Chen Yanan, An Dong, Sun Sainan, Gao Jiayi, Qian Linping
Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai 200433, China.
Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Materials (Basel). 2018 Feb 9;11(2):269. doi: 10.3390/ma11020269.
Cr adsorption on wood-based powdered activated carbon (WPAC) was characterized by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The highest Cr(VI) adsorption (40.04%) was obtained under acidic conditions (pH 3), whereas Cr removal at pH 10 was only 0.34%. The mechanism of Cr(VI) removal from aqueous solutions by WPAC was based on the reduction of Cr(VI) to Cr(III) with the concomitant oxidation of C-H and C-OH to C-OH and C=O, respectively, on the surface of WPAC, followed by Cr(III) adsorption. Raman spectroscopy revealed a change in the WPAC structure in terms of the / band intensity ratio after Cr(VI) adsorption. SEM-EDS analysis showed that the oxygen/carbon ratio on the WPAC surface increased from 9.85% to 17.74%. This result was confirmed by XPS measurements, which showed that 78.8% of Cr adsorbed on the WPAC surface was in the trivalent state. The amount of oxygen-containing functional groups on the surface increased due to the oxidation of graphitic carbons to C-OH and C=O groups.
通过扫描电子显微镜结合能谱仪（SEM-EDS）、拉曼光谱和X射线光电子能谱（XPS）对木质粉状活性炭（WPAC）上的Cr吸附进行了表征。在酸性条件（pH 3）下获得了最高的Cr(VI)吸附率（40.04%），而在pH 10时Cr的去除率仅为0.34%。WPAC从水溶液中去除Cr(VI)的机制是基于WPAC表面上Cr(VI)还原为Cr(III)，同时C-H和C-OH分别氧化为C-OH和C=O，随后Cr(III)被吸附。拉曼光谱显示，Cr(VI)吸附后WPAC结构在/带强度比方面发生了变化。SEM-EDS分析表明，WPAC表面的氧/碳比从9.85%增加到17.74%。XPS测量证实了这一结果，其表明吸附在WPAC表面的Cr中有78.8%处于三价状态。由于石墨碳氧化为C-OH和C=O基团，表面含氧官能团的数量增加。
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