聚二甲基二烯丙基氯化铵改性油页岩灰渣吸附水中Cr(Ⅵ)

Adsorption of Cr(Ⅵ) in Water by Polydiene Dimethyl Ammonium Chloride Modified Oil Shale Ash

利用聚二烯二甲基丙基氯化铵(PDMDAAC)对油页岩灰渣进行了改性,并将其用于模拟含Cr(Ⅵ)废水的吸附。对改性前后的油页岩灰渣进行了表征。结果表明,改性后油页岩灰渣的BET比表面积增大(为50.75 m2/g),可为Cr(Ⅵ)提供大量的吸附位点。当Cr(Ⅵ)的质量浓度为20 mg/L时,改性油页岩灰渣在常温和振摇转速180 r/min条件下,综合优化吸附条件为:吸附时间30 min,体系pH为5.0,吸附剂投加量20 g/L,在此条件下Cr(Ⅵ)去除率达到95.77%。改性油页岩灰渣对水中Cr(Ⅵ)离子的吸附作用符合准2级动力学模型;相比于Langmuir方程,其吸附等温模型更符合Freundlich吸附模型,且吸附过程可能受2个或多个速控步骤控制。

The oil shale ash was modified by polydiene dimethyl ammonium chloride（PDMDAAC）, and the modified oil shale ash was used for adsorption of simulated Cr（Ⅵ） containing wastewater. The oil shale ash before and after modification were characterized. The results showed that, he modified oil shale ash had a larger BET specific surface area（50.75 m^2/g）, it could provide more adsorption sites for Cr（Ⅵ）. The modified oil shale ash had the optimizing adsorption under normal temperature and when mass concentration of Cr（Ⅵ）, shaking rotate speed, adsorption time, pH and dosage was 20 mg/L, 180 r/min, 30 min, 5.0 and 20 g/L respectively, the Cr（Ⅵ） removal rate was up to 95.67%. The modified oil shale ash adsorption process of Cr（Ⅵ）could be confirmed to the quasi-second order dynamic model. Compared with the Langmuir equation, this adsorption isotherm model was more consistent with the Freundlich adsorption model. And the adsorption process might be affected by two or multiple speed-control steps.