Fe-Mn doped powdered activated carbon pellet as ozone catalyst for cost-effective phenolic wastewater treatment: Mechanism studies and phenol by-products elimination

• Published in: Journal of hazardous materials 2022-02, Vol.424 (Pt B), p.127483-127483, Article 127483
• Main Authors: Jothinathan, L., Cai, Q.Q., Ong, S.L., Hu, J.Y.
• Format: Article
• Language: English
• Subjects: Catalysis; Charcoal; Cost-Benefit Analysis; Fe-Mn bimetallic; Microbubble-catalytic ozonation; Ozone; Ozone decomposition; Phenol; Phenolic wastewater; Powdered activated carbon; Powders; Spectroscopy, Fourier Transform Infrared; Waste Water; Water Pollutants, Chemical - analysis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.127483

A novel bimetallic doped PAC (Fe-Mn/PAC) pellet was prepared with a facile sol-gel method and used as an ozone catalyst for phenolic wastewater (PWW) treatment. Adoption of Fe-Mn/PAC pellet in microbubble ozonation enhanced the 1-h chemical oxygen demand (COD) and phenol removal in PWW to 79% and 95%, respectively. With ozone dosage of 10 mg/L, 1 g/L Fe-Mn/PAC pellet exhibited ozone conversion of 92%. In comparison to microbubble ozonation process, Fe-Mn/PAC induced microbubble-catalytic ozonation process promoted ozone decomposition rate by 1.9 times. In terms of •OH production, Fe-Mn/PAC pellet enhanced •OH exposure by 10 times, with a Rct value of 2.92 × 10 -8. Rct kinetic model also suggested that Fe-Mn/PAC pellet obtained higher kinetic rate constants for initiating and promoting •OH generation. Usage of Fe-Mn/PAC pellet in microbubble ozonation for phenolic wastewater treatment also reduced the total ozone consumption by 70%. In Fe-Mn/PAC induced microbubble-catalytic ozonation process, the ratio between ozone consumption and COD removal (ΔO3/ΔCOD) was 0.91. Fe-Mn/PAC pellet characterization with X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) and X-ray powder diffraction (XRD) analysis revealed successful doping of Fe-Mn on PAC substrate and larger numbers of carbon-oxygen/hydroxyl surface groups, which played key roles in ozone decomposition and •OH production. [Display omitted] •Fe-Mn/PAC pellet obtained larger amount of C-O/-OH surface groups.•Fe-Mn/PAC pellet promoted ozone decomposition and •OH exposure by 1.9 and 10 times.•Catalyst kinetic performance for •OH production was determined with Rct modelling.•Fe-Mn/PAC reduced ozone consumption in PWW treatment by 70% with ΔO3/ΔCOD of 0.91.•Fe-Mn/PAC pellet posed stable long-term performance with 74% COD removal in PWW.