铁锰氧化物改性沸石对Cr(Ⅵ)的吸附性能

Experimental study on the adsorption of Cr(Ⅵ) on modified zeolite by iron and manganese oxides

铬污染是水环境的重要威胁之一。本文采用广东云浮产天然沸石制取了铁锰氧化物改性沸石,并对改性沸石进行了表征,对其吸附去除Cr(Ⅵ)的特性进行了研究。结果表明,铁锰氧化物改性沸石表面松散的颗粒杂质显著减少,多孔状结构得到加强。改性沸石和天然沸石对Cr(Ⅵ)的去除率均呈快速上升然后逐渐趋于稳定,分别在30min和50min时达到平衡状态。改性沸石吸附速率较快,去除率也得到明显提高。拟合结果表明,两种沸石对Cr(Ⅵ)的吸附符合准二级反应动力学。加大沸石投加量在提高Cr(Ⅵ)去除率的同时也产生浑浊,综合考虑去除效果和实用性,用于除Cr(Ⅵ)的改性沸石最佳投加量为1.0g/L。随pH值的升高改性沸石的去除率略有增加,但pH值低于2.0时去除率显著下降。共存腐殖酸等有机物会产生竞争吸附,并降低Cr(Ⅵ)的去除率。

Chromium pollution in water bodies is one of the most server threats to public health. . This research studied Cr（Ⅵ） adsorption using modified zeolite as adsorbent. The modified zeolite was covered with compound iron and manganese oxides. The adsorption properties of natural zeolite and the modified zeolite were studied. Results indicated that loose impurities on the adsorbent surface were reduced significantly and the porous structure of zeolite was strengthened. The removals of chromium increased quickly in the first 20 to 40 minutes,and the adsorption equilibriums were achieved at 30 and 50 minutes for the natural zeolite and the modified zeolite respectively. The modified zeolite had faster adsorption velocity and higher removal rate. Second-order reaction best described the adsorption kinetics. Increasing adsorption dosage could promote chromium removal and water turbidity simultaneously. Considering the effects and feasibility,the most reasonable dosage was 1.0g/L. Higher initial pH could promote chromium removal slightly. When the initial pH was below 2.0,the removal efficiency decreased significantly. The adsorption could be influenced by the coexistence of humic acid and the competitive adsorption.