Europium-doped ZnO as a visible light responsive nanocatalyst: Sonochemical synthesis, characterization and response surface modeling of photocatalytic process

Abstract Pure and Eu-doped ZnO nanostructures with different amounts of Eu were synthesized using a simple sonochemical method. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, UV–Vis spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity of as-prepared Eu-doped ZnO was investigated based on the decolorization of Acid Red 17 (AR17) under visible light irradiation. The decolorization efficiency was found to be 25.2%, 55.6%, 63.1% and 30.3% for undoped, 1% Eu-ZnO, 3% Eu-ZnO and 5% Eu-ZnO, respectively. Using 3% Eu-doped ZnO nanoparticles, the decolorization efficiency reached 100% by adding 0.1 mM S 2 O 8 2− . Response surface methodology based on five-level central composite design was applied to model and optimize the decolorization of AR17 over 3% Eu-doped ZnO/S 2 O 8 2− . Accordingly, the value of correlation coefficients ( R 2  = 0.970 and adjusted- R 2  = 0.935) obtained from analysis of variance confirmed the adequacy of fitted model. The maximum decolorization efficiency of 99% was achieved at an initial dye concentration of 5 mg/L, catalyst dosage of 1.25 g/L, S 2 O 8 2− concentration of 0.25 mM and reaction time of 150 min. The decolorization efficiency decreased only 7% after 4 repeated runs.

[1]  K. Ariga,et al.  Photocatalytic activity of La-doped ZnO for the degradation of monocrotophos in aqueous suspension , 2007 .

[2]  A. Ismail,et al.  Highly efficient photocatalyst based on Ce doped ZnO nanorods: Controllable synthesis and enhanced photocatalytic activity , 2013 .

[3]  M. Swaminathan,et al.  The effect of operational parameters on the photocatalytic degradation of acid red 18 by ZnO , 2007 .

[4]  Xiao Hu,et al.  Uniform hamburger-like mesoporous carbon-incorporated ZnO nanoarchitectures: One-pot solvothermal synthesis, high adsorption and visible-light photocatalytic decolorization of dyes , 2013 .

[5]  S. Joo,et al.  Sonocatalytic degradation of a textile dye over Gd-doped ZnO nanoparticles synthesized through sonochemical process. , 2015, Ultrasonics sonochemistry.

[6]  Song Gao,et al.  Magnetic properties of EuS nanoparticles synthesized by thermal decomposition of molecular precursors , 2005 .

[7]  A. Khataee.  Synthesis and characterization of ErxZn1-xSe nanoparticles: A novel visible light responsive photocatalyst , 2013 .

[8]  Wei Xu,et al.  Facile synthesis of ZnO nanorod arrays and hierarchical nanostructures for photocatalysis and gas sensor applications. , 2011, Journal of hazardous materials.

[9]  T. Thongtem,et al.  Morphology development of ZnO produced by sonothermal process , 2011 .

[10]  Chang Woo Kim,et al.  Single-crystal like mesoporous ZnO:Mn2+ nanorings of high optoelectronic quality formed by self-assembly of nanoparticles in an ultrasonic hydrolysis process , 2011 .

[11]  Chang Woo Kim,et al.  Ultrasound-Assisted Synthesis of Mesoporous ZnO Nanostructures of Different Porosities , 2009 .

[12]  A. Mohamed,et al.  Preparation and photocatalytic properties of visible light-driven samarium-doped ZnO nanorods , 2013 .

[13]  D. Yuan,et al.  Structure evaluation and highly enhanced luminescence of Dy3+ -doped ZnO nanocrystals by Li+ doping via combustion method. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[14]  M. Kasiri,et al.  Optimization of C.I. Acid Red 14 azo dye removal by electrocoagulation batch process with response surface methodology , 2008 .

[15]  X Wang,et al.  X-ray photoelectron spectroscopy and auger electron spectroscopy studies of Al-doped ZnO films , 2000 .

[16]  M. Khatamian,et al.  Heterogeneous photocatalytic degradation of 4-nitrophenol in aqueous suspension by Ln (La3+, Nd3+ or Sm3+) doped ZnO nanoparticles , 2012 .

[17]  S. Joo,et al.  Sonochemical synthesis of Pr-doped ZnO nanoparticles for sonocatalytic degradation of Acid Red 17. , 2015, Ultrasonics sonochemistry.

[18]  Yan Zong,et al.  Synthesis and high photocatalytic activity of Eu-doped ZnO nanoparticles , 2014 .

[19]  A. Khataee,et al.  UV/peroxydisulfate oxidation of C. I. Basic Blue 3: modeling of key factors by artificial neural network. , 2010 .

[20]  Alireza Aslani,et al.  Sonochemical synthesis, characterization and optical analysis of some metal oxide nanoparticles (MO-NP; M=Ni, Zn and Mn) , 2010 .

[21]  N. Modirshahla,et al.  Effect of operational parameters on decolorization of Acid Yellow 23 from wastewater by UV irradiation using ZnO and ZnO/SnO2 photocatalysts , 2011 .

[22]  T. Thongtem,et al.  Sonochemical synthesis of Dy-doped ZnO nanostructures and their photocatalytic properties , 2013 .

[23]  Q. Li,et al.  Controllable microwave and ultrasonic wave combined synthesis of ZnO micro-/nanostructures in HEPES solution and their shape-dependent photocatalytic activities , 2013 .

[24]  T. Thongtem,et al.  Sonochemical synthesis, photocatalysis and photonic properties of 3% Ce-doped ZnO nanoneedles , 2013 .

[25]  G. Zeng,et al.  Effective photocatalytic decolorization of methyl orange utilizing TiO2/ZnO/chitosan nanocomposite films under simulated solar irradiation , 2012 .

[26]  U. Pal,et al.  Photocatalytic behavior of ZnO and Pt-incorporated ZnO nanoparticles in phenol degradation , 2011 .

[27]  V. Ivanov,et al.  Hydrothermal and microwave-assisted synthesis of nanocrystalline ZnO photocatalysts , 2007 .

[28]  B. Likozar,et al.  The impact of ZnO load, stability and morphology on the kinetics of the photocatalytic degradation of caffeine and resazurin , 2013 .

[29]  Jianfeng Huang,et al.  Microwave hydrothermal synthesis of Sr2+ doped ZnO crystallites with enhanced photocatalytic properties , 2014 .

[30]  J. Dutta,et al.  Enhanced visible light photocatalysis by manganese doping or rapid crystallization with ZnO nanoparticles , 2011 .

[31]  A. Khataee,et al.  Photoelectro-Fenton/nanophotocatalysis decolorization of three textile dyes mixture: Response surface modeling and multivariate calibration procedure for simultaneous determination , 2012 .

[32]  A. Khataee,et al.  Photocatalytic treatment of a dye solution using immobilized TiO2 nanoparticles combined with photoelectro-Fenton process: Optimization of operational parameters , 2010 .

[33]  David G. Evans,et al.  Preparation, characterization and photocatalytic activity of Si-doped and rare earth-doped TiO2 from mesoporous precursors , 2005 .

[34]  R. S. Tiwari,et al.  Structural and hydrogenation studies of ZnO and Mg doped ZnO nanowires , 2012 .

[35]  D. Isa,et al.  Photocatalytic study of two-dimensional ZnO nanopellets in the decomposition of methylene blue , 2010 .

[36]  Xiao Hu,et al.  Microwave-assisted non-aqueous route to deposit well-dispersed ZnO nanocrystals on reduced graphene oxide sheets with improved photoactivity for the decolorization of dyes under visible light , 2012 .

[37]  M. Maaza,et al.  Temperature-dependent growth mode of W-doped ZnO nanostructures , 2011 .

[38]  L. Palmisano,et al.  Characterization and photoactivity of coupled ZnO–ZnWO4 catalysts prepared by a sol–gel method , 2014 .

[39]  S. Jian,et al.  A CTAB-assisted hydrothermal and solvothermal synthesis of ZnO nanopowders , 2011 .

[40]  R. Ganesan,et al.  Effect of Cobalt Doping on Structural, Optical, and Magnetic Properties of ZnO Nanoparticles Synthesized by Coprecipitation Method , 2014 .

[41]  A. Singh,et al.  Optimizing adsorption of crystal violet dye from water by magnetic nanocomposite using response surface modeling approach. , 2011, Journal of hazardous materials.

[42]  Jing-lan Feng,et al.  Enhanced sunlight photocatalytic performance of Sn-doped ZnO for Methylene Blue degradation , 2011 .

[43]  S. Joo,et al.  Synthesis and Characterization of Dysprosium-Doped ZnO Nanoparticles for Photocatalysis of a Textile Dye under Visible Light Irradiation , 2014 .

[44]  U. Pal,et al.  Use of diffuse reflectance spectroscopy for optical characterization of un-supported nanostructures , 2007 .

[45]  A. Khataee,et al.  Combined heterogeneous and homogeneous photodegradation of a dye using immobilized TiO2 nanophotocatalyst and modified graphite electrode with carbon nanotubes , 2012 .

[46]  T. Thongtem,et al.  Preparation, characterization and photocatalytic properties of Ho doped ZnO nanostructures synthesized by sonochemical method , 2014 .

[47]  A. Rezaee,et al.  Photocatalytic decolorization of methylene blue using immobilized ZnO nanoparticles prepared by solution combustion method , 2012 .

[48]  A. Rezaee,et al.  Optimisation of the operational parameters during a biological nitrification process using response surface methodology , 2014 .

[49]  A. Rezaee,et al.  Photocatalytic process by immobilized carbon black/ZnO nanocomposite for dye removal from aqueous medium: Optimization by response surface methodology , 2014 .

[50]  A. Rezaee,et al.  Combination of Carbon Black–ZnO/UV Process with an Electrochemical Process Equipped with a Carbon Black–PTFE-Coated Gas-Diffusion Cathode for Removal of a Textile Dye , 2013 .

[51]  A. Mohamed,et al.  Preparation of rare earth-doped ZnO hierarchical micro/nanospheres and their enhanced photocatalytic activity under visible light irradiation , 2014 .

[52]  A. Khataee,et al.  Removal of C.I. Acid Orange 7 from aqueous solution by UV irradiation in the presence of ZnO nanopowder. , 2007, Journal of hazardous materials.

[53]  Qingjie Zhang,et al.  Fabrication, characterization and photocatalytic activity of La-doped ZnO nanowires , 2009 .

[54]  D. Poelman,et al.  An XPS study of the dopants' valence states and the composition of CaS1 − xSex:Eu and SrS1 − xSex:Ce thin film electroluminescent devices , 1995 .

[55]  M. Swaminathan,et al.  Enhanced photocatalytic performance of WO3 loaded Ag–ZnO for Acid Black 1 degradation by UV-A light , 2013 .

[56]  A. Niaei,et al.  The photooxidative destruction of C.I. Basic Yellow 2 using UV/S2O82− process in a rectangular continuous photoreactor , 2008, Journal of Hazardous Materials.