State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China.
Sci Total Environ. 2022 Mar 10;811:152112. doi: 10.1016/j.scitotenv.2021.152112. Epub 2021 Dec 4.
The present study explored the immobilization of mixed bacteria-loaded biochar on As, Pb, and Cd was explored. Physisorption and sodium alginate encapsulation were used to synthesize two kinds of mixed bacteria-loaded biochars, referred to as BCM and BCB. The observations of Scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy distinctly demonstrated the colonization of mixed bacteria on biochar. Besides, the addition of BCM and BCB could increase soil pH with increasing incubation time. The residual fraction of heavy metals and soil dehydrogenase activities were also enhanced after 28 days of incubation. Pb was mainly immobilized by co-precipitation, which meant that Pb could be converted into a consistent crystalline form such as Pb(PO)OH. The X-ray photoelectron spectroscopy and X-ray diffraction analyses of materials identified the formation of CaAsO and the presence of oxidation from trivalent arsenic to pentavalent arsenic. Cd was adsorbed by forming precipitations (CdCO) and exchanging ions with the BCM and BCB. Synergistic reactions between anions and cations also contributed to the immobilization of heavy metals, such as the formation of PbAsO and Cd(AsO). These results confirmed that mixed bacteria-loaded biochar was a feasible technology for the remediation of heavy metals contamination in site soils.
本研究探索了固定化负载混合细菌的生物炭对砷、铅和镉的固定作用。采用物理吸附和海藻酸钠包埋的方法合成了两种负载混合细菌的生物炭，分别称为 BCM 和 BCB。扫描电子显微镜、X 射线衍射和傅里叶变换红外光谱的观察结果明显表明了混合细菌在生物炭上的定殖。此外，随着培养时间的增加，BCM 和 BCB 的添加可以提高土壤 pH 值。重金属的残留部分和土壤脱氢酶活性在 28 天后的培养中也得到了增强。Pb 主要通过共沉淀固定，这意味着 Pb 可以转化为一致的结晶形式，如 Pb(PO)OH。材料的 X 射线光电子能谱和 X 射线衍射分析确定了 CaAsO 的形成和三价砷向五价砷的氧化存在。Cd 通过形成沉淀（CdCO）和与 BCM 和 BCB 进行离子交换被吸附。阴离子和阳离子的协同反应也有助于重金属的固定，例如 PbAsO 和 Cd(AsO)的形成。这些结果证实，负载混合细菌的生物炭是一种可行的原位土壤重金属污染修复技术。
