摘要
以重金属Cr(Ⅵ)为目标污染物,在两种实验条件下(实验柱Ⅰ为模拟污染水样,实验柱Ⅱ为实际污染水样)考察了壳聚糖稳定纳米铁对Cr(Ⅵ)的去除能力。实验柱Ⅰ和实验柱Ⅱ分别在第160PV和127PV时发生了击穿效应。与实验柱Ⅰ相比,实验柱Ⅱ中壳聚糖稳定纳米铁对Cr(Ⅵ)的去除能力降低了25%。SEM表征显示,实验柱Ⅱ中壳聚糖稳定纳米铁的表面形成了许多葡萄状晶体,它们的存在导致实验柱Ⅱ中纳米铁的去除能力明显低于实验柱Ⅰ。XPS表征显示,由于Ca和Mg的氢氧化物替代了部分铁氢氧化物,导致实验柱Ⅱ中壳聚糖稳定纳米铁表面Fe原子的相对含量低于实验柱I。Cr元素高分辨率XPS能谱分析显示,在实验柱Ⅰ的条件下Cr(Ⅵ)被还原得更充分,而且在两种实验条件下都有部分Cr(Ⅵ)被吸附在纳米铁表面最终没有被零价铁所还原。
The capacity of chitosanstabilized Fe^0 nanoparticles （chitosanFe^0） to remove Cr（ V[ ） from water was examined with column experiment（column Ⅰ： stimulated Cr（ VI ） contaminated water, column Ⅱ ： Cr（V[） contaminated surface water）. In column Ⅰ and column Ⅱ, Cr（VI ） attained its breakthrough after 160 pore volume（PV） and 127 PV, respectively. Compared with column I, column Ⅱ decreased by 25% in the Cr（ VI ） removal capacity of chitosanFe^0. According to the SEM micrographs, in the presence of calcium and magnesium hardness botryoidal clusters were observed on the chitosanFe^0 from column Ⅱ which led to the decrease of Cr（ VI ） removal capacity for chitosanFe^0. Characterizations with XPS revealed that the Fe atom ratio on chitosanFe^0 in column I was lower than that in column Ⅱ, due to the replacement of ferric oxyhydroxide by passivated precipitates containing calcium and magnesium. The results of highresolution XPS demonstrated that Cr（ VI ） was easier to be reduced in column I than in column Ⅱ and under both conditions a little proportion of Cr（ VI ） was adsorbed on the chitosanFe^0 surface which was not reduced by zerovalent iron at the end of experiment.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2012年第3期593-597,共5页
Journal of Agro-Environment Science
基金
天津市基金重点项目(07JCZDJC01800)
国家水体污染控制与治理科技重大专项(2008ZX07425-008-002)
中央级公益性科研院所基本科研业务费(BSRF201010)
关键词
壳聚糖
纳米铁
六价铬Cr(Ⅵ)
chitosan
nanoscale zerovalent iron
hexavalent chromium Cr（ VI ）
