负载ZnO的赤泥吸附剂对刚果红的吸附试验研究

Adsorption Performance of a Novel Red-Mud Adsorbent Loading ZnO for Congo Red

研究了用赤泥(RM)负载氧化锌(ZnO)制备新型吸附剂RM-ZnO并用于从刚果红(CR)染料中吸附去除刚果红,通过分析形貌、元素组成、晶体形态及官能团和化学键,探讨了吸附机制,并通过试验考察了RM-ZnO对刚果红的吸附效果。结果表明:在温度25℃、中性条件下,RM-ZnO对刚果红的平衡吸附量达305.17 mg/g,吸附效果优于纯ZnO吸附剂;吸附过程符合Langmuir等温吸附模型和准二级动力学模型,吸附反应为吸热反应,吸附机制涉及化学作用和物理作用。化学作用可能是刚果红上的磺酸基与RM-ZnO上的Zn原子发生配位,物理作用可能是刚果红上去质子化的磺酸基与RM-ZnO质子化后的氧原子产生的静电引力。

A new adsorbent RM-ZnO was prepared by loading ZnO on red-mud for adsorbing Congo red in dye wastewater.The adsorbent morphology,element composition,crystal morphology,functional groups and chemical bond were analyzed.Through experiments,the adsorption kinetics and effect were examined.The experimental results show that the equilibrium adsorption capacity of RM-ZnO for Congo red is 305.17 mg/g at 25℃and neutral conditions.The adsorption effect is better than that of pure ZnO adsorbent.The adsorption process is in line with Langmuir isotherm model and pseudo-second-order kinetics model.The adsoption reaction is an endothermic reaction.The adsorption mechanism involves chemical adsoption and physical adsoption.The chemical adsoption may be the coordination effect of sulfonic group in Congo red and zinc atom in the adsorbent,while physical adsoption may be the electrostatic attraction generated by sulfonic group in Congo red and protonated oxygen atom in RM-ZnO.