Performance of Advanced Oxidization UV/S2O8-2 in Removing Acid Green 3 from Aqueous Solutions: Modeling Based Linear Regression, Kinetic Studies

Abstract

Background: Used in the dyeing industry, Acid Green 3 has a complicated molecular structure and a low level of biodegradability. The present study investigated the removal of Acid Green 3 from synthetic solutions by UV/S2O8-2. Methods: This cross-sectional study was conducted at the laboratory scale. The effect of time (5-60 min), pH (3-11), Acid Green 3 concentration (50-150 mg/L), and dose of S2O8 (10-50 mg/L) was studied under the UV radiation with 510 mJ/cm 2 intensity and 636 nm wavelength. Spectrophotometer (wavelength of 636 nm) was used to measure remaining concentration of Acid Green 3 after each experiment. Linear regression was used to create an appropriate linear model. Results: Results showed a removal percentage of 95% was achieved under the optimal conditions of the studied variables: pH = 3, Acid Green 3 = 50 mg/L, S2O8-2 = 50 mg/L and time = 60 min. The kinetics of UV/S2O8-2 process for all the investigated variables followed the pseudo-first-order kinetic model. In addition, the removal efficiency of COD for Acid Green concentrations of 50, 100, and 150 mg/L were about 78%, 53%, and 41%, respectively. Linear regression analysis yielded a model with R 2 = 0.852 and adjusted R 2 = 0.792. Conclusions: In the current study, the variables of Acid Green 3, S2O8-2 , contact time, and pH were effective on the process efficiency. Regarding the high efficiency of UV/S2O8-2 , this process could be employed for the removal of Acid Green 3 and similar compounds from industrial effluents.