Department of Environmental Nano-materials, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; School of Environmental Science and Engineering, Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China.
Department of Environmental Nano-materials, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
Bioresour Technol. 2018 Jul;260:294-301. doi: 10.1016/j.biortech.2018.03.116. Epub 2018 Mar 31.
Heavy metal ions coexisting with salts in the contaminant water are difficult to remove due to the interference of salts. Herein, biochars were pyrolyzed by corn straw at different temperatures, aiming to remove Cr(VI) in the presence of salts. Results show that biochars had surprisingly selective adsorption of Cr(VI). X-ray photoelectron and X-ray absorption near edge spectra revealed that Cr(VI) was reduced to Cr(III). All the adsorption was conducted at pH ∼ 7, which differed from the previous studies that Cr(VI) could only be reduced at pH 2-4. Environmental persistent free radicals (EPFRs) on biochars were found to play the role in reducing Cr(VI) in neutral solutions, which was confirmed by electron spin resonance and free radical quenching. The biochar with EPFRs reveals a highly selective removal of Cr(VI), which has implications for the remediation of contaminated water. This work provides a new insight into biochar's properties and potential environmental applications.
由于污染物水中盐分的干扰，重金属离子与盐共存时难以去除。在此，采用玉米秸秆在不同温度下热解制备生物炭，旨在去除盐存在下的 Cr(VI)。结果表明，生物炭对 Cr(VI)具有惊人的选择性吸附。X 射线光电子能谱和 X 射线吸收近边谱表明 Cr(VI)被还原为 Cr(III)。所有吸附均在 pH∼7 下进行，这与之前的研究不同，之前的研究表明 Cr(VI)只能在 pH 2-4 下被还原。在中性溶液中，生物炭上的环境持久性自由基（EPFRs）被发现起到还原 Cr(VI)的作用，这通过电子自旋共振和自由基猝灭得到了证实。具有 EPFRs 的生物炭对 Cr(VI)具有高选择性去除能力，这对污染水的修复具有重要意义。这项工作为生物炭的性质和潜在的环境应用提供了新的见解。
