Browsing by Author "Mugunthan, E."

Now showing 1 - 6 of 6

Photocatalytic activity of ZnO-WO3 for diclofenac degradation under visible light irradiation
(2019) Mugunthan, E.; Saidutta, M.B.; Jagadeeshbabu, P.E.
Diclofenac is known to be a persistent pharmaceutical compound, and their effective removal from water sources has been a rising concern. This study reports the visible light irradiated photocatalytic degradation of diclofenac using ZnO-WO3 mixed oxide catalysts, prepared by the hydrothermal method with variation in molar ratios of tungsten precursor. The prepared catalysts were characterized using a different technique, and the photocatalytic activity has been tested under visible light irradiation. Adsorption isotherm studies were performed to elucidate the preferential adsorption nature of the mixed oxide catalyst. The interaction of diclofenac and the prepared mixed oxides is based on the positively charged ZnO-WO3 surface and anionic diclofenac at solution pH 6. The adsorption and photodegradation kinetics is best expressed by the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. Results indicated that all the prepared catalysts exhibited better catalytic activity than the bare ZnO under the visible light irradiation. The catalyst prepared with a molar ratio of 10:1 is proven to be an efficient catalyst and achieved 76%mineralization of diclofenac during the irradiation. The effect of operating variables like pH, initial diclofenac concentration, and catalyst loading was investigated and reported. The ZnO-WO3 mixed oxide catalysts were showed better stability, and the results revealed that the photocatalytic efficiency was retained up to 80% over the repeated reaction cycles. Several intermediate compounds formed during the photocatalytic reaction have been analyzed using LC MS, and their degradation pathways have been found to primarily follows hydroxylation, dechlorination and decarboxylation reactions. 2019 Elsevier B.V.
Photocatalytic activity of ZnO-WO3 for diclofenac degradation under visible light irradiation
(Elsevier B.V., 2019) Mugunthan, E.; Saidutta, M.B.; JagadeeshBabu, J.
Diclofenac is known to be a persistent pharmaceutical compound, and their effective removal from water sources has been a rising concern. This study reports the visible light irradiated photocatalytic degradation of diclofenac using ZnO-WO3 mixed oxide catalysts, prepared by the hydrothermal method with variation in molar ratios of tungsten precursor. The prepared catalysts were characterized using a different technique, and the photocatalytic activity has been tested under visible light irradiation. Adsorption isotherm studies were performed to elucidate the preferential adsorption nature of the mixed oxide catalyst. The interaction of diclofenac and the prepared mixed oxides is based on the positively charged ZnO-WO3 surface and anionic diclofenac at solution pH 6. The adsorption and photodegradation kinetics is best expressed by the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. Results indicated that all the prepared catalysts exhibited better catalytic activity than the bare ZnO under the visible light irradiation. The catalyst prepared with a molar ratio of 10:1 is proven to be an efficient catalyst and achieved 76%mineralization of diclofenac during the irradiation. The effect of operating variables like pH, initial diclofenac concentration, and catalyst loading was investigated and reported. The ZnO-WO3 mixed oxide catalysts were showed better stability, and the results revealed that the photocatalytic efficiency was retained up to 80% over the repeated reaction cycles. Several intermediate compounds formed during the photocatalytic reaction have been analyzed using LC–MS, and their degradation pathways have been found to primarily follows hydroxylation, dechlorination and decarboxylation reactions. © 2019 Elsevier B.V.
Photocatalytic degradation of diclofenac using TiO2 SnO2 mixed oxide catalysts
(2019) Mugunthan, E.; Saidutta, M.B.; Jagadeeshbabu, P.E.
The complex nature of diclofenac limits its biological degradation, posing a serious threat to aquatic organisms. Our present work aims to eliminate diclofenac from wastewater through photocatalytic degradation using TiO2 SnO2 mixed-oxide catalysts under various operating conditions such as catalyst loading, initial diclofenac concentration and initial pH. Different molar ratios of Ti Sn (1:1, 5:1, 10:1, 20:1 and 30:1) were prepared by the hydrothermal method and were characterized. The results indicated that addition of Sn in small quantity enhances the catalytic activity of TiO2. Energy Band gap of the TiO2 SnO2 catalysts was found to increase with an increase in Tin content. TiO2 SnO2 catalyst with a molar ratio of 20:1 was found to be the most effective when compared to other catalysts. The results suggested that initial drug concentration of 20 mg/L, catalyst loading of 0.8 g/L and pH 5 were the optimum operating conditions for complete degradation of diclofenac. Also, the TiO2 SnO2 catalyst was effective in complete mineralization of diclofenac with a maximum total organic carbon removal of 90% achieved under ultraviolet irradiation. The repeatability and stability results showed that the TiO2 SnO2 catalyst exhibited an excellent repeatability and better stability over the repeated reaction cycles. The photocatalytic degradation of diclofenac resulted in several photoproducts, which were identified through LC-MS. 2017, 2017 Informa UK Limited, trading as Taylor & Francis Group.
Photocatalytic degradation of diclofenac using TiO2–SnO2 mixed oxide catalysts
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Mugunthan, E.; Saidutta, M.B.; JagadeeshBabu, P.E.
The complex nature of diclofenac limits its biological degradation, posing a serious threat to aquatic organisms. Our present work aims to eliminate diclofenac from wastewater through photocatalytic degradation using TiO2–SnO2 mixed-oxide catalysts under various operating conditions such as catalyst loading, initial diclofenac concentration and initial pH. Different molar ratios of Ti–Sn (1:1, 5:1, 10:1, 20:1 and 30:1) were prepared by the hydrothermal method and were characterized. The results indicated that addition of Sn in small quantity enhances the catalytic activity of TiO2. Energy Band gap of the TiO2–SnO2 catalysts was found to increase with an increase in Tin content. TiO2–SnO2 catalyst with a molar ratio of 20:1 was found to be the most effective when compared to other catalysts. The results suggested that initial drug concentration of 20 mg/L, catalyst loading of 0.8 g/L and pH 5 were the optimum operating conditions for complete degradation of diclofenac. Also, the TiO2–SnO2 catalyst was effective in complete mineralization of diclofenac with a maximum total organic carbon removal of 90% achieved under ultraviolet irradiation. The repeatability and stability results showed that the TiO2–SnO2 catalyst exhibited an excellent repeatability and better stability over the repeated reaction cycles. The photocatalytic degradation of diclofenac resulted in several photoproducts, which were identified through LC-MS. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.
Visible light assisted photocatalytic degradation of diclofenac using TiO2-WO3 mixed oxide catalysts
(2018) Mugunthan, E.; Saidutta, M.B.; Jagadeeshbabu, P.E.
The TiO2-WO3 catalysts were synthesized using hydrothermal method with different molar ratios of tungsten (W) precursor. The prepared catalysts were characterized using different techniques and assessed for its photocatalytic efficiency in the degradation of diclofenac under visible light irradiation. It was found that all the prepared catalysts produced better performance than the pure TiO2 under the visible light irradiation. It was observed that the mineralization of diclofenac reached up to 91% within 4 h of treatment. The effect of the initial diclofenac concentration, pH and catalyst loading were also investigated. The improved photocatalytic activity of the TiO2-WO3 mixed oxide catalysts could be attributed to the enhanced electron-hole separation under visible light. The TiO2-WO3 mixed oxide catalysts were further analysed for its stability in aqueous environments and the results revealed that the as-prepared photocatalyst remains highly active and the efficiency was retained up to 80% over the repeated reaction cycles. LC�MS analysis revealed that several degradation products were formed during the course of irradiation and their degradation pathway primarily follows hydroxylation, dechlorination and decarboxylation reactions. � 2018 Elsevier B.V.
Visible light assisted photocatalytic degradation of diclofenac using TiO2-WO3 mixed oxide catalysts
(Elsevier B.V., 2018) Mugunthan, E.; Saidutta, M.B.; JagadeeshBabu, P.E.
The TiO2-WO3 catalysts were synthesized using hydrothermal method with different molar ratios of tungsten (W) precursor. The prepared catalysts were characterized using different techniques and assessed for its photocatalytic efficiency in the degradation of diclofenac under visible light irradiation. It was found that all the prepared catalysts produced better performance than the pure TiO2 under the visible light irradiation. It was observed that the mineralization of diclofenac reached up to 91% within 4 h of treatment. The effect of the initial diclofenac concentration, pH and catalyst loading were also investigated. The improved photocatalytic activity of the TiO2-WO3 mixed oxide catalysts could be attributed to the enhanced electron-hole separation under visible light. The TiO2-WO3 mixed oxide catalysts were further analysed for its stability in aqueous environments and the results revealed that the as-prepared photocatalyst remains highly active and the efficiency was retained up to 80% over the repeated reaction cycles. LC–MS analysis revealed that several degradation products were formed during the course of irradiation and their degradation pathway primarily follows hydroxylation, dechlorination and decarboxylation reactions. © 2018 Elsevier B.V.