铁改性煤矸石去除废水中镉的研究

Preparation of iron-modified coal gangue and removal of cadmium ions from wastewater

废水中的镉会严重威胁环境和人体健康。采用水热法制备铁改性煤矸石,并将其应用于含镉废水的处理。利用红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM)、比表面积(BET)和Zeta电位等方法对材料的结构和表面性质进行分析,研究铁改性煤矸石对Cd^(2+)的吸附行为,考察了pH和共存离子等因素对其吸附性能的影响,探讨了其吸附动力学、吸附等温线。结果表明:铁改性煤矸石经改性后其比表面积提高了2.85倍,最佳反应pH为8,共存离子CO_(3)^(2-)、SO_(4)^(-)、F-促进吸附反应;据伪二级动力学和Freundlich吸附等温式,表明对Cd^(2+)的吸附是单分子层化学吸附,吸附过程是自发吸热过程;30℃和50℃时铁改性煤矸石对Cd^(2+)最大拟合吸附量分别为32mg/g和34.18mg/g。铁改性煤矸石对废水中的Cd^(2+)具有良好的吸附性,有望用于重金属离子废水的处理。

Cadmium in wastewater can seriously threaten the environment and human health.In this paper,iron-modified coal gangue was prepared by hydrothermal method and applied for the treatment of wastewater containing cadmium.The structure and surface properties of the materials were analyzed by FT-IR,XRD,SEM,BET and zeta potential analysis.The adsorption behavior of iron-modified coal gangue for Cd^(2+)was studied.The effects of pH and coexisting ions on its adsorption performance were investigated.The adsorption kinetics and adsorption isotherms were discussed.The results showed that the specific surface area of iron-modified coal gangue was increased by 2.85 times after modification,the optimal reaction pH was 8,and the coexisting ions CO_(3)^(2-)、SO_(4) and F-promoted the adsorption reaction.According to pseudo second-order kinetics and Freundlich adsorption isotherm,the adsorption of Cd^(2+)was a monomolecular layer chemical adsorption,and the adsorption process was a spontaneous endothermic process.At 30℃and 50℃,the maximum fitted adsorption capacities of iron-modified coal gangue for Cd^(2+)were 32mg/g and 34.18mg/g,respectively.Iron-modified coal gangue had a good adsorption property for Cd^(2+)in wastewater,and was expected to be used in the treatment of wastewater with heavy metal ions.