Abstract: Three kinds of coal fly ash were collected from three thermal power plants. Raw coal fly ash was ball milled and ultra-fine coal fly ash was obtained. The ultra-fine coal fly ash was modified by HCl，H2SO4，NaOH，Ca(OH)2 and Na2CO3，respectively. The results showed that Ca(OH)2 was the best modifier and the removal rates of Cr6+ increased by 2.01～2.44 times after modification. The isotherms of Cr6+ adsorption onto three kinds of modified ultra-fine coal fly ash all could be described by the Langmuir isotherms at 25 ℃，35 ℃ and 45 ℃，and the adsorption process was spontaneous and exothermic. The modification mechanism of Ca(OH)2 and methods of regeneration by desorption were also discussed.

摘要： 将3个不同电厂的粉煤灰球磨后得到超细粉煤灰，选择HCl、H2SO4、NaOH、Ca(OH)2和Na2CO3等对超细粉煤灰进行化学改性。结果表明，采用Ca(OH)2改性效果最好，经过Ca(OH)2改性的3种超细粉煤灰对Cr6+的去除率提高2.01～2.44倍。Ca(OH)2改性超细粉煤灰对Cr6+的吸附热力学研究表明，3种改性超细粉煤灰在25℃、35 ℃和45 ℃对Cr6+的吸附符合Langmuir吸附等温式，吸附过程为自发、放热过程。同时，分析了Ca(OH)2改性超细粉煤灰的机理，研究了吸附饱和改性超细粉煤灰的脱附再生方法。