ABSTRACT

In this work, attapulgite (ATP)-based dual sensitive poly (N-isopropylacrylamide-co-acrylic acid) composite hydrogel, P(NIPAM-co-AA)/ATP, was prepared by free radical polymerization. The prepared composite hydrogel was characterized via methods of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta potential analysis and Brunauer, Emmett, and Teller (BET) etc. The composite hydrogel showed pH and temperature sensitive behaviour, with lower critical solution temperature (LCST) of 35°C and highest swelling occurred at pH 8.0. The adsorption of methyl violet (MV) can be controlled by the hydrogel responsiveness, and 95.78% of MV can be removed at pH 8.0 and 35°C. The addition of a small amount of ATP (3 Wt%) can improve the swelling ratio and adsorption capacity. Kinetic analysis demonstrated that the experimental data were best fitted to the pseudo-second order model. Isotherm analysis showed that the equilibrium data followed Langmuir model with the adsorption capacity of 168.35 mg g⁻¹. In addition, the composite hydrogel has high adsorption selectivity for cationic dyes, and MV-loaded hydrogel is easy to regenerate, which can be used for successive adsorption cycles. These results demonstrate that the composite hydrogel has potential application in dye wastewater treatment.

摘要

在这项工作中，通过自由基聚合制备了基于凹凸棒石（ATP）的双敏聚（N-异丙基丙烯酰胺-共-丙烯酸）复合水凝胶P（NIPAM-co-AA）/ ATP。采用扫描电子显微镜（SEM）、傅里叶变换红外光谱（FT-IR）、zeta电位分析和Brunauer、Emmett和Teller（BET）等方法对制备的复合水凝胶进行表征。复合水凝胶表现出pH和温度敏感行为，较低的临界溶解温度 (LCST) 为 35°C，最高溶胀发生在 pH 8.0。甲基紫 (MV) 的吸附可以通过水凝胶的响应性来控制，在 pH 8.0 和 35°C 时可以去除 95.78% 的 MV。添加少量ATP（3 Wt%）可以提高溶胀率和吸附能力。动力学分析表明，实验数据最适合伪二阶模型。等温线分析表明，平衡数据符合Langmuir模型，吸附量为168.35 mg g^-1。此外，复合水凝胶对阳离子染料具有较高的吸附选择性，载有MV的水凝胶易于再生，可用于连续吸附循环。这些结果表明复合水凝胶在染料废水处理中具有潜在的应用价值。