Elwakeel Khalid Z, Elgarahy Ahmed M, Mohammad Samya H
Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia and Environmental Science Department, Faculty of Science, Port-Said University, Port-Said, Egypt E-mail:
Zoology Department, Faculty of Science, Port-Said University, Port-Said, Egypt.
Water Sci Technol. 2017 Jul;76(1-2):35-48. doi: 10.2166/wst.2017.184.
Magnetic Schiff's base chitosan composite has been prepared starting from shrimp peels as a raw material. Chitosan extraction involved three main stages as preconditioning, demineralization deproteinization and deacetylation. Chitosan modification process took place through the reaction between chitosan and polymeric Schiff's base of thiourea/glutaraldehyde in the presence of magnetite. The synthetic hybrid composite was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy-energy dispersive X-ray analyses and tested as sorbent for Cr(VI) recovery from aqueous solution. The performance of the sorbent was systematically evaluated by batch sorption experiments, followed by equilibrium and kinetic studies with different mathematical models. The isotherm study demonstrate that the sorbent achieved 99.1% (sorption capacity; 252.45 mg g) removal efficiency in Cr(VI) solution with concentrations up to 400 mg/L. Experimental data gave better mathematical fitting towards pseudo-second-order kinetic model and Langmuir isotherm model. The distribution coefficient was obtained at different temperatures and the thermodynamic parameters have been calculated: the sorption is endothermic, spontaneous and contributes to increase the randomness of the system. The sorbent could be recycled for three cycles of sorption/desorption.
磁性席夫碱壳聚糖复合材料是以虾壳为原料制备的。壳聚糖的提取包括预处理、脱矿质、脱蛋白和脱乙酰化三个主要阶段。壳聚糖的改性过程是在磁铁矿存在的情况下，通过壳聚糖与硫脲/戊二醛的聚合席夫碱之间的反应进行的。通过傅里叶变换红外光谱、扫描电子显微镜-能量色散X射线分析对合成的杂化复合材料进行了表征，并将其作为从水溶液中回收Cr(VI)的吸附剂进行了测试。通过批量吸附实验，随后用不同的数学模型进行平衡和动力学研究，系统地评估了吸附剂的性能。等温线研究表明，该吸附剂在浓度高达400mg/L的Cr(VI)溶液中实现了99.1%（吸附容量；252.45mg/g）的去除效率。实验数据对伪二级动力学模型和朗缪尔等温线模型具有更好的数学拟合。在不同温度下获得了分配系数，并计算了热力学参数：吸附是吸热的、自发的，有助于增加系统的随机性。该吸附剂可以进行三个吸附/解吸循环的回收利用。
