改性棉铃壳吸附含铬废水研究

Adsorption of Cr(VI) from Aqueous Solution by Modified Cotton Shell

对酸改性棉铃壳用于去除水中的铬离子进行研究。比较了改性前后棉铃壳吸附性能,考察了吸附时间、溶液p H、棉铃壳投加量以及吸附温度等因素对改性棉铃壳吸附水中铬离子性能的影响,并分析了改性棉铃壳对水中铬离子的吸附动力学。实验结果表明,改性后的棉铃壳吸附效果较未改性棉铃壳明显提高;增加吸附时间和温度都有利于改性棉铃壳对铬离子的吸附。在室温时,溶液p H为2、吸附时间为120 min时,铬离子的去除率可达99.3%。改性棉铃壳对刚果红的吸附过程更符合Lagergren准二级动力学模型,吸收速率受表面扩散和颗粒内扩散控制,吸附属于吸热过程。改性棉铃壳是一种成本低、吸附效果显著且稳定的吸附剂,有望在含铬重金属废水处理中发挥重要作用。

In this study, acid modified cotton shell was applied to remove Cr（Ⅵ） from aqueous solutions. The adsorption property of the cotton shell with and without modification was compared. The effects of contact time, solution pH value, adsorbent dosage, and temperature on the adsorption capacity of Cr （Ⅵ） by modified cotton shell were investigated and the kinetics of adsorption was explored by a large number of experiments. The results showed that the adsorptive capacity of cotton shell was enhanced after being modified. Adsorption amount was increased with enhancing the adsorption time and temperature. The removal rate of Cr（Ⅵ） reached 99.3% under room temperature, the solution with pH 2, adsorption time with 120 min. The adsorption of Cr （Ⅵ） on the modified cotton shell was a spontaneous and endothermic process, and more followed the Lagergren pseudo-second order kinetics equation. The adsorption rate was controlled by surface diffusion and intra-particle diffusion. And modified cotton shell is thus inferred to be an economic, effective and stable adsorbent, which would favor the treatment of chromium wastewater.