改性高岭土对水中磷的吸附行为研究

Study on Adsorption of Phosphate in Water by Modified Kaolinite

[目的]探讨改性高岭土吸附磷的规律和最佳吸附条件。[方法]先取一定量的高岭土加入含Al3+和Mg2+的溶液,制备成改性高岭土,然后在6mg/LKH2PO4的水溶液中,加入改性高岭土,恒温振荡一定时间,静止过滤,分析滤液中磷的含量,计算磷去除率,研究pH值和改性高岭土用量对磷吸附处理效果的影响以及吸附时间对磷去除时间的影响。[结果]改性高岭土对磷具有较好的吸附去除效果,其最佳吸附条件为:pH值为5～7,反应时间控制在30min,吸附剂的合适投加量为4g/L,在此条件下,磷的去除率超过80%。改性高岭土对磷的吸附符合Langmuir吸附等温线,以化学吸附为主。[结论]改性高岭土吸附磷效果好,运行操作稳定,吸附磷后的高岭土还可作为农田肥料,实现了废水治理和污染物磷资源化的双重目的。

[Objective]The study aimed to explore the law about adsorption of the phosphate by modified kaolinite and its optimum process condition.[Method]Firstly,some Kaolinite was taken to add into the solution with Al3＋ and Mg2＋ to prepare the modified kaolinite,and then,the modified kaolinite was added in the water solution with 6 mg/L KH2PO4 to oscillate for some time at constant temperature and filter at a standstill,lastly,the phosphate content in the filter liquor was analyzed and the phosphate removing rate was counted.The effects of pH value and modified kaolinite dosage on the phosphorus adsorption and the effects of the adsorption time on the phosphorus removal time were studied.[Result]The modified kaolinite had better effect on the adsorption and removal to the phosphate and its optimum adsorption condition was as that pH value was 5-7,the reaction time was controlled by 30 min and the suitable dosage of adsorbent was 4 g/L,under which,the removing rate of phosphate could be over 80% .The adsorption process of the phosphate by modified kaolinite conformed to the Langmuir adsorption isotherm equation and was a chemical adsorption process.[Conclusion]The modified kaolinite showed the better adsorption and removal effects on the phosphate,with stable operation and the kaolinite,after adsorbing the phosphate,could be used as the farmland fertilizer, which realized the double objects for the management of waster water and the reclamation of contaminant phosphate.