Marjan Tanzifi; Mohsen Jahanshahi; Majid Peyravi; Soodabeh Khalili
Abstract
Dye-containing wastewater is a major pollutant that can irreversibly damage the environment. Ultrafiltration membrane technology combined with photocatalysis is used for treatment of dye-containing solutions. To remove dye pollution, Methylene blue (MB) and Congo red (CR), graphitic carbon nitride (CNG) ...
Read More
Dye-containing wastewater is a major pollutant that can irreversibly damage the environment. Ultrafiltration membrane technology combined with photocatalysis is used for treatment of dye-containing solutions. To remove dye pollution, Methylene blue (MB) and Congo red (CR), graphitic carbon nitride (CNG) and its zirconium dioxide nanocomposite (CNGZ) were used in the photocatalytic dynamic membrane system in both self-forming and pre-coated modes under household LED light. The filtration results of the self-forming membrane showed that the pure CNG- and nanocomposite-based photocatalytic membrane systems were more efficient for MB and CR dyes removal than the photocatalytic system in batch mode. In addition to improving dye molecule removal efficiency, adding the photocatalyst to the PES membrane also significantly increased water flux. Moreover, the respective MB and CR rejection rates were 29% and 47% for the pure PES membrane and 89% in 120 min and 100% in 80 min for the CNGZ-based photocatalytic membrane. This suggests that the photocatalytic membrane system is a more effective dye pollution remover than the pure PES. For comparison, the pre-coated dynamic membrane system used for MB dye removal was good for removing 98.6% within 20 min. The results suggest that CNGZ-based photocatalytic dynamic membrane is a promising technology for increasing dye molecules removal efficiency and flux in remediation of dye-containing wastewater.
Ahmed El Nemr; Mohamed A. Hassaan; Fedekar Fadel Madkour
Abstract
HPLC-MS/MS degradation mechanism of Direct Yellow 12 (DY-12) dye using O3 associated with UV was studied. The influent of different conditions such as pH, initial DY-12 dye concentration and reaction time were studied in a batch reactor method. The results revealed that the pH value and DY-12 initial ...
Read More
HPLC-MS/MS degradation mechanism of Direct Yellow 12 (DY-12) dye using O3 associated with UV was studied. The influent of different conditions such as pH, initial DY-12 dye concentration and reaction time were studied in a batch reactor method. The results revealed that the pH value and DY-12 initial concentration controlled the removal process. The maximum color removal was achieved in alkaline condition (pH 9) as compared to neutral or acidic conditions. The color removal of DY-12 dye followed the first-order kinetics. When UV was applied with ozone simultaneously, the first order rate constant (kd) increased, and the time of dye decolorization shortened to 10 min for 200 ppm dye concentration. These results indicated that the application of UV can reduce the reaction time and dose of ozone. Gas chromatography-mass spectrum and HPLC-MS/MS analyses of the treated synthetic dye solution at the end of the treatment time showed no toxic organic compounds were detected. The COD decreased by more than 85% of the initial COD of the untreated DY-12 dye concentration.
Samad Sabbaghi; Fateme Doraghi
Abstract
In this study, considering the importance of protecting the environment and preventing the pollution caused by industrial plants, a nanocomposite each component thereof is capable of removing the desired combination to solve this problem has been produced. To achieve this goal, ZnO/SnO2nanocomposite ...
Read More
In this study, considering the importance of protecting the environment and preventing the pollution caused by industrial plants, a nanocomposite each component thereof is capable of removing the desired combination to solve this problem has been produced. To achieve this goal, ZnO/SnO2nanocomposite was synthesized using the co-precipitation method. The characterization of this nanocomposite was conducted by DLS, XRD, FTIR and SEM. The nanocomposite size was about 15nm. Several parameters such as the initial concentration of the wastewater, as well as the amount of catalyst and time were investigated. The reduction of the particle size due to an increase in the surface area of the nanocomposite increased the amount of decolorization. For all the performed experiments, the dye removal rate was 100% and the difference was to do with the time of the complete removal of methylene blue. A decrease in the concentration of methylene blue in the range of the tested concentrations reduced the decolorization, and by increasing the amount of nanocomposite in the range of the tested values, a decline in decolorization was observed.