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目的研制锆改性壳聚糖吸附剂用于除去水中的氟离子。方法取1.00 g壳聚糖,溶于60 ml的5%乙酸溶液,按锆与壳聚糖质量比为3∶20加入氧氯化锆溶液,搅拌反应60 min,然后滴加25%~28%氨水使改性壳聚糖完全析出,过滤、洗涤、70℃烘干,制得锆改性壳聚糖吸附剂。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:pH 3~9,140 r/min振荡速度下于室温吸附120 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1.0 g/L时,除氟率在90.7%,平衡吸附量为8.12 mg/g。拟合Langmuir吸附等温线(30℃)方程的R2=0.999 4,最大吸附量为12.30 mg/g,吸附平衡常数为1.58 L/mg。拟合二级动力学方程的R2值为1。结论锆改性壳聚糖对高氟水吸附容量大,除氟效率高。
Objective To develop zirconium modified chitosan adsorbent for the removal of fluoride ions in water. Methods Chitosan 1.00 g, dissolved in 60 ml of 5% acetic acid solution, zirconium oxychloride solution by mass ratio of zirconium to chitosan ratio of 3:20, the reaction was stirred for 60 min, and then dropped 25% to 28% Ammonia makes the modified chitosan completely precipitated, filtered, washed and dried at 70 ℃ to obtain zirconium modified chitosan adsorbent. The adsorbent was used to carry out static fluoride removal experiment on 8.95 mg / L fluorine-containing water (suitable conditions: pH 3 ~ 9, adsorption speed of 120 r / min at room temperature at 140 r / min). The Langmuir adsorption isotherm and the second-order kinetic equation were fitted. Results When the amount of adsorbent was 1.0 g / L, the removal rate was 90.7% and the equilibrium adsorption capacity was 8.12 mg / g. R2 = 0.999 4, the maximum adsorption capacity was 12.30 mg / g and the adsorption equilibrium constant was 1.58 L / mg for the fitted Langmuir adsorption isotherm (30 ℃) equation. The R2 value of the fitted second-order kinetic equation is 1. Conclusion Zirconium modified chitosan has high adsorption capacity for high fluorine water and high fluoride removal efficiency.