硝酸改性煤基活性炭吸附处理垃圾渗滤液

Enhanced adsorption treatment of landfill leachate using coal⁃based activated carbon modified by nitric acid

  • 摘要: 采用硝酸对煤基粉末活性炭进行改性处理,考察不同改性条件下活性炭吸附性能的变 化,并将最优改性条件下所得的活性炭用于对垃圾渗滤液的深度处理,考察活性炭的不同投加量 和吸附时间等参数对污染物的去除效果。 试验结果表明:在硝酸浓度15%、改性温度60℃、改性 2h后,改性活性炭中孔孔径的比例最大,吸附性能最佳;在改性活性炭处理垃圾渗滤液试验中, 当活性炭投加量为4g/150mL、吸附时间为12h、溶液pH值为7时,化学需氧量(COD)、氨氮 (NH3-N)、总氮(TN)、六价铬(Cr6+)的去除率分别为79*0%、43*3%、52*6%和100%。 改性后, 活性炭对COD和TN的去除率较改性前分别提高10*1%和17*3%。 对COD吸附降解动力学分 析发现,改性活性炭12h内吸附降解COD的反应更符合零级动力学反应。 对降解过程进行非线 性拟合表明,降解过程可由Logistic函数模型模拟和预测。 利用超声波法,在pH值为4*5的酸性 条件下超声2h以上时,对改性活性炭再生后恢复效果较好,以UV254为参考值,再生后处理率相 比初次使用时仅降低12%,可重复利用。

     

    Abstract: The coal based powder activated carbon was modified by nitric acid, the adsorption propertiesofactivatedcarbonunderdifferentmodificationconditionswasinvestigatedthemodifiedacti⁃ vatedcarbonobtainedundertheoptimalmodificationconditionswasusedfortheadvancedtreatmentof landfillleachatetoinvestigatedthepollutantsremovalefficiencywithvaryingdifferentparameterssuch as input dosage and absorption time*The ratio of mesoporous aperture diameter and absorption propertiesofactivatedcarbonattainedthehighestaftermodification2hwiththeconcentrationofnitric acid15% andthetemperatureofmodification60℃*TheremovalratesofCOD,NH3-N,TNandCr6+were79*0%,43*3%,52*6% and100%,respectively,whenthedosageofmodifiedactivatedcarbon was4g/150mg/L,theadsorptiontimewas12h,andthesolutionpHof7*Andaftermodification,the removalrateofCODandTNincreasedby10*1% and17*3% comparedwithpreviousactivatedcar⁃ bon*ItwasfoundthatthereactionofadsorptionanddegradationofCODin12hwasmoreconsistent withzeroorderreactionwhenanalyzingthekineticsofCODadsorptionanddegradation*Inaddition, thenonlinearfittingofdegradationprocessindicatesthatthedegradationprocesscanbesimulatedand predictedby Logistic function model*A better regenerative result was achieved by using ultrasonic methodwiththeoptionsofpHwas4*5andultrasonictimemorethan2h*TakingUV254 asreference value,theregenerativepost⁃treatmentratewasreducedby12% comparedwiththeinitialusingwhich indicatedthatthenitricacidmodifiedcoal⁃basedactivatedcarbonhasgoodregenerativecapacityand couldbereused*

     

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