College of Environmental Science and Engineering, Hunan University, Changsha, People's Republic of China.
Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, People's Republic of China.
Environ Toxicol Chem. 2019 Oct;38(10):2337-2347. doi: 10.1002/etc.4542. Epub 2019 Sep 16.
Biochar has frequently been used for the treatment of heavy metal pollution in water and soil; its effect on contaminated sediments requires further research. To improve the ability of biochar to immobilize heavy metals in sediment, we prepared a functionalized biochar/attapulgite composite by pyrolysis of the clay attapulgite and zinc chloride-pretreated rice straw biomass. Compared with the original biochar, the biochar/attapulgite composite had a large increase in specific surface area, pore volume, oxygen-containing functional groups, and cation exchange capacity. Biochar effectively improved the dispersibility of attapulgite as a matrix. The results showed that the biochar/attapulgite composite effectively reduced the bioavailable fraction of arsenic (As) and cadmium (Cd) in river sediment, which was a great improvement compared with the raw biochar. After the sediment was treated with different biochar/attapulgite composites, the concentrations of As and Cd in the overlying water and the porewater, and the content of acid-extractable and toxicity characteristic leaching procedure (TCLP)-extractable As and Cd in the solid phase of the sediment decreased significantly. Both zinc chloride activation and attapulgite improved As and Cd immobilization in sediment when we used the biochar/attapulgite composite. The results suggest that biochar/attapulgite composite can be used as an efficient in situ sorbent amendment to improve the heavy metal immobilization ability of the sediment. Environ Toxicol Chem 2019;38:2337-2347. © 2019 SETAC.
生物炭常用于水和土壤中重金属污染的处理；但其对污染沉积物的影响仍需要进一步研究。为提高生物炭对沉积物中重金属的固定能力，我们通过热解粘土凹凸棒石和氯化锌预处理的稻草生物质制备了功能化的生物炭/凹凸棒石复合材料。与原始生物炭相比，生物炭/凹凸棒石复合材料的比表面积、孔体积、含氧官能团和阳离子交换容量均大幅增加。生物炭有效地改善了凹凸棒石作为基质的分散性。结果表明，生物炭/凹凸棒石复合材料有效地降低了河流沉积物中砷（As）和镉（Cd）的生物可利用部分，与原始生物炭相比有了很大的提高。用不同的生物炭/凹凸棒石复合材料处理沉积物后，上覆水和孔隙水中的 As 和 Cd 浓度，以及沉积物固相中可酸提取和毒性特征浸出程序（TCLP）可提取的 As 和 Cd 含量均显著降低。氯化锌活化和凹凸棒石均提高了生物炭/凹凸棒石复合材料中沉积物中 As 和 Cd 的固定能力。结果表明，生物炭/凹凸棒石复合材料可用作一种有效的原位吸附剂改良剂，以提高沉积物中重金属的固定能力。环境毒理化学 2019；38:2337-2347。© 2019 SETAC。
