that both sides of adsorption thick piece can contact with groundwater, avoid that the particle filling of adsorption thick piece inside is too thick, lead to that the particle of one side of adsorption thick piece is saturated to be absorbed chromium, and the other side is not absorbed to chromium, conversion absorption surface, improve absorption amount.

This application relates to the field of hexavalent chromium contaminated soil remediation, specifically disclosing a hexavalent chromium contaminated soil remediation agent. Taking 100 kg of hexavalent chromium contaminated soil as an example, it comprises the following raw materials in the following amounts: molasses: 10-50 kg; vinegar residue wastewater: 10-50 kg; modified nano-iron: 5-15 kg; the pH value of the vinegar residue wastewater is 2-3. The remediation agent of this application can more quickly and thoroughly reduce hexavalent chromium in the soil, improving the remediation effect.

The present application relates to waste disposal technical field, especially to a kind of processing method for treating chromium-containing contaminated soil by synergistically disposing waste desulfurization residue and waste organic solvent, comprising the following steps: step one, the chromium-containing contaminated soil is broken, after processing, spray a certain proportion of waste organic solvent and water, ensure that the moisture content is 30-50%, obtain mixture A;Step two, a certain amount of catalyst is added to mixture A to catalyze the reaction, stir evenly, obtain mixture B;Step three, waste desulfurization residue is added to mixture B, stir evenly, obtain mixture C.In the present application, a kind of harmless treatment method for chromium-containing contaminated soil is provided, realizes detoxification while chromium-containing contaminated soil is used as another detoxification agent, waste is turned into treasure, reaches the effect of waste pollution control, while simplifying operation process, reduces processing cost, improves economic benefit, meets landfill standard and becomes the problem that the present technical personnel in the field urgently need to solve.

The invention relates to the technical field of planting, and discloses a root system protection and chromium enrichment strengthening device and method for plant planting in chromium-contaminated soil, the structure of the root system protection and chromium enrichment strengthening device comprises a planting fixing device, a root system isolation device and a chromium enrichment device.According to the root system protection and chromium enrichment strengthening device, the three functions of physical planting fixing, root system isolation protection and repair strengthening of plants are integrated; in addition, by means of the rough filtration layer, the adsorption conversion layer and the slow release layer with the selective blocking function, a protection barrier can be arranged between the plant root system and the chromium-contaminated soil, so that the initial chromium exposure concentration of the root system is reduced, and the survival rate and the early growth speed of seedlings are remarkably increased; the lower expansion ring is arranged on the planting fixing device, and the diameter of the lower expansion ring can be adjusted by means of angle rotation of the clamping seat on the universal ball, so that the device is suitable for planting and fixing plants with different root system sizes.

The application discloses a steel slag conversion method for total chromium removal, and belongs to the field of functional materials. The steel slag is subjected to water bath treatment in an alcohol-water mixed solvent by using an organic carboxylic acid, then the obtained powder is dispersed in water, the suspension is adjusted to an alkaline pH of 8-11, and then a phosphate is added to perform a heating reaction in a water bath. In the application, by controlling the reaction conditions, the elements such as Fe and Ca rich in the steel slag can be effectively utilized, the iron ions in the steel slag are converted into carboxylic acid complexes, and the calcium ions are converted into calcium hydroxyphosphates, so that the illumination reduction of Cr(Ⅵ) and the adsorption and fixation of Cr(III) products are realized respectively, and the purpose of effectively removing chromium is achieved. Therefore, the application not only realizes the effective utilization of the steel slag solid waste, but also realizes the removal of chromium pollutants in sewage, and has good economic value and environmental effect.

The application discloses a kind of stabilized reducing iron sulfur-based slurry and its preparation method and application, the slurry is organic matter-coagulant-ferrous sulfide nanoparticle suspension, including the following components by mass percentage concentration: the slurry includes the following components by mass percentage concentration: organic matter: 0.5-5%, coagulant: 1-10%, ferrous sulfide nanoparticles: balance.It is prepared as follows: organic matter solution is mixed with ferrous sulfate solution and stirred, then mixed with coagulant solution and stirred, then slowly drop sodium sulfide solution, stirring, so that nano ferrous sulfide particles are formed in mixed solution, then centrifuged, and the supernatant is discarded to obtain the slurry.The slurry of the application can be prepared in a short process and at a low cost, can efficiently and quickly treat hexavalent chromium contaminated water, can be stored at normal temperature and pressure for at least one month without deterioration, has a small dosage, the precipitate after treatment is stable, avoids secondary pollution, and has potential application value.

The application relates to the technical field of planting, and discloses a root protection and chromium enrichment strengthening device and method for plant planting in chromium-polluted soil, which comprises a planting fixing device, a root isolation device and a chromium enrichment device. The three functions of physical planting fixation, root isolation protection and repair strengthening of plants are integrated in one body, the survival rate of chromium enrichment plant planting is improved, and with the help of a coarse filtration layer, an adsorption conversion layer and a slow-release layer with selective barrier function, a protective barrier can be established between the plant roots and the chromium-polluted soil, so that the initial chromium exposure concentration of the roots is reduced, the survival rate of seedlings and the early growth speed are significantly improved, and a lower expansion ring is arranged on the planting fixing device, the angle of the lower expansion ring on the universal ball can be adjusted through the angle rotation of the clamping seat, and the planting fixation of plants with different root sizes can be realized.

The invention discloses a hexavalent chromium polluted soil curing agent and a preparation method thereof, and a road subgrade filler and a preparation method thereof, and belongs to the technical field of environmental geotechnical engineering materials. The hexavalent chromium polluted soil curing agent provided by the invention is prepared from the following raw materials in parts by weight: 20-40 parts of an alkali-activated component, 40-60 parts of a gelling-reducing component, 5-15 parts of cation exchange resin and 5-15 parts of an early strength component, wherein the alkali-activated component is selected from one or more of red mud, carbide slag or alkaline residue; the gelling-reducing component is selected from one or two of blast furnace slag or steel slag; the early strength component is selected from one or more of phosphogypsum or desulfurized gypsum. The hexavalent chromium polluted soil curing agent disclosed by the invention has good gelling property, reducibility and self-alkali excitation property, has relatively high curing efficiency and reduces the leaching toxicity of chromium, and the preparation method and the application method are simple to operate and short in treatment period.

The invention belongs to the technical field of sewage treatment, and particularly relates to a combined remediation method for underground water polluted by high-concentration hexavalent chromium. A combined remediation method for underground water polluted by high-concentration hexavalent chromium comprises the following steps that the underground water polluted by the high-concentration hexavalent chromium is pumped out to ground surface sewage treatment equipment, and chemical reduction, alkaline water adjustment and precipitation and flocculation sand filtration and carbon filtration treatment are adopted; a reducing agent is injected into the extracted underground water pollution area, and hexavalent chromium is converted into trivalent chromium with relatively low toxicity; and the concentration of hexavalent chromium in the underground water is monitored regularly, a reducing agent is supplemented and injected in a substandard area, and finally the concentration of hexavalent chromium in the underground water reaches the remediation target. According to the method, the high-concentration hexavalent chromium polluted groundwater extraction treatment technology and the low-concentration hexavalent chromium polluted groundwater in-situ chemical reduction remediation technology are combined, the dosage of a reducing agent is greatly reduced, the groundwater remediation cost is reduced, meanwhile, the pollution remediation period is shortened, and good economic benefits are achieved.

The present invention discloses a chemical-microbial synergistic remediation method and treatment solution for hexavalent chromium, belonging to the technical field of hexavalent chromium pollution remediation. The present invention takes Penicillium oxalicum SL2 and nano-zero valent iron as the research objects and establishes a chemical-microbial synergistic remediation method. The remediation method provided by the present invention can completely reduce hexavalent chromium with a concentration of 200 mg / L in water within 24 h, reduce the soil hexavalent chromium concentration to 3.4 mg / kg (less than the soil pollution risk screening value of 5.7 mg / kg), and still be lower than 5.7 mg / kg after 360 d, verifying the long-term stability of the remediation method and the remediation products. In addition, Penicillium oxalicum SL2 not only has high hexavalent chromium reduction ability, but also can dissolve chromium-iron precipitate, drive the reduction of trivalent iron, activate nano-zero valent iron, and significantly improve the reaction activity of nano-zero valent iron. The synergistic remediation of Penicillium oxalicum SL2 and nano-zero valent iron can improve the reduction and stabilization efficiency of hexavalent chromium while reducing the treatment cost, and has broad application prospects.

The present application relates to the technical field of metal smelting, and particularly relates to a method for reducing hexavalent chromium in chromium-contaminated soil or chromium residue. The method comprises the following steps: S1, crushing the chromium-contaminated soil or the chromium residue, mixing the chromium-contaminated soil or the chromium residue with a detoxifying agent and water, and then feeding the mixture into a stirring tank to obtain slurry 1; S2, feeding the slurry 1 into a mechano-chemical reactor to perform mechano-chemical treatment for 5-60 min to obtain slurry 2; and S3, feeding the slurry 2 into a high-pressure filter to perform pressure filtration to obtain a filter cake and pressure filtrate; the filter cake is scattered by a silt machine and stored for aging, and the completely detoxified chromium-contaminated soil or chromium residue is obtained after the aging is completed. The present application realizes long-term removal of hexavalent chromium in high-concentration chromium-contaminated soil or chromium residue through high-concentration mechano-chemical treatment of the chromium-contaminated soil or the chromium residue and a specific compound detoxifying agent, and then through an aging reaction, and the detoxified product has no risk of resolubilization.

The present invention discloses a reducing agent and a repair and treatment method for hexavalent chromium-contaminated groundwater, and relates to the technical field of contaminated groundwater repair. The reducing agent includes a solid zero-valent iron material and acidic biological fermentation organic waste, the particle size of the solid zero-valent iron material is 1-100 μm, and the acidic biological fermentation organic waste is the acidic solid residue after the organic biological material is fermented by microorganisms. The repair and treatment method includes: forming a permeable reaction wall with a wall, a permeable separation layer, a biomass anti-sedimentation layer and an adsorption reduction layer; wherein the adsorption reduction layer is located in the biomass anti-sedimentation layer, and the adsorption reduction layer contains a reducing agent, and the hexavalent chromium-contaminated groundwater is passed through the permeable reaction wall, so that the hexavalent chromium in the groundwater can be reduced to low-toxic trivalent chromium. The present application improves the reduction efficiency and durability of micron-level zero-valent iron in repairing hexavalent chromium-contaminated groundwater, and can also utilize waste, save resources, and be more environmentally friendly.

The application discloses a kind of septal inflammation pseudomonas LH-Cr-2, belong to microbial technical field.The biological preservation number of septal inflammation pseudomonas LH-Cr-2 is CGMCC NO.27552.The application also discloses the fermentation culture method of septal inflammation pseudomonas LH-Cr-2 for use as a way.The septal inflammation pseudomonas LH-Cr-2 of the application can efficiently reduce different concentrations of soluble hexavalent chromium, provides experimental technology and theoretical basis for the application of microbial reduction technology in chromium-contaminated soil remediation.Six valence chromium is efficiently reduced, and in-situ remediation of chromium-contaminated soil or groundwater can be applied, and can also be used in other related fields that can solve problems by reducing hexavalent chromium.

The invention provides a multi-stage leaching system and method for leaching remediation of hexavalent chromium contaminated soil, and belongs to the technical field of multi-stage leaching methods.The multi-stage leaching system and method for leaching remediation of hexavalent chromium contaminated soil comprise a leaching tank body, and a porous spraying pipe network is arranged at the bottom of the leaching tank body; the porous spraying pipe network is connected with the MOF-based eluting agent storage tank through an acid and alkali resistant pipeline; a composite eluting agent is stored in the MOF-based eluting agent storage tank; the filter unit comprises an MOF-activated carbon composite column, and an inlet of the MOF-activated carbon composite column is connected with the diversion trench through a pipeline; the regeneration unit comprises a hydrochloric acid elution tank and a regeneration liquid storage tank, and is connected with a backwashing inlet of the MOF-activated carbon composite column through a pipeline; the regeneration liquid storage tank is communicated with the MOF-based eluting agent storage tank through a pipeline; and the fluid driving assembly comprises a peristaltic pump and a manual valve which are arranged on the pipeline. The problems of low repairing efficiency and high secondary pollution risk existing in a traditional leaching repairing technology are solved.

The application discloses a remediation agent for high-concentration hexavalent chromium contaminated soil and a preparation method and a remediation method thereof, and belongs to the technical field of soil pollution remediation. The remediation agent for high-concentration hexavalent chromium contaminated soil comprises an acid precursor, an iron-sulfur reducing agent and a synergist; the acid precursor comprises an organic acid and alginate propylene glycol ester; the iron-sulfur reducing agent comprises an iron-based reducing agent and a sulfur-based reducing agent; and the synergist comprises sophorolipid and alkyl glucoside. The remediation agent can be used for high-concentration hexavalent chromium contaminated soil, can replace hexavalent chromium in the soil as much as possible to expose Cr 6+ in the form of ions, and then convert the Cr into trivalent chromium by using a reducing agent, so that the removal efficiency of hexavalent chromium is as high as 99.6%. In addition, the soil remediation agent is simple to use, and has rapid and thorough reaction and long-lasting effect.

The invention relates to the technical field of environmental pollution remediation, in particular to a chromium pollution site pumping-injecting combined remediation system and method based on underground water power regulation and control. The method includes: surveying and paying off an engineering area to determine an engineering area repair range; carrying out underground water pumping-treatment; and in-situ injection repairing and regular monitoring of underground water are carried out. According to the method disclosed by the invention, the injected reducing agent is in full contact with residual Cr (VI) in the aquifer and is subjected to oxidation-reduction reaction through a hydrodynamic regulation effect, so that the Cr (VI) is converted into Cr (III), and the use amount of a chemical reagent is effectively reduced; meanwhile, by utilizing the alkaline condition of the underground water environment, Cr (III) is promoted to form precipitates with high stability and weak mobility, so that the residual quantity of Cr (VI) in water is further reduced, and a secondary diffusion path of chromium pollution can be blocked; the problems that in the prior art, the concentration of Cr (VI) in underground water is reduced slowly, and the trailing phenomenon is remarkable are solved.