Reduction coupling immobilization is one of the most commonly adopted strategies for the remediation of Cr(VI) contamination. Biochar is a carbon-rich material with abundant active functional groups for sorption and reduction reactions. In previous reports, phytomass derived biochars and organic functional groups have been emphasized, while the performance of sludge derived biochar (SBC) has often been understated. In the present study, a 30 d kinetic study proved that the removal route involved the sorption of Cr(VI), reduction to Cr(III) and immobilization of Cr(III), and that the sorption process was the primary and rate determining step. As a result of the SBC alkalinity, the solution pH increased, and sorption was largely inhibited, which then governed the overall removal ratio. The FTIR spectra suggested the involvement of hydroxyls in these processes. Low molecular weight organic acids accelerated the removal process in the early phase and improved the reduction process.

还原偶联固定是修复 Cr(VI) 污染最常用的策略之一。生物炭是一种富碳材料，具有丰富的吸附和还原反应活性官能团。在之前的报告中，植物团衍生的生物炭和有机官能团得到了强调，而污泥衍生的生物炭 (SBC) 的性能往往被低估了。在本研究中，30 d 的动力学研究证明，去除途径涉及 Cr(VI) 的吸附、还原为 Cr(III) 和 Cr(III) 的固定化，并且吸附过程是主要和速率决定步骤. 由于 SBC 的碱度，溶液 pH 值增加，吸附受到很大抑制，从而控制了整体去除率。FTIR 光谱表明羟基参与了这些过程。低分子量有机酸加速了早期的去除过程，改善了还原过程。