Qi Tieyue, Zhang Shuo, Zhang Jingzhao, Li Tong, Xing Lei, Fang Zhimo, An Shanlong, Xu Zhongfei, Xiao Huining, Wang Lidong
Hebei Key Laboratory of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, China.
MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China.
Environ Sci Technol. 2023 Mar 7;57(9):3905-3916. doi: 10.1021/acs.est.2c09606. Epub 2023 Feb 22.
Hexavalent chromium (Cr(VI)) is a highly toxic substance in wastewater, triggering grievous detriment to aquatic life and human health. Magnesium sulfite is spawned along with the desulfurization process in coal-fired power plants, which is usually disposed of as solid waste. Here, a "waste control by waste" method was proposed upon the redox of Cr(VI)-sulfite, in which highly toxic Cr(VI) is detoxicated and sequent enriched on a novel biochar-induced cobalt-based silica composite (BISC) due to the forced electron transfer from chromium to surface hydroxyl. The immobilized Cr on BISC gave rise to the reconstruction of catalytic active sites "Cr-O-Co", which further enhance its performance in sulfite oxidation by elevating O adsorption. As a result, the sulfite oxidation rate increased by 10 times compared with the non-catalysis benchmark together with the maximum chromium adsorption capacity being 120.3 mg/g. Therefore, this study provides a promising strategy to simultaneously control highly toxic Cr(VI) and sulfite, achieving high-grade sulfur resource recovery for wet magnesia desulfurization.
六价铬（Cr(VI)）是废水中的一种剧毒物质，会对水生生物和人类健康造成严重损害。亚硫酸镁是燃煤电厂脱硫过程中产生的，通常作为固体废物处理。在此，基于Cr(VI)-亚硫酸盐的氧化还原反应提出了一种“以废治废”的方法，其中剧毒的Cr(VI)被解毒，并由于铬向表面羟基的强制电子转移而随后富集在一种新型生物炭诱导的钴基二氧化硅复合材料（BISC）上。固定在BISC上的Cr导致催化活性位点“Cr-O-Co”的重构，通过提高O吸附进一步增强其在亚硫酸盐氧化中的性能。结果，亚硫酸盐氧化速率比非催化基准提高了10倍，同时最大铬吸附容量为120.3 mg/g。因此，本研究提供了一种同时控制剧毒Cr(VI)和亚硫酸盐的有前景的策略，实现了用于湿式氧化镁脱硫的高品位硫资源回收。
