123rd General Meeting of the KCS

Type Oral Presentation
Area Student Oral Presentation
Room No. Room 203
Time THU 10:00-10:15
Code ENVR.O-5
Subject Red mud induced photocatalysis in the presence of peroxides
Authors Joohyun Kim, Sungjun Bae*
Department of Environmental Engineering, Konkuk University, Korea
Abstract Red mud (RM) is a solid waste from Bayer process, which can cause severe environmental problems. To reutilize the RM, we developed a novel photocatalysis system (RM + peroxides (i.e. hydrogen peroxide (H2O2), peroxymonosulfate (PMS) and persulfate (PS)) for wastewater treatment under visible light irradiation. Acid orange 7 (AO7)) was selected as a target pollutant in this study. The amount of peroxide consumed after the complete decolourization was ordered as follows: PS < PMS < H2O2, indicating the highest efficiency of PS for the AO7 decolourization. In order to investigate the photocatalysis mechanism, we prepared different metal oxide (MxOy) composites and Fe2O3 was found to be a main player for the degradation of AO7 by forming AO7-Fe3+ complex. Compared to pure Fe2O3, Fe2O3-Na2O composite showed enhancement in decolourization rate due probably to the peroxide activation by continuous extraction of OH− anion, whereas Fe2O3-Al2O3 and Fe2O3-SiO2 composites showed a remarkable inhibition effect on decolourization. To investigate the main reactive radical species, we used various radical scavengers (i.e. 2-propanol, phenol, p-benzoquinone, sodium azide and N2 purging) and found out that superoxide radical (O2• −) or hydroperoxy radical (HO2• ) were the main radical species as an initiator, resulting in the activation of peroxides for AO7 decolourization. The results of this study revealed that red mud can be successfully utilized for AO7 decolourization as a catalyst without any pre-treatment or modification. Keywords: Red mud, Acid Orange 7, Visible light, Decolourization, Persulfate Acknowledgments This work is supported by the National Research Foundation of Korea (project no. 2016R1D1A1B03930142 and 2019R1C1C1003316).
E-mail rlawngus38@naver.com