基于响应面法的改性玉米芯吸附水中Zn^(2+)的工艺条件优化及机理研究

Study of the Mechanism Analysis and Process Condition Optimization of Adsorption of Zn^(2+) onto the Modified Corncob Based on the RSM

运用玉米芯作为生物吸附剂去除水溶液中Zn^(2+)。以单因素控制变量法考察了玉米芯用量、吸附时间、改性盐浓度和摇床转速对吸附性能的影响,并运用响应面法对吸附条件进行优化,通过吸附等温线、吸附动力学和热力学研究来探讨吸附机理。结果表明,当Zn^(2+)初始浓度为50 mg/L、改性盐浓度为0.26%、玉米芯用量为20 g/L、转速为203 r/min,于30℃的恒温振荡器中振荡吸附反应35 min后,吸附率可达80.40%。玉米芯对水溶液中Zn^(2+)的吸附是一个自发的吸附过程,其吸附行为符合二级反应速率方程和Langmuir吸附等温式,具有一定的应用前景。

In this study, corncob was used as biosorbent for removal of Zn^2＋ from wastewater. Single factor variable control method was used to investigate the influences of corncob quantity, adsorption time, mass concentration of modified NaCl and shanking speed on the adsorption performance. Moreover, response surface methodology was adopted to optimize the adsorption conditions and adsorption mechanism was discussed on the basis of the adsorption isotherms, adsorption kinetics and thermodynamics analysis. The results indicated that when the initial concentration of Zn^2＋ was 50 mg/L, mass concentration of modified NaCl was 0.26%, corncob quantity was 20 g/L, shaking speed was 203 rpm, adsorption time was 35 min and adsorption temperature was 30 ℃ , the adsorption rate of Zn^2＋ reached to 80.40%. The adsorption process was a spontaneous process and the adsorption behavior analysis indicated that the process followed Pseudo-second-order model and Langmuir isotherm, with a good application prospect.