柠檬酸改性粉煤灰脱除水体中阴阳离子染料的试验研究

Study on absorption treatment on the anionic and cationic dyesin water by fly ash modified with citric acid

以柠檬酸为浸溶剂对粉煤灰进行水热改性,利用改性后粉煤灰分别吸附处理亚甲基蓝、甲基红、溴酚蓝和溴甲酚绿四种阴、阳离子染料水体,研究改性酸浓度、温度、时间和染料pH值对吸附效率的影响,并利用因子分析法计算权重配比,扫描电镜(SEM)进行改性表征。研究发现,经柠檬酸改性后粉煤灰颗粒分散度明显增加,孔容孔道结构扩张显著;脱除效率最佳的改性、吸附条件组合为柠檬酸浓度0.6 mol/L、反应温度90℃、时间6 h、染料初始pH为4,四种染料脱除率分别达55.74%、94.54%、97.86%和96.04%,尤其对阴离子染料吸附强于阳离子;影响因子权重分配结果显示,柠檬酸浓度对改性粉煤灰吸附效率起主导作用,权重均超过78%,改性时间和染料初始pH属于弱势影响因子。

Fly ash modification by citric acid as a dipping solvent was explored in this work and the adsorption performance of modified fly ash in methylene blue,methyl red,bromophenol blue and bromocresol green dying wastewater treatment were also studied.The effects of modification acid concentration,temperature,time and pH on adsorption efficiency were studied and weight ratio calculated by factor analysis method.Scanning electron microscopy(SEM)was used to characterize the modification.The study found that the dispersion of fly ash particles was significantly increased after citric acid modification,and the pore volume and pore structure expanded significantly.The best combination of modification and adsorption conditions to the best removal efficiency was a concentration of 0.6 mol/L citric acid,a reaction temperature of 90℃,a modification time of 6 hours,and an initial pH of 4.The modified fly ash could achieve the removal rates for the four dyes at 55.74%,94.54%,97.86%,and 96.04%,especially it had stronger adsorption for anionic dyes than cations.The weight distribution of impact factors showed that the concentration of citric acid with over 78%weight played a leading role in the adsorption efficiency of modified fly ash.The modification time and initial pH of the dye were weak impact factors.