Destruction Of Organic Dyes Research Articles

Synergetic effect of silver molybdenum tungsten oxide heterostructures for enhanced photocatalytic reaction

A plasmonic Ag/MoxW1-xO3-y heterostructure was synthesised using a solvothermal followed by photodeposition method. The resulting plasmonic Ag/MoxW1-xO3-y heterostructure displayed high localised surface plasmon resonance (LSPR) after detailed characterisation by using XRD, XPS, TEM, and UV–Vis measurements. The high LSPRs were attributed to crystal vacancies, particularly mutual doping vacancies of molybdenum and tungsten ions, as well as oxygen vacancies. We also investigated into whether such plasmonic Ag/MoxW1-xO3-y might be employed as a highly efficient catalyst for ammonia borane (NH3BH3; AB) dehydrogenation and catalytic destruction of RhB and MB under visible light irradiation as well as in dark condition. As a result when irradiated by visible light for 120 min, it yielded 24 μmol/min of H2 and was very effective in destruction of organic dyes, degrading 90% of RhB and 98% of MB within 40 min. This efficiency was not achieved by MoO3, WO3 or MoxW1-xO3-y alone. These results demonstrates that Ag/MoxW1-xO3-y is a promising a candidate for hydrolysis of ammonia borane and destruction of RhB and MB.

Synthesis, characterization, and photocatalytic activity of ZnS and Mn-doped ZnS nanostructures

Semiconductor quantum dots such as zinc sulfide have interesting potential applications, due to their size-dependent optical properties. These nanostructures can be used for applications in agriculture, environmental chemistry, and fluorescence microscopy. The great rise in nanotechnology has sparked the scientific community’s interest in nanomaterials for the use of photodegradation in aquatic bodies. Quantum Dots (QDs) such as ZnS nanoparticles (NPs) can absorb electromagnetic radiation and generate subsequently reactive oxygen species (ROS) directly in aqueous phase. The presence of ROS in aquatic environments can be used to destroy organic contaminants by photocatalysis. Previous studies had evidenced that the presence of impurities (i.e. copper, manganese, nickel) in the crystalline structures of QDs can enhance their optical properties and consequently their catalytic capacity. Because of this, the present investigation was focused on generating water stable ZnS nanoparticles with catalytic properties. In this work, we have synthesized pure and doped ZnS nanoparticles using a reflux method. The morphology of these QDs was characterized by transmission electron microscopy (TEM). We also studied the photocatalytic properties of these nanostructures. A red shift was observed in the photoluminescence peak of pure ZnS nanoparticles when they were doped with heavy metals. Pure ZnS NPs and Mn-doped ZnS NPs showed luminescent peaks at 444 nm and 596 nm, respectively. Photodegradation studies were evaluated in the presence of organic dyes like Tropaeolin O (TO) and different concentrations of quantum dots (250 ppm and 500 ppm). The photodegradation of TO was dependent on the QDs concentration and exposure time. The destruction of organic dyes in the presence of photo-excited ZnS nanoparticles is envisioned as a fast and clean technology. The destruction of organic dyes in the presence of photo-excited ZnS nanoparticles is envisioned as a fast and clean technology.

Destruction of organic dyes in aqueous solution by low-temperature plasma jet treatment

A method for the destruction of organic compounds in their aqueous solutions using a plasma jet, generated by a pulse power source, at atmospheric pressure in air has been proposed. The acid–base dyes Phenol Red and Methyl Orange have been used as model compounds. The kinetics of degradation of these compounds and the formation kinetics of some products have been studied.

Cobalt-containing catalysts based on Al2O3 for the oxidative destruction of organic dyes in the aqueous phase

Alumina-based cobalt-containing catalysts have been synthesized for the oxidation of organic dyes with hydrogen peroxide in the aqueous phase. According to X-ray photoelectron spectroscopy data, cobalt on the support surface is in the divalent state, specifically in oxide and spinel forms. Both phases are highly active in a wide pH range, but cobalt in spinel form is more resistant to leaching into the solution.