纳米复合水凝胶的制备及其对重金属离子的吸附  

Preparation of Nanocomposite Hydrogel and Its Adsorption of Heavy Metal Ions

作　　者：朱倩[1] 李正魁[1] 张一品[1] 韩华杨 王浩[1] 

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023

出　　处：《环境科学》2016年第8期3192-3200,共9页Environmental Science

基　　金：国家水体污染控制与治理科技重大专项(2013ZX07101-014)

摘　　要：以N-羟甲基丙烯酰胺(HMAm)和2-丙烯酸羟乙酯(HEA)为共聚单体,采用60Co-γ射线低温辐照法,制备了具酰胺基和羟基的新型聚合物水凝胶p(HMAm/HEA),运用原位沉淀法制备了纳米复合水凝胶HMO-p(HMAm/HEA),用于对重金属离子Pb^(2+)和Cu^(2+)的去除.应用SEM、TEM、FTIR等方法对水凝胶进行表征,表征结果证明p(HMAm/HEA)是HMAm和HEA的共聚产物,且纳米水合氧化锰(HMO)成功负载.探讨了溶液初始p H值、反应温度、重金属初始浓度、反应时间、竞争性Ca^(2+)和Na+浓度等因素对纳米复合水凝胶吸附过程的影响,研究表明HMO-p(HMAm/HEA)对Pb^(2+)和Cu^(2+)的吸附过程不受温度的影响;吸附量随着溶液初始p H的升高而增加;吸附过程属于Langmuir单分子层吸附;吸附动力学过程符合准二级动力学吸附;高浓度的Ca^(2+)和Na^+对吸附过程影响不大.XPS图谱进一步证明吸附机制是重金属离子与羟基间的离子交换作用.采用0.05 mol·L^(-1)的HCl溶液为脱附剂,经过4次吸附-脱附循环再生后,纳米复合水凝胶重复利用性好.An acylamino and hydroxyl functionalized hydrogel [p（ HMAm / HEA） ] was newly prepared by the60Co-γ-induced polymerization of N-hydroxymethyl acrylamide（ HMAm） and 2-hydroxyethyl acrylate（ HEA）. Then the copolymer p（ HMAm / HEA）hydrogel was utilized for in situ nanosized hydrous manganese dioxide（ HMO） loading to prepare nanocomposite hydrogel HMO-p（ HMAm/HEA） for Pb2＋and Cu2＋removal. The nanocomposite hydrogel was characterized by SEM,TEM and FTIR,showing that p（ HMAm / HEA） hydrogel was indeed a copolymer of HMAm and HEA monomers,and the loading of HMO nanoparticles onto p（ HMAm / HEA） was successful. Various influencing parameters on heavy metal ions removal by HMO-p（ HMAm / HEA）,such as initial p H,temperature,initial heavy metal concentration,contact time and competing Ca2＋and Na~＋,were estimated. The results showed that the adsorption process was temperature-independent,p H-sensitive,Langmuir monolayer adsorption and followed a pseudosecond-order rate equation. The presence of high concentrations of competing Ca2＋and Na＋had no significant effect on the adsorption process. The XPS spectra analyses further indicated that Pb2＋and Cu2＋were adsorbed via the ion exchange of —OH groups.Moreover,HMO-p（ HMAm / HEA） could be regenerated by 0. 05 mol·L-1 of HCl,and obtained excellent repeated use.

关 键 词：水合氧化锰 纳米复合水凝胶 重金属离子 吸附机制 

分 类 号：X131[环境科学与工程—环境科学] X703.1