有机无机杂化层状硫属化合物对水中六价铬的吸附  

Adsorption of hexavalent chromium in water by organic-inorganic hybrid layered chalcogenide

作　　者：蔡节奎 李建荣[2] CAI Jiekui;LI Jianrong(School of Civil Engineering,Yango University,Fuzhou,350015,China;Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,361021,China)

机构地区：[1]阳光学院土木工程学院,福州350015 [2]中国科学院城市环境研究所,厦门361021

出　　处：《环境化学》2022年第3期1060-1068,共9页Environmental Chemistry

基　　金：国家自然科学基金(51708535)资助.

摘　　要：有机无机杂化层状硫属化合物[CH_(3)NH_(3)]_(2x)Mn_(x)Sn_(3−x)S_(6)·_(0.5)H_(2)O(x=0.5—1.1)(CMS)对水中Cr(Ⅵ)具有良好的吸附性能。采用XRD、SEM、XPS、EDS等手段表征了CMS吸附前后的化学组成、结构和微观形貌。CMS吸附Cr(Ⅵ)后导致层间距变大和颗粒表面变粗糙。考察了pH、反应时间、反应温度、初始浓度和共存离子等因素对CMS吸附Cr(Ⅵ)的影响。溶液pH明显影响CMS对Cr(Ⅵ)的吸附量。结果表明,在pH=2时,CMS的吸附量达到最大值。吸附过程的活化能为47.34 kJ·mol^(−1)且是一个吸热过程。在不同温度下,动力学数据符合准二级动力学模型。Langmuir等温吸附模型可以用来描述不同反应温度下的吸附平衡过程。在10、25、40℃下,CMS对Cr(Ⅵ)的最大吸附量分别是122.4、251.9、271.1 mg·g^(−1)。溶液中共存阴离子对吸附的影响顺序为:磷酸盐>硫酸盐>氯盐>硝酸盐。一部分被吸附的Cr(Ⅵ)会被还原为Cr(Ⅲ)。吸附后的CMS可以用NaOH(1 mol·L^(−1))再生并重复使用。本研究将为有机无机杂化层状硫属化合物去除重金属阴离子提供科学依据和技术基础。The organic–inorganic hybrid layered chalcogenide[CH_(3)NH_(3)]_(2x)Mn_(x)Sn_(3−x)S_(6)·_(0.5)H_(2)O(x=0.5—1.1)(CMS)exhibited excellent adsorption properties for Cr(Ⅵ)removal in water.XRD,SEM,XPS and EDS were used to characterize the chemical composition,crystal structure and micro-morphologies of CMS before and after adsorption.The interlayer of CMS became larger and the particle surface became coarse after adsorption of Cr(Ⅵ).The effects of pH,reaction time,reaction temperature,initial concentration and coexisting ions on Cr(Ⅵ)removal by CMS were investigated.The pH had obvious effect on the adsorption capacity.The adsorption on CMS reached the maximum point at pH of 2.The activation energy for the adsorption process was calculated to be 47.34 kJ·mol^(−1)and the adsorption process is endothermic.Kinetic data were fit well to a pseudo-second-order kinetic model at different temperatures.The Langmuir adsorption isotherm was used to fit the adsorption equilibrium process at different temperatures.The maximum adsorption capacity of CMS at temperature of 10℃,25℃and 40℃were 122.4 mg·g^(−1),251.9 mg·g^(−1)and 271.1 mg·g^(−1),respectively.The degree of inhibition by coexisting anion followed the sequence:phosphate>sulfate>chloride>nitrate.A part of adsorbed Cr(Ⅵ)was reduced to Cr(Ⅲ).The adsorbed CMS can be regenerated by using NaOH(1 mol·L^(−1))and reused again.This study will provide the basis in theory and technique for the application of organic-inorganic hybrid layered chalcogenide compounds to remove heavy metal anions.

关 键 词：硫属化合物 铬 吸附 有机无机杂化 

分 类 号：X703[环境科学与工程—环境工程]