碱热改性粉煤灰对含氟废水的吸附性能研究

Adsorption of Fluorine in Wastewater by Alkali-Thermal Modified Fly Ash

在碱性条件下,利用水热法制备改性粉煤灰,用于去除废水中的氟离子。采用XRD和SEM对碱热改性前后的粉煤灰进行表征,对比了改性前后粉煤灰对模拟废水中氟离子的吸附性能,并研究了改性粉煤灰投加量、初始pH值和反应温度对吸附性能的影响。结果表明,粉煤灰碱热后改性表面吸附位点增多且孔隙增加,吸附潜力明显提升。当改性粉煤灰投加量为2 g/L、废水初始pH值为7.6、反应温度20℃时,氟离子的去除率高达94.7%。反应在60 min达到吸附平衡,该吸附反应是一个吸热过程。碱热改性的粉煤灰处理含氟废水不存在二次污染风险。

hydrothermal modified fly ash was prepared under alkaline conditions and employed to remove fluorine in wastewater.Both the ash and the modified fly ash were characterized by XRD and SEM,and fluoride adsorption performance of the fly ash before and after modification were compared in simulated wastewater.The effects of the fly ash dosage,initial pH,and temperature on fluoride adsorption were also investigated.The results showed that the adsorption sites and pores on the fly ash surfaces increased after alkali-thermal modification.The adsorption potential was significantly improved.The removal rate of fluoride ion was as high as 94.7 % under 2 g/L of modified fly ash dosage,initial pH 7.6,and 20℃ conditions.The reaction reached adsorption equilibrium at 60 min,and the adsorption process was endothermic.There was no risk of secondary pollution in fluorine removal from wastewater by the alkali-thermal modified fly ash.The results provided theoretical basis and technical reference for the high-value utilization of fly ash and fluorine removal from wastewater.