Energy efficient photocatalytic activation of peroxymonosulfate by g-C3N4 under 400 nm LED irradiation for degradation of Acid Orange 7. (January 2022)

• Record Type: Journal Article
• Authors: Kokate, Santosh; Gupta, Smita; Kopuri, Vijayakumar Gupta; Prakash, Halan
• Is Part Of: Chemosphere. Volume 287:Part 2(2022)
• Publication Date: 2022-01
• Subjects: Sulfate radical anion -- Photocatalyst -- Electrical energy per order -- Light emitting diode -- Advanced oxidation process; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.132099
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Photocatalytic activation of peroxymonosulfate (PMS) by graphitic carbon nitride (g-C3 N4 ) is emerging as a sulfate radical anion based advanced oxidation process (S-AOP) for degradation of organic pollutants. Importantly, photocatalytic activation of PMS by g-C3 N4 is energy intensive as light irradiation requires high electrical energy. Here, we studied activation of PMS by g-C3 N4 under 400 nm light emitting diode (LED) irradiation (g-C3 N4 /PMS/400-LED system) for degradation of Acid Orange 7 (AO7). LED array having optical emission maximum around 400 nm (FWHM = 16 nm), with electrical input power of 1.54 W (14 V and 110 mA) was used for irradiation. Pseudo-first order rate constant (kobs ) value for degradation of AO7 by g-C3 N4 /PMS/400-LED system was determined to be 0.094 min −1 . O2 ·-, SO4 ·- were revealed by radical scavenging and ESR investigations. kobs value in simulated ground and real tap water were determined to be 0.068 min −1 and 0.063 min −1, respectively. g-C3 N4 was stable, and reused four times without any significant loss in its photocatalytic activity. Importantly, electrical energy per order ( E E O ) for degradation of AO7 by g-C3 N4 /PMS/400-LED system was determined to be 24.51 kWh m −3 order −1 . In contrast, the E E O value for the degradation of AO7 by g-C3 N4 activated PMS under visible light irradiation (>400 nm), using conventional xenon lamp, (g-C3 N4 /PMS/Vis-Xe system) was found to be very high as 2702 kWh m −3 order −1 . Thus, the study highlights, LED irradiation source is promising for the development of energy efficient g-C3 N4 photocatalytic activation of PMS for removal of organic pollutants. Graphical abstract: Image 1 Highlights: Pseudo-first-order rate constant of Acid Orange 7 degradation was 0.094 min −1 . Electrical energy per order ( E E O ) to degrade Acid Orange 7 was 24.51 kWh m −3 order −1 . O2 . -, SO4 - revealed by radical scavenging and ESR investigations E E O value obtained with 400 nm LED was 110 times lower than Xenon lamp.