Solar Photocatalytic Removal of Chemical and Bacterial Pollutants from Water Using Pt/TiO2-Coated Ceramic Tiles

Semiconductor photocatalysis has become an increasingly promising technology in environmental wastewater treatment. The present work reports a simple technique for the preparation of platinum-deposited TiO2 catalysts and its immobilization on ordinary ceramic tiles. The Pt/TiO2 is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), and diffuse reflectance spectroscopy (DRS). Deposition of Pt on TiO2 extends the optical absorption of the latter to the visible region which makes it attractive for solar energy application. Optimum loading of Pt on TiO2 was found to be 0.5%. The Pt/TiO2 is coated on ceramic tiles and immobilized. This catalyst was found effective for the solar photocatalytic removal of chemical and bacterial pollutants from water. Once the parameters are optimized, the Pt/TiO2/tile can find application in swimming pools, hospitals, water theme parks, and even industries for the decontamination of water

Fenton and solar Fenton processes: inexpensive green technologies for the decontamination of wastewater from toxic Rhodamine B dye pollutant

Advanced oxidation processes (AOPs) are projected as relatively cleaner technologies for the abatement of water pollution. This paper investigates the Fenton process as a potential tool for the degradation and eventual mineralization of a textile dye, Rhodamine B (RhB), in water. The effects of activation sources such as microwave (MW), ultrasound (US), and solar energy (SL) on the efficiency of the process were tested. Solar and solar catalytic Fenton processes are identified as the best processes and accordingly, relevant reaction parameters are identified and optimized. The optimum ratio of Fe2+:H2O2 obtained is 1:3 at 15 mg/l of RhB concentration and at pH 3–3.5, showing a degradation efficiency of 47% within 30 min of solar irradiation. ZnO enhanced solar Fenton mineralization of RhB. Persulfate (PS) enhances degradation moderately. The study demonstrated the potential of recycling Fe2+ by periodic replenishment of H2O2. Major reaction intermediates formed were identified by the LC-MS method. Photoluminescence (PL) spectral studies showed a progressive increase in •OH radical formation during solar irradiation. The study has proven that solar Fenton and solar catalytic Fenton processes are efficient AOPs for the complete mineralization of RhB and thus present an economic and environment-friendly technology to remove recalcitrant RhB pollutants from water. HIGHLIGHTS Solar Fenton and solar photocatalytic Fenton processes are identified as efficient treatment processes for the complete removal of dye pollutants.; The presence of ZnO as the catalyst enhanced Fenton-assisted mineralization of RhB under solar irradiation.; The recycling of Fe2+ by periodic replenishment of H2O2 offers an environment-friendly solution to the accumulation of iron in the waste sludge.

Sono, Photo and Sonophoto Catalytic Removal of Chemical and Bacterial Pollutants from Wastewater

The term ‘water pollution’ broadly refers to the contamination of water and water bodies (e.g. lakes, rivers, oceans, groundwater etc). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove the harmful contaminants. This affects not only the plants and organisms living in these bodies of water but also the entire natural biological communities and the biodiversity.Advanced Oxidation Processes (AOPs) have been tested as environment-friendly techniques for the treatment of contaminated water, in view of their ability to convert pollutants into harmless end products. These techniques refer to a set of treatment procedures designed to remove organic or inorganic contaminants in wastewater by oxidation. The contaminants are oxidized by different reagents such as air, oxygen, ozone, and hydrogen peroxide which are introduced in precise, preprogrammed dosages, sequences and combinations under appropriate conditions. The procedure when combined with light in presence of catalyst is known as photocatalysis. When ultrasound (US) is used as the energy source, the process is referred as sonication. Sonication in presence of catalyst is referred as sonocatalysis. Of late, combination of light and sound as energy sources has been tested for the decontamination of wastewater in the presence of suitable catalyst. In this case, the process is referred as sonophotocatalysis. These AOPs are specially advantageous in pollution control and waste water treatment because unlike many other technologies, they do not just transfer the pollutant from one phase to another but completely degrade them into innocuous substances such as CO2 and H2O.Cochin University of Science Technolog

Semiconductor Oxides Mediated Photocatalytic Removal of Chemical and Bacterial Pollutants from Wastewater

School of Environmental Studies, Cochin University of Science and Technolog

Periodic Change in Concentration of Peroxide During Photocatalytic Oxidation of Aliphatic Alcohols in Cyclohexane

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