14results about How to "Reduce arsenic levels" patented technology

The invention discloses an arsenic removal method for purifying waste acid, and belongs to the technical field of sulfuric acid preparation. The method comprises the following steps: settling wastewater, and carrying out filter pressing on slurry through a first filter press; in the first-stage reaction tank, the waste acid reacts with a desulfurizing agent from a sodium hydrosulfide preparation tank, and after the reaction is completed, the waste acid is sent to a first-stage FBL filter to be filtered; in the second-stage reaction tank, the waste acid reacts with a desulfurizing agent from the sodium hydrosulfide preparation tank, and after the reaction is completed, the waste acid is sent to a second-stage FBL filter to be filtered; the filtrate of the second-stage FBL filter is sent to a dynamic wave scrubber for recycling; a flocculating agent is added into the first-stage FBL filter and the second-stage FBL filter; tail gas of the first-stage reaction tank, the first-stage FBL filter, the second-stage reaction tank, the first-stage FBL filter and the sodium hydrosulfide preparation tank is sent to a spray tower, washing liquid containing sodium hydrosulfide and sodium sulfide in the spray tower is sent to the sodium hydrosulfide preparation tank, and sodium hydrosulfide solids are added into the sodium hydrosulfide preparation tank.

The invention relates to a zeaxanthin adenine dinucleotide synthetase gene ZmFADS1 and an encoded protein and application thereof, and belongs to the technical field of plant genetic engineering, the ZmFADS1 gene has a nucleotide sequence shown as SEQ ID NO.1, zeaxanthin adenine dinucleotide synthetase encoded by the gene has an amino acid sequence shown as SEQ ID NO.2, and the zeaxanthin adenine dinucleotide synthetase has a nucleotide sequence shown as SEQ ID NO.1. The zeaxanthin adenine dinucleotide synthetase has a nucleotide sequence shown as SEQ ID NO.2. The overexpression of the gene in plants can improve the quality of corn kernels. The ZmFADS1 gene is cloned from corn for the first time, and the mechanism that the ZmFADS1 can improve the FAD synthesis capacity of plant leaves through overexpression in the corn and further improve the enrichment capacity of the leaves on heavy metal arsenic so as to reduce the arsenic content in corn kernels is found, so that a theoretical basis is provided for cultivating corn varieties with low-arsenic-content kernels.

The invention discloses a preparation method, a use method and application of a composite soil conditioner, and relates to the technical field of soil remediation. Compared with the prior art, the composite soil conditioner is prepared by uniformly mixing calcined oyster shells and limestone with biochar, organic activated carbon and mineral source humic acid; the composite soil conditioner is simply applied to arsenic-polluted soil, and can improve the soil structure, improve the composition of organic matters in the soil, increase the Eh value of crop rhizosphere soil and increase the biomass of crops, so that the soil quality is improved. The biological availability and toxicity of arsenic are remarkably reduced through multiple effects of soil in-situ passivation, iron-arsenic precipitation forming, iron film / titanium film forming and the like, the content of arsenic absorbed and accumulated at edible parts of stems and leaves of crops is reduced, arsenic is intercepted at unedible root parts, solid waste resource utilization is achieved, and the method is low in cost and environmentally friendly.

The utility model relates to the technical field of arsenic-removed ammonium polyphosphate production equipment, in particular to an arsenic-removed ammonium polyphosphate production device, which comprises an arsenic-removed reactor and a polymerization reactor, one side of the polymerization reactor is connected to the bottom discharge end of the arsenic-removed reactor through a pipeline, the bottom output end of the polymerization reactor is connected with a cooler, and the cooler is connected with the arsenic-removed reactor through a pipeline. The output end of the cooler is connected with a crusher through a product conveying belt, the output end of the top of the polymerization reactor is connected with a plate-type absorption tower through a pipeline, the output end of the plate-type absorption tower is sequentially connected with a first-stage absorption tower, a second-stage absorption tower and a third-stage absorption tower, and one side of the top of the polymerization reactor is connected with a second reactant storage tank through a pipeline. According to the arsenic-removed ammonium polyphosphate production device, the arsenic removal reactor and the polymerization reactor are combined, so that efficient removal of arsenic in the ammonium polyphosphate production process is realized. According to the device, the operation process is simplified, the production cost is reduced, and the quality and the safety of products are remarkably improved.

The invention provides hydrothermal carbon-based biological nano-selenium as well as a preparation method and application thereof, the hydrothermal carbon-based biological nano-selenium is prepared by taking a selenium-resistant functional strain as a chassis cell and inorganic selenium as a precursor substance; then, with garden waste as a carbon-based raw material and biological nano-selenium as a selenium source, synthesizing hydrothermal carbon-based biological nano-selenium through a one-step hydrothermal carbonization method; finally, the obtained hydrothermal carbon-based biological nano-selenium is applied to harmful substance removal and biomass energy production of an arsenic-containing breeding wastewater anaerobic digestion system. The preparation process of the hydrothermal carbon-based biological nano-selenium is the combination of biological fermentation and hydrothermal reaction, the method is green, safe and low in energy consumption, the arsenic content in an anaerobic digestion final product of the aquaculture wastewater and the abundance of antibiotic resistance genes (ARGs) and pathogenic bacteria can be effectively reduced by adding the hydrothermal carbon-based biological nano-selenium prepared by the method into the arsenic-containing aquaculture wastewater, and the yield of the aquaculture wastewater is improved. Meanwhile, the methane yield is increased.

The application discloses a method for reducing the content of arsenic in overproof molten steel and a billet obtained by the method. The method comprises the following steps: providing overproof molten steel, wherein the content of arsenic in the overproof molten steel is higher than 0.015%; providing scrap steel, wherein the scrap steel comprises one or more of carbon scrap steel and low-alloy scrap steel; providing refined molten steel, wherein the content of impurity elements in the refined molten steel is lower than 0.013%, and the impurity elements comprise one or more of As, Cu, Mo and Ni; mixing the overproof molten steel, the scrap steel and the refined molten steel in a refining furnace; and adding a dearsenization agent after deoxidization and desulfurization treatment to obtain clean molten steel, wherein the content of arsenic in the clean molten steel is lower than 0.015%. According to the embodiment of the application, the content of arsenic in molten steel can be reduced at low cost, the production rhythm can be stabilized, and the quality of steel can be improved.

The present invention relates to the technical field of rice planting, and specifically discloses a method for reducing the cadmium content of rice in moderately polluted soil, comprising: (1) applying a passivating agent to the soil 2-4 days before rice transplanting to reduce the biological effectiveness of soil cadmium and form a root protection film, thereby reducing the absorption and accumulation of cadmium by the rice plant during the growth period, especially the tillering and jointing periods; (2) spraying a leaf surface barrier control agent once during the heading period of rice, and blocking the transport of cadmium ions to grains through complexation with cadmium ions in the rice body and ion channel inhibition. The method is simple to operate, labor-saving and time-saving, and has a high efficiency in reducing cadmium in rice. The method can reduce the cadmium and arsenic content of brown rice in rice fields with moderate cadmium pollution by more than 80%, and increase the rice yield by more than 5%. The method has a stable effect and is suitable for industrial application in rice production in rice fields with less than moderate cadmium pollution.

This invention provides a method for efficiently removing arsenic and separating and recovering zinc and cadmium from arsenic-containing waste acid, comprising the following steps: filtering the arsenic-containing waste acid solution to remove suspended solids and particulate impurities, and then performing diffusion dialysis to allow H₂ to form a solution. + The arsenic is separated from metal ions to obtain recovered acid and residual acid containing metal ions. The residual acid is added to an autoclave along with an iron salt coagulant, and oxygen or air is simultaneously introduced to carry out a high-pressure oxidation precipitation reaction. After the reaction, liquid-solid separation is performed to obtain arsenic-containing precipitate and arsenic-precipitated liquid. The arsenic-precipitated liquid is added to carbide slag water for neutralization treatment to obtain gypsum slag and neutralized liquid. Zinc powder is added to the neutralized liquid for displacement, and after liquid-solid separation, sponge cadmium and zinc sulfate solution are obtained. This invention uses high-pressure oxidation precipitation of arsenic, which has a better arsenic precipitation effect. The arsenic content in the precipitated liquid is extremely low and a stable arsenic-containing precipitate is formed, which can be safely stored for a long time. At the same time, zinc and cadmium are recovered, realizing the high value of zinc and cadmium elements, and no wastewater is generated in the whole process.

The invention belongs to the field of vanadium batteries, and particularly relates to a method for removing arsenic in a vanadium-containing solution. The method comprises the following steps: (1) providing a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5; (2) mixing the vanadium-containing solution with an impurity removing agent, adjusting the pH value of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity-removed solution and impurity-removed slag; (3) the impurity removal liquid is subjected to vanadium precipitation treatment, and vanadate is obtained; and (4) dissolving the impurity-removed slag through a dissolving solution, and recovering the obtained solution to the step (1) for recycling. By applying the method and the device provided by the invention, the arsenic content can be reduced to 0.01-10mg / L or below, meanwhile, the vanadium loss rate can be controlled to be 1-10%, the impurity removal effect is good, and the impurity removal cost is low.

The invention belongs to the technical field of mineral processing, discloses a method for flotation separation of chalcopyrite and arsenopyrite by using an oxidizing agent and a complexing agent, and provides a method for flotation separation of chalcopyrite and arsenopyrite by using the oxidizing agent (chlorine dioxide, hydrogen peroxide, ozone and the like) and the complexing agent (ammonium carbamate). An oxidizing agent is added into a flotation pulp system, the arsenopyrite can be inhibited after being oxidized, the recovery rate of the arsenopyrite is controlled to be inhibited to be 10% or below, meanwhile, part of the chalcopyrite is inhibited, then a complexing agent ammonium carbamate is added, copper on the surface of the chalcopyrite can react with anions and cations ionized by the ammonium carbamate, and the concentration of the copper on the surface of the chalcopyrite is reduced. And double complexing is performed to form stable adsorption, so that more active sites exist on the surface of the mineral, the chalcopyrite is further activated, and more effective separation of the chalcopyrite and the arsenopyrite is realized.

The invention discloses an arsenic-polluted bottom mud synchronous dehydration curing agent and an application method thereof, the curing agent comprises the following components by mass: 0.1%-5% of a coagulant A, 1%-5% of a curing stabilizer B and 0.05%-0.5% of a flocculant C, the addition amounts of the coagulant A, the curing stabilizer B and the flocculant C are respectively 0.1%-5%, 1%-5% and 0.05%-0.5% of the dry matter content of sludge; the coagulant A is at least one of ferric salt and aluminum salt; the curing stabilizer B comprises an alkaline curing material and an arsenic fixing agent; and the flocculant C is at least one of cationic polyacrylamide, anionic polyacrylamide or nonionic polyacrylamide. The method is synchronously added in the conditioning process of the arsenic-polluted bottom mud, secondary conditioning generated by separation in dehydration and solidification stabilization links of the arsenic-polluted bottom mud is avoided, the dehydrated mud cake can reach a certain strength after being cured and stabilizes the arsenic element in the sludge, the arsenic content in the leachate can be reduced by 90% or above, and the arsenic content in the leachate can be reduced by 90% or above. And the maintained mud cake can be used for resource utilization of land such as roadbed soil and filling soil.

The invention relates to an arsenic fixing composition in a coal washing process and a use method of the arsenic fixing composition, in the arsenic fixing composition, dolomite powder, an auxiliary absorbent and a catalyst generate a good synergistic effect, so that arsenic in a product of the coal washing process is adsorbed after being converted, the content of arsenic in the product of the coal washing process can be reduced, and the yield of the product of the coal washing process is improved. The removal efficiency of the arsenic element is improved. The dolomite powder which is low in price, low in preparation cost and wide in raw material source is adopted as the main adsorbent, the problem of environmental pollution in a traditional coal washing process can be solved, and the environmental protection performance of the coal washing process is improved. The composition of the petroleum sulfide and the Fe-Mn composite oxide is adopted as the auxiliary absorbent, on one hand, sulfur elements in the petroleum sulfide can convert trivalent arsenic in the coal into pentavalent arsenic, and absorption of the absorbent is facilitated; on the other hand, Fe and Mn in the Fe-Mn composite oxide can form iron sulfide and manganese sulfide with the S element, and the situation that sulfur enters washing water to cause environmental pollution is avoided.

The application provides a treatment method of epitaxial high-concentration arsenic-containing wastewater, comprising the following steps: adding calcium hypochlorite into the epitaxial high-concentration arsenic-containing wastewater, and stirring and aerating; then adding ferric chloride, and stirring and aerating; then using lime milk solution to adjust the pH of the system to 6.5-7, and continuing to stir and aerate; performing pressure filtration to obtain primary arsenic-containing wastewater; adding calcium chloride solution and ferric chloride solution into the primary arsenic-containing wastewater obtained by pressure filtration, using lime milk solution to adjust the pH of the system to 6.5-7, and then standing, taking supernatant to test, discharging the supernatant after reaching the standard; if the supernatant does not reach the standard, continuously adding calcium chloride solution and ferric chloride solution for cyclic treatment until the supernatant reaches the standard and is discharged. The method has the advantages of small reagent dosage, low cost, high arsenic removal rate, high stability of arsenic-containing hazardous waste and the like, and after being treated by the method, the arsenic content is lower than 0.3 mg / L, which meets the national discharge standard.

The application provides an arsenic pollutant treatment device for mineral processing wastewater and a preparation method of an adsorbent thereof. The arsenic pollutant treatment device for mineral processing wastewater comprises a base, and a reaction box fixed to the base, which is used for containing the mineral processing wastewater and putting in the adsorbent to make the adsorption reaction between the mineral processing wastewater and the adsorbent. The arsenic pollutant treatment device for mineral processing wastewater and the preparation method of the adsorbent thereof can be used for different concentrations and complexities of the mineral processing wastewater, can effectively reduce the arsenic content in the mineral processing wastewater to below the discharge standard, and can guarantee the environmental safety. Through the initial state stirring operation, the wastewater and the adsorbent can be fully contacted. Through the first extension of the pushing assembly, the filter plate can be displaced to the bottom of the discharge slot, so that the device can be switched from the stirring state to the solid-liquid separation state, and the adsorbent can be recycled.