Preparation method of Fe3O4-based biochar soil passivating agent

Abstract

The invention discloses a preparation method of a Fe3O4-based biochar soil passivating agent. The preparation method of the Fe3O4-based biochar soil passivating agent comprised the steps of (1) carbonizing Sinkiang walnut shells into biochar in nitrogen condition; (2) adding the biochar into a water solution of acetic acid and acetylacetone for modifying; (3) weighing a certain amount of FeCl3 andFeCl2 and dissolving FeCl3 and FeCl2 in water to form a solution; (4) adding the biochar into the solution of step (3) with stirring and then pouring ammonium hydroxide into the solution until no more precipitation is generated; (5) separating solid from liquid and the Fe3O4-based biochar soil passivating agent is obtained by cleaning the solid part with distilled water, drying to constant weight, crushing and sieving through a sample sieving screen. The soil passivating agent is based on the huge specific surface area and strong micropore structure of the biochar, so that heavy metal compound in soil can be effectively adsorbed and immobilized; the charge capacity of the surface of the biochar and the heavy metal ions of the soil generate static electricity, so that the adsorbing capacity can be improved; the form and transfer behavior of heavy metal in the soil can be significantly affected, the stability of the heavy metal can be improved and the heavy metal can be prevented from being absorbed by crops.

Description

technical field [0001] The invention belongs to the technical field of heavy metal polluted soil treatment, in particular to a kind of Fe 3 O 4 Preparation method of biochar-based soil passivator. Background technique [0002] Soil is an important part of the earth's ecological environment, and it is also the natural basis for human survival and development for thousands of years. However, with the continuous development of human society and the continuous expansion of human activity areas, the heavy metal pollution of soil caused by urban pollution, industry, mining and agriculture has become increasingly serious. The heavy metals that cause soil pollution are mainly toxic and biologically harmful elements. These heavy metal pollutants have poor mobility in soil, long residence time and are difficult to be degraded by microorganisms. In addition to damaging the ecological environment and degrading the soil, they also It will spread through scouring, runoff and rainwater ...

AI Technical Summary

Problems solved by technology

The magnetic chaff biochar can remove Pb, Cd and other heavy metals in the water body, but because the soil environment is more complex than the water body, the heavy metal ions in the soil migrate slowly, and most of the elements are not in the form of ions, but in the form of stable compounds However, parameters such as the adsorption pore diameter, the number of adsorption pores, the failure resistance and the state of active sites of the passivating agent treated by the existing technology cannot meet the requirements of soil adsorption of heavy metals. Therefore, the test found that simply adding the existing The BC-Fe produced in the technology is diverted into the soil, and the removal effect on Pb and Cd is not obvious, and the ideal effect cannot be achieved

[0005] In addition, in the prior art, calcareous substances, bentonite, humus and other organic and inorganic chemical mixed fertilizers are used as passivating agents to restore polluted soil. Although certain effects have been achieved, each passivating agent has its scope of application. and limitations, and the production cost is high or the process is too complicated

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