Brijesh Pare

Mineralization and toxicity reduction of textile dye neutral red in aqueous phase using BiOCl photocatalysis.

The BiOCl catalyst was prepared by hydrolysis method. The compound was extensively characterized by XRD, SEM, TEM, UV-vis measurements and BET surface area. The prepared material had average pore diameter about 6-13 nm. The BET surface area of the sample is about 40 m(2)/g. The photocatalytic degradation and toxicity reduction of textile dye neutral red (NR) was investigated in the presence of as prepared BiOCl. The analysis of (·)OH radical formation was performed by fluorescence technique. The intermediates and the final products of degradation were detected by high-performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry (HPLC-ESI-DAD-MS) technology. Decrease in chemical oxygen demand (COD) and dye absorbance of the photodegraded dye solution revealed a complete mineralization of NR into CO(2) and inorganic ions. The recycling experiments confirmed the relative stability of the catalyst. Finally, the luminescent marine bacteria Vibrio fischeri was used to assess the acute toxicity of samples prior to and after the photocatalytic treatment and it was found that toxicity was fully eliminated following photocatalytic degradation.

Visible light-driven photocatalytic degradation and mineralization of the malachite green dye in a slurry photoreactor

ABSTRACT The as-synthesized BiOCl nanoparticles were characterized by x-ray diffraction (XRD) and ultraviolet–visible (UV–Vis) techniques. The XRD pattern showed that a highly pure and crystalline phase has been obtained. The UV–vis diffuse reflectance spectroscopy (DRS) studies revealed the indirect band gap value of about 3.32 eV for the fabricated semiconductor. The disappearance of the dye, monitored spectrophotometrically, follows approximately pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. Besides, the effect of some parameters such as the influence of the initial pH, catalyst weight, initial dye concentration, oxidant concentration, and salt concentration on the degradation of malachite green dye solution under visible light irradiation were investigated. The optimum conditions for the degradation of dye were 25 mg L−1 dye concentration, pH of 8, and a catalyst amount of 0.7 g mL−1. The addition of an optimal amount of hydrogen peroxide and potassium persulfate increases the degradation rate while NaCl and Na2CO3 decrease the rate. Complete mineralization has been confirmed by UV–Vis spectroscopy