多种铁改性和未改性生物炭对模拟地下水中六价铬的去除  

Removal of Hexavalent Chromium from Simulated Groundwater by Variety of Iron-Modified and Unmodified Biochars

作　　者：王晟 冯翔 李兵 郭林 曹坤 刘鹏 Wang Sheng;Feng Xiang;Li Bing;Guo Lin;Cao Kun;Liu Peng(College of Environment,China University of Geosciences,Wuhan 430074,China;Henan Institute of Geological Survey,Zhengzhou 450001,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074 [2]河南地质调查院,郑州450001

出　　处：《吉林大学学报（地球科学版）》2021年第1期247-255,共9页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41877478);国家重点研发计划项目(2018YFC1801706-04)。

摘　　要：为了研究不同类型的生物炭对模拟地下水中去除Cr(Ⅵ)的影响,选用杨木、柳木、桃木和松木为原料,分别在300℃和600℃热解温度下,制备不同粒径、经氯化铁改性的和未改性的20种生物炭,设计了一系列批实验,探究不同种类的生物炭对模拟地下水中Cr(Ⅵ)的去除效果;并采用傅里叶变换红外光谱(FTIR)和X射线近边吸收光谱(XANES)研究了生物炭去除Cr(Ⅵ)的机理。结果表明:在300℃下热解制成的改性生物炭,对Cr(Ⅵ)去除率均达到了99.0%以上;和粒径2 mm的生物炭相比,粒径<0.5 mm的生物炭对Cr(Ⅵ)有更好的去除效果;拟一级动力学方程较好地描述了300℃热解温度下杨木铁改性生物炭(FeCl3BC300Y)对Cr(Ⅵ)的去除过程。XANES分析结果表明,FeCl3BC300Y中的铬以三价的形态(Cr(Ⅲ))存在,FTIR分析表明羟基和羧基参与了Cr(Ⅵ)的去除。生物炭通过氧化还原和络合作用去除Cr(Ⅵ)。铁改性生物炭有望作为可渗透反应墙的填充材料,成为修复Cr(Ⅵ)污染地下水的新型材料。Biochar is usually used in Cr(Ⅵ) removal due to its micro porous structure and huge specific surface area, but different biochar has different removal efficiency. Choosing poplar, willow, peach,and pine as feedstocks, twenty types of biochar were prepared through pyrolysis of the FeCl3-modified and unmodified biomass with different particle sizes at 300 °C or 600 °C, respectively. A batch of experiments were performed to evaluate the efficiency of different biochar in removing hexavalent chromium from the simulated groundwater. The mechanism of Cr(Ⅵ) removal by biochar was investigated using Fourier transform infrared(FTIR) spectroscopy and X-ray absorption near edge spectrum(XANES). The results showed that the removal efficiency of the modified biochar by pyrolysis at 300 °C was over 99.0% of Cr(Ⅵ);The biochar(<0.5 mm) showed better removal efficiency than the biochar with a particle size of 2 mm;The Cr(Ⅵ) removal process by FeCl3 BC300 Y could be well described by the pseudo-first-order equation;XANES analysis suggested that the chromium on FeCl3 BC300 Y was in a trivalent state, and FTIR analysis indicated that hydroxyl and carboxylate groups contributed to Cr(Ⅵ) removal. The mechanism of Cr(Ⅵ) removal by biochar included reduction and complexation. The biochar modified by iron is expected as a filler material of permeable reactive barriers, and will become a new material to repair groundwater contaminated by hexavalent chromium.

关 键 词：生物炭 铁改性 六价铬去除 

分 类 号：X523[环境科学与工程—环境工程]