Photocatalytic Degradation of Methylene Blue Dye Using Silica Oxide Nanoparticles as a Catalyst

Abstract

The present research deals with the development a fast and low-cost method for removing color dye from water using nanosized semiconductors SiO2 as photocatalyst. The studies of kinetic photocatalytic degradation were carried out on an aqueous solution of soluble methylene blue dye, which contained SiO2 nanoparticles and under an ultraviolet light source. Different parameters affecting the process have been studied: catalyst concentration, dye concentration, temperature, and pH of solution. The color variation was detected at three absorption bands (662, 293, and 243 nm). It was found that the dye completely degraded in 90 s, using 10 g/L SiO2 nanoparticles at 25 °C and pH 1.5 and 11.0. The adsorption of the dye well-fitted pseudo-second-order kinetic models. The Langmuir-Hinshelwood model was acquired to analyze the photocatalytic degradation process. A possible molecular mechanism for photocatalytic degradation of the dye by SiO2 nanoparticles is also given.

Lignocellulosic Nanocrystals from Sawmill Waste as Biotemplates for Free-Surfactant Synthesis of Photocatalytically Active Porous Silica

“…In the present work and based on the obtained results and on previous studies, − a probable photodegradation mechanism of MB by the synthesized nanostructured silica photocatalysts (nanoSiO 2 ), which were acting as semiconductors, is illustrated in Figure .…”

Renewable and eco-friendly ZnO immobilized onto dead sea sponge floating materials with dual practical aspects for enhanced photocatalysis and disinfection applications

“…The kinetics analysis again confirms that the DSS has superior capability to accelerate the degradation rate with a rate constant value of 2.14×10 -3 min −1 , whereas pure ZnO has shown degradation rate constant of 1.61×10 -3 min −1 and the dye solution without catalyst has a shown rate constant of 7.32×10 -4 min −1 and followed by the pseudo first order kinetics. This indicates that the degradation efficiency of bare DSS for MB was observed higher than pure ZnO and pure MB solution due to combined effect of adsorption of porous structure and the oxidation of MB by the presence of SiO 2 within the composition of bare DSS [47]. The low degradation efficiency of pure ZnO for MB is according to the reported work [48], and the several reasons impair the degradation efficiency of pure ZnO such as morphology, the adapted synthetic process for pure ZnO, and the wide band gap which allows the fast charge recombination rate of electron and hole pairs within the pure ZnO during the illumination of light.…”

Biogenic Nanosilica Synthesis Employing Agro-Waste Rice Straw and Its Application Study in Photocatalytic Degradation of Cationic Dye

“…The photocatalytic effect of different concentrations of the optimum synthesized SiNPs (0.2-0.5 g/L) on methylene blue (100 ppm) at alkaline pH 11.0 was investigated following the protocols of Saleh and Dijaja [29] and Aly and Elhamid [26] with slight modifications. The photocatalytic experiment was conducted in a glass beaker equipped with continuous stirring under exposure to ultraviolet light (Philips 30 W, two tubes).…”

“…It is documented that intense exposure to this dye leads to release of aromatic amines with severe environmental and health hazards. In previous years, chemical-based products have been designed to degrade toxic pollutants effectively; yet again, the persistent and non-degradable nature with its known tendency to bioaccumulate serves well as another potential environmental health hazard, demanding an adequate replacement [26,27].…”