1. K. Yu, J. Shi, Z. Zhang, Y. Liang, W. Liu, Synthesis, characterization, and photocatalysis of ZnO and Er-doped ZnO, J. Nanomater., 2013 (2013) 1–5, doi: 10.1155/2013/ 372951.
  2. A. Akbari, S. Desclaux, J.C. Remigy, P. Aptel, Treatment of textile dye effluents using a new photografted nanofiltration membrane, Desalination, 149 (2002) 101–107.
  3. G. Ciardelli, L. Corsi, M. Marucci, Membrane separation for wastewater reuse in the textile industry, Resour. Conserv. Recycl., 31 (2000) 189–197.
  4. A. Bhatnagar, M. Sillanpaa, Utilization of agro-industrial and municipal waste materials as potential adsorbents for water treatment: a review, Chem. Eng. J., 157 (2010) 277–296.
  5. P. Chandran, P. Kumari, S. Sudheer Khan, Photocatalytic activation of CdS NPs under visible light for environmental cleanup and disinfection, Sol. Energy, 105 (2014) 542–547.
  6. N. Kislov, J. Lahiri, H. Verma, D.Y. Goswami, E. Stefanakos, M. Batzill, Photocatalytic degradation of methyl orange over single crystalline ZnO: orientation dependence of photoactivity and photostability of ZnO, Langmuir, 25 (2009) 3310–3315.
  7. G. Yanga, Z. Yanb, T. Xiao, Preparation and characterization of SnO2/ZnO/TiO2 composite semiconductor with enhanced photocatalytic activity, Appl. Surf. Sci., 258 (2012) 8704–8712.
  8. A. Hamrouni, N. Moussa, F. Parrino, A.D. Paola, A. Houas, L. Palmisano, Sol-gel synthesis and photocatalytic activity of ZnO-SnO2 nanocomposites, Mol. Catal. A, 390 (2014) 133–141.
  9. H. Chemingui, T. Missaoui, J. Chékir Mzali, T. Yildiz, M. Konyar, M. Smiri, N. Saidi, A. Hafiane, H.C. Yatmaz, Facile green synthesis of zinc oxide nanoparticles (ZnO NPs): antibacterial and photocatalytic activities, Mater. Res. Express, 6 (2019) 1050b4.
  10. J. Cui, U. Gibson, Low-temperature fabrication of single-crystal ZnO nanopillar photonic bandgap structures, Nanotechnology, 18 (2007) 155302.
  11. S. Chakrabarti, B.K. Dutta, Photocatalytic degradation of model textile dyes in wastewater using ZnO as semiconductor catalyst, J. Hazard. Mater., 112 (2004) 269–278.
  12. A.B. Djurisic, X.Y. Chen, Y.H. Leung, A.M.C. Ng, ZnO nanostructures: growth, properties and applications, J. Mater. Chem., 22 (2012) 6526–6535.
  13. A. Elkhidir Suliman, Y. Tang, L. Xu, Preparation of ZnO nanoparticles and nanosheets and their application to dyesensitized solar cells, Sol. Energy Mater. Sol. Cells, 91 (2007) 1658–1662.
  14. K. Tang, S.L. Gu, S.Z. Li, J.D. Ye, S.M. Zhu, H. Chen, Temperaturedependent photoluminescence of ZnO films codoped with tellurium and nitrogen, J. Vac. Sci. Technol., A, 29 (2011) 1–7.
  15. N. Bouhssira, S. Abed, E. Tomasella, J. Cellier, A. Mosbah, M.S. Aida, M. Jacquet, Influence of annealing temperature on the properties of ZnO thin films deposited by thermal evaporation, Appl. Surf. Sci., 252 (2006) 5594–5597.
  16. S. Jurablu, M. Farahmandjou, T.P. Firoozabadi, Sol-gel synthesis of zinc oxide (ZnO) nanoparticles: study of structural and optical properties, J. Sci. Islamic Republic of Iran, 26 (2015) 281–285.
  17. H. Chemingui, M. Smiri, T. Missaoui, A. Hafiane, Zinc oxide nanoparticles induced oxidative stress and changes in the photosynthetic apparatus in fenugreek (Trigonella foenumgraecum L.), Bull. Environ. Contam. Toxicol., 102 (2019) 326.
  18. X. Qiu, G. Li, X. Sun, L. Li, X. Fu, Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties, Nanotechnology, 19 (2008) 215–703.
  19. M. Sharrouf, R. Awad, S. Marhaba, D. El-Said Bakeer, Structural, optical and room temperature magnetic study of Mn doped ZnO nanoparticles, NANO: Brief Rep. Rev., 11 (2016) 1650042.
  20. N, Aisah, D. Gustiono, V. Fauzia, I. Sugihartono, R. Nuryadi, Synthesis and enhanced photocatalytic activity of Ce-doped zinc oxide nanorods by hydrothermal method, Mater. Sci. Eng., 172 (2017) 012037.
  21. P.V. Korake, A.N. Kadam, K.M. Garadkar, Photocatalytic activity of Eu3+-doped ZnO nanorods synthesized via microwave assisted technique, J. Rare Earths, 32 (2014) 306–313.
  22. M. Rezaei, A. Habibi-Yangjeh, Microwave-assisted preparation of Ce-doped ZnO nanostructures as an efficient photocatalyst, Mater. Lett., 110 (2013) 53–56.
  23. M. Faisal, A.A. Ismail, A.A. Ibrahim, H. Bouzid, S.A. Al-Sayari, Highly efficient photocatalyst based on Ce doped ZnO nanorods: controllable synthesis and enhanced photocatalytic activity, Chem. Eng. J., 229 (2013) 225–233.
  24. S. Gao, H. Zhang, R. Deng, X. Wang, D. Sun, G. Zheng, Ballisticity of nanotube field-effect transistors: role of phonon energy and gate bias, Appl. Phys. Lett., 89 (2006) 23125–23128.
  25. N. Mais, J.P. Reithmaier, A. Forchel, M. Kohls, L. Spanhel, G. Muller, Er doped nanocrystalline ZnO planar waveguide structures for 1.55 μm amplifier applications, J. Appl. Phys. Lett., 75 (1999) 2005–2008.
  26. A. Polman, Erbium implanted thin film photonic materials, J. Appl. Phys., 82 (1997) 1–39.
  27. K. Takahei, A. Taguchi, Selective formation of an efficient Er–O luminescence center in GaAs by metal organic chemical vapor deposition under an atmosphere containing oxygen, J. Appl. Phys., 74 (1993) 1979–1983.
  28. R. Zamiri, A. Kaushal, A. Rebelo, J.M.F. Ferreira, Er doped ZnO nanoplates: synthesis, optical and dielectric properties, Ceram. Int., 40 (2014) 1635–1639.
  29. G.J. Lee, Ch.Y. Lin, J.J. Wu, Preparation of Dumbbell-like Er/ZnO Microrods with efficient energy upconversion for the catalytic degradation of tartaric acid in water, Topics Catal., 60 (2017)1359.
  30. J.Ch. Sin, S.M. Lam, K.T. Lee, Abd. R. Mohamed, Fabrication of erbium-doped spherical-like ZnO hierarchical nanostructures with enhanced visible light-driven photocatalytic activity, Mater. Lett., 91 (2013) 1–4.
  31. A. Khataee, S. Saadi, M. Safarpour, S.W. Joo, Sonocatalytic performance of Er-doped ZnO for degradation of a textile dye, Ultrason. Sonochem., 27 (2015) 379–388.
  32. N.K. Divya, P.P. Pradyumnan, Solid state synthesis of erbium doped ZnO with excellent photocatalytic activity and enhanced visible light emission, Mater. Sci. Semicond. Process., 41 (2016) 428–435.
  33. W. Raza, S.M. Faisal, M. Owais, D. Bahnemann, M. Muneer, Facile fabrication of highly efficient modified ZnO photocatalyst with enhanced photocatalytic, antibacterial and anticancer activity, RSC Adv., 6 (2016) 78335.
  34. A. Kocakusakoglu, M. Daglar, M. Konyar, H.C. Yatmaz, K. Öztürk, Photocatalytic activity of reticulated ZnO porous ceramics in degradation of azo dye molecules, J. Eur. Cerm. Soc., 35 (2015) 2845–2853.
  35. P. Klug, L.E. Alexander, X-Ray Diffraction Procedures: For Polycrystalline and Amorphous Materials, 2nd ed., Wiley, New York, 1954.
  36. R. John, R. Rajakumari, Synthesis and characterization of rare Earth ion doped nano ZnO, Nano-Micro Lett., 4 (2012) 65–72.
  37. A. Guesmi, C. Bouzidi, H. Elhouichet, Spectroscopic properties of Dy3+ doped ZnO for white luminescence applications, Spectrochim. Acta Part A, 177 (2017) 164–169.
  38. Y. Zhou, S.X. Lu, W.G. Xu, Photocatalytic activity of Nd‐doped ZnO for the degradation of C.I. Reactive Blue 4 in aqueous suspension, Environ. Prog. Sustainable Energy, 28 (2009) 226–233.
  39. J.-C. Sin, Sze-Mun Lam, Ichikawa Satoshi, Keat-Teong Lee, A.R. Mohamed, Sunlight photocatalytic activity enhancement and mechanism of novel europium-doped ZnO hierarchical micro/nanospheres for degradation of phenol, Appl. Catal. B, 148–149 (2014) 258–268.
  40. S. Anandan, A. Vinu, T. Mori, N. Gokulakrishnan, P. Srinivasu, V. Murugesan, K. Ariga, Photocatalytic degradation of 2,4,6-trichlorophenol using lanthanum doped ZnO in aqueous suspension, Catal. Commun., 8 (2007) 1377–1382.
  41. D. Suresh, P.C. Nethravathi, Udayabhanu, M.A. PavanKumar, H. Raja Naika, H. Nagabhushana, S.C. Sharma, Chironji mediated facile green synthesis of ZnO nanoparticles and their photoluminescence, photodegradative, antimicrobial and antioxidant activities, Mater. Sci. Semicond. Process., 40 (2015) 759–765.
  42. B. El Filali, T.V. Torchynska, A.I. Diaz Cano, Defect related emission of ZnO and ZnO Cu nanocrystals prepared by electrochemical method, J. Lumin., 161 (2015) 25–30.
  43. A. Jagannatha Reddy, M.K. Kokila, H. Nagabhushana, J.L. Rao, C. Shivakumara, B.M. Nagabh ushana, R.P.S. Chakradhar, Combustion synthesis, characterization and Raman studies of ZnO nanopowders, Spectrochim. Acta A, 81 (2011) 53–58.
  44. S. Arunkumar, K. Marimuthu, Concentration effect of Sm3+ ions in B2O3–PbO–PbF2–Bi2O3–ZnO glasses–structural and luminescence investigations, J. Alloys Compd., 565 (2013) 104–114.
  45. N.A. Salahuddin, M. El-Kemary, E.M. Ibrahim, Synthesis and characterization of ZnO nanoparticles via precipitation method: effect of annealing temperature on particle size, Nanosci. Nanotechnol., 5 (2015) 82–88.
  46. G.A. Suganya Josephine, A. Sivasamy, Nanocrystalline ZnO doped Dy2O3 a highly active visible photocatalyst: the role of characteristic f orbital’s of lanthanides for visible photoactivity, Appl. Catal. B, 150 (2014) 288.
  47. S.-m. Chang, R.-a. Doong, The effect of chemical states of dopants on the microstructures and band gaps of metal-doped ZrO2 thin films at different temperatures, J. Phys. Chem. B, 108 (2004) 18098–18103.
  48. S. Zhang, Y. Chen, Y. Yu, H, Wu, S. Wang, B. Zhu, W. Huang, S. Wu, Synthesis, characterization of Cr-doped TiO2 nanotubes with high photocatalytic activity, J. Nanopart. Res., 10 (2008) 871–875.
  49. M. Faraz, F.K. Naqvi, M. Shakir, N. Khare, Synthesis of samarium-doped zinc oxide nanoparticles with improved photocatalytic performance and recyclability under visible light irradiation, New J. Chem., 42 (2018) 2295–2305.
  50. P.V. Korake, A.N. Kadam, K.M. Garadka, Photocatalytic activity of Eu3+-doped ZnO nanorods synthesized via microwave assisted technique, J. Rare Earths, 32 (2014) 306–313.
  51. R.Y. Hong, J.H. Li, L.L. Chen, D.Q. Liu, H.Z. Li, Y. Zheng, J. Ding, Synthesis, surface modification and photocatalytic property of ZnO nanoparticles, Powder Technol., 189 (2009) 426–432.
  52. A. Jagannatha Reddy, M.K. Kokila, H. Nagabhushana, J.L. Rao, C. Shivakumara, B.M. Nagabhushana, R.P.S. Chakradhar, Spectrochim. Acta A, 81 (2011) 53–58.
  53. J. Lang, J. Wang, Q. Zhang, S. Xu, D. Han, J. Yang, Q. Han, L. Yang, Y. Sui, X. Li, X. Liu, Structural, optical and EPR studies on ZnO:Cu nanopowders prepared via low temperature solution combustion synthesis, Mater. Sci. Semicond. Process., 41 (2016) 32–37.
  54. W. Bousslama, H. Elhouichet, B. Gelloz, B. Sieber, A. Addad, M. Moreau, M. Férid, N. Koshida, Structural and luminescence properties of highly crystalline ZnO nanoparticles prepared by sol–gel method, Jpn. J. Appl. Phys., 51 (2012) 04–13.
  55. A. Joseph, G.L Praveen, K. Abha, G.M. Lekha, S. George, Photoluminescence study on amino functionalized dysprosium oxide–zinc oxide composite bifunctional nanoparticles, J. Lumin., 132 (2012) 1999–2004.
  56. N. Karak, B. Pal, D. Sarkar, T. Kumar Kundu, Growth of Co-doped ZnO nanoparticles by porous alumina assisted sol–gel route: structural optical and magnetic properties, J. Alloys Compd., 647 (2015) 252–258.
  57. F. Empizo Melvin John, K. Fukuda, R. Arita, Y. Minami, K. Yamanoi, T. Shimizu, N. Sarukura, M. Vargas Ray, A. Salvador Arnel, V. Sarmago Roland, Photoluminescence properties of a single ZnO microstructure for potential scintillator applications, Opt. Mater., 38 (2014) 256–260.
  58. A. Kovalenko, G. Pourroy, O. Crégut, M. Gallart, B. Hönerlage, P. Gilliot, Evidence of unintentional n-doping in ZnO nanorods, J. Phys. Chem. C, 114 (2010) 9498–9502.
  59. M. Navaneethan, J. Archana, M. Arivanandhan, Y. Hayakawa, Functional properties of amine-passivated ZnO nanostructures and dye-sensitized solar cell characteristics, Chem. Eng. J., 213 (2012) 70–77.
  60. M. Navaneethan, J. Archana, M. Arivanandhan, Y. Hayakawa, Chemical synthesis of ZnO hexagonal thin nanodisks and dye‐sensitized solar cell performance, Phys. Status Solidi RRL, 6 (2012) 120–122.
  61. L.-L. Yang, J.-H. Yang, D.-D. Wang, Y.-J. Zhang, Ya-Xin Wang, Hui-Lian Liu, Hou-Gang Fan, Ji-Hui Lang, Photoluminescence and Raman analysis of ZnO nanowires deposited on Si (1 0 0) via vapor–liquid–solid process, Physica E, 40 (2008) 920–923.
  62. A. Van Dijken, E.A. Meulenkamp, D. Vanmaekelbergh, A. Meijerink, The kinetics of the radiative and nonradiative processes in nanocrystalline ZnO particles upon photoexcitation, J. Phys. Chem. B, 104 (2000) 1715–1723.
  63. D. Sarkar, S. Tikku, V. Thapar, R.S. Srinivasa, K.C. Khilar, Formation of zinc oxide nanoparticles of different shapes in water-in-oil microemulsion, Colloids Surf. A, 381 (2011) 123–129.
  64. K. Vanheusden, C.H. Seager, W.L. Warren, D.R. Tallant, J.A. Voigt, Correlation between photoluminescence and oxygen vacancies in ZnO phosphors, Appl. Phys. Lett., 68 (1996) 403–407.
  65. P.K. Sanoop, S. Anas, S. Ananthakumar, V. Gunasekar, R. Saravanan, V. Ponnusami, Synthesis of yttrium doped nanocrystalline ZnO and its photocatalytic activity in methylene blue degradation, Arabian J. Chem., 9 (2016) S1618–S1626.
  66. Z. Zhao, J.-l. Son, G.-h. Zhen, G.J.-s. Lian, Optical properties and photocatalytic activity of Nd-doped ZnO powders, Trans. Nonferrous Met. Soc. China, 24 (2014) 1434–1439.
  67. I. Jlassi, H. Elhouichet, M. Ferid, R. Chtourou, M. Oueslati, Study of photoluminescence quenching in Er3+-doped tellurite glasses, Opt. Mater., 32 (2010) 743–747.
  68. R.S. Ajimsha, A.K. Das, B.N. Singh, P. Misra, L.M. Kukreja, Structural, electrical and optical properties of Dy doped ZnO thin films grown by buffer assisted pulsed laser deposition, Physica E, 42 (2010) 1838–1843.
  69. J. Zhang, S.J. Deng, S.Y. Liu, J.M. Chen, B.Q. Han, Y. Wang, Y.D. Wang, Preparation and photocatalytic activity of Nd doped ZnO nanoparticles, J. Mater. Technol., 29 (2013) 263–267.
  70. M.A. Behnajady, N. Modirshahla, R. Hamzavi, Kinetic study on photocatalytic degradation of C.I. Acid Yellow 23 by ZnO photocatalyst, J. Hazard. Mater. B, 133 (2006) 226–232.
  71. N. Daneshvar, D. Salari, A. Khataee, Photocatalytic degradation of azo dye acid red 14 in water: investigation of the effect of operational parameters, J. Photochem. Photobiol. A, 157 (2003) 111–128.
  72. A. Khataee, R. Darvishi, Ch. Soltani, Y. Hanifehpour, M. Safarpour, H.G. Ranjbar, S.W. Joo, Synthesis and characterization of dysprosium doped ZnO nanoparticles for photocatalysis of a textile dye under visible light irradiation, Ind. Eng. Chem. Res., 53 (2014) 1924–1932.
  73. A. Khataee, Y. Hanifehpour, M. Safarpour, M. Hosseini, S. Joo, Synthesis and characterization of ErxZn(1–x)Se nanoparticles: a novel visible light responsive photocatalyst, Sci. Adv. Mater., 5 (2013) 1074–1082.
  74. M. Khatamian, B. Divband, A. Jodaei, Degradation of 4-Nitrophenol (4-NP) using ZnO nanoparticles supported on zeolites and modeling of experimental results by artificial neutral networks, Mater. Chem. Phys., 134 (2012) 31.