原位合成层状双氢氧化物处理含镍废水

利用配制的含镍模拟废水,研究了金属离子在层状双氢氧化物(layer double hydroxide,LDH)结构中的嵌入作用和利用原位合成LDH方法处理含重金属废水的可行性.通过单因素实验和正交实验,研究了pH值、温度、Mg2 与Al3 的摩尔比值对镍去除率的影响.结果表明:影响镍离子去除效率的因素主要是Mg2 与Al3 的摩尔比、pH值及镍离子初始浓度,且主次关系为pH值＞Ni2 初始浓度＞Mg与Al摩尔比.当pH在8.5,Mg2 /Al3 比值为1～2时,镍离子去除率最高,Mg2 ,Al3 利用率也较高.同时沉淀出的固体样品经X射线衍射和红外图谱分析证实为LDH晶体结构,Ni2 取代了部分Mg2 嵌入到LDH的八面体层板中.

TREATMENT OF WASTEWATER CONTAINING NICKEL BY LAYER DOUBLE HYDROXIDE SYNTHESIS IN SITU

The possibility of removing Ni2+ from imitative wastewater in the laboratory by its embedding effect during layer double hydroxide (LDH) synthesis in situ was studied. The effects of pH value, reaction temperature, molar ratio of Mg2+ to Al3+and initial concen-tration of Ni2+ on removal efficiency of Ni2+ from wastewater was studied by the single factor test and orthogonal experiment methods. The results show that the key factors affecting the removal of Ni2+ are the molar ratio of Mg2+ to Al3+, pH value and initial concentration of Ni2+, and the order of the degree of effect is: pH>concentration of Ni2+>molar ratio of Mg2+ to Al3+ ratio. The maximal removal efficiency of Ni2+ was obtained when the pH was 8.5, and the molar ratio of Mg2+ to Al3+ ranged from 1 to 2. Addition of Mg and Al can be beneficial. The precipitate of the sample was analyzed by X-ray diffraction and infrared spectrometry. The results show that the precipitate is the LDH crystal. This indicates that some Mg2+ is replaced by Ni2+, and Ni2+ is embedded into the structure of the LDH octahedron.