含咪唑啉基偕胺肟化共聚物对Cu(Ⅱ)吸附性能

Amidoxime-modifided Polymer Containing Imidazolinyl for Adsorption of Copper(Ⅱ) from Aqueous Solution

摘要:

本文以丙烯酰胺（AM）、丙烯腈（AN）、1-(2-N-烯丙基氨乙基)-2-油酸基咪唑啉（NIPA）为原料，制备了咪唑啉基偕胺肟化聚合物AM/AO/NIPA。对其进行了FTIR、SEM和TG表征，通过静态吸附实验考察了pH、吸附时间、溶液初始浓度对聚合物AM/AO/NIPA和吸附剂聚丙烯酰胺（PAM ）吸附低浓度Cu2+过程的影响，并拟合吸附动力学和等温吸附曲线探讨了吸附机理。结果表明：聚合物AM/AO/NIPA的铜吸附容量受溶液pH影响不大；当聚合物AM/AO/NIPA加入量为0.05 g时，在30 ℃，pH=5，吸附3 h后，对铜离子质量浓度为100 mg/L的溶液吸附达到平衡 ，此时吸附容量为37.32 mg/g；整个吸附过程服从准二级动力学模型，以化学吸附为主；对Langmuir和Freundlich等温吸附模型均能较好的拟合。通过Langmuir模型拟合计算得到，偕胺肟化聚合物AM/AO/NIPA的Cu2+饱和吸附量为267.38 mg/g，超过相同条件下吸附剂PAM的饱和吸附量3倍以上。AM/AO/NIPA循环使用5次后，其吸附量保留率可高达92.99%。

Abstract:

In this work, amidoxime-modified polymer containing imidazolinyl (AM/AO/NIPA) was synthesized by acrylamide (AM), acrylonitrile (AN) and 1-(2-N-allyl ammonia ethyl)-2-oleic acid imidazole (NIPA). Then, the copolymer was characterized by FT-IR, FE-SEM and TG. By the static adsorption experiment, the adsorption capacity of Cu2+ by AM/AO/NIPA was investigated and was compared with typical adsorbent polyacrylamide (PAM); also, equilibrium kinetics and isotherms were obtained and further discussed adsorption mechanism. The results showed that the Cu2+ adsorption capacity of AM/AO/NIPA was seldom effected by the pH of the weak solution. The Cu2+ adsorption to AM/AO/NIPA reached equilibrium at 30 ℃ after 3 h, the pH of original solution is 5 and initial concentration is 100 mg/L; and the adsorption capacity is 37.32 mg/g at that time. The whole adsorption process is subject to the pseudo-second-order model, which is dominated by chemical adsorption. The experimental data of the adsorption of Cu2+ by AM/AO/NIPA can be fitted well by both Langmuir and Freundlich isotherm models. Moreover, the maximum adsorption capacity of Cu2+ by AM/AO/NIPA was 267.38 mg/g, three times higher than PAM, which is calculated by fitting Langmuir isotherm models. Furthermore, the amidoxime polymer AM/AO/NIPA remain up to 92.99% of its original adsorption capacity after five circles.