热活化自来水厂铁盐污泥的磷吸附特性

PHOSPHORUS ADSORPTION ONTO IRON SLUDGE FROM WATERPLANT ACTIVATED BY HEAT TREATMENT

研究了经不同温度活化处理的自来水厂铁盐污泥的磷吸附特性.结果表明,经100℃、300℃、500℃和900℃活化的污泥(分别称为IS100、IS300、IS500和IS900)对溶液中无机磷的吸附都符合Langmuir方程,其磷吸附容量分别为6.329、12.20、8.197和3.401 g.kg-1,这说明热活化能改变污泥对磷的吸附性能,300℃为最佳活化温度.对IS300的吸附特性研究表明,IS300对磷的吸附能力随吸附反应温度的升高而升高,随溶液初始pH的升高而降低.反应的焓变ΔH0>0,熵变ΔS0>0,自由能变ΔG0<0,这表明吸附是自发的吸热反应,推动力是ΔS0.IS300对磷的吸附动力学过程符合双常数方程和Elovich方程.

Phosphorus adsorption on iron sludge（IS） from waterplant activated by heat treatment was investigated.The results indicated that the Langmuir adsorption isotherm fit the phosphorus adsorption on IS treated at 100 ℃,300 ℃,500 ℃ and 900 ℃（the corresponding sludge is denoted as IS100,IS300,IS500 and IS900 repectively）,and the corresponding adsorption capacities were 6.329,12.20,8.197 and 3.401 g·kg-1 respectively.Heat treatment affected adsorption capacity,and 300 ℃ was the optimal temperature for sludge activation.Higher temperature and lower pH were favorable for phosphorus adsorption on IS300.Both the enthalpy ΔH0 and the entropy ΔS0 were positive,the free energyΔG0 was negetive,so the reaction was spontaneous and endothermic,and the reaction was driven by ΔS0.Both the double-constant rate equation and Elovich equation fit the adsorption processes of phosphorus on IS300.