Soil Chemistry Laboratory, Department of Soil Science, Faculty of Agriculture, University of Maragheh, P. O. Box 55181-83111, Maragheh, Iran.
Polymer Research Laboratory, Department of Chemistry, Faculty of Science, University of Maragheh, Maragheh, Iran.
Environ Sci Pollut Res Int. 2018 May;25(15):14977-14988. doi: 10.1007/s11356-018-1485-5. Epub 2018 Mar 17.
In this study, magnetic nanocomposite hydrogels based on polyvinyl alcohol were synthesized. Magnetic polyvinyl alcohol/laponite RD (PVA-mLap) nanocomposites were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results indicated that PVA-mLap had desirable magnetic-sorption properties and magnetic-laponite nanoparticles were successfully synthesized and added to polyvinyl alcohol. The present nanocomposites were applied to remove Cd from aqueous solution. The influence of initial Cd concentration, magnetic-laponite concentration, pH, and ionic strength on adsorption isotherm was investigated. Heterogeneity of adsorption sites was intensified by increasing magnetic concentration of adsorbents and by rising pH value. Results of ionic strength studies indicated that by increasing ionic strength more than four times, the adsorption of Cd has only decreased around 15%. According to the results, the dominant mechanism of Cd sorption by the present adsorbents was determined chemical and specific sorption. Therefore, the use of the present nanocomposites as a powerful adsorbent of Cd in the wastewater treatment is suggested. Isotherm data were described by using Freundlich and Langmuir models, and better fitting was introduced Langmuir model.
本研究合成了基于聚乙烯醇的磁性纳米复合水凝胶。采用扫描电子显微镜、X 射线衍射、透射电子显微镜和傅里叶变换红外光谱对磁性聚乙烯醇/拉蓬土 RD（PVA-mLap）纳米复合材料进行了表征。结果表明，PVA-mLap 具有良好的磁吸附性能，成功合成了磁性拉蓬土纳米颗粒并添加到聚乙烯醇中。本研究将纳米复合材料应用于从水溶液中去除 Cd。考察了初始 Cd 浓度、磁性拉蓬土浓度、pH 值和离子强度对吸附等温线的影响。通过增加吸附剂的磁性浓度和提高 pH 值，增强了吸附位点的不均匀性。离子强度研究结果表明，当离子强度增加四倍以上时，Cd 的吸附仅降低了约 15%。根据结果，确定了本研究中吸附剂对 Cd 的吸附主要是化学和特异性吸附。因此，建议将本纳米复合材料用作废水处理中 Cd 的有效吸附剂。等温线数据分别采用 Freundlich 和 Langmuir 模型进行描述，Langmuir 模型的拟合更好。
