Zhang Ling, Jin SuWan, Wang Yong, Ji Jiang
a School of Environmental and Chemical Engineering , Shanghai University , Shanghai , People's Republic of China.
b XiaMen JiangTian Membrane Biotechnology LTD , Xiamen , People's Republic of China.
Environ Technol. 2018 Apr;39(8):997-1006. doi: 10.1080/09593330.2017.1317843. Epub 2017 Apr 27.
In this study, a novel adsorbent of expanded graphite loaded with lanthanum (III)-iron (III) hydroxide (EG-LaFe) was prepared for phosphate removal. The single factor of oscillating time, La/Fe molar ratio and total concentration of EG-LaFe were studied for optimization of preparation conditions. Effects of contact time, initial phosphate concentration, adsorption temperature and coexisting ions on the phosphate removal performance of EG-LaFe were investigated in detail. Adsorption kinetics and isothermal adsorption studies showed that the pseudo-second-order and the Langmuir model fitted the experimental data quite well. Thermodynamic analysis showed that the phosphate adsorption of EG-LaFe was spontaneous and endothermic. In addition, EG-LaFe exhibit high sorption selectivity toward phosphate over other coexisting ions. The phosphate adsorption mechanism was investigated by means of pH study, scanning electron microscopy and Fourier transform infrared spectroscopy. The results demonstrated that the probable mechanisms of phosphate adsorption on EG-LaFe were the replacement of surface hydroxyl groups (M-OH), electrostatic interaction and Lewis acid-base interaction.
在本研究中，制备了一种负载氢氧化镧（III）-铁（III）的新型膨胀石墨吸附剂（EG-LaFe）用于去除磷酸盐。研究了振荡时间、La/Fe摩尔比和EG-LaFe总浓度等单因素以优化制备条件。详细考察了接触时间、初始磷酸盐浓度、吸附温度和共存离子对EG-LaFe去除磷酸盐性能的影响。吸附动力学和等温吸附研究表明，准二级动力学模型和朗缪尔模型与实验数据拟合良好。热力学分析表明，EG-LaFe对磷酸盐的吸附是自发的且吸热的。此外，EG-LaFe对磷酸盐的吸附选择性高于其他共存离子。通过pH研究、扫描电子显微镜和傅里叶变换红外光谱对磷酸盐吸附机理进行了研究。结果表明，磷酸盐在EG-LaFe上吸附的可能机理是表面羟基（M-OH）的置换、静电相互作用和路易斯酸碱相互作用。
