| Abstract [eng] |
This study presents a novel approach to addressing the persistent challenge of organic pollutant removal from textile industry wastewater. Leveraging the principles of sustainability and circular economy, the study focuses on utilizing Ni-Fe bimetallic catalysts recovered from semiconductor industry wastewater to enhance the heterogenous Fenton-like process for Reactive Black 5 (RB5) dye degradation. Through a comprehensive investigation, including catalyst synthesis by using fluidized bed crystallization (FBC) reactor, characterization of the catalyst structure, and performance evaluation, key insights are garnered. Results demonstrate the efficacy of a Ni-Fe catalyst with a specific 3:1 molar ratio, exhibiting optimal performance at initial reaction pHi of 6,5. Characterization techniques such as SEM, XRD, FTIR and XPS reveal a unique porous structure consistent with Ni-Fe layered double hydroxide, confirming the catalyst's suitability for the intended application. Moreover, operational parameters such as hydrogen peroxide concentration and catalyst dosage are identified as crucial factors influencing RB5 removal efficiency. Using 1 g/L of Ni-Fe bimetallic catalyst, 1 mM of H2O2 and 100 mg/L of RB5 in 90 min. 86,4 % of it was decolorized and 82,6 % of TOC was removed. The study further explores the potential of UVC radiation to enhance catalysis, highlighting its significant impact on decolorization by improving it 12,4 % and negative effect on TOC removal. Structural changes in the catalyst under varying pH conditions underscore its adaptability to different wastewater compositions. Mechanistic insights elucidate the dominance of adsorption over oxidation at pHi 6,5, offering valuable guidance for process optimization. Langmuir adsorption isotherm with a KL value of 0,91 mg/L was observed which fit to the model best. Following the comprehensive determination of first and second-order kinetic constants across diverse conditions encompassing varying pHi levels, H2O2 concentrations, and catalyst dosages, it was ascertained that second-order kinetics consistently provides the most robust model fit. First-order kinetics exhibited the most favorable agreement solely in a specific scenario where the catalyst, H2O2, and UVC were applied. Overall, this research contributes to the advancement of sustainable wastewater treatment technologies, offering a promising solution to the challenges posed by textile and semiconductors industries effluents. Through the utilization of industrial waste materials and the implementation of inventive approaches, the research embodies a shift in perspective towards resource conservation and environmental responsibility in managing wastewater. |
