【摘要】 目的研究镧改性壳聚糖去除水中氟离子的性能。方法取1.00 g壳聚糖,溶于60 ml 5%乙酸溶液,按镧与壳聚糖质量比为1∶10加入硝酸镧溶液,用5%氨水调节至p H 5.0~6.0,搅拌反应60 min,然后滴加25%氨水使改性壳聚糖完全析出,过滤,洗涤,70℃烘干,制得镧改性壳聚糖吸附剂。采用该吸附剂对8.95 mg/L含氟水样进行静态除氟实验(适宜条件为:p H 4~8,140 r/min振荡速度下于室温吸附150 min)。并拟合Langmuir吸附等温线和二级动力学方程。结果吸附剂用量为0.4 g/L时,除氟率在90.9%,平衡吸附量为20.23 mg/g。拟合Langmuir吸附等温线(30℃)方程的R2=0.996,最大吸附量为25.64 mg/g,吸附平衡常数为1.77 L/mg。拟合二级动力学方程的R2值为1。结论镧改性壳聚糖对高氟水吸附容量大,除氟效率高。更多还原

【Abstract】 Objective To study the defluoridation of water using lanthanum-modified chitosan. Methods A lanthanum-modified chitosan(La-CTS) adsorbent was prepared by dissolving 1.00 g chitosan in 60 ml 5% acetic acid solution,adding lanthanum nitrate solution with 1 ∶10 La-chitosan, adjusting p H 5-6 with 5% ammonia water and lanthanum incorporated chitosan for stirring 60 min,then adding 25% ammonia water for precipitation,filtering, washing and drying at 70 ℃. The water containing 8.95 mg/L F-was treated with La-CTS in static adsorption test(the suitable adsorption conditions :p H value was 4-8,contact time was 150 min by oscillating 140 r/min at room temperature). And equilibrium adsorption data fitted to Langmuir adsorption isotherm model and kinetics data fitted to pseudo-second-order kinetics model. Results The removal rate of fluoride was 90.9% at the dosage of 0.4 g/L adsorbent against the water containing F-of 8.95 mg/L and the equilibrium adsorption capacity was 20.23 mg/g. The equilibrium adsorption data at 30 ℃ fitted well to Langmuir adsorption isotherm and showing R2=0.996,maximum fluoride adsorption capacity of 25.64 mg/g. Kinetics data fitted well to pseudo-second-order kinetics and showing R2=1. Conclusion The La-CTS adsorbent shows high adsorption capacity and efficiency in fluoride removal.更多还原