The solidification of heavy metal Pb2+-contaminated soil by enzyme-induced calcium carbonate precipitation combined with biochar

IF 3.7 3区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Biochemical Engineering Journal Pub Date : 2024-09-17 DOI:10.1016/j.bej.2024.109496

Bing Bai , Jing Chen , Bin Zhang , Liang Chen , Yongchen Zong

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Abstract

The remediation of heavy metal Pb²⁺-contaminated soil by enzyme (urease)-induced calcium carbonate precipitation (EICP) combined with biochar was studied. The solidification efficiency of Pb²⁺ reached 98.41 % when the mass ratio of CaCl₂/urea was 1:1 using EICP technology to remedy Pb²⁺-contaminated water. However, the formed precipitate was accompanied by unstable vaterite, and Pb²⁺ had the risk of secondary leaching. When the biochar of 5 wt% was added to the Pb²⁺-contaminated soil, the soil structure tended to be dense and the toxic leaching concentration of Pb²⁺ was less than 5 mg/L, which met the national standard of China. The addition of biochar increased the pH of the contaminated soil and changed the free Pb²⁺ into insoluble Pb(OH)₂. The biochar provided more nucleation sites for urease, and part of Pb²⁺ were adsorbed on its surface or diffused into the pores of biochar, which effectively solidified Pb²⁺ in the soil.

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通过酶诱导碳酸钙沉淀结合生物炭固化重金属 Pb2+ 污染的土壤

研究了酶（脲酶）诱导碳酸钙沉淀（EICP）与生物炭相结合对重金属 Pb2+污染土壤的修复。当 CaCl2/ 尿素的质量比为 1:1 时，使用 EICP 技术处理 Pb2+ 污染的水，Pb2+ 的固化效率达到 98.41%。然而，形成的沉淀物伴随着不稳定的辉绿岩，Pb2+ 有二次沥滤的风险。在 Pb2+ 污染土壤中添加 5 wt%的生物炭后，土壤结构趋于致密，Pb2+ 的毒性浸出浓度小于 5 mg/L，达到了中国国家标准。生物炭的加入提高了污染土壤的 pH 值，使游离的 Pb2+ 转化为不溶性的 Pb(OH)2。生物炭为脲酶提供了更多的成核位点，部分 Pb2+ 被吸附在其表面或扩散到生物炭的孔隙中，从而有效固化了土壤中的 Pb2+。

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来源期刊

Biochemical Engineering Journal 工程技术-工程：化工

CiteScore

7.10

自引率

5.10%

发文量

380

审稿时长

34 days

期刊介绍： The Biochemical Engineering Journal aims to promote progress in the crucial chemical engineering aspects of the development of biological processes associated with everything from raw materials preparation to product recovery relevant to industries as diverse as medical/healthcare, industrial biotechnology, and environmental biotechnology. The Journal welcomes full length original research papers, short communications, and review papers* in the following research fields: Biocatalysis (enzyme or microbial) and biotransformations, including immobilized biocatalyst preparation and kinetics Biosensors and Biodevices including biofabrication and novel fuel cell development Bioseparations including scale-up and protein refolding/renaturation Environmental Bioengineering including bioconversion, bioremediation, and microbial fuel cells Bioreactor Systems including characterization, optimization and scale-up Bioresources and Biorefinery Engineering including biomass conversion, biofuels, bioenergy, and optimization Industrial Biotechnology including specialty chemicals, platform chemicals and neutraceuticals Biomaterials and Tissue Engineering including bioartificial organs, cell encapsulation, and controlled release Cell Culture Engineering (plant, animal or insect cells) including viral vectors, monoclonal antibodies, recombinant proteins, vaccines, and secondary metabolites Cell Therapies and Stem Cells including pluripotent, mesenchymal and hematopoietic stem cells; immunotherapies; tissue-specific differentiation; and cryopreservation Metabolic Engineering, Systems and Synthetic Biology including OMICS, bioinformatics, in silico biology, and metabolic flux analysis Protein Engineering including enzyme engineering and directed evolution.