Budimir Filip, Ptacek Carol J, Amos Richard T, Blowes David W
Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2N 3G1, Canada.
Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
Chemosphere. 2024 Dec;369:143880. doi: 10.1016/j.chemosphere.2024.143880. Epub 2024 Dec 6.
Chromium, especially in its hexavalent form (Cr(VI)), poses significant health risks due to its carcinogenic properties. Emerging research suggests that biochar, a carbon-rich material derived from biomass pyrolysis, holds promise as an effective and sustainable solution for Cr(VI) remediation. Biochar's unique physicochemical properties, such as its high surface area, porous structure, and functional groups, contribute to its exceptional adsorption capacity for metals. In a series of batch experiments with varying durations, an oak-based biochar was exposed to a 48 mg L⁻ Cr(VI) solution. The results demonstrate that the biochar effectively removed 99% of the Cr(VI) after 100 h, with a removal capacity greater than 5 mg g⁻. Fourier transform infrared (FTIR) spectroscopy suggests that the removal of Cr(VI) involved aliphatic and aromatic C-H bonds. X-ray photoelectron spectroscopy (XPS) also indicated the role of aliphatic groups in the removal process and suggested the involvement of carbonyl groups. XPS analysis also detected both Cr(III) and Cr(VI) on the surface of the biochar, indicating the occurrence of reduction and sorption processes. The presence of Cr(III) and Cr(VI) was further confirmed at the Canadian Light Source (CLS) synchrotron facility using X-ray absorption near edge structure (XANES) spectroscopy. Cr isotope analysis showed an increase in δ⁵³Cr as the concentration of Cr in solution decreased, indicating Cr(VI) reduction. The isotope data followed a Rayleigh curve with a kinetic fractionation εCr of -1.33‰, highlighting that Cr stable isotopes can effectively be used as an indicator of biochar-Cr reactions.
铬，尤其是其六价形式（Cr(VI)），因其致癌特性而带来重大健康风险。新出现的研究表明，生物炭这种源自生物质热解的富含碳的材料，有望成为一种有效且可持续的Cr(VI)修复解决方案。生物炭独特的物理化学性质，如高比表面积、多孔结构和官能团，使其对金属具有出色的吸附能力。在一系列不同时长的批量实验中，将一种基于橡木的生物炭暴露于48 mg L⁻的Cr(VI)溶液中。结果表明，该生物炭在100小时后有效去除了99%的Cr(VI)，去除容量大于5 mg g⁻。傅里叶变换红外（FTIR）光谱表明，Cr(VI)的去除涉及脂肪族和芳香族C-H键。X射线光电子能谱（XPS）也表明脂肪族基团在去除过程中的作用，并暗示了羰基的参与。XPS分析还在生物炭表面检测到了Cr(III)和Cr(VI)，表明发生了还原和吸附过程。在加拿大光源（CLS）同步加速器设施中使用X射线吸收近边结构（XANES）光谱进一步证实了Cr(III)和Cr(VI)的存在。Cr同位素分析表明，随着溶液中Cr浓度的降低，δ⁵³Cr增加，表明Cr(VI)发生了还原。同位素数据遵循瑞利曲线，动力学分馏εCr为-1.33‰，突出表明Cr稳定同位素可有效用作生物炭与Cr反应的指标。
