摘要
具有多级结构的半导体金属氧化物,其特有的立体空间结构使材料具有超高活性,在吸附领域具有应用潜力。研究采用简单的一步溶剂热法制备了空心球状的MoO_2前驱体,400℃热处理后得到多级结构α-MoO_3空心微球。空心球的直径为600~800 nm,由宽度约70 nm的纳米棒构筑而成。该球状α-MoO_3纳米材料对亚甲基蓝(MB)染料具有优良的吸附性能。当α-MoO_3吸附剂用量为0.5 g/L、MB染料浓度为20 mg/L、吸附时间为5 min时,移除率可达到73.40%。吸附60min时,吸附达到平衡,此后移除率为97.53%~99.65%。该吸附动力学过程符合拟二级动力学模型,吸附等温线符合Langmuir模型拟合,最大吸附量为1543.2 mg/g。α-MoO_3微球由于多级且中空的纳米结构,对MB染料具有用量少、吸附速率快和吸附完全等特点。该材料可以用于吸附废水中其他有机染料。
Hierarchical semiconducting metal oxide is highly active due to its special stereostructure, which is potential adsorbent for dye contaminants. Precursors of MoO_2 hollow spheres were successfully synthesized via a simple and one-step solvothermal method. And hierarchical α-MoO_3 hollow microspheres were obtained after subsequent calcination at 400 ℃. Diameters of the α-MoO_3 microspheres were about 600-800 nm which were assembled by nanorods with a width of 70 nm. The as-obtained α-MoO_3 nanomaterials presented excellent adsorption performance for methylene blue(MB). MB removal percentage attained 73.40% in the first 5 min when the concentration of α-MoO_3 absorbent was 0.5 g/L in MB solution at the concentration of 20 mg/L. The equilibrium was established after adsorption for 60 min, and the removal percentages stabilized in the range of 97.53%-99.65%. Their adsorption kinetics was well fitted to a pseudo-second-order model. The adsorption isotherm conformed to Langmuir isotherm model, and the maximum uptake capacity was 1543.2 mg/g. The α-MoO_3 microspheres are cost-effective, fast and complete for MB removal owing to its hierarchical and hollow nanostructures, which also can be employed for adsorption of other organic dyes in waste water.
引文
[1]KUMAR K Y,ARCHANAr S,VINUTH T N,et al.Superb adsorption capacity of hydrothermally synthesized copper oxide and nickel oxide nanoflakes towards anionic and cationic dyes.J.Sci.:Adv.Mater.Devices,2017,2(2):183-191.
[2]JIN Y J,LI N,LIU H Q,et al.Highly efficient degradation of dye pollutants by Ce-doped MoO3 catalyst at room temperature.Dalton Trans.,2014,43(34):12860-12870.
[3]HOKKANEN S,BHATNAGAR A,SILLANPAA M.A review on modification methods to cellulose-based adsorbents to improve adsorption capacity.Water Res.,2016,91:156-173.
[4]TIAN P,HAN X Y,NING G L,et al.Synthesis of porous hierarchical MgO and its superb adsorption properties.ACS Appl.Mater.Interfaces,2013,5(23):12411-12418.
[5]RONG X S,QIU F X,QIN J,et al.A facile hydrothermal synthesis,adsorption kinetics and isotherms to Congo Red azo-dye from aqueous solution of NiO/grapheme nanosheets adsorbent.J.Indust.Eng.Chem.,2015,26:354-363.
[6]SONG L X,YANG Z K,TENG Y,et al.Nickel oxide nanoflowers:formation,structure,magnetic property and adsorptive performance towards organic dyes and heavy metal ions.J.Mater.Chem.A,2013,1(31):8731-8736.
[7]ZHU D Z,ZHANG J,SONG J M,et al.Efficient one-pot synthesis of hierarchical flower-likeα-Fe2O3 hollow sphereswith excellent adsorption performance for water treatment.Appl Surf.Sci.,2013,284:855-861.
[8]LIU B X,WANG J S,WU J S,et al.Controlled fabrication of hierarchical WO3 hydrates with excellent adsorption performance.J.Mater.Chem.A,2014,2(6):1947-1954.
[9]LEE J H.Gas sensors using hierarchical and hollow oxide nanostructures:overview.Sens.Actuators,B,2009,140(1):319-336.
[10]LIU Y,FENG P Z,WANG Z,et al.Novel fabrication and enhanced photocatalytic MB degradation of hierarchical porous monoliths of MoO3 nanoplates.Sci.Rep.,2017,7(1):1845-1854.
[11]WANG M,SONG X X,CHENG X L,et al.Highly selective and efficient adsorption dyes selfassembled by 3D hierarchical architecture of molybdenum oxide.RSC Adv.,2015,5(104):85248-85255.
[12]SUI L L,ZHANG X F,CHENG X L,et al.Au-Loaded hierachical MoO3 hollow spheres with enhanced gas sensing performance for the detection of BTX(benzene,toluene,and xylene)and the sensing mechanism.ACS Appl.Mater.Interfaces,2017,9(2):1661-1670.
[13]ZHANG J,SONG P,LI J,et al.Template-assisted synthesis of hierarchical MoO3 microboxes and their high gas-sensing performance.Sens.Actuators,B,2017,249:458-466.
[14]XIA Y C,WU C S,ZHAO N Y,et al.hierarchical nanostructures for excellent performance ethanol sensor.Mater.Lett.,2016,171:117-120.
[15]YAN H H,SONG P,ZHANG S,et al.Facile fabrication and enhanced gas sensing properties of hierarchical MoO3 nanostructures.RSC Adv.,2015,5(89):72728-72735.
[16]WANG S T,ZHANG Y G,MA X C,et al.Hydrothermal route to single crystallineα-MoO3 nanobelts and hierarchical structures.Solid State Commun.,2005,136(5):283-287.
[17]YU X Y,ZHANG G X,LU Z Y,et al.Green sacrificial template fabrication of hierarchical MoO3 nanostructures.CrystEngComm,2014,16(19):3935-3939.
[18]LIANG R L,CAO H Q,QIAN D,et al.MoO3 nanowires as electrochemical pseudocapacitor materials.Chem.Commun.,2011,47(37):10305-10307.
[19]JIAN J B,LIU J L,PENG S J,et al.Facile synthesis ofα-MoO3nanobelts and their pseudocapacitive behavior in an aqueous Li2SO4 solution.J.Mater.Chem.A.,2013,1(7):2588-2594.
[20]CHEN D L,LIU M N,YIN L,et al.Single-crystalline MoO3 nanoplates:topochemical synthesis and enhanced ethanol-sensing performance.J.Mater.Chem.,2011,21(25):9332-9342.
[21]XU B Y,LI Y,WANG G F,et al.In situ synthesis and high adsorption performance of MoO2/Mo4O11 and MoO2/MoS2 composite nanorods by reduction of MoO3.Dalton Trans.,2015,44(13):6224-6228.
[22]LEI C S,ZHU X F,ZHU B C,et al.Hierarchical NiO-SiO2 composite hollow microspheres with enhanced adsorption affinity towards Congo red in water.J.Colloid Inter.Sci.,2016,466:238-246.
[23]ZHANG P P,MA X M,GUO Y M,et al.Size-controlled synthesis of hierarchical NiO hollow microspheres and the adsorption for Congo red in water.Chem.Eng.J.,2012,189-190(5):188-195.
[24]DHANAVEL S,NIVETHAA E A K,DHANAPA K,et al.?-MoO3/polyaniline composite for effective scavenging of Rhodamine B,Congo red and textile dye effluent.RSC Adv.,2016,6(34):28871-28886.
[25]MA Y,JIA Y L,JIA Z B,et al.Facile synthesizeα-MoO3 nanobelts with high adsorption property.Mater.Lett.,2015,157:53-56.
[26]LI J,LIU X H,HAN Q F,et al.Formation of WO3 nanotube-based bundles directed by NaHSO4 and its application in water treatment.J.Mater.Chem.A,2013,1(7):1246-1253.
[27]ZHU J,WANG S L,XIE S H,et al.Hexagonal single crystal growth of WO3 nanorods along a[110]axis with enhanced adsorption capacity.Chem.Commun.,2011,47(15):4403-4405.
[28]JEON S,YONG K.Morphology-controlled synthesis of highly adsorptive tungsten oxide nanostructures and their application to water treatment.J.Mater.Chem.,2010,20(45):10146-10151.
[29]PERES E C,SLAVIERO J C,CUNHA A M,et al.Microwave synthesis of silica nanoparticles and its application for methylene blue adsorption.J.Environ.Chem.Eng.,2018,6(1):649-659.
[30]SAINI J,GARG V K,GUPTA R K.Removal of methylene blue from aqueous solution by Fe3O4@Ag/SiO2 nanospheres:synthesis,characterization and adsorption performance.J.Mol.Liq.,2018,250:413-422.