基于改性粉煤灰吸附脱硫废水中Cl-动力学研究

Study on the Kinetics of Cl in Desulfurization Wastewater Based on Modified Fly Ash Adsorption

通过对粉煤灰进行复合改性制备了一种多孔结构的吸附剂,并将其应用于燃煤电厂脱硫废水中Cl-的吸附研究。考察了pH、反应时间、投加量等因素对Cl-吸附性能的影响,并进行了吸附动力学研究。采用扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)对粉煤灰改性及吸附前后进行表征。结果表明,临界投加量为2.5 g/100 mL,pH为5时吸附量最大、反应达到吸附饱和时间为300 min左右,最大吸附量达到80.9 mg/g,吸附过程符合准2级动力学模型,并且内扩散模型拟合结果表明孔道扩散制约着整个吸附速率。改性后的粉煤灰Si-O和Al-O发生断裂,表面孔隙增多,提高了吸附性能。

A porous structure adsorbent was prepared by compound modification of fly ash,and it was applied to the study of the adsorption of Cl- in the desulfurization wastewater of coal-fired power plants.The effects of pH,reaction time,dosage and other factors on the adsorption performance of Cl- were investigated,and the adsorption kinetics was studied.Scanning electron microscope(SEM) and X-ray photoelectron spectrometer(XPS)were used to characterize fly ash before and after modification and adsorption.The results showed that the optimal reaction conditions were as follow,the critical dosage was 2.5 g/100 mL,the maximum adsorption capacity was at pH of 5,the reaction time to reach adsorption saturation was 300 min,the maximum adsorption capacity for Cl- reached 80.9 mg/g,and the adsorption process conformed to pseudo-second-order kinetic model.Internal diffusion model fitting showed that channel diffusion restricts the adsorption rate,and the Si-O and Al-O fractured after the fly ash modification,and the surface pores increased,which improved the adsorption performance.