Thermodynamic and kinetic studies of Victoria blue B removal using the photocatalyst of flower-like cadmium sulfide microspheres synthesized via hydrothermal process

The synthesis of flower-like cadmium sulfide (CdS) with the presence of amino acid as a shaping agent is exposed in the present study. The influence of two different amino acids (alanine and phenylalanine) on the morphology and photocatalytic ability of the obtained cadmium sulfide (denoted as A-CdS and P-CdS) is compared. The characteristics of the materials are clarified by methods including X-ray diffraction (XRD), Raman spectrum, energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms (BET), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS). The flower-like microspheres with a size of about 0.5 to 1 mm were formed from nanosheets. With the 10 mg L<sup>-1</sup> solution of Victoria blue B, a photocatalytic dosage of 1 g L<sup>-1</sup>, A-CdS exhibited higher removal efficiency (95,1%) than P-CdS (85,8%). The kinetic and thermodynamic investigations of Victoria blue B dye photocatalytic decomposition were carried out for A-CdS at initial Victoria blue B concentration of 20 mg L<sup>-1</sup> and CdS dosage of 1.0 g L<sup>-1</sup>. The photocatalytic kinetic of Victoria blue B removal is described using Langmuir-Hinshelwood kinetic model. The endothermic and spontaneous nature of VBB decomposition has been demonstrated through the thermodynamic parameters. The catalyst is recycled to be reused five times.