氯化铁改性沸石的除磷性能与机理

The Removal Performance and Mechanism of Phosphorus by Ferric Chloride Modified Zeolite

为提高沸石对磷的去除能力,对天然沸石进行了氯化铁改性,通过静态试验比较了改性前后沸石对磷的去除效果,并考察了接触时间、磷初始浓度、沸石投加量、pH值和接触温度等因素对氯化铁改性沸石除磷效果的影响.同时利用吸附等温线模型、吸附热力学和动力学探讨了改性沸石的除磷机理.研究结果表明,氯化铁改性后沸石除磷能力有很大程度提高,对50mg·L-1的模拟废水磷去除率可达97.33%;改性沸石吸附除磷的最佳pH值为8;氯化铁改性沸石对水中磷的吸附动力学过程满足Pseudo second-order模型;热力学分析结果表明,改性沸石对磷的吸附是熵增的吸热吸附过程;改性沸石对磷的吸附平衡数据可以用Freundlich吸附等温模型加以描述.

In order to improve the phosphorus removal capacity of zeolite,the natural zeolite was modified by FeCl3.Static adsorption experiments were carried out to compare phosphorus removal between FeCl3 modified zeolite and the natural zeolite.The effect of the contact time,the initial phosphorus concentration,the dosage of modified zeolite,the value of pH and the contact temperature on the phosphorus adsorption by modified zeolite was investigated.The adsorption mechanism was examined in detail by the adsorption isotherm,the adsorption thermodynamics and the kinetic model.It was demonstrated that larger phosphorus removal of modified zeolite is obtained.When the initial concentration of phosphate was 50mg/L,the removal rate of phosphorus reached 97.33%.The adsorption capacity reached the maximum at pH 8.The adsorption kinetics of phosphorus on modified zeolite followed Pseudo second-order model.Thermodynamic analysis showed that the adsorption is endothermic and exhibits physical adsorption,and it is the process of entropy entropy increase.The equilibrium adsorption data of phosphorus on modified zeolite can be described by Freundlich isotherm model.