Mechanisms of Cr(VI) removal by FeCl3-modified lotus stem-based biochar (FeCl3@ LS-BC) using mass-balance and functional group expressions
Mechanisms of Cr(VI) removal by FeCl3-modified lotus stem-based biochar (FeCl3@ LS-BC) using mass-balance and functional group expressions
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DOI：
10.1016/j.colsurfa.2018.04.054
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发表时间：
2018-08-20
影响因子：
5.2
通讯作者：
Gao, Yu
中科院分区：
文献类型：
--
作者：
Feng, Zhengyuan;Chen, Nan;Gao, Yu
合成了一种新型的氯化铁改性莲茎基生物炭（FeCl3@LS-BC）作为低成本吸附剂，用于去除水溶液中的 Cr(VI)。采用正交设计选择最佳制备条件，包括碳化温度、碳化时间、活化温度和活化时间。优化了生物炭与FeCl3的质量比。 FeCl3@LS-BC 通过表面吸附和还原机制，在 pH 值 2.03 至 10.04 范围内非常有效地去除 Cr(VI)。当Cr(VI)初始浓度为10.02 mg/L时，还原和表面吸附去除的Cr(VI)百分比分别为81.70%和18.30%。主要还原工艺步骤去除 Cr(VI) 的以下两步机理是： (1) Fe(III) 的水解提供了足够的 H+，为水溶液中的 Cr(VI) 还原创造了有利的酸性环境； (2) Cr(VI)在水相中通过与FeCl3@LS-BC的电子给体基团(C=O、-OH和C=C)接触被还原为Cr(III)。本研究证明了 FeCl3@LS-BC 作为一种适应性强、环保且有效的 Cr(VI) 去除吸附剂的前景。
A novel lotus stem-based biochar modified by ferric chloride (FeCl3@LS-BC) was synthesized as a low-cost adsorbent for the removal of Cr(VI) from aqueous solutions. The optimum preparation conditions, including carbonization temperature, carbonization time, activation temperature and activation time, were chosen using orthogonal design. Mass ratios of biochar to FeCl3 were optimized. FeCl3@LS-BC removed Cr(VI) very efficiently within the pH range from 2.03 to 10.04 by the surface sorption and reduction mechanisms. The percentage of Cr (VI) removed by reduction and surface sorption was 81.70% and 18.30%, respectively, at the initial Cr(VI) concentration of 10.02 mg/L. The following two-step mechanism of the Cr(VI) removal by the dominant reduction process step is : (1) the hydrolysis of Fe(III) supplied sufficient H+ to create a favorable acidic environment for Cr(VI) reduction in aqueous solution; (2) Cr(VI) was reduced to Cr(III) in the aqueous phase by contact with the electron donor groups of FeCl3@LS-BC (C=O, -OH and C=C). The present study demonstrated a promise of FeCl3@LS-BC as an adaptable, eco-friendly and effective sorbent for the Cr(VI) removal.