凹凸棒土应用于重金属离子吸附剂的研究

Application of Attapulgite to Adsorption of Heavy Metal Ions

以新型无机矿物材料凹凸棒土作为吸附剂处理废水中的重金属离子。通过扫描电镜、红外光谱及等温吸附-脱附曲线对凹凸棒土进行了表征,并阐述了凹凸棒土对重金属离子的可能吸附机理。在室温下,分别将0.05 g凹凸棒土投入初始质量浓度为500 mg.L-1的Cu(Ⅱ)、Cd(Ⅱ)、Ni(Ⅱ)和Cr(Ⅵ)的溶液中,凹凸棒土对上述离子的平衡吸附量分别高达99、56、117、198 mg.g-1。结果表明,用凹凸棒土吸附废水中的重金属离子切实可行、经济有效。

Attapulgite is a crystalline hydrated magnesium silicate with fibrous morphology,large specific surface area and moderate cationic exchange capacity.In this paper,the adsorption capacity of attapulgite to heavy metal ions,viz.Cu（Ⅱ）,Cd（Ⅱ）,Ni（Ⅱ） and Cr（Ⅵ） were studied in detail.The results showed that by adding 0.05 g attapulgite to each of the heavy metal ion solutions（500 mg·L-1）at ambient temperature,the adsorption capacities for Cu（Ⅱ）,Cd（Ⅱ）,Ni（Ⅱ） and Cr（Ⅵ） were 99,56,117,198 mg·g-1,respectively.The attapulgite was characterized by scanning electron microscope（SEM）,Fourier transform infrared spectroscopy（FTIR） and adsorption-desorption isotherms,respectively.In addition,the mechanisms of the adsorption were also discussed.It was found that the main adsorption mechanisms of the heavy metal ions on attapulgite were complexion,ion exchange and electrostatic attraction.This study demonstrated that the application of attapulgite to the removal of heavy metal ions from industrial wastewater was feasible and cost-effective.