Iranian Journal of Oil and Gas Science and Technology, 2013
In last decades, oil spill pollution has become an important issue of concern due to its serious ... more In last decades, oil spill pollution has become an important issue of concern due to its serious environmental impacts; therefore, necessary actions should be taken to prevent or reduce these types of pollution and their environmental consequences. Natural organic sorbents are emerging as proper choices for oil spill cleanup due to their availability, eco-friendliness, and low cost. In this study, phragmites australis, sugarcane leaves straw, and sugarcane bagasse were used for crude oil sorption in dry (only oil) systems. The results indicated that sugarcane bagasse had a higher oil sorption capacity compared to the others. Therefore, sugarcane bagasse was selected as the preferred sorbent and the effects of sorbent contact time and its particle size on oil adsorption capacity were evaluated for the systems of dry and crude oil layer on water. The results showed that the maximum adsorption capacity of raw sugarcane bagasse for dry system and crude oil layer system was about 8 and 6...
In last decades, oil spill pollution has become an important issue of concern due to its serious ... more In last decades, oil spill pollution has become an important issue of concern due to its serious environmental impacts; therefore, necessary actions should be taken to prevent or reduce these types of pollution and their environmental consequences. Natural organic sorbents are emerging as proper choices for oil spill cleanup due to their availability, eco-friendliness, and low cost. In this study, phragmites australis, sugarcane leaves straw, and sugarcane bagasse were used for crude oil sorption in dry (only oil) systems. The results indicated that sugarcane bagasse had a higher oil sorption capacity compared to the others. Therefore, sugarcane bagasse was selected as the preferred sorbent and the effects of sorbent contact time and its particle size on oil adsorption capacity were evaluated for the systems of dry and crude oil layer on water. The results showed that the maximum adsorption capacity of raw sugarcane bagasse for dry system and crude oil layer system was about 8 and 6...
Abstract Nowadays, visible light-driven nanophotocatalysts are being developed for high-efficienc... more Abstract Nowadays, visible light-driven nanophotocatalysts are being developed for high-efficiency removal of organic pollutants. Carbon quantum dots (CQDs) have been widely investigated as a superior candidate for improving the photocatalytic activity of various nanocomposites. In this paper, a nickel-doped ZnO photocatalyst was surface-modified using hydrothermally prepared nitrogen-doped carbon quantum dots for the first time. The synthesized nanocomposite (N-CQDs/Ni-ZnO) was then characterized using SEM, EDX, XRD, FT-IR, PL, and DRS analyses. The presence of Ni and N-CQDs and their effects on the band gap reduction of the ZnO and improvement of electron/hole pairs separation were confirmed with XRD, EDX, PL and DRS tests. The photocatalytic activity of the N-CQDs/Ni-ZnO was tested for methylene blue dye removal from aqueous solution under visible light irradiation. After 120 min of irradiation, the optimum photocatalyst could degrade about 87 % of the MB under the visible light irradiation. The kinetics of the MB dye degradation was modeled according to Langmuir–Hinshelwood model and k was 0.015. Also, the effects of pH and photocatalyst dosage were examined for optimizing the photocatalytic activity of the N-CQDs/Ni-ZnO. According to the results, the optimum pH was approximated at 11 (alkaline) and the best results were obtained with 0.05 g of the photocatalyst per 50 ml of a 50 ppm MB dye solution for the top synthesized nanophotocatalyst (1.5 N-CQDs/6 wt.% Ni-ZnO). The reusability experiments for the prepared nanophotocatalyst showed that the prepared N-CQDs/Ni-ZnO possessed excellent stability after four reaction cycles. The findings of this study can be used in industrial applications.
Journal of Photochemistry and Photobiology A: Chemistry
Abstract In this study CuO/Al2O3 nanocomposite was synthesized with some aid of microwave irradia... more Abstract In this study CuO/Al2O3 nanocomposite was synthesized with some aid of microwave irradiation in ethylene glycol for the first time. The effect of irradiation power and calcination temperature on the morphology and crystallinity was investigated by FESEM, FTIR, XRD, EDS and BET tests. The photocatalytic degradation ability of samples was evaluated with methylene blue removal from aqueous solution under UV irradiation. To gain the efficient removal, optimum conditions were determined by the power of microwave irradiation and calcination temperature in 900 W and 700 °C, respectively. XRD results showed that calcination at 700 °C provided clearly Al2O3 crystals and the formed nanocomposite was more efficient; meanwhile the average particle size was increased due to the agglomeration of particles. The results of methylene blue (MB) removal exhibited that the CuO/Al2O3 nanocomposite prepared with 900 W has the highest photocatalytic ability and that about 90% of dye was removed after 100 min.
Journal of Inorganic and Organometallic Polymers and Materials
During the last decade, dye pollution has been a major environmental concern, making it necessary... more During the last decade, dye pollution has been a major environmental concern, making it necessary to develop removal methods. In this study, three nanophotocatalysts, namely ZnO, CuO, and ZnO/CuO composite, were synthesized via a hydrothermal method and then examined for degradation of methylene blue (MB) dye solution under visible light irradiation. Pure ZnO and CuO showed rather poor photocatalytic activities due to their limited photo response ranges under visible light. Accordingly, in order to overcome this limitation and improve the photocatalytic activity of ZnO and CuO, nitrogen-doped graphene quantum dots (N-GQDs) were employed. Results proved that the N-GQDs can significantly enhance photocatalytic activity of the ZnO sample, while no significant effect was observed on CuO sample. Furthermore, effects of synthesis method and added content of N-GQDs on the activity of the N-GQDs/ZnO composite samples were studied. Firstly, pure ZnO was synthesized via a hydrothermal reaction and then added to the N-GQDs precursor solution to produce N-GQD/ZnO composite in a final hydrothermal reaction (method I ). Alternatively, a hydrothermal method was used to prepare the N-GQDs firstly, and then zinc acetate was introduced into this solution for final hydrothermal process (method II ). The results showed higher elimination performance of the second method, by which the MB dye could be removed completely. The best nanophotocatalyst (the sample containing 3 mmol of ascorbic acid in the primary solution, prepared via the second method) demonstrated maximum dye removal efficiency (70% in about 30 min, 100% < 60 min). Thus, nanophotocatalysts of similar characteristics are suggested for industrial effluent purification under visible light.
Iranian Journal of Oil and Gas Science and Technology, 2013
In last decades, oil spill pollution has become an important issue of concern due to its serious ... more In last decades, oil spill pollution has become an important issue of concern due to its serious environmental impacts; therefore, necessary actions should be taken to prevent or reduce these types of pollution and their environmental consequences. Natural organic sorbents are emerging as proper choices for oil spill cleanup due to their availability, eco-friendliness, and low cost. In this study, phragmites australis, sugarcane leaves straw, and sugarcane bagasse were used for crude oil sorption in dry (only oil) systems. The results indicated that sugarcane bagasse had a higher oil sorption capacity compared to the others. Therefore, sugarcane bagasse was selected as the preferred sorbent and the effects of sorbent contact time and its particle size on oil adsorption capacity were evaluated for the systems of dry and crude oil layer on water. The results showed that the maximum adsorption capacity of raw sugarcane bagasse for dry system and crude oil layer system was about 8 and 6...
In last decades, oil spill pollution has become an important issue of concern due to its serious ... more In last decades, oil spill pollution has become an important issue of concern due to its serious environmental impacts; therefore, necessary actions should be taken to prevent or reduce these types of pollution and their environmental consequences. Natural organic sorbents are emerging as proper choices for oil spill cleanup due to their availability, eco-friendliness, and low cost. In this study, phragmites australis, sugarcane leaves straw, and sugarcane bagasse were used for crude oil sorption in dry (only oil) systems. The results indicated that sugarcane bagasse had a higher oil sorption capacity compared to the others. Therefore, sugarcane bagasse was selected as the preferred sorbent and the effects of sorbent contact time and its particle size on oil adsorption capacity were evaluated for the systems of dry and crude oil layer on water. The results showed that the maximum adsorption capacity of raw sugarcane bagasse for dry system and crude oil layer system was about 8 and 6...
Abstract Nowadays, visible light-driven nanophotocatalysts are being developed for high-efficienc... more Abstract Nowadays, visible light-driven nanophotocatalysts are being developed for high-efficiency removal of organic pollutants. Carbon quantum dots (CQDs) have been widely investigated as a superior candidate for improving the photocatalytic activity of various nanocomposites. In this paper, a nickel-doped ZnO photocatalyst was surface-modified using hydrothermally prepared nitrogen-doped carbon quantum dots for the first time. The synthesized nanocomposite (N-CQDs/Ni-ZnO) was then characterized using SEM, EDX, XRD, FT-IR, PL, and DRS analyses. The presence of Ni and N-CQDs and their effects on the band gap reduction of the ZnO and improvement of electron/hole pairs separation were confirmed with XRD, EDX, PL and DRS tests. The photocatalytic activity of the N-CQDs/Ni-ZnO was tested for methylene blue dye removal from aqueous solution under visible light irradiation. After 120 min of irradiation, the optimum photocatalyst could degrade about 87 % of the MB under the visible light irradiation. The kinetics of the MB dye degradation was modeled according to Langmuir–Hinshelwood model and k was 0.015. Also, the effects of pH and photocatalyst dosage were examined for optimizing the photocatalytic activity of the N-CQDs/Ni-ZnO. According to the results, the optimum pH was approximated at 11 (alkaline) and the best results were obtained with 0.05 g of the photocatalyst per 50 ml of a 50 ppm MB dye solution for the top synthesized nanophotocatalyst (1.5 N-CQDs/6 wt.% Ni-ZnO). The reusability experiments for the prepared nanophotocatalyst showed that the prepared N-CQDs/Ni-ZnO possessed excellent stability after four reaction cycles. The findings of this study can be used in industrial applications.
Journal of Photochemistry and Photobiology A: Chemistry
Abstract In this study CuO/Al2O3 nanocomposite was synthesized with some aid of microwave irradia... more Abstract In this study CuO/Al2O3 nanocomposite was synthesized with some aid of microwave irradiation in ethylene glycol for the first time. The effect of irradiation power and calcination temperature on the morphology and crystallinity was investigated by FESEM, FTIR, XRD, EDS and BET tests. The photocatalytic degradation ability of samples was evaluated with methylene blue removal from aqueous solution under UV irradiation. To gain the efficient removal, optimum conditions were determined by the power of microwave irradiation and calcination temperature in 900 W and 700 °C, respectively. XRD results showed that calcination at 700 °C provided clearly Al2O3 crystals and the formed nanocomposite was more efficient; meanwhile the average particle size was increased due to the agglomeration of particles. The results of methylene blue (MB) removal exhibited that the CuO/Al2O3 nanocomposite prepared with 900 W has the highest photocatalytic ability and that about 90% of dye was removed after 100 min.
Journal of Inorganic and Organometallic Polymers and Materials
During the last decade, dye pollution has been a major environmental concern, making it necessary... more During the last decade, dye pollution has been a major environmental concern, making it necessary to develop removal methods. In this study, three nanophotocatalysts, namely ZnO, CuO, and ZnO/CuO composite, were synthesized via a hydrothermal method and then examined for degradation of methylene blue (MB) dye solution under visible light irradiation. Pure ZnO and CuO showed rather poor photocatalytic activities due to their limited photo response ranges under visible light. Accordingly, in order to overcome this limitation and improve the photocatalytic activity of ZnO and CuO, nitrogen-doped graphene quantum dots (N-GQDs) were employed. Results proved that the N-GQDs can significantly enhance photocatalytic activity of the ZnO sample, while no significant effect was observed on CuO sample. Furthermore, effects of synthesis method and added content of N-GQDs on the activity of the N-GQDs/ZnO composite samples were studied. Firstly, pure ZnO was synthesized via a hydrothermal reaction and then added to the N-GQDs precursor solution to produce N-GQD/ZnO composite in a final hydrothermal reaction (method I ). Alternatively, a hydrothermal method was used to prepare the N-GQDs firstly, and then zinc acetate was introduced into this solution for final hydrothermal process (method II ). The results showed higher elimination performance of the second method, by which the MB dye could be removed completely. The best nanophotocatalyst (the sample containing 3 mmol of ascorbic acid in the primary solution, prepared via the second method) demonstrated maximum dye removal efficiency (70% in about 30 min, 100% < 60 min). Thus, nanophotocatalysts of similar characteristics are suggested for industrial effluent purification under visible light.
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