277results about How to "Not easy to cause secondary pollution" patented technology

The invention discloses a preparation method of a lignin-based dithiocarbamate heavy metal ion capture agent. The method comprises the steps of: (1) adding water into lignin and stirring them, adding an alkaline conditioning agent to adjust the pH to 9-11, then adding an oxidizing agent, conducting heating to raise the temperature to 80-90DEG C for reacting for 1-2 hours; (2) adding an amination reagent, maintaining the reaction temperature at 80-90DEG C, then adding formaldehyde to react for 5-6 hours; (3) cooling the solution to room temperature, adjusting the pH value to 10-11, then adding carbon disulfide to perform an esterification reaction for 4-5 hours at 40-45DEG C; and (4) adding a modifier for reacting for 1-2 hours, then carrying out pumping filtration, and then conducting washing 2-3 times with water and absolute ethyl alcohol, thus obtaining a solid product, i.e. the lignin-based dithiocarbamate. The lignin-based dithiocarbamate heavy metal ion capture agent provided in the invention has the advantages of simple preparation process, low production cost, excellent performance, adaptability to treatment of various heavy metal ion polluted wastewater, good stability, and wide applicable range.

The invention relates to a high Cu-RE refining agent which has high efficiency and low burning loss rate and can be used for copper and copper alloy, applied to mass refining of the copper and the copper alloy, especially applied to refining and modification of red impure copper and white impure copper. The Cu-RE interalloy refining agent is prepared by a vacuum melting method, wherein, rare earth content is up to 30-65%; and only 2-6g / kg refining agent is added while the Cu-RE interalloy refining agent is applied to remelting refining of scrap copper. The Cu-RE refining agent enhances slagging and deslagging of copper fused mass, reduces deleterious substances in the fused mass of the scrap copper, and improves texture and performance of the copper and the copper alloy, therefore, products prepared from the red impure copper as a raw material reach or exceed the quality of the products prepared from electrolytic copper as a raw material, and the white copper process waste can be used for directly producing high-quality products after remelting refined, thus promoting recycle and reutilization of the scrap copper, saving energy and resource, reducing environmental pollution and generating significant economic and social benefits.

The invention discloses a method and device for preparing ceramsite from sludge pyrolytic biochar. The method includes the steps that powder grinding, humidifying, pelleting, low-temperature drying, middle-temperature presintering, high-temperature sintering and cooling are carried out on the sludge pyrolytic biochar to obtain the ceramsite. The device comprises a quantitative feeding device, a water adding device, a humidifying device, a forming and pelleting device, a drying device, a middle-temperature presintering device, a high-temperature sintering device and a cooling device. The sludge pyrolytic biochar is used for preparing the ceramsite, large-scale utilization of the sludge pyrolytic biochar is achieved, heavy metal element in the sludge pyrolytic biochar is further efficiently solidified and passivated, potential heavy metal accumulated pollution of the sludge pyrolytic biochar in the land using process is avoided, and the method and device are particularly suitable for resource utilization of sludge pyrolytic biochar with heavy metal content exceeding standard. The method is simple, practical, low in equipment investment and low in cost and has good economic benefits and environmental benefits.

The invention discloses an adsorbing material prepared from waste straws and capable of adsorbing trivalent arsenic from water as well as a preparation method and an application thereof, and belongs to the field of synthesis and application of environment functional materials. The adsorbing material is prepared by using the waste straws as matrixes through one-step quaternary ammoniated reaction. The preparation method is simple and the sources of the raw materials are wide; the prepared adsorbing material is capable of effectively adsorbing and removing the trivalent arsenic out of water; after adsorption, the trivalent arsenic in the adsorbing material can be desorbed by using a sodium chloride or sodium hydroxide solution; and the adsorbing material regenerated after desorption has stable arsenic adsorption property. The adsorbing material prepared by the method is an effective way of the resource utilization of the waste straws in farmlands.

The invention discloses a leaching method for remediating hexavalent chromium contaminated soil. The method comprises the following steps: (1) slurrying the contaminated soil; (2) fully acidizing materials; (3) adding a reducing agent which is a mixture of calcium polysulfide and ferrite to reduce hexavalent chromium; (4) adding a neutralizing precipitant to precipitate trivalent chromium; and (5) separating solid and liquid, and preparing slurry through supernate. According to the method, a leaching agent and the leaching step are correspondingly simple and convenient to operate, high in safety, low in cost, high in hexavalent chromium recovering efficiency, and hard to cause secondary contamination; meanwhile, wastewater can be recycled, so that the requirement on water for leaching can be met, and as a result, the water resource can be greatly saved, and the secondary contamination caused by drained sewage can be avoided.

A process for reclaiming the rejected polypropene composition, that is, the leftover of internal decoration for car, includes such steps as pulverizing, proportionally mixing it with polypropene, coupling agent and assistant, heating until the mixture is fused, putting glass fibre cloth in mould, pouring the fused mixture in it, pressing, cooling and demoulding.

The invention discloses a repair method of cadmium and lead polluted soil and an electric-microorganism united permeable reaction wall repair device. The device comprises a reaction tank, an electrode, a power supply and permeable reaction walls, space between the two permeable reaction walls is filled with to-be-treated cadmium and lead polluted soil added with microorganisms, pollutants which are migrated to an electrode from the soil are adsorbed by the permeable reaction walls, and therefore, heavy metals including cadmium and lead are removed from the to-be-treated soil. The soil is repaired by uniting the microorganisms, an ecological adsorption material and electrodynamics, a plurality of methods are used, a plurality of systems are used in an integrated manner, the pollutants which are transferred to two poles are adsorbed and fixed through PRB, so that the heavy metals are removed from the soil, by use of the permeable reaction walls and an electric method, an electric pollutant extracting system is omitted, the repair method is close to reality, and the repair performance of an electrokinetic system is optimized. By the method, soil repair period is short, cost is low, efficiency of repair to the cadmium and lead polluted soil is high, and secondary pollution is not caused easily.

The invention belongs to the technical field of materials and provides cellulose / tannin hydrogel. The cellulose / tannin hydrogel is a product which is obtained by adding a cross-linking agent into a mixed liquid of tannin and cellulose to perform cross-linking and immobilization reaction. A preparation method of the cellulose / tannin hydrogel comprises the following steps: (1) dissolving the cellulose into a solvent which consists of urea, alkaline and water or thiourea, alkaline and water at a low temperature to obtain a cellulose liquid; (2) adding tannin into the cellulose liquid to obtain a mixture I, putting the mixture I into an ice bath for ultrasonically dispersing uniformly to obtain a mixed liquid of tannin and cellulose; and (3) adding the cross-linking agent into the mixed liquid obtained in the step (2) and performing cross-linking and immobilization reaction at the same time to obtain the cellulose / tannin hydrogel. According to the cellulose / tannin hydrogel and the preparation method of the cellulose / tannin hydrogel disclosed by the invention, the cellulose is taken as an immobilization carrier, and tannin, especially condensed tannin with relatively good stability is fixed to the cellulose by adopting a homogeneous reaction way, so that the tannin is immobilized and processed into material so as to obtain a gel adsorbent with good performance, and thus, the cellulose / tannin hydrogel can be widely applied to water treatment.

The invention belongs to the field of soil remediation, and particularly relates to an application of a biochar-based combination to improvement of heavy metal contaminated soil. The biochar-based combination is made from biochar and an alkaline modifier. The biochar is prepared from forestry and agricultural residues. The invention further provides the application of the biochar-based combination in soil improvement, and particularly provides the application of the biochar-based combination to reduction of the heavy metal content in soil. The experimental determination shows that by means of the technical scheme, the content of heavy metal in soil can be effectively reduced, the pH value of soil is improved, and furthermore the yield of crops planted in the soil is improved. The technical defects that in the prior art, in the remediation process of heavy metal contaminated soil, the remediation effect is unstable and the time of duration is short are primarily overcome. Meanwhile, the biochar-based combination has the advantages of being low in cost, convenient and easy to obtain and free of secondary pollution.

The invention discloses a method for degrading phenol by a solid catalyst. The method is characterized in that a nanometer bimetallic CuCo2O4 catalyst is prepared by a chemical precipitation method; meanwhile, the phenol is degraded into pollution-free CO2 and H2O; when a catalytic oxidation reaction is carried out, the catalyst can efficiently activate potassium peroxodisulfate to generate SO4 and OH; the SO4 and OH have higher oxidation reduction potentials and can be used for directly oxidizing the phenol. Meanwhile, the catalyst CuCo2O4 is good in stability, and still has good catalytic activity after being repeatedly utilized for 7 times; the phenol still can be completely removed. A preparation method of the catalyst, disclosed by the invention, is simple and safe.

The invention relates to an ultrasonic algal-removing boat used for water bloom emergency treatment. The boat is loaded with an ultrasonic algal-removing device, adopts the sedimentation function of ultrasound on the blue-green algae of water to sedimentate the blue-green algae to the water bottom, is applied in the emergency treatment when the water bloom in the lake outbreaks and can reach the effect of removing floated blue-green algae on the surface of the lake. The boat of the invention comprises a catamaran (1) with an algae-laden water drainage channel (3), an ultrasonic transmitter array (2) and other parts, wherein the ultrasonic transmitter array (2) is arranged in the algae-laden water drainage channel (3) of the catamaran (1); and the ultrasonic transmitter array (2) radiates the ultrasound to act on the blue-green algae of water in the algae-laden water drainage channel (3) and ensure that the blue-green algae loses the floatability and is discharged and sedimentated to the water bottom under the action of a boat-pushing propeller (5), thus achieving the aim of removing the blue-green algae. The system is an environmental technology which adopts the ultrasonic technology to remove the blue-green algae of water body in water head site safely and economically.

This invention relates to pnenolic aldehyde resin compound waste materials recycle and shaping process, which in detail to a car inner decoration materials recycle and adopts pnenolic aldehyde waste materials grinding and joins mixture materials of polypropylene and couple agent and assistant agent. It heats the mixture materials and sends it to melting status and puts glass fiber cloth into model and transfers the mixture into model and gets the product through molding and cooling and demolding.

The invention relates to an integrated process for treating heavy metal wastewater. A reactor adopted in the integrated process is simple to construct, compact in structure, high in heavy metal wastewater treatment efficiency, and easy to operate, manage and maintain. The integrated process is free of a nanometer zero-valent iron mixed solution refluxing device, capable of increasing the nanometer zero-valent iron by sufficiently utilizing flow fields, which are formed by a stirring device on the inner part of the reactor, and capable of realizing solid-liquid separation and zero-valent iron refluxing by utilizing the gravity of the nanometer zero-valent iron, so that the nanometer zero-valent iron is sufficiently mixed and circulated in the reactor, and the high-adsorption performance and strong reduction characteristic to the heavy metals are greatly utilized. An integrated device is used to treat simulated wastewater and the pre-treated electroplating wastewater containing heavy metals, so that the concentration of various heavy metals in the treated outlet water are better than the emission standards of the national pollutant I. Moreover, the reactor has short hydraulic retention time and high treatment efficiency, and is free of additionally added chemical coagulant, capable of separating and recycling the nanometer zero-valent iron containing heavy metals and capable of avoiding the secondary pollution of the heavy metals.

The invention discloses a nanometer cobalt ion-doped titanic anhydride catalyst and a preparation method thereof, which relates to a titanic anhydride catalyst and a preparation method thereof. The invention solves the problem of difficult improvement of TOC removal rate of the yielding water during the water treatment process by the existing advanced oxidation technique. The catalyst of the invention is prepared by butyl titanate, absolute ethyl alcohol, cobalt chloride, concentrated chlorhydric acid and distilled water. The preparation method comprises the following steps of: 1. dripping the butyl titanate into the absolute ethyl alcohol under magnetic stirring; 2. continuously stirring the solution for 1h, then dripping the concentrated chlorhydric acid and adding the cobalt chloride successively and continuously stirring the solution until the solution is clear; 3. continuously stirring the solution for 90 min, dripping the distilled water and conducting static ageing; 4. drying and grinding; and 5. sintering to obtain the catalyst. The catalyst of the invention has the advantages of good activity and high stability and can effectively reduce the TOC of yielding water. The preparation method of the invention has simple technique and convenient operation.

The invention discloses a method for degrading bisphenol A through a white-rot fungus crude enzyme. The white-rot fungi crude enzyme is prepared, a tartaric acid buffer solution, a bisphenol A solution, a hydrogen peroxide solution and veratryl alcohol are added, the pH value of a reaction system is controlled to range from 2.5 to 3, the concentration of the veratryl alcohol is 10 mmol / L, the temperature is kept between 20 DEG C and 50 DEG C, the reaction lasts for 30 minutes to 50 minutes, 1.0 mL-3.0 mL methyl alcohol is added for stopping the reaction, and therefore the bisphenol A is degraded through the white-rot fungi crude enzyme. A bio-enzyme catalytic process is adopted in the method, and the method has the beneficial effects of being high in removing efficiency, convenient, safe, free of pollution and the like; and as amboceptor matter is added, the biocatalysis reaction efficiency can be improved, the reaction time can be shortened, the enzyme using amount is reduced, and the running cost is reduced.

The invention discloses a microbial strain which can effectively degrade phenol and relates to alcaligenes faecalis JH1013 CCTCC NO: M 208006 and a method for degrading phenol wastewater by using a fixed alcaligenes faecalis that is produced by alcaligenes faecalis. The method has the following advantages that: 1. the alcaligenes faecalis is easy to culture, the fixing technique is simple, the catalytic degradation effect is good, the high-concentration phenol can be resistance, the phenol degradation capacity is strong, which can high efficiently degrade the phenol wastewater with the concentration of as high as 2000mg. L<-1> and be used repeatedly; 2. hydrotalcite, hydrotalcite-like compounds, nano calcium carbonate, Gamma-Al2O3 or the loading solid base are used as carriers for preparing the fixed alcaligenes faecalis, the elasticity is good, the temperature and pH value resistances are strong, the mechanical strength is high, the degradation performance is stable and the half-time is long; 3. the carriers of the hydrotalcite, the hydrotalcite-like compounds, the nano calcium carbonate and the Gamma-Al2O3 of the fixed cell can be used repeatedly by calcinations; 4. the fixed alcaligenes faecalis is used for degrading the phenol, the degradation process is simple, the conditions are moderate, the environment is friendly, the bacterial cells are difficult to loss, the concentration of the microorganisms in the carriers is high, the degradation speed is fast, the degradation efficiency is high and the secondary pollution is not easy to be caused.

A process for reclaiming the rejected polyurethane composition, especially the leftover of internal decoration for car, includes such steps as pulverizing, adding polypropene, coupling agent and assistant, stirring, heating until the mixture is fused, loading it in mould, cooling and demoulding.

The invention relates to a method for degrading azo dye wastewater. In the invention, firstly the liquid-phase electroless plating method is used for loading Fe-Ni double metallics on the surface of hollow glass microballoon so as to modify the hollow glass microballoon; then the hollow glass microballoon after modification is taken as a sorbent for degrading azo dye wastewater. In one aspect, the loading problem of catalyzer (Fe-Ni) is solved, and the catalyzer can exist in solid state and also separate from the wastewater easily; in the other aspect, the absorption ability of the carrier (hollow glass microballoon) also provides concentration environment for catalytic reaction, and the rate of reaction is improved; additionally, the surface area of catalyzer is increased, thus facilitating the active center to increase. The operation of the method is simple, a secondary pollution can not be aroused, the cost is relatively low, the treatment efficiency is relatively high, and the method is a better method for disposing azo dye wastewater.

The invention discloses a remediation method for heavy-metal-contaminated soil and relates to the field of ecological environment remediation. The method comprises the steps that ragweed is planted on the heavy-metal-contaminated barren land; and the ragweed is reaped, transferred, incinerated and subjected to heavy metal extraction sequentially in the period before the start of the flowering period of the ragweed. According to the remediation method, the heavy-metal-contaminated soil is remedied through the ragweed, the ragweed grows fast in the growing period and branching period, and the ragweed has the high absorption function and enrichment function on the heavy metal pollution in the soil; and the ragweed has the beneficial effects of being high in growth speed, large in biomass, high in adaptability, low in cost, wide in distribution and the like, a lot of lead, cadmium and the like in the soil, especially in the overground part, can be transferred into the plants, the ragweed is reaped and transferred manually before the flowering period and is incinerated, then heavy metals are extracted, and therefore the soil pollution such as lead and cadmium is remedied, and the higher economic value and economical environment value are provided for the effective utilization of heavy metal soil remediation by the plants and invasive alien species.

The invention discloses a cerium ion doped tungsten trioxide catalyst and a preparation method and application thereof and belongs to the technical field of catalysts. The preparation method of the cerium ion doped tungsten trioxide catalyst comprises the steps of (A), adding tungsten powder into H2O2 which is subjected to magnetic stirring at the speed of 200-300r / min; (B), adding cerous nitrate into CH3CH2OH which is subjected to magnetic stirring at the speed of 150-200r / min; (3) adding yellow sol-like matters obtained in the step (A) into the solution obtained in the step (B), heating the mixture with stirring, and aging the mixture; (D) placing the gel obtained in the step (C) into a drying oven to perform drying at the temperature of 100-105 DEG C, and grinding the dried gel into powder; and (E), placing the powder obtained in the step (D) into a muffle furnace, heating the powder, and calcining the powder to obtain the cerium ion doped tungsten trioxide catalyst. The cerium ion doped tungsten trioxide catalyst produced by the preparation method is good in stability, high in activity, simple in preparation, low in cost, convenient to operate and not liable to cause secondary pollution.

The invention provides a desilting geotextile tube bag on-site rapid dehydration method which comprises the following steps: step 1, pretreatment: pretreating river bottom silt through a pretreatmentdevice to form slurry with the silt content not lower than 50%; step 2, filling: filling the pretreated slurry into a geotextile tube bag body through a sludge conveying system; step 3, rapid dehydration: adding a soluble flocculating agent into the geotextile tube bag to rapidly remove water in the slurry, and depositing solids in the slurry to form blocky sludge; and step 4: solidification: depositing the blocky sludge on the inner wall of the geotextile tube bag, filtering out small particles, and then performing first-section continuous dehydration through gravity factors, rheological factors and the like so as to form dry sludge. With application of the technical scheme, dehydration can be conducted on site without pumping out river water, full-closed construction is achieved, and secondary pollution is not liable to be caused; the slurry with the mud content not lower than 50% is formed through stirring, more labor is saved during pumping, and the efficiency is higher.

The invention discloses a heavy metal sewage composite treatment agent and a preparation method and application thereof. The heavy metal sewage composite treatment agent is prepared from 20-30 crop waste, 10-30 parts of humic acid, 20-30 parts of xanthic-acid-modified quartz sand, 4-6 parts of sodium alginate, 4-6 parts of chitosan, 4-10 parts of calcium thioglycolate and 3-6 parts of calcium chloride. The treatment agent contains various heavy metal reactive groups and can achieve simultaneous high-efficiency adsorption of various heavy metals, the sedimentation speed, the treatment efficiency, the stability and the environmental tolerance are high, the problem that the crop waste is difficult to treat is solved, the waste is turned into treasure, and the resource utilization of the cropwaste is achieved. Under suitable conditions, the removal rate of the heavy metals can reach 99%. The heavy metal treatment agent is wide in raw material source and simple in preparation process, andhas good application prospects in the aspect of heavy metal treatment.

The invention provides a preparation method of modified red mud, and belongs to the technical field of water disposal. The modified red mud is prepared by roasting waste slag red mud, acquiring a roasting product and performing acid immersion on the roasting product by sulfuric acid. Through the roasting treatment, the content of impurities in the waste slag red mud can be reduced, and method is good for the reaction of sulfate radical and calcium ion in the subsequent acid immersion process, and can improve the content of effective component CaSO4 (H2O)2 (plaster stone) of a final product; the waste slag red mud surface after roasting is in porous state, thus it is good for the sufficient contact between the waste slag red mud and sulfuric acid, thereby benefiting the formation of the calcium sulfate crystal. Data of an embodiment shows that the removal rate of fluorine in the waste water by the modified red mud is up to 99% above in 1h, and the arsenical removal rate is over 99%, thus the synchronous removal of fluorine and arsenic can be realized; the water quality after absorbing can completely meet the national Hygienic Standard for Drinking Water.

The invention provides a method of preparing a CoPi catalyst through a green recovered waste lithium cobaltate battery. The method comprises the steps that the battery is disassembled, and copper foil, aluminum foil, anode material lithium cobaltate and a negative material are separated; citric acid and a methanol aqueous solution are used for hydrothermally dissolving the lithium cobaltate material to obtain a leach liquor A; and a three-electrode deposition method is adopted, a mixed solution of the leach liquor A and a phosphoric acid buffer solution is used as an electrolytic solution, andelectro-deposition is performed on a cleaned FTO conductive glass substrate or the surface of an iron oxide thin film to obtain the CoPi catalyst. According to the method, the citric acid is adoptedto hydrothermally dissolve lithium cobaltate in the waste lithium cobaltate battery, the leach liquor is combined with the phosphoric acid buffer solution to serve as the electrolytic solution, and the three-electrode method is adopted to perform constant-voltage electrochemical deposition to obtain the CoPi catalyst; and the method has the advantages that the environment is protected, energy andtime are saved, equipment is simple, operation is easy and convenient to perform, the obtained target product has high electrochemical activity, and the process is simple, controllable, suitable for large-scale production and the like.

The invention discloses a preparation method for synthesizing a photo-catalytic material by using a MOF as a precursor, and belongs to the field of catalysts. The method adopts a manner that the MOF is used as the precursor to synthesize the photo-catalytic material. Firstly, a metal organic framework MOF of bismuth (such as CAU-17) with uniform morphology and stable structure is synthesized, theMOF and a metal salt aqueous solution are stirred under a water bath condition, a mixed solution formed after stirring is subjected to centrifugal drying, and calcination is carried out at a certain temperature to obtain the photo-catalytic material which can maintain a MOF appearance frame. The method has the advantages of short cycle, large output, simple process operation, stable product performance, good catalytic performance, and being not easy to cause secondary pollution. The method is suitable for large-scale mass production, and has a relatively broad scientific research and practicalvalue.

The invention discloses an electrostatic-type air purification device with an ultraviolet lamp. The electrostatic-type air purification device comprises a bottle body, a bottle mouth, a base, an electrostatic adsorption device, an exhaust fan, a first positioning block, a second positioning block and a suction fan, and further comprises the ultraviolet lamp, an active carbon filter layer, a pure plant layer, a buckle, a clamping seat, a clamping groove, a third positioning block and a rubber pad; the bottle body and the bottle mouth are inlaid together through the buckle and the clamping seat, the bottom end of the bottle body is connected with the base, the electrostatic adsorption device is arranged in the bottle body, and the clamping groove is formed in the bottom face of the bottle body; the ultraviolet lamp is arranged on the inner wall of the bottle body, the active carbon filter layer is fixed on the inner wall of the bottle mouth through the third positioning block, and the pure plant layer covers the surface of the active carbon filter layer. According to the electrostatic-type air purification device with the ultraviolet lamp, the internal parts are convenient to clean, exhausted ozone can be well controlled, and organic matter such as formaldehyde and benzene can be filtered; in addition, the whole device is attractive and elegant in appearance and has a certain anti-slip function.

The invention relates to a novel arsenic removal material and a preparation method thereof. The specific preparation raw materials include de-ionized water, ferric chloride, natural zeolite and a sodium hydroxide (NaOH) solution. When the material is prepared, the natural zeolite is taken as a base and the ferric chloride is loaded on the surface of the natural zeolite to obtain a natural zeolite-ferric chloride composite arsenic removal material. According to the preparation method provided by the invention, a prepared adsorbing material is high in adsorption efficiency, strong in alkali resistance and convenient for solid-liquid separation; and the novel arsenic removal material has the advantages of high adsorption efficiency, strong alkali resistance, convenience for solid-liquid separation, cheapness, easiness for obtaining, simple preparation method and good application prospect.

The invention belongs to the technical field of medicines, and particularly relates to a preparation method for 130 / 0.4 hydroxyethyl starch. The method mainly comprises the following steps of gelatinizing and hydrolyzing, performing hydroxyethyl etherification, performing rough filtration, decolorizing and clarifying, performing refined filtration, performing ultrafiltration and drying. According to the method, insoluble chitosan is used for decolorization and clarification, and the conventional process in which activated carbon is used for decolorization is improved, so production efficiency and the quality of hydroxyethyl starch are improved. The method overcomes the defects that decolorization efficiency is low, the adsorption amount is limited, filtration time of feed liquid is long, and toxin in the feed liquid exceeds the limit and the like because the active carbon is used for decolorization in the conventional process, adsorption speed of insoluble chitosan is 6 times that of the active carbon, and the adsorption amount of insoluble chitosan is 5.5 times more than that of the active carbon; the insoluble chitosan can be repeatedly used, secondary pollution is avoided, high mechanical intensity is achieved, and filtration is not influenced; and the raw materials of the produced hydroxyethyl starch are stable in batch, and the quality of the produced hydroxyethyl starch is reliable and meets the national standard.

The invention belongs to the field of remediation methods of soil heavy metal pollution, and particularly relates to an in-situ remediation method of arsenic soil pollution. The method comprises the following steps: adding a liquid medium into arsenic-polluted soil to be treated to allow the arsenic-polluted soil to be treated to be in reduction environment, stimulating the soil microbial growth, distributing arsenic from the soil solid phase to the soil liquid phase, then transferring the arsenic to a layer below a plough layer, fixing the arsenic in deep soil to realize remediation of the arsenic-polluted soil. According to the method of the invention, arsenic is distributed from the soil solid phase to the soil liquid phase through a series of biochemical reactions, and then is transferred to a layer below the plough layer and fixed in deep soil, so as to realize remediation of arsenic-polluted soil. The method is simple in operation and low in cost, and when compared with conventional methods, the method is safer and more reliable.

The invention provides cellulose / tannin micro-nano fibers. The cellulose / tannin micro-nano fibers are products obtained after an immobilized reagent is added to mixed liquor of microfibrillated cellulose and a tannin water solution for a reaction. The immobilized reagent is aldehydes or acids or epoxy of polyfunctional groups. A preparation method of the cellulose / tannin micro-nano fibers includes the following steps that 1, tannin is dissolved in water to prepare the tannin water solution; 2, the microfibrillated cellulose is added to the tannin water solution to prepare the microfibrillated cellulose-tannin mixed liquor; 3, the immobilized reagent is added to the microfibrillated cellulose-tannin mixed liquor, and the cellulose / tannin micro-nano fibers are obtained after the reaction. The microfibrillated cellulose serves as a fixed carrier of tannin, the raw materials are easy to obtain, and production cost is greatly reduced. The microfibrillated cellulose and tannin are both biomass resources and can be repeatedly used and naturally degraded, environment friendliness is achieved, and secondary pollution is not likely to be caused with the product serving as a wastewater treatment adsorbent. The whole preparation process is simple in step, mild in reaction condition, high in operability and beneficial for industrial popularization.