18 research outputs found
Photocatalysed reaction of meso-tetraphenylporphyrin on mesoporous TiMCM-41 molecular sieves
A preliminary study involving 254 nm irradiation of dichloromethane suspension containing TiMCM-41 catalyst and meso-tetraphenylporphyrin (TPP) was carried out at pH 5.0. The rate of the photoreaction was considerably increased in the presence of the catalyst. Increasing the amount of the catalyst at a fixed TPP concentration enhances the rate, indicating its catalytic role in the reaction. The effect of pH, TPP concentration and calcination temperature of the catalyst on the photoreaction was also investigated. (C) 2000
Anodic oxidation of isothiazolin-3-ones in aqueous medium by using boron-doped diamond electrode
Photocatalytic coatings for building industry: study of 1 year of activity in the NO x degradation
Degradation Pathways and Efficiencies of Acid Blue 1 by Photocatalytic Reaction with ZnO Nanopowder
Efficiency evaluation of the photocatalytic degradation of telmisartan anti-hypertensive drug with Fenton, photo-Fenton and recyclable TiO2 heterogeneous catalyst
Photo-oxidation process of indole in aqueous solution with ZnO Catalyst: Study and optimization
Optimizing photo-mineralization of aqueous methyl orange by nano-ZnO catalyst under simulated natural conditions.
Photo-degradation of organic contaminants into non-hazardous mineral compounds is emerging as a strategy to purify water and environment. Tremendous research is being done using direct solar light for these purposes. In this paper we report on optimum conditions for complete mineralization of aqueous methyl orange using lab-prepared ZnO nanopowder catalyst under simulated solar light. Nano-scale ZnO powder was prepared in the lab by standard methods, and then characterized using electronic absorption spectra, photolumenscence emission (PL) spectra, XRD, and SEM. The powder involved a wurtzite structure with ~19 nm particles living in agglomerates. Photo-degradation progressed faster under neutral or slightly acidic conditions which resemble natural waters. Increasing catalyst concentration increased photodegradation rate to a certain limit. Values of catalyst turn over number and degradation percentage increased under higher light intensity, whereas the quantum yield values decreased. The photocatalytic efficiency of nano-ZnO powders in methyl orange photodegradation in water with solar light has been affected by changing the working conditions. More importantly, the process may be used under natural water conditions with pH normally less than 7, with no need to use high concentrations of catalyst or contaminant. The results also highlight the negative impact of possible high concentrations of CO2 on water purification processes. Effects of other added gaseous flows to the reaction mixture are also discussed. ZnO nano-particles are useful catalyst for complete mineralization of organic contaminants in water. Photo-degradation of organic contaminants with ZnO nano-particles, methyl orange being an example, should be considered for future large scale water purification processes under natural conditions