含Al、Ca复合除氟剂在含氟硫酸锌溶液中的除氟性能

摘要

s:A novel Al, Ca-containning composite defluoridation agentwassynthetized by co-precipitation method.The results show that the optimum conditions to defluoridation from zinc sulfate solution (ρ(F−)=450 mg/L,ρ(H2SO4)=160 g/L,ρ(Zn)=60 g/L) are as follows: pH=3,t=90 min,w=4 g/L,θ=25℃. The finalρ(F−)is below 20 mg/L, the fluoride ions removal efficiencyisabout 96%, and the adsorption capacityis108 mg/g. The results show that only when theρ(Cl−) is above 800 mg/L,thefluoride removal efficiency slightly descendsto 93%. Theρ(SO42−)andρ(Zn2+)show no influence on the removal efficiency, zinc lossrateis less than 5% during the defluoridation process. The equilibrium isotherm reasonablyfitsthe Langmuir isotherm model, and the maximum monolayer sorption capacityis143.3 mg/g.%采用共沉淀法制备新型的含Al、Ca复合除氟剂。结果表明：在含100 g/L Zn2+、160 g/L H2SO4和450 mg/L F−的硫酸锌电解液中复合除氟剂除氟的最优条件为：pH=3，t=90 min，w=4 g/L，θ=25℃。此时，F−浓度可降低至20mg/L以下，除氟率可达96%，除氟剂吸附容量达108 mg/g。结果表明：仅当Cl−浓度大于800 mg/L时，复合除氟剂的除氟率降至93%。SO42−和 Zn2+的浓度对复合除氟剂的除氟效果没有影响，除氟率一直保持在96%左右，除氟过程锌损失率小于5%。吸附平衡曲线结果表明：该型复合除氟剂的吸附过程符合Langmuir 单层吸附模型，最大理论吸附容量143.3 mg/g。