Catalytic effects of activated-carbon particle size on the oxidative degradation mechanisms of a pharmaceutical. Issue 2 (April 2022)

• Record Type: Journal Article
• Authors: Kim, Do Gun; Pham, Van Luan; Ko, Seok Oh
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 2(2022)
• Publication Date: 2022-04
• Subjects: Activated carbon catalyst -- Non-radical pathway -- Persulfate -- Pharmaceutical -- Radical pathway -- Size; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.107179
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: The effects of the size of activated carbon (AC) on the catalytic degradation of organic micropollutants was investigated by the removal of a pharmaceutical (acetaminophen, ACT) using persulfate (PS). The removal of ACT, either by adsorption or oxidative degradation, and PS decomposition were enhanced by decreasing the size of the AC. The smallest AC particle (AC1) showed higher specific surface area, pore volume, macropores, and fractions of sp 2 -C and CO, but lower I D /I G, I 2D /I G, and fractions of sp 3 -C and of O-CO, compared with the largest AC particle (AC6). Electron paramagnetic spectroscopy revealed a strong SO4 − signal for AC1, but the signal for AC6 appeared weaker after 30 min of reaction time. Decomposition of PS and peroxymonosulfate (PMS) was significantly enhanced by increasing the concentration of the electron donor (ACT) when AC1 was used, but it was not affected when AC6 was used. In addition, degradation of micropollutants and PS decomposition were seriously affected by their ionization potential when AC1 was used, and less affected when AC6 was used. These results suggest that the degradation of organic pollutants by AC1 + PS and AC6 + PS can be attributed primarily to the non-radical and radical pathways, respectively. Meanwhile, the catalytic activity was decreased as AC1 and AC6 were reused because of deactivation process. This indicates that the size of AC is a powerful determinant of the characteristics and can be optimized for the catalytic degradation of organic micropollutants. Graphical Abstract: ga1 Highlights: The characteristics of activated carbon (AC) depend on size and composition. The mechanisms of catalytic degradation by ACs depend on size. A non-radical pathway dominates in the degradation of acetaminophen with small AC and persulfate. A radical pathway dominates in the degradation of acetaminophen with large AC and persulfate.