Soil passivation improver, and preparation method and application thereof

Abstract

The invention discloses a soil passivation improver, and a preparation method and an application thereof. The soil passivation improver is prepared by the following steps: crushing bentonite, diatomite, magnesium oxide, ferric oxide and humic acid through a micro-wet ball mill process; spraying water which is 2-5% of the material; and fully grinding the mixture for 2-4 hours. According to the soil passivation improver, the activity of heavy metals in the soil is reduced and the concentration of effective heavy metals is reduced through natural mineral components such as bentonite and diatomite, and magnesium oxide; the air permeability of the soil is improved through the humic acid component, and nitrogen, sulfur, potassium and phosphorus and trace elements necessary to plants are supplemented while the heavy metals are complexed and the effective states of the heavy metals are reduced by means of functional groups, such as quinonyl, alcoholic hydroxyl group, carboxyl and carbonyl, in the humic acid; and meanwhile, fulvic acid rich in the soil is chelated with the heavy metals, so that the absorption amount of the plants on the heavy metals is reduced. The soil passivation improver has a wide application in heavy metal-polluted soil repair.

Description

technical field [0001] The invention belongs to the technical field of passivation improvement of heavy metal polluted soil, and more specifically relates to a soil passivation improver and its preparation method and application. Background technique [0002] On April 17, 2014, the "National Soil Pollution Survey Bulletin" reported that the national cultivated land soil site exceeded the standard rate of 19.4%, of which the proportions of slightly, lightly, moderately and heavily polluted sites were 13.7%, 2.8%, and 1.8% respectively. % and 1.1%, the main pollutants are cadmium, lead, nickel, copper, arsenic, mercury and other heavy metals. These heavy metals have poor mobility in soil, long residence time, and cannot be degraded by microorganisms, causing serious deterioration of soil environmental quality. For heavy metal pollution in farmland, there are mainly three remediation technologies as follows: [0003] ① Use physical, chemical or biological methods to directly ...

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Problems solved by technology

Chinese invention patent "a heavy metal curing agent for polluted soil and its use method" (authorization number ZL201410107493.9) mixes bentonite, diatomite, sepiolite and phosphate rock powder in a certain proportion to obtain a combined curing agent, and uses the curing agent and The heavy metal polluted soil is fully mixed according to 1-3:100 (weight ratio) and a certain proportion of water is added for aging to achieve the effect of curing heavy metals such as cadmium, lead, copper, etc. The curing agent prepared by this method uses a large amount and can only Increase the phosphorus content in the soil

Chinese invention patent "a conditioner for heavy metal-contaminated soil" (application number 201610558435.7) fully mixed and fermented cow dung, poultry manure, pig manure and yeast powder, and then mixed with mechanically crushed limestone, humic acid and phosphoric acid Diammonium hydrogen, ammonium dihydrogen phosphate, calcium dihydrogen phosphate, dicalcium hydrogen phosphate, potassium dihydrogen phosphate, ethylenediaminetetraacetic acid, potassium permanganate, calcium oxide, magnesium oxide, and potassium chloride are fully mixed and stirred to obtain heavy metal Contaminated soil conditioner, the patented method requires a wide variety of raw materials and a complicated preparation process

At present, there are only passivators and improvers in the market. Although passivators have a good effect on passivating heavy metals, they are easy to cause soil compaction. Dissolution and long repair time, etc., it is not easy to cultivate crops after repair

The amendment can significantly increase the nitrogen, phosphorus, and potassium content of the soil, but the long-term effect of passivating heavy metals is not good.

Therefore, how to use natural materials to prepare economical and practical heavy metal polluted farmland passivation improvers with both heavy metal passivation and soil improvement has not been reported.