阳离子表面活性剂改性的活性炭吸附砷(V)和砷(Ⅲ)  

Adsorption of arsenate and arsenite by cationic surfactant-modified activated carbon

作　　者：陈维芳[1] 王宏岩[1] 于哲[1] 林淑英[1] 

机构地区：[1]上海理工大学环境与建筑学院,上海200093

出　　处：《环境科学学报》2013年第12期3197-3204,共8页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金面上项目(No.51078233);上海浦江人才计划(No.10PJ1407900);上海教委科研创新项目(No.11YZ115)~~

摘　　要：选用阳离子表面活性剂十六烷基三甲基氯化铵(CTAC)、癸基三甲基溴化铵(MTAB)以及三甲基正十四烷溴化铵(DTAB)改性活性炭.结果发现,表面活性剂加载使得活性炭的比表面积、孔径体积和表面Zeta电位发生改变.改性后的活性炭用来吸附水中的砷酸盐和亚砷酸盐.吸附等温实验结果显示,改性后活性炭对砷酸盐的吸附能力有显著提高,但对亚砷酸盐则只有在pH>10才有明显吸附.无论对砷酸盐还是亚砷酸盐,CTAC改性效果均要好于MTAB和DTAB.改性后活性炭对砷酸盐的吸附主要通过离子交换,但离子交换并不是唯一的吸附机理.砷酸盐的吸附受到溶液pH值和水中其他阴离子的竞争吸附的影响.中性pH范围内吸附最佳,而阴离子对砷酸盐的竞争则是PO3-4>SO2-4>NO-3.Cationic surfactants cetyltrimethylammonium chloride, decyltrimethylammonium bromide （DTAB） and myristyltrimethylammonium bromide （MTAB） were employed to modify activated carbon. Surfactant modification resulted in changes in surface area, pore volume and surface Zeta potential. Modified activated carbons were investigated for adsorption of arsenate and arsenite. Results from isotherm tests revealed that surfactant modification was able to greatly enhance arsenate adsorption while significant improvement in arsenite uptake only occurred when pH was above 10. For both arsenate and arsenite, modification by CTAC was better than MTAB and DTAB. Ion exchange was proven to be the predominant but not the sole mechanism in arsenate removal by the surfactant-modified activated carbon. Also, arsenate adsorption was affected by factors such as solution pH and the presence of other anions. Arsenate adsorption peaked around neutral pH while competition with anions followed the order of PO43- 〉SO42- 〉NO3-.

关 键 词：阳离子表面活性剂 活性炭 砷酸盐 亚砷酸盐 吸附 

分 类 号：X703.1[环境科学与工程—环境工程]