Preparation method of lead-arsenic-cadmium adsorption material and application

Abstract

The invention discloses a preparation method of a lead-arsenic-cadmium adsorption material. The method comprises the following steps of (1) drying and crushing rape straw, sieving and compacting the crushed rape straw, carrying out pyrolysis carbonization under an oxygen limiting condition or an oxygen-free condition, and performing cooling under an inert gas environment to obtain a material A; (2) drying and crushing tea leaf residues, mixing the crushed tea leaf residues with an iron salt solution, then performing aging, drying and compacting on the obtained mixture, carbonizing the mixtureunder the oxygen limiting condition or the oxygen-free condition, and cooling the mixture under an inert gas environment to obtain a material B; (3) mixing the material A with the material B to obtainthe lead-arsenic-cadmium adsorption material. The lead-arsenic-cadmium adsorption material prepared through the method can adsorb ions of heavy metal such as lead, arsenic and cadmium at the same time, the competitive adsorption is small, and the adsorption performance is excellent; meanwhile, the effective arsenic content of ammonium nitrate leached from soil can be reduced by 71% or above, theeffective cadmium content can be reduced by 66% or above, the effective lead content can be reduced by 72% or above, and the removal rate of lead, arsenic and cadmium is high at the same time.

Description

technical field [0001] The invention belongs to the field of soil pollution restoration, and in particular relates to a preparation method and application of a lead, arsenic and cadmium adsorption material. Background technique [0002] Heavy metal elements refer to elements with strong biological toxicity such as Pb, Cd, Hg, Cr, and metalloid As. Secondly, they refer to elements necessary to maintain normal physiological activities of living organisms within a certain range. is toxic at times. Heavy metal pollution has the characteristics of accumulation, concealment and long-term nature. Heavy metal pollution has brought great harm to the ecological environment and human health. At present, the status of heavy metal pollution in the country's soil is not optimistic. The 2014 Soil Pollution Survey Bulletin shows that the soil polluted by heavy metal pollutants accounts for 1 / 6 of the total, and the exceeding standards of Pb, Cd and As reach 1.5% and 7% respectively. and 2...

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Problems solved by technology

[0003] As an adsorption material, biochar has a high specific surface area and pore structure, and is effective against cationic metal pollutants (Cd 2+ , Pb 2+ etc.) have strong adsorption capacity, while for anionic heavy metal pollutants AsO 4 3- The adsorption capacity is poor, and the method of iron modification can improve the biochar anionic heavy metal AsO 4 3- However, there are still technical problems that the adsorption capacity of arsenic is not high, or the cationic metal pollutants cannot be simultaneously adsorbed

The patent (CN 104388094 A) proposes a restoration material that combines the environmental effects of biochar and zero-valent iron. Although the removal of arsenic and cadmium pollutants is considered at the same time, the zero-valent iron introduced has a strong reducing ability , will also have a certain impact on the soil environment; at the same time, its preparation process needs to involve reduction and emulsification processes, and there are many process steps

The patent (CN 104941583 A) proposes a method of reacting pyrolytic carbonized biochar with iron salt solution to make a modified biochar material for the adsorption of cadmium and / or arsenic. The preparation process involves multiple heating and cooling, and energy consumption Higher, and the modified material has competitive adsorption for simultaneous adsorption of cadmium and arsenic, and the adsorption capacity is not high when simultaneously adsorbing cadmium and arsenic

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