Erdem Murat, Yüksel Erdinç, Tay Turgay, Cimen Yasemin, Türk Hayrettin
Anadolu University, Faculty of Science, Department of Chemistry, 26470 Eskişehir, Turkey.
J Colloid Interface Sci. 2009 May 1;333(1):40-8. doi: 10.1016/j.jcis.2009.01.014. Epub 2009 Jan 15.
The polymeric adsorbents were synthesized from 2-dimethylaminoethyl methacrylate (DMA) and [2-(methacryloyloxy)ethyl]dimethylhexadecylammonium bromide (DMAC(16)) monomers in the presence of ethylene glycol dimethacrylate (EDMA) cross-linking monomer using suspension polymerization technique and their adsorption efficiencies in the removal of p-nitrophenol from aqueous solutions were investigated. DMAC(16) monomer was prepared by means of modification of DMA monomer with 1-bromohexadecane. Adsorption experiments were carried out in a batch system and the experimental parameters were evaluated with respect to pH, agitation time, temperature and initial p-nitrophenol concentration. It was observed that the adsorbent poly[2-(methacryloyloxy)ethyl]dimethylhexadecylammonium bromide (p-DMAC(16)) prepared from DMAC(16) monomer was more effective in the removal of p-nitrophenol than the adsorbent poly(2-dimethylaminoethyl methacrylate) (p-DMA) prepared from DMA monomer. The effective pH ranges for the adsorption of p-nitrophenol onto p-DMAC(16) and p-DMA were 2-12 and 3-9, respectively. Langmuir and Freundlich adsorption models were used to describe the isotherms and find isotherm constants. The Langmuir model was well agreed with experimental data for both adsorbents. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models were used to understand the mechanism of the adsorption process and it fitted very well the pseudo-second-order kinetic model for each adsorbent. Thermodynamic parameters such as activation energy and changes of free energy, enthalpy, and entropy were also evaluated for the adsorption of p-nitrophenol onto each adsorbent. Additionally, reusability of the adsorbents was investigated and the results showed that both adsorbents can be employed many times without a significant loss in their adsorption capacities for the removal of p-nitrophenol from water.
采用悬浮聚合技术，以乙二醇二甲基丙烯酸酯（EDMA）为交联单体，在2-甲基丙烯酸二甲氨基乙酯（DMA）和[2-（甲基丙烯酰氧基）乙基]二甲基十六烷基溴化铵（DMAC(16)）单体存在的条件下合成了聚合物吸附剂，并研究了它们从水溶液中去除对硝基苯酚的吸附效率。DMAC(16)单体是通过用1-溴十六烷对DMA单体进行改性制备的。在间歇系统中进行吸附实验，并针对pH值、搅拌时间、温度和初始对硝基苯酚浓度对实验参数进行了评估。结果发现，由DMAC(16)单体制备的吸附剂聚[2-（甲基丙烯酰氧基）乙基]二甲基十六烷基溴化铵（p-DMAC(16)）在去除对硝基苯酚方面比由DMA单体制备的吸附剂聚（2-甲基丙烯酸二甲氨基乙酯）（p-DMA）更有效。对硝基苯酚在p-DMAC(16)和p-DMA上吸附的有效pH范围分别为2-12和3-9。采用朗缪尔和弗伦德利希吸附模型来描述等温线并求出等温常数。朗缪尔模型与两种吸附剂的实验数据都吻合得很好。采用准一级、准二级和颗粒内扩散动力学模型来理解吸附过程的机理，并且它与每种吸附剂的准二级动力学模型拟合得非常好。还评估了对硝基苯酚在每种吸附剂上吸附的热力学参数，如活化能以及自由能、焓和熵的变化。此外，研究了吸附剂的可重复使用性，结果表明两种吸附剂都可以多次使用，且在从水中去除对硝基苯酚时其吸附容量不会有显著损失。
