College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China.
College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
Sci Total Environ. 2020 Apr 20;714:136550. doi: 10.1016/j.scitotenv.2020.136550. Epub 2020 Jan 8.
Cadmium (Cd) pollution in soils has received considerable research attention globally, and sulphur-modified biochar (SBC) could combine the advantages of biochar and the sulphur element for Cd remediation. Biochar from agricultural waste is feasible, which has a low preparation cost. However, there are few studies regarding the effects of the sulphur modification of biochar on the Cd immobilization mechanism. This study aimed to research the Cd immobilization mechanism of pristine wheat straw biochar (BC) and sulphur-modified biochar (SBC), and the Cd immobilization effects of BC and SBC in Cd-contaminated soils. Elemental and SEM analysis confirmed that sulphur was successfully loaded on the pristine biochar. XPS analysis confirmed that there was a considerable discrepancy between adsorption mechanisms of Cd on BC and SBC. In particular, cadmium sorption on BC was due to Cd(OH) and CdCO precipitation formation and interaction with carbonyl and carboxyl groups, whereas on SBC, sorption was mainly due to CdS and CdHS formation and interaction with organic sulphide. In the incubation experiment, SBC and BC additions increased pH value and also reduced the available Cd concentrations in the soil. Compared with the control, the contents of available Cd in soil were significantly decreased by 15.86% ~ 22.10% and 22.72% ~ 27.90%, following treatments with BC and SBC, respectively.
土壤中的镉（Cd）污染受到了全球的广泛关注，而硫改性生物炭（SBC）可以结合生物炭和硫元素的优势来修复 Cd。农业废弃物制备生物炭具有可行性，且制备成本低。然而，关于生物炭的硫改性对 Cd 固定机制的影响的研究较少。本研究旨在研究原状小麦秸秆生物炭（BC）和硫改性生物炭（SBC）对 Cd 的固定机制，以及 BC 和 SBC 在 Cd 污染土壤中的 Cd 固定效果。元素分析和 SEM 分析证实硫已成功负载在原状生物炭上。XPS 分析证实，BC 和 SBC 对 Cd 的吸附机制存在较大差异。特别是，BC 上 Cd 的吸附是由于 Cd(OH)和 CdCO 的沉淀形成以及与羰基和羧基的相互作用，而在 SBC 上，吸附主要是由于 CdS 和 CdHS 的形成以及与有机硫化物的相互作用。在培养实验中，SBC 和 BC 的添加提高了 pH 值，并降低了土壤中有效 Cd 的浓度。与对照相比，BC 和 SBC 处理分别使土壤中有效 Cd 的含量显著降低了 15.86%22.10%和 22.72%27.90%。
