矸石基X型分子筛对水中Co^(2+)、Cu^(2+)、Cd^(2+)和Cr^(3+)的去除

Removal of Co^2,Cu^(2+),Cd^(2+) and Cr^(3+) from aqueous solution by zeolite X prepared from coal gangue

以煤矸石为原料,采用碱熔后水热合成法制备X型分子筛并进行XRD、SEM、BET和Zeta电位分析。研究其对水中Co2+、Cu2+、Cd2+和Cr3+4种离子的吸附性能,包括吸附等温线、吸附动力学以及初始金属离子浓度、pH值对吸附性能的影响。所合成的矸石基X型分子筛的BET比表面积为676.02 m2/g,微孔孔容为0.263 cm3/g。吸附实验表明,矸石基X型分子筛能有效去除上述4种离子,同时实现煤矸石的资源化和金属离子的去除。4种离子的平衡吸附量均随初始浓度的增大而增大,相同条件下平衡吸附量的大小顺序为Cd2+>Cr3+>Cu2+>Co2+。准二级动力学模型能很好地描述4种离子的吸附动力行为。Langmuir模型对Co2+、Cu2+和Cd2+吸附的拟合较Freundlich模型高,说明其主要表现为物理吸附过程。4种离子的吸附速率均由液膜扩散和颗粒内扩散共同控制。

The removal performance of metal ions( Co2 +,Cu2 +,Cd2 +,Cr3 +) adsorption from aqueous solution was investigated by adsorption process on zeolite X prepared from coal gangue. The zeolite X was synthesized with a hydrothermal method after alkali fusion,and then characterized with XRD,SEM,BET and Zeta analysis. The result showed that the BET specific surface area and microspore volume were 676. 02 m2/g and0. 263 cm3/g,respectively. Batch method was employed to study the influential parameters such as initial metal ions concentration,contact time and initial pH of the solution on the sorption process. Sorption study suggested that metal ions can be effectively removed by the synthesized zeolite X from coal gangue. The experimental data were well fitted by the Pseudo-second-order kinetics model and the equilibrium data were better fitted by the Langmuir model. The adsorption was found to concentration dependent and showed the equilibrium adsorption capacity order: Cd2 +> Cr3 +> Cu2 +> Co2 +. The sorption capacity of metal ions could be significantly improved by increasing metal ions concentration which can be controlled by liquid diffusion step and intra-particle diffusion step simultaneously.