几种离子交换树脂对电镀废水中Ni^2+的吸附性能评价

Evaluation of adsorption of nickel onto several cation-exchange resins in plating wastewater

为提高离子交换树脂对电镀废水中镍离子的去除效率,选用732、D751和CH-90Na三种离子交换树脂吸附电镀废水中Ni^2+,考察了pH、温度和杂质离子强度的影响,评价其吸附性能。结果表明,3种离子交换树脂吸附Ni^2+的最佳pH为5~6,温度对732、D751型树脂的影响较小,杂质离子对732型树脂吸附容量影响较大,D751、CH-90Na型树脂对Ni^2+具有更高的选择性。改变初始浓度和吸附反应时间,探究了3种离子交换树脂的吸附等温线和吸附动力学过程,发现3种离子交换树脂均符合Langmuir吸附等温线,且均符合准二级动力学方程,说明其对Ni^2+的吸附属于单分子层吸附和定点吸附、吸附过程主要是离子交换控制的,D751型树脂饱和吸附容量最大且为123.9 mg/g。综合考虑,D751型树脂可以作为处理含镍废水的最佳离子交换树脂。

To improve the removal efficiency of nickel ion in plating wastewater by cation-exchange resins,three kinds of cation-exchange resins 732,D751 and CH-90Na were used to adsorb Ni^2+ in plating wastewater.The influences of pH,temperature and impurity ionic strength on adsorption properties were investigated.The results showed that optimum pH of three cation-exchange resins for adsorbing Ni^2+ is 5~6.The effect of temperature on 732 and D751 resin was small,and impurity ions had a greater influence on 732 resin,the type D751,CH-90Na resins have higher selectivity to Ni^2+ than 732 resins.The adsorption isotherms and adsorption kinetics of three ion exchange resins were evaluated by changing the initial concentration and adsorption reaction time.It was found that the three cation-exchange resins were all in line with the Langmuir adsorption isotherm,and all met the quasi-second-order kinetic equation.Results showed that the adsorption of Ni^2+ can be classified as monolayer adsorption and site-specific adsorption,and the adsorption process was mainly controlled by ion-exchange,and D751 resin saturated adsorption capacity is 123.9 mg/g exceeding others.In summary,D751 resin can be used as the optimal cation-exchange resin for treating nickel-containing wastewater.