复合分子筛去除水中氟化物的研究

Study on removal of fluoride from water by composite molecular sieve

通过使用复合分子筛对模拟含氟水进行静态吸附实验,研究了复合分子筛对水中氟化物的吸附性能,并分析了吸附过程中温度、pH值和停留时间等因素对分子筛除氟效率的影响。结果表明,用80 g粒径<0.9 mm的分子筛处理150 mL浓度为5 mg/L的模拟含氟水,分子筛的除氟效率达到90%以上,而同样条件下天然沸石和改性涂铁沸石的去除率分别为23.35%和80.69%。分子筛的除氟效率随着温度呈现先上升后下降的趋势,50℃时去除效率达到最高,为92.7%;在弱酸性条件下的去除率比碱性条件要高,在pH=4时去除率最大,为91.8%;停留时间初始阶段与去除率保持正相关,在45 min后反应达到平衡。分子筛的吸附速率符合二级动力学方程dqe/dt=k(qe-qt)2,吸附等温线符合Langmuir方程。

The ability of F.F composite molecular sieve for removing fluoride from water through static adsorption was studied on simulated fluorine water by using composite molecular sieve in this experiment.The effects of various factors,such as temperature,pH value,contact time consistency,on the removal efficiency during the adsorption of molecular sieve were analyzed.The results showed that： by using the composite molecular sieve with the amount of 80 g and the size of less than 0.9 mm to treat 150 mL fluoride water with the concentration of 5 mg/L,the fluoride removal efficiency of molecular is up to more than 90%,while the removal rates of natural zeolite and modified zeolite coated iron were 23.35% and 80.69% under the same conditions.The variation of the removal of F-with the temperature increased first followed by decreasing,and reached the peak with the removal efficiency of 92.7% at 50 ℃.The removal of F-was higher in weak acidic condition than alkali,and shown the best removal efficiency of 91.8% when pH=4.The contact time was proportional to the defluoridation efficiency at the initial stage and reached the equilibrium state in 45 min.The absorption rate followed the second-order kinetic equation dqe/dt=k（qe-qt）2 and the curve of absorption isotherm agreed with the Langmuir equation well.