摘要
将粉煤灰（FA）经沉淀焙烧法制得的FA/ZnO复合材料用于水体中活性艳蓝KN-R（RBB KN-R）的吸附去除,通过吸附动力学、平衡和热力学研究,并结合SEM和比表面积测定,详细分析了材料的吸附性能和吸附机理.结果表明：FA/ZnO复合材料对RBB KN-R有很好的吸附性能,且受水体酸度的影响较大,在25℃和溶液pH值为2时的吸附量和去除率分别可达147.06mg/g和98%,比FA增大10倍以上.等温吸附数据通过用Langmuir,Freundlich和DubininRadushkevich（D-R）模型分别进行拟合发现,FA/ZnO对RBB KN-R在不同温度（25～55℃）的吸附行为完全符合Langmuir模型,结合D-R模型所得不同温度下的平均吸附能值（14.14～16.22kJ/mol）和由A.S.Arrhenius方程所得吸附活化能值（56.16kJ/mol）表明,吸附主要为化学作用,同时伴有物理吸附.热力学参数吸附自由能变的负值及焓变和熵变的正值说明该吸附具有界面上混乱度趋增的自发吸热性质,且可用拟二级吸附速率模型进行很好地描述,吸附开始的快吸附过程主要受颗粒内扩散控制.
FA/ZnO composite prepared by precipitation-calcination method was used for removing reactive brilliant blue KN-R（RBB KN-R）dye from aqueous solution.The adsorption property and mechanism were discussed by studying dynamics,equilibrium,thermodynamics and analysis of SEM and specific surface area.The results show that FA/ZnO composite has excellent adsorption performance for RBB KN-R,which is strongly dependent on the solution pH.The adsorption amount and removal rate at 25 ℃ and pH=2are 147.06mg/g and 98%,10 times more than those of FA.The results of experimental isotherm data analyzed using three isotherm models,namely Langmuir,Freundlich and Dubinin-Radushkevich（D-R）reveal that the adsorption behavior of RBB KN-R on FA/ZnO entirely fits Langmuir model at different temperatures（25—55 ℃）.In addition,the mean adsorption energy（14.14—16.22kJ/mol）from D-R model and the activation energy（56.16kJ/mol）from A.S.Arrhenius equation indicate that the adsorption process should be the dual nature of physisorption and chemisorption,and is mainly chemical action.Negative values of adsorption free energy changes for ther-modynamic parameters and positive values of adsorption enthalpy changes and entropy changes illustrate that the adsorption process is spontaneous and endothermic nature accompanied by increasing randomness on the liquid-solid interface.The dynamical data follow the pseudo-second-order adsorption model well.The initial fast adsorption process after the beginning of the adsorption is mainly controlled by intraparticle diffusion.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2016年第2期418-425,共8页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(21167011)
内蒙古自治区自然科学基金项目(2015MS0226)
关键词
粉煤灰
ZNO
复合材料
活性艳蓝KN-R
吸附
fly ash（FA）
ZnO
composite material
reactive brilliant blue KN-R
adsorption
