摘要
以壳聚糖为生物质碳源,通过一步水热碳化法对凹凸棒石进行亲有机改性,对改性凹凸棒石进行表征,研究了其对Cr(Ⅵ)的静态和动态吸附性能,对其除Cr(Ⅵ)机制进行了初步探讨.结果表明,改性凹凸棒石表面有丰富的羟基、氨基和羧基等有机官能团,壳聚糖碳化产物成功负载于凹凸棒石表面.在实验的pH值范围内,总铬去除率随pH值增加先增大后减小,pH为1和2时总铬去除率分别为11.7%和80.8%,pH为3时总铬去除率降至10.2%.总铬吸附量随Na^+浓度增加而降低.对总铬的吸附等温线符合Langmuir模型,最大吸附量高达204.1 mg/g.改性凹凸棒石对总铬的动态吸附主要受颗粒内扩散控制,在强酸性条件下(pH=2),去除Cr(Ⅵ)是吸附-还原-再吸附的耦合过程.
Attapulgite was organically modified through one-step hydrothermal carbonization of chitosan as a carbon source under mild temperature, its haracterization was examined. The static and dynamic adsorption properties of Cr（VI） on modified attapulgite were investigated, and the mechanism of the removal of Cr（VI） was discussed in detail. The results indicated that a large number of hydroxyl, carboxyl and amino groups were loaded on attapulgite, suggesting that product of hydrothermal carbonization of chitosan was deposited on the surface of attapulgite. The removal rate of total chromium increased firstly and then decreased with the increase ofpH values, and the removal rate of total chromium get up to 11.7% and 80.8% at pH 1 and 2, respectively, and then decreased sharply to 10.2% at pH 3. Adsorption capacity for total chromium on modified attapulgite decreased with the increase of the concentration of sodium ion, adsorption isotherm of total chromium could be well described by Langmuir model, the maximum adsorption capacity for total chromium attained 204.1 mg/g. The results of dynamic adsorption curves implied that the adsorption of total chromium was mainly controlled by the intra particle diffusion. The removal of total chromium was a coupling process of adsorption, reduction and adsorption again under strong acidic condition （pH=2）.
出处
《过程工程学报》
CAS
CSCD
北大核心
2017年第2期263-270,共8页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:41401553)
关键词
凹凸棒石
壳聚糖
水热碳化
Cr(Ⅵ)
吸附
还原
attapulgite
chitosan
hydrothermal carbonization
Cr（VI）
adsorption
reduction
