Wang Wei-Dong, Hao Rui-Xia, Zhang Xiao-Xian, Wan Jing-Jing, Zhong Li-Yan
Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing 100124, China.
Huan Jing Ke Xue. 2017 Feb 8;38(2):572-579. doi: 10.13227/j.hjkx.201606187.
Aiming at the problem of phosphorus removal in water, Mg/Al-layered double hydroxides (Mg/Al-LDHs) were synthesized via optimized constant pH co-precipitation method, and highly efficient phosphorus adsorbent Mg/Al-layered double oxide(Mg/Al-LDO) was obtained when it was calcined at high temperature. Based on the adsorption characteristics of phosphorus removal, the study combined Zeta potential, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to analyze the changes of isoelectric point, crystal structure and functional group before and after adsorption. In addition, Mg/Al-LDO of phosphorus adsorption mechanism was discussed. The results indicated that using the optimized co-precipitation method in the conditions of Mg/Al=2:1, calcination temperature 450℃, and calcination time 2 h, the Mg/Al-LDO adsorption capacity of phosphate was the best, and the maximum adsorption capacity could reach 176.94 mg·g, which was basically consistent with the theoretical adsorption capacity of 191.57 mg·g, far higher than those of Mg/Al-LDHs and other phosphorus adsorbents. The results showed that the experimental data has the best fitting result with pseudo-second-order kinetics model. The adsorption process was consistent with Langmuir adsorption isotherm model. The results of Zeta potential, XRD and FTIR showed that phosphorus adsorption of Mg/Al-LDO was accomplished co-operatively by electrostatic attraction, anion in layer, ions exchange, and surface co-ordination.
针对水中除磷问题，采用优化的恒pH共沉淀法合成了镁铝层状双氢氧化物（Mg/Al-LDHs），高温煅烧后得到高效磷吸附剂镁铝层状双氧化物（Mg/Al-LDO）。基于磷去除的吸附特性，该研究结合Zeta电位、X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析了吸附前后等电点、晶体结构和官能团的变化。此外，还探讨了Mg/Al-LDO对磷的吸附机理。结果表明，在Mg/Al=2:1、煅烧温度450℃、煅烧时间2 h的条件下，采用优化的共沉淀法，Mg/Al-LDO对磷酸盐的吸附容量最佳，最大吸附容量可达176.94 mg·g，与理论吸附容量191.57 mg·g基本一致，远高于Mg/Al-LDHs和其他磷吸附剂。结果表明，实验数据与伪二级动力学模型拟合效果最佳。吸附过程符合Langmuir吸附等温线模型。Zeta电位、XRD和FTIR结果表明，Mg/Al-LDO对磷的吸附是通过静电吸引、层间阴离子、离子交换和表面配位协同完成的。
