膨润土的改性及其对废水中磷吸附效果的研究

Study on the Modification of Bentonite and Its Phosphorus Adsorption in Waste Water

[目的]研究改性膨润土对废水中磷吸附的影响。[方法]采用盐酸和煅烧两种方法对鹏润土分别进行酸改性和热改性,研究了不同浓度酸改性及不同温度热改性对膨润土磷吸附的影响,并探讨了热改性膨润土的最佳温度及pH值。[结果]在废水浓度20 mg/L、膨润土投加量2%(重量比)时,对磷的吸附效果随着酸用量的增加而增加,9%盐酸改性后磷去除率由18.14%提高到45.59%;热改性后磷去除率上升为41.17%,最佳热改性温度为500℃,在弱酸及弱碱性条件下有利于500℃热改性膨润土吸附除磷,pH=9时,10 mg/L磷溶液中磷的去除率可达92.77%,磷剩余浓度为0.47 mg/L,达到国家城镇污水处理厂一级A排放标准。[结论]酸改性和热改性均可显著提高膨润土的磷吸附效果。

[Objective]The aim was to study the effect of bentonite modification on phosphorus adsorption in waste water.[Methods]The methods of hydrochloric acid and calcination were adopted for acid modification and thermal modification of bentonite,moreover,the effect of modification of different concentrations of acids on bentonite phosphorus adsorption was studied,in addition,the optimum temperature and pH value of thermal modification bentonite were discussed.[Results]When the concentration of phosphate was 20 mg/L and the dosage of modified bentonite was 2%（weight ratio）,the adsorption of phosphorus increased with the increasing of acid dosage,after 9% hydrochloric acid was modified,the removing rate of phosphate increased to 45.59% from 18.14%,after thermal modification,the removing rate of phosphate increased to 41.17%,the optimum temperature of thermal modification was 500 ℃,under the condition of weak acid or weak base,it was beneficial to the adsorption of phosphate,when pH=9,the removing rate of phosphate in 10 mg/L phosphate solution could reach to 0.47%,and the residual concentration was 0.47 mg/L,which reached to Grade A discharge standards of national wastewater treatment plant.[Conclusion]Both acid modification and thermal modification could improve the adsorption of phosphorus by bentonite.