195 results about "Soil cadmium" patented technology

The invention discloses a restoration agent for lowering cadmium/lead effective state content in soil, which is composed of quicklime, calcium sulfate, wood charcoal, iron chloride and water, wherein the weight ratio of the quicklime, calcium sulfate, wood charcoal and iron chloride is (1-2):(1-2):(1-2):(0.5-1), and the water accounts for 30-45 wt% of the soil. The restoration agent can be used for treating heavily polluted soil; and common chemical passivators can only restore lightly polluted soil, and do not have obvious effect on heavy pollution. The restoration agent can be used for treating both acidic soil and neutral soil. The restoration agent has high remediation efficiency for cadmium polluted soil; the reaction mechanisms relate to chemical precipitation and physical adsorption; and when one action fails due to change of the outside conditions, the other action can perform the guarantee function. The restoration agent has certain control actions on the lead effective state content in the polluted soil.

The invention belongs to the technical field of heavy metal pollution soil restoration, and particularly relates to a soil heavy metal passivator, a preparation method thereof, and a passivation method thereof on soil cadmium. The soil heavy metal passivator provided by the invention is prepared from the following materials in parts by weight: 30 to 50 parts of modified alkali minerals, 10 to 15 parts of rotten agriculture and forestry wastes, 1 to 10 parts of soil conditioners, 1 to 5 parts of pH sensitive gel, 1 to 5 parts of phosphogypsum, and 0.1 to 5 parts of graphene. The soil heavy metal passivator provided by the invention has stronger adsorbing and chelating functions, can effectively fix heavy metal cadmium in the soil, and prevents effective cadmium from entering into crops; regulation can be carried out according to the soil pH, so that the utilization ratio and the long-term stability of the soil heavy metal passivator are improved; meanwhile, with an added soil conditioner, the soil environment can be improved, and the soil fertility is improved. The passivator provided by the invention can better meet the urgent demand of heavy metal pollution soil restoration in China currently on strong stability, no secondary pollution, and durable and stable effect.

The invention discloses a multi-functional composite conditioner for controlling cadmium-polluted soil and a remediation method for soil cadmium pollution. The multi-functional composite conditioner comprises an inorganic passivation agent for soil heavy metal cadmium, an organic passivation agent and a cadmium antagonist, wherein the inorganic passivation agent is selected from red mud, hydroxyapatite, bentonite, zeolite or dolomite; the organic passivation agent comprises cruciferous plant residues or liliaceous plant residues. The cruciferous plant residues are Chinese cabbage plant residues, rape plant residues, leaf mustard plant residues or cabbage plant residues, and the liliaceous plant residues are garlic plant residues, onion plant residues or Chinese chive plant residues. The cadmium antagonist is a compound containing Zn, Ca or Fe. The multi-functional composite conditioner adopts a composite cadmium remediation mode, can reduce the content of cadmium in plant bodies, and provides an effective, feasible and economic means for the planting of agricultural products with normal content of cadmium.

The invention discloses a passivating agent for reducing the cadmium activity of acidic vegetable soil and a use method thereof. The passivating agent contains the following components by weight: 31.3-46.2% of lime, 26.7-39.0% of potassium humate, and 25.0-37.8% of rice husk carbon. The use method consists of: subjecting the passivating agent to basal application totally according to a dose of 150-450kg per 667 square meters, then conducting plowing and uniform raking to make the passivating agent and contaminated soil mixed uniformly, spraying water, performing balancing for 1-3 days, and then carrying out sowing or transplanting. Through the synergistic effect of various components, the passivating agent involved in the invention can reduce the cadmium activity of the soil and the heavy metal content of vegetables, and improve the crop yield and quality, thus being able to be widely applied to remediation of acidic vegetable soil suffering moderate and mild cadmium pollution or severe pollution.

The invention belongs to the technical field of remediation of soil contamination, and particularly relates to a method for continuously remediating soil cadmium contamination by using a chelating agent EDDS and ramie. The method comprises the following steps: after ramie survives, applying the biodegradable chelating agent EDDS to the soil, wherein the application amount of the chelating agent is 75-300kg/mu; irrigating the ramie every 30 days by using an 0.005-0.015mol/L EDDS solution, and normally irrigating the ramie in the rest of time; and regularly harvesting aboveground stems and leaves of the ramie, and leaving the underground parts of the ramie to further grow. Compared with the prior art, the method disclosed by the invention is better in remediation effect and more environmentally-friendly; and the method is easy to operate, and has certain economic benefits, and therefore, the method has a board promotion prospect.

The invention provides a composite passivator for reducing oilseed rape land soil cadmium pollution, a preparation method thereof and an application of the composite passivator. The composite passivator is prepared from rice husk biochar, humus, limestone, ammonium sulfate, nano-hydroxyapatite, sepiolite and attapulgite. By the aid of the composite passivator, the available cadmium content of soiland the cadmium content of an overground part and an underground part of an oilseed rape can be remarkably reduced, the pH (potential of hydrogen) value of the soil can be improved, the composite passivator can be used for treating extensive heavy metal cadmium polluted oilseed rape land soil, the content of organic matters is greatly increased, and soil physical and chemical properties are obviously improved.

The invention provides a soil cadmium passivant which comprises the following raw materials in parts by weight: 30-85% of red mud, 10-70% of rape stalk, less than or equal to 10% of lime, less than or equal to 5% of phosphatic fertilizer, and less than or equal to 1% of zinc, wherein when pH of soil is greater than 6, the lime is equal to 0%. The soil cadmium passivant aims at reducing effective cadmium in the soil; the main raw materials belong to recycled wastes; the consumption of the auxiliary materials is less; the total cost is very low; the pretreatment of the raw materials is very simple, convenient and easy; special treatment processes such as chemical method modification are not required; the passivant can be obtained only by simple air drying, crushing, screening and mixing; the technology is simple; an application method of a passivant product is relatively simple; the passivation on soil cadmium is higher; the passivant has specificity and is wide in application scope; secondary pollution cannot be generated on the soil; the quality and the yield of crops cannot be influenced; the content of effective cadmium in the soil can be reduced effectively; and the passivant is suitable for various moderately and slightly polluted soil types.

The invention provides a soil cadmium passivator. The soil cadmium passivator is prepared from biological carbon, quick lime and sodium alginate; by means of the quick lime in the soil cadmium passivator, a pH value of soil can be improved, available cadmium in an ionic state is converted into a cadmium sediment in an invalid state such as cadmium hydroxide; the sodium alginate has a good chelating effect on heavy metal cadmium; the biological carbon has certain adsorbing effects on the available cadmium in the ionic state, the cadmium hydroxide and invalid cadmium such as in cadmium a complexing state; the biological carbon, the quick lime and the sodium alginate in the soil cadmium passivator can be mutually matched and cooperated at a specific mixture ratio, so that the effects of reducing the content of the cadmium in an available state in soil and the content of the cadmium in a living body grown in the soil are realized; the soil cadmium passivator also has the advantages that a PH value in the soil is improved, the functions of the soil are improved, and secondary pollution is avoided.

The invention relates to an application of oxalic acid in removal of soil cadmium pollution. High-level pure oxalic acid is selected to prepare an oxalate solution with the concentration of 0.05wt%-1wt%, and the oxalate solution is used as an eluting agent; the eluting agent is added into polluted soil; an eluting process can be finished by oscillating, centrifuging and collecting an eluted solution at room temperature and then filtering the eluted solution; and a liquid to solid ratio of the chemical eluting agent to the polluted soil is 10:1 (ml/g). The chemical eluting agent formula is simple; the effect is outstanding; the operability is high; the application cost is low; the eluting rate is high; and a relatively good effect of removing cadmium ions in the soil is achieved. A test shows that when the concentration is 0.2 percent, the eluting rates are respectively 65.91 percent and 48.065 percent; and secondary pollution to the soil is avoided.

The invention discloses a soil cadmium passivator which is characterized by comprising the following raw materials in parts by weight: 15-25 parts of bentonite, 5-10 parts of lime, 15-25 parts of ferric chloride, 20-35 parts of decomposed straws and 10-15 parts of phosphatic fertilizer. The soil cadmium passivator has the advantages that the heavy metal passivator in the invention has an excellentadsorption-chelation effect, cadmium in soil can be effectively fixed, and available cadmium in the soil is prevented from entering crops; and by controlling the conditions such as the soil pH value,soil moisture content, passivator addition and the like, the utilization rate and stability of the soil heavy metal passivator can be effectively improved. The method is low in cost, simple and easyto operate, high in practicality, high in safety, excellent in stability and excellent in soil cadmium passivating effect, does not cause secondary pollution to the soil, does not influence the quality and yield of crops, can effectively reduce the content of available cadmium in the soil, is suitable for farmland soil subjected to moderate heavy metal pollution, and has wide application value andmarket space.

The invention discloses a method for planting suaeda salsa at a medium-low-cadmium saline-alkaline land and for extracting plant salt. The method comprises the steps of saline-alkaline land selection, saline-alkaline land improvement, soil cadmium adsorption treatment, and plant salt extraction. According to the soil cadmium adsorption treatment step, amaranthus retroflexus and elymus dahuricus are inter-planted and used for adsorbing cadmium in soil, wherein a preferable inter-planting ratio of amaranthus retroflexus and elymus dahuricus is 4:1, and a planting density is preferably 10*40cm. In the plant salt provided by the invention, cadmium content is reduced to 0.002mg/kg, sodium chloride content is 39%, potassium chloride content is 12%, Mg content is 4%, Ca content is 8%, and Fe content is 750mg/kg. With the method, a problem of excessively high cadmium content in plant salt extracted from suaeda salsa planted in the medium-low-cadmium saline-alkaline land is effectively solved.

The invention discloses a method for improving remediation effect of cadmium polluted soil. The method adopts a direct-current electric field-plant combined remediation method, so that the remediation effect of cadmium polluted soil is effectively improved, and remediation efficiency of soil cadmium pollution is improved by 20%-38%.

The invention provides a method for repairing vegetable garden soil cadmium pollution. Nano-zeolite with the soil weight being 0.5% to 1.0% and nano-magnesium hydroxide with the land fertilizer amount being 0.1% to 0.5% are used and are sufficiently and evenly mixed with soil through broadcasting, furrow dressing and hole application, the soil turning depth ranges from 15 cm to 20 cm, and after balance is conducted for 5 days to 7 days, vegetables or other crops are transplanted. According to the method, multiple repairing technologies such as in-situ passivation, plant repairing and microorganism repairing are organically combined, and soil Cd pollution is effectively repaired through a synergistic effect.

The invention discloses a method for mid-season rice-wheat rotation in cadmium mild contamination soil and belongs to the technical field of contamination soil environment management. The method includes: (1), in 5-8d before crop transplanting, applying a soil cadmium passivation conditioner on the cadmium mild contamination soil, and well mixing with plough layer soil; (2), transplanting mid-season rice Yongyou 7850, waterflooding in the whole growth period, spraying a zinc reinforced cadmium blocking and controlling agent to leaves in the tillering period, the booting period and the groutingand fruiting period respectively, and draining field water in one week before harvesting mid-season rice; (3), fully moving out straw after the mid-season rice is harvested, directly sowing wheat Ningmai 13, cultivating to harvesting, and removing wheat straw completely. According to the mid-season rice-wheat rotation mode in the method, repair of the cadmium mild contamination soil is completedwhen agricultural production is completely normal, and the method is free of economic benefit loss and easy for farmers to accept; harvested straw is moved out of farmland, so that no secondary pollution is caused.

The invention provides an application of rape stalks to reducing the content of effective cadmium in soil. The rape stalks as raw materials are collected, baked or dried in the sun, crushed and sieved to 30 to 100 meshes by a standard sieve to obtain a granular rape stalk soil cadmium passivator, and the rape stalk soil cadmium passivator is applied to the surface soil by using an application method of broadcasting application, furrow application or hole application. According to the preparation method, by utilizing the adsorption principle of the rape stalks to prepare a vega soil cadmium special passivator, the content of the effective cadmium in the soil and the content of cadmium in tobaccos which grow in the soil can be effectively reduced. The rape stalks as the raw materials belong to the field of agricultural waste recycling with low cost, have a high passivating effect on the cadmium in the soil and a high reducing effect on the cadmium in the tobaccos, have the advantages of specificity and wide application range and cannot cause secondary pollution to the soil or influence the quality and yield of crops.

The invention relates to a phosphate for lowering the content of cadmium in plants planted in acidic cadmium-containing soil and/or improving the yield of the plants planted in the acidic cadmium-containing soil, and mainly provides an application method and the like of the phosphate for lowering the content of cadmium in the plants planted in the acidic cadmium-containing soil and/or improving the yield of the plants planted in the acidic cadmium-containing soil.

The invention relates to a cadmium passivating agent with an improved soil function and a production method thereof. The production method comprises the following steps: pre-processing crop straw, preparing a fulvic acid mixture, mixing, drying and the like. According to the cadmium passivating agent disclosed by the invention, the effectiveness of cadmium in soil can be greatly reduced, and the absorption amount of the crop on the cadmium is reduced; moreover, the physical and chemical properties of soil and the soil fertility are improved at the same time, and the cadmium passivating agent has generality. The cadmium passivating agent disclosed by the invention has an important application and popularization value in a high-risk area of out-of-standard cadmium content of soil and a cadmium middle-pollution and mild-pollution area, and has very remarkable social, ecological and economic benefits.

The invention relates to a clay mineral-based trace element regulator used for treating rice field cadmium pollution. The clay mineral-based trace element regulator comprises the following raw materials: 8-16 weight parts of EDTA.Na2Mn, 0.5-3 weight parts of silicon dioxide, 24-32 weight parts of zinc sulfate, 1-5 weight parts of magnesium sulfate, 0.4-1.2 weight parts of ferrous sulfate, 0.6-1.4 weight parts of calcium oxide, and 80-160 weight parts of clay mineral. The rice field cadmium pollution treatment technology is based on environmental geochemistry and an antagonism principle, on one hand, by increasing the pH value of the soil and changing the soil cadmium occurrence mode, bio-availability of the soil cadmium is reduced, on the other hand, by reducing the rice cadmium absorption through element antagonism, so that the remediation effect and efficiency are ensured.

The invention discloses a practical method for repairing cadmium pollution in farmland soil by planting Suliu 795, and belongs to the field of soil restoration. A practical method for repairing cadmium-contaminated farmland soil by planting Suliu 795, the steps are: (1) after selecting the cadmium-contaminated farmland, plowing, breaking up the soil, dividing ridges, and designing drainage ditches; (2) planting Suliu 795 795 young branches; (3) ensure the survival of more than 90% of willow trees through agronomic management and protection, and reduce the Cd content of the original polluted farmland soil by 30% within 2 years. This method can make the Cd content in the polluted soil be reduced by more than 20% on average in the first year by planting the young branches of Suliu 795 in the farmland soil with serious Cd pollution; The farmland with soil Cd content greater than 3.0mg/kg was restored until the Cd content of farmland soil was all less than 1.0mg/kg.

The invention discloses a phytoremediation method for restoring farmland soil heavy metal cadmium pollution. The phytoremediation method comprises the following steps: selecting a rice variety Meilianzao, planting the rice variety in the heavy metal cadmium polluted soil according to a conventional planting method of rice, draining the water and sunning the farmland from the booting stage to the pustulation stage and the milk ripening stage, so as to enable the heavy metal cadmium in the soil to be adsorbed in rice straws and rice through planting. The cadmium content in the soil can be effectively lowered by planting the rice variety Meilianzao in the farmland with cadmium exceeding the standard, draining water and sunning the farmland from the booting stage to the milk ripening stage, and enabling the heavy metal cadmium in the soil to be adsorbed by and transferred to the rice. The technical support is provided for restoring the soil cadmium pollution and ensuring the aftercrop food safety. The method is simple and feasible and easy to grasp by farmers; the harvest can be purchased from the farmers, so that the secondary pollution can be avoided.

The invention provides a method for hindering control over farmland soil heavy metal and belongs to the technical field of farmland heavy metal pollution treatment. The method comprises the steps thatbefore seeding, a soil conditioner is added into soil and uniformly mixed through ploughed fallow; heavy metal low-accumulated crops are planted, and farmland management measures are implemented; andafter grains are formed, a heavy metal hindering agent is sprayed, and after the crops are harvested, hindering control over heavy metal pollution is completed. The raw material of the conditioner comprises the main components of 20-30% of red mud, 20-30% of rape straw powder, 5-15% of dolomite powder, 25-35% of lime powder, 20-30% of a calcium-silicon-potash fertilizer and 1-10% of amino acid. The main component of the hindering agent is Na2SeO3, wherein the Se content is 40 mg/L. According to the method for hindering control over the farmland soil heavy metal, the three-stage measures thatthe soil conditioner passivates the heavy metal, the low-accumulating crops hinder the heavy metal, and a hindering agent conducts hindering control over the heavy metal, the soil heavy metal, cadmium, is hindered from entering agricultural products, the soil cadmium activity is lowered, and guarantee is better achieved compared with one single hindering control measure.