氨基化丙烯酸基磁性树脂对Cu^(2+)的吸附特性

Adsorption Properties of Amine Chelating Acrylate-Based Magnetic Resin Toward Cu^(2+) Ions

以N,N'-亚甲基双丙烯酰胺为交联剂,利用悬浮聚合法制备聚丙烯酸甲酯磁性树脂(RM),并经乙二胺改性后制得一种新型磁性吸附剂(RMA)。采用差热/热重分析(DTA/TGA)以及红外光谱等对其进行了表征,并考察了它对Cu2+的吸附性能。结果表明,RMA树脂粒径30~60μm,Fe3O4质量分数为6.7%,对Cu2+的吸附等温线符合Langmuir模型,饱和吸附容量2.13 mmol/g,高于未改性树脂(RM,1.15 mmol/g)。吸附动力学可用拟二级反应模型拟合。热力学分析表明RMA对Cu2+的吸附过程能自发进行,焓变为-17.88 kJ/mol,熵变为-2.06 J/(mol.K),Bibbs自由能为-17.26^-17.19 kJ/mol。吸附剂用1 mol/L HCl洗脱再生,脱附率高于97%。

Magnetic poly （acrylate methyl ester） resin （RM） was prepared by suspension polymerization using N, N＇- methylenebisacrylamide as a crosslinker. Then RM was modified with ethylenediamine to give a novel amine- chelating magnetic resin（RMA）. This adsorbent was characterized by thermal analysis （DTA/TGA） and FT--IR. The adsorption behaviour of the adsorbent toward Cu^2＋ ions was investigated. The results show that the diameter of RMA is 30-60μm and the mass fraction of Fe3O4 is 6.7%. The isotherm adsorption data obeyed the Langmuir model. In the aspect of maximum adsorptiom capacity, RMA displayed higher （2. 13 mmol/g） for Cu^2＋ than that of RM （1. 15 mmol/g）. Kinetics studies indicate that the adsorption reaction followed the pseudo-- second order kinetics. Thermodynamic analysis indicates that the adsorption process was spontaneous, and that the value of enthalpy changes was --17.88 kJ/mol, the entropy changes was - 2.06 J/（mol · K） and the Gibbs free energy was -- 17.26 - -- 17.19 kJ/mol. Regeneration of the adsorbent was achieved using 1 mol/L HC1 with the desorption ratio of more than 97%.