Eco-friendly synthesis and photocatalytic application of flowers-like ZnO structures using Arabic and Karaya Gums

Flowers-like ZnO structures were synthesized using Arabic Gum (AGZnO) or Karaya Gum (KGZnO). The AGZnO and KGZnO were characterized by X-ray diffractometry, Fourier Transformed Infrared, Scanning Electron Microscopy, Photoluminescence, nitrogen adsorption/desorption and diffuse reflectance techniques. The materials were tested in the discoloration of Methylene Blue (MB) dye under visible light and scavenger studies were also performed. The toxicity of the MB irradiated was investigated in bioassays with Artemia salina. The structural characterization demonstrated the formation of hexagonal ZnO. All samples presented flower-like morphology with presence of mesopores identified by BET method. The optical properties indicated band gap of 2.99 (AGZnO) and 2.76 eV (KGZnO), and emission in violet, blue and green emissions also were observed. The KGZnO demonstrated better photocatalytic performance than the AGZnO, and scavenger studies indicated that OH radicals are the main species involved in the degradation of the pollutant model. The photodiscoloration of MB solution did not demonstrate toxicity. Therefore, KGZnO is a promising material for photocatalysis application.