Solar Light Photocatalytic Degradation of Malachite Green by Hydrothermally Synthesized Strontium Arsenate Nanomaterial through Response Surface Methodology

Nanostructured Sr2As2O7 samples were synthesized by hydrothermal crystal growth reactions between Sr(NO3)(2) and As2O3 with different stoichiometric Sr:As molar ratios as 1:1 (S-1), 1:2 (S-2), and 2:1 (S-3). The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FT-IR) spectroscopy. Rietveld analysis showed that the obtained materials were crystallized well in the monoclinic crystal structure with the space group P2(1). The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. TEM images verified formation of the particles with nanometer size. Ultraviolet-visible spectra analysis showed that the synthesized Sr2As2O7 nanomaterials had strong light absorption in the ultraviolet light region. Photocatalytic performance of the synthesized nanomaterials was also investigated for the degradation of pollutant Malachite Green (4-{[4-(dimethylamino)phenyl](phenyl)methylidene}-NN-dimethylcyclohexa-25-dien-1-iminium chloride) (MG) in aqueous solution under solar light condition. The optimal conditions were obtained by design expert software for S-1. It was found that the optimum condition was 0.14 mL H2O2, 20 mg catalyst, and 33 min time. The volume and concentration of the as prepared MG solution were 70 mL and 100 ppm, respectively, for obtaining the optimum conditions. The degradation yield in the optimized conditions was 97% for S-1.