改性核桃壳处理含Cr(Ⅵ)废水的效果

Treatment effect of modified walnut shells on wastewater containing Cr(Ⅵ)

【目的】研究改性核桃壳对含六价铬[Cr(Ⅵ)]废水的吸附效果,为核桃壳资源化开发利用提供新途径。【方法】以废弃核桃壳为原料,采用磷酸改性法制备核桃壳基吸附材料,通过扫描电镜(SEM)和红外光谱仪(FTIR)表征材料结构,并考察溶液初始p H、改性核桃壳投加量、吸附时间等因素对改性核桃壳处理含Cr(Ⅵ)废水效果的影响,同时研究改性核桃壳对Cr(Ⅵ)吸附过程的动力学模型和等温线模型。【结果】改性后核桃壳表面更粗糙且多孔,官能团结构改变;在Cr(Ⅵ)初始质量浓度100 mg/L、改性核桃壳投加量1.0 g、溶液p H 2.0的条件下吸附处理180 min,改性核桃壳对Cr(Ⅵ)的吸附率达99.65%,高于未改性核桃壳的吸附率(43.64%);改性核桃壳的废水处理过程符合准二级动力学方程和Langmuir等温吸附式。【结论】采用磷酸改性法制备的改性核桃壳对Cr(Ⅵ)有较强的吸附能力,且操作简单、反应条件易于控制,可用于含Cr(Ⅵ)废水处理。

【Objective】The present experiment was conducted to investigate adsorption effect of walnut shells on wastewater containing Cr（Ⅵ）, in order to provide new approach for development and utilization of walnut shells. 【Method】Using waste walnut shells as raw materials, the absorbent materials were prepared by phosphoric acid modification method.And both SEM and FTIR were used to characterize material structure. Then the influences of some factors viz., p H, modified walnut shells dosage, adsorption time on treatment effect of modified walnut shells on wastewater containing Cr（Ⅵ）were investigated. Meawhile, adsorption kinetics models and isotherm models of adsorption process of modified walnut shell and Cr（Ⅵ） were systematically studied. 【Result】The results showed that, the modified walnut shells＇ surface became rougher and more porous, and its functional structure was changed. In addition, when the initial Cr（Ⅵ） concentration was 100 mg/L, the dosage of modified walnut shell was 1.0 g, and p H of solution was 2.0 and the adsorption time was 180 min, the adsorption rate of modified walnut shells was up to 99.65%, which was higher than the adsorption rate of unmodified walnut shells（43.64%）. The process of wastewater treatment fitted pseudo-second order kinetics equation and Langmuir adsorption isotherms. 【Conclusion】The walnut shell modified by phosphoric acid modification method has strong ability to adsorb Cr（Ⅵ）, which can be used to treat wastewater containing Cr（Ⅵ）, and this operational process is simple,and easy to control reaction condition.