焙烧态MCNOs/LDH复合材料的制备及其对水体F-去除的研究

Preparation of calcined MCNOs/LDH composites and study on their performance in removing F^- from water

采用水热法制备磁性纳米洋葱碳/层状双金属氢氧化物(MCNOs/LDH)复合材料,高温煅烧制备了焙烧态MCNOs/LDH复合材料(MCNOs/CLDH),并通过正交试验确定最佳煅烧工艺参数。利用XRD、FT-IR、SEM、N2吸附-脱附(BET)和VSM等对其结构形貌进行表征,并通过静态吸附实验考察MCNOs/CLDH对F-的吸附性能。结果表明,在焙烧温度为550℃、焙烧时间为2 h的最佳条件下制备的MCNOs/CLDH对F-的吸附容量为28.95 mg/g,去除效率为57.9%。此外,结合MCNOs/CLDH吸附F-后的XRD分析可知,吸附机理包括表面吸附、离子交换和混合金属氧化物的再水化以及氟离子向层间区域的嵌入,从而重建原始的LDH结构。

Magnetic carbon nano onions/layered double hydroxides( MCNOs/LDH) composites are synthesized via hydrothermal process,and calcinated at high temperature to prepare calcinated MCNOs/LDH( MCNOs/CLDH).The optimal calcination process parameters are determined through orthogonal experiments.The as-synthesized composites are characterized by SEM,XRD,FT-IR,N2 adsorption-desorption isotherms and VSM.Adsorption performance of MCNOs/CLDH to F-is investigated by static adsorption experiments.The results suggest that MCNOs/CLDH composites prepared at the optimal conditions such as a calcination temperature of 550℃ and a calcination time of 2 h exhibit an adsorption capacity of 28.95 mg·g-1 to F-and a removal rate of 57.9% for F-.What’s more,analysis results demonstrate that the adsorption mechanism involves in surface adsorption,ion exchange interaction and original LDH structure reconstruction by rehydration of mixed metal oxides and concomitant intercalation of fluoride ions into the interlayer region.