改性棉铃壳对水中刚果红的吸附性能

Adsorption of Congo red from aqueous solution by modified cotton shell

通过甲醇酯化制备改性棉铃壳吸附剂,利用红外光谱仪、扫描电镜等表征了改性前后棉铃壳表面结构和官能团变化情况,考察了改性棉铃壳投加量、刚果红初始浓度和溶液pH等因素对改性棉铃壳吸附水中刚果红的性能影响,并通过实验分析了改性棉铃壳对水中刚果红吸附动力学。结果表明,改性后棉铃壳表面官能团明显改变,表面光滑、致密。改性棉铃壳对刚果红的吸附效果较未改性棉铃壳明显提高,增加刚果红初始浓度和吸附时间可以增加改性棉铃壳对刚果红的吸附量。在溶液pH为6、吸附剂投加量为20 g·L-1,吸附时间为120 min时,刚果红的去除率可达79.1%。改性棉铃壳对刚果红的吸附过程符合Lagergren准二级动力学模型,吸附过程属于化学吸附,吸收速率受表面扩散和颗粒内扩散控制。

An adsorbent from cotton shell was obtained via esterification with methanol. The changes in surface structures and functional groups were examined using scanning electron microscopy（ SEM） and Fourier transform infrared spectroscopy（ FTIR）. The effects of adsorbent dosage,initial concentration of Congo red,and solution pH value on the adsorption capacity were investigated. The kinetics of adsorption was explored. The results showed that the adsorptive capacity of cotton shell was enhanced after modification. Adsorption amount was increased with increased adsorption time and initial concentration. The removal rate of Congo red reached 79. 1% under the conditions of adsorbent dosage of 20 g·L^（-1）,adsorption time of 120 min,and solution pH of 6. The adsorption of Congo red on the modified cotton shell was a chemical adsorption process,and followed the Lagergren pseudo-second-order kinetics equation. The adsorption rate was controlled by surface diffusion and intra-particle diffusion.