响应面法优化石英砂负载壳聚糖去除海水中磷的吸附条件

Condition Optimization for Adsorption of Phosphate in Seawater by Chitosan Coated Quartz Sand Using Response Surface Methodology

以壳聚糖为改性剂,采用共混沉降法制成石英砂负载壳聚糖改性滤料,进行净化海水中磷的静态吸附试验,并利用Box-Behnken响应面法分析投加量、p H值、反应时间对磷酸盐去除率的影响及交互作用。试验结果表明:改性砂对磷酸盐的饱和吸附量为0.019 8 mg/g,是石英砂的5.7倍;吸附过程均符合Langmuir吸附等温模型和Freundlich吸附等温模型,反应过程中物理吸附和化学吸附作用共同存在。各因素对磷酸盐去除率的影响主次顺序依次为:投加量>p H值>反应时间,吸附去除磷酸盐的最佳条件为:投加量13 g/L,p H值为7.16,反应时间26 h,该条件下磷酸盐去除率为99.14%,与预测结果基本一致。

By using chitosan as modifier, chitosan coated quartz sand was prepared by co - mixing sedimentation method. Static adsorption of phosphorus in seawater is investigated in the paper. The effect of factors including pH, dosage and reaction time on the removal rate of phosphate and interaction was studied using Box - Behnken response surface method. The result indicated that the saturated adsorption amount of phosphate on modified sand was 0.0198 mg/g, and the adsorption capacity was 5.7 times of quartz sand. The adsorption kinetic followed the Langmuir adsorption iso- therm model and the Freundlich adsorption isotherm model. Physical adsorption and chemical adsorption was coexisting during the reaction process. The order of the factors was as follows ： dosage, pH and reaction time. The optimum adsorption condition was dosage 13 g/L, pH 7. 16, reaction time 26 hours and the removal rate of phosphate is 99.14%, which is basically identical with the prediction result.