制备焙烧Mg/Al水滑石及同时去除水中氟和硬度

Preparation of Calcined Mg/Al Hydrotalcite and Simultaneous Removal of Fluorine Ions and Hardness in Water

通过共沉淀法制备焙烧Mg/Al水滑石(HTCs-400-MgAl),利用X射线衍射(XRD)和傅里叶变换红外线光谱(FTIR)对材料进行表征,研究焙烧水滑石投加的质量浓度、温度、溶液初始pH值、吸附动力学和等温吸附等对吸附效果的影响.结果表明:当焙烧水滑石在最佳投加质量浓度为6g·L^(-1)时,其在4h内对初始质量浓度为10mg·L^(-1)的氟离子和500mg·L^(-1)的硬度(以CaCO_3的质量浓度计算)的吸附量分别为1.57,47.50mg·g^(-1);焙烧水滑石吸附氟离子的过程更符合拟二级动力学模型和Langmuir等温吸附模型,其去除机理为结构重建;焙烧水滑石吸附硬度的过程更符合拟二级动力学模型和Freundlich等温吸附模型,其去除机理包括表面吸附和生成沉淀去除.

Calcined Mg/Al hydrotalcite was prepared by co-precipitation method.The materials were characterized by X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The effects of calcined hydrotalcite dosage,temperature,initial pH value,adsorption kinetics and isothermal adsorption on the adsorption efficiency were studied.The results showed that when the optimum dosage of calcined hydrotalcite was 6 g·L-1,the adsorption of 10 mg·L-1 fluoride ions and 500 mg·L-1 hardness(calculated with CaCO 3 mass concentration)was 1.57 and 47.50 mg·g-1 respectively within 4 h.The adsorption process of fluoride ions by calcined hydrotalcite was more consistent with the quasi-second-order kinetic model and Langmuir isothermal adsorption model,and the removal mechanisms included structural reconstruction.The adsorption process of hardness by calcined hydrotalcite was more in line with the quasi-second-order kinetic model and Freundlich isothermal adsorption model,and the removal mechanisms included surface adsorption and precipitation formation.