CoNiFe三元类水滑石的制备及吸附性能研究

Preparation of CoNiFe ternary hydrotalcite and study on its adsorption properties

采用共沉淀法制备了不同物质的量比的CoNiFe水滑石,利用FT-IR、SEM、BET等对其性能进行表征。以酸性红88为模拟废水,考察溶液初始pH、吸附剂投加量、吸附温度以及吸附时间等因素对吸附性能的影响,并对吸附动力学、吸附等温线和吸附热力学进行研究,探讨了CoNiFe-LDH的循环再生性能。结果表明,在25℃、pH=7的条件下,向40 mL 50 mg/L酸性红88溶液中投加50 mg CoNiFe-LDH,对酸性红的去除率可达94.9%。CoNiFe-LDH对酸性红的吸附过程符合准二级动力学模型和Langmuir等温模型,该吸附过程为物理吸附,是一个自发的放热反应。经过4次循环利用后,CoNiFe-LDH对酸性红88的吸附率仍可达88.34%。

CoNiFe hydrotalcite with different molar ratios is prepared by co-precipitation method,and characterized by FT-IR,SEM and BET.Taking acidic red 88 as simulated wastewater,the impacts of initial pH of the solution,adsorbent dosage,adsorption temperature and adsorption time on the adsorption performance of CoNiFe hydrotalcite are investigated.Adsorption kinetics,adsorption isotherm and adsorption thermodynamics are also studied.Cyclic regeneration performance of CoNiFe hydrotalcite is discussed.The results show that the removal rate of acidic red 88 can reach 94.9%when the temperature remains at 25℃,pH=7,and 50 mg of CoNiFe hydrotalcite is added into 40 mL of acidic red 88 solution with a concentration of 50 mg·L-1.The adsorption process conforms to the quasi-second-order kinetic model and Langmuir isothermal model.It is a physical adsorption process,which is a spontaneous exothermic reaction.After four times of recycling,the adsorption rate of acidic red 88 by CoNiFe hydrotalcite can still achieve 88.34%.