马来酸改性花生壳对Cr(Ⅵ)的吸附性能

Preparation of Maleic acid Modified Peanut Shells Adsorbent and Its Adsorption Performance for Cr(Ⅵ)

通过微波预处理和马来酸改性制备花生壳吸附剂,用于研究Cr(Ⅵ)的吸附性能,并进行结构表征,吸附条件优化,探讨等温吸附及吸附动力学特性。XRD分析表明:微波预处理后花生壳的结晶度明显下降。FTIR显示:改性后花生壳结构中有酯基和羧基成功引入。正交试验和单因素试验结果表明:pH值对Cr(Ⅵ)的吸附影响最大,在温度80℃,投加量6 g,吸附时间45 min, pH=3,Cr(Ⅵ)初始浓度30 mg/L最佳条件下,吸附率达到最大值99.3%,远高于未改性花生壳。吸附行为符合准二级动力学方程和Langmuir等温吸附模型,以单层吸附为主。

Peanut shell adsorbents were prepared by microwave pretreatment and maleic acid modification technology,which were used to study the adsorption properties of Cr(Ⅵ).Meanwhile,structural characterization,optimization of adsorption conditions,isotherm adsorption and adsorption kinetics were critically investigated through experiments and detection techniques.XRD analysis showed that the crystallinity of peanut shells decreased significantly after microwave pretreatment.FTIR analysis testified that carboxyl groups and ester groups were successfully introduced into the structure of maleic acid modified peanut shells(MMPS).The results of orthogonal test and single factor experiments indicated that pH value had the greatest effect on Cr(Ⅵ)adsorption process.Moreover,the Cr(Ⅵ)adsorption rate(CrAR)reached the maximum value of 99.3%under the optimal condition(MMPS dosage:6 g,adsorption time:45 min,pH:3,adsorption temperature:80°C,Cr(Ⅵ)initial concentration:30 mg/L),which was much higher than that of unmodified peanut shells.The adsorption behavior conformed to quasi-second-order kinetic equation and Langmuir isothermal adsorption model,and the adsorption was dominated by monolayer.