改性核桃壳对Cr(Ⅵ)的吸附

采用甲醛-硫酸改性法制备改性核桃壳吸附剂,利用静态吸附法研究了改性核桃壳对模拟废水中低浓度Cr(Ⅵ)的吸附性能,并采用SEM和FTIR技术对改性前后的核桃壳进行表征。表征结果显示,改性后的核桃壳表面更粗糙,孔隙轮廓更清晰,更有利于对Cr(Ⅵ)的吸附。实验结果表明:在初始Cr(Ⅵ)质量浓度为20 mg/L、初始废水p H为1、吸附温度为30℃、吸附时间为100 min、改性核桃壳加入量为24 g/L的条件下,改性核桃壳对Cr(Ⅵ)的去除率为98.4%,高于在相同条件下未改性核桃壳对Cr(Ⅵ)的去除率(93.1%);改性核桃壳对Cr(Ⅵ)的吸附更符合Freundlich等温吸附方程,对Cr(Ⅵ)的吸附行为满足拟二级动力学方程。

Adsorption of Cr (Ⅵ) on Modified Walnut Shells

Walnut shell was modified by methanol and sulphuric acid to prepare adsorbent. The adsorption capability of the modified walnut shell to Cr（Ⅵ）in the simulated low concentration wastewater was studied by static adsorption process,and the walnut shells before and after modification were characterized by SEM and FTIR. The characterization results show that after modification,the surface of the walnut shell is rougher and the pore outline is clearer,which are more favorable for Cr（Ⅵ）adsorption. The experimental results show that：When the initial Cr（Ⅵ）mass concentration is 20 mg/L,the initial wastewater pH is 1,the adsorption temperature is 30 ℃,the adsorption time is 100 min and the dosage of modified walnut shell is 24 g/L,the removal rate of Cr（Ⅵ）is 98.4%,which is higher than that on the unmodified walnut shell（93.1%）;The adsorption isotherm of Cr（Ⅵ）fits better with Freundlich equation, and the adsorption of Cr（Ⅵ）on the adsorbent meets the pseudo second order kinetic equation.