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1、中国环境科学2013,33(8):1379~1385ChinaEnvironmentalScience磁性氧化石墨烯制备及去除水中刚果红的研究张秀蓉,龚继来*,曾光明,邓久华(湖南大学环境科学与工程学院,湖南长沙410082)摘要:采用Hummer方法制备了氧化石墨烯(GO),采用化学共沉淀法把铁氧化物纳米粒子覆盖在GO上制成磁性氧化石墨烯(MGO),并把MGO用作吸附剂去除水中阴离子染料刚果红.采用扫描电镜(SEM)、透射电镜(TEM)、Zeta电位仪和磁强计对MGO进行了表征.研究了吸附动力学,吸附等温线
2、及初始pH值,离子强度对吸附的影响.考察了MGO对自来水中刚果红的去除效果.结果表明,GO具有片状的二维纳米结构,表面有许多的褶皱;当pH<3.5,吸附剂表面带正电荷,当pH>3.5,吸附剂表面带负电荷,等电点为3.5;MGO的饱和磁化强度为31.2emu/g,足够从水溶液中分离出来.刚果红的吸附符合准二级动力学模型,且在吸附时间为7h内基本达到吸附平衡.在超纯水中最大吸附容量高达140.6mg/g,且吸附量随pH值升高先增加再降低,当pH4~5达到最大值.MGO对自来水中刚果红的最大吸附容量为287.6mg
3、/g,为在超纯水中的2倍,表明MGO对刚果红具有很好的去除效果.关键词:磁性氧化石墨烯;吸附;刚果红中图分类号:X703.5文献标识码:A文章编号:1000-6923(2013)08-1379-07Synthesisofmagneticgrapheneoxideadsorbentforcongoredremovalfromaqueoussolution.ZHANGXiu-rong,GONGJi-lai*,ZENGGuang-ming,DENGJiu-hua(CollegeofEnvironmentalScie
4、nceandEngineering,HunanUniversity,Changsha410082,China).ChinaEnvironmentalScience,2013,33(7):1379~1385Abstract:Grapheneoxide(GO)wassynthesizedusingHummer’smethodandmagneticgrapheneoxide(MGO)waspreparedbycoprecipitationofironoxidenanoparticlesonGOnanosheets.
5、MGOwasusedasadsorbentforremovinganionicdyecongoredfromaqueoussolutionandwascharacterizedbyscanningelectronmicroscope(SEM),transmissionelectronmicroscope(TEM),ZetaSIZERandvibratingsamplemagnetometer(VSM).Adsorptionkinetics,isotherms,theeffectsofinitialpHandi
6、onicstrengthonadsorption,andcongoredremovalefficiencyintapwaterwerealsoinvestigated.ResultsshowedthatGOexhibitedlayered2Dnanostructurewithmanywrinklesonthesurface.ThesurfacechargewaspositiveatpH<3.5,butwasnegativeatpH>3.5,thepHPZCvalueofMGOwas3.5.Thesaturat
7、ionmagnetizationofMGOadsorbentwas31.2emu/g,whichwassufficienttoseparatefromaqueoussolution.Thesorptionprocessescoincidedwiththepseudo-second-orderkineticmodelandtheadsorptionequilibriumwasreachedwithin7h.Themaximumadsorptioncapacityreachedupto140.6mg/ginult
8、rapurewater.AdsorptionquantityfirstincreasedandthendecreasedgraduallywithincreasingpHvalue,andreachedthemaximumatpH4~5.Theadsorptioncapacityforcongoredintapwaterwas287.6mg/g,whichwastwotimesofthatinult