高比表面积氧化铝微粉从碱性废水中除氟

2020,Vol郾34,No郾2摇www.mater鄄rep.com摇liugh303@csu.edu.cnDOI:10郾11896/cldb郾19010220摇请扫描二维码访问本文网络展示页面以获取补充信息(SupplementaryInformation)摇基金项目:国家自然科学基金(51874366)摇摇摇摇ThisworkwasfinanciallysupportedbytheNationalNaturalScienceFoundationofChina(51874366).高比表面积氧化铝微粉从碱性废水中除氟张摇婷,刘桂华,陈斌斌,齐天贵,周秋生,彭志宏,李小斌中南大学冶金与环境学院,长沙410083以合成的活性氧化铝微粉为吸附剂,研究了碱性含氟废水中pH值、初始氟浓度、吸附时间、氧化铝添加量等对除氟率和吸附容量的影响,讨论了其吸附机理。以铝酸钠溶液为原料,经氢氧化铝、丝钠铝石、碳酸铝铵和氧化铝等物相转化,制备了比表面积为409郾03m2·g-1的介孔氧化铝微粉。当pH值为7郾0~9郾4时,氧化铝微粉的除氟率较高。延长吸附时间、降低氟浓度或提高微粉加入量有利于提高除氟率。Zeta电位随溶液pH值的增大而减小,等电点为9郾77。当pH值为8郾1时,高比表面积、静电吸引、多层吸附是碱性条件下氧化铝微粉吸附容量大(9郾28mg·g-1)、除氟率高(94郾20%)的主要原因。同时,吸附也符合拟二级动力学模型,对氟的吸附受化学吸附控制。关键词摇摇活性氧化铝摇比表面积摇氟摇碱性溶液摇脱除中图分类号:TU991郾266摇摇文献标识码:ARemovalofFluorideinAlkalineSolutionUsingFineAluminawithHighSpecificSurfaceAreaZHANGTing,LIUGuihua,CHENBinbin,QITiangui,ZHOUQiusheng,PENGZhihong,LIXiaobinSchoolofMetallurgyandEnvironment,CentralSouthUniversity,Changsha410083,ChinaEffectofpH,initialfluorideconcentration,duration,aluminadosageonremovalrateandadsorptioncapacitywerestudiedbyaddingthefineactivatedalumina,andremovalmechanismwasthendiscussed.Afineactivatedaluminawithspecificsurfaceareaof409郾03m2·g-1waspreparedbyphaseevolutionfromgibbsite,dawsonite,ammoniaaluminatecarbonatehydratetomesoporous酌鄄Al2O3aftergibbsiteprecipitatedfromsodiumaluminatesolution.ResultsindicatethatfluorideisefficientlyremovedwithinpHrangefrom7to9郾4.Prolongingadsorptiontime,re鄄ducingfluorideconcentration,andincreasingaluminadosageimproveremovalrate.Meanwhile,increaseinpHreduceszetapotential,andIEPisequalto9郾77.Highspecificsurfacearea,electrostaticattraction,andmultilayeradsorptioncontributetoadsorptioncapacityof9郾28mg·g-1andremovalrateof94郾20%insolutionofpH8郾1.Inaddition,chemisorptionisratecontrollingstepaccordingtopseudo鄄secondrateequationinremovaloffluorideinalkalinesolution.Keywords摇摇activatedalumina,specificsurfacearea,fluoride,alkalinesolution,removal0摇引言活性氧化铝(主要是酌鄄Al2O3)对氟的亲和性和选择性高,且稳定性好、无毒、使用成本低,是一种应用广泛的除氟吸附剂[1鄄2],因此一直是吸附除氟领域的研究热点。目前,研究较多的是活性氧化铝微粉或微球在酸性或近中性条件下吸附除氟。以铝