Augmented photocatalytic degradation of Acetaminophen using hydrothermally treated g-C3N4 and persulfate under LED irradiation

Smita Gupta; Jemi Gandhi; Santosh Kokate; Laxman G Raikar; Vijayakumar Gupta Kopuri; Halan Prakash

doi:10.1016/j.heliyon.2023.e16450

Augmented photocatalytic degradation of Acetaminophen using hydrothermally treated g-C₃N₄ and persulfate under LED irradiation

Heliyon. 2023 May 19;9(5):e16450. doi: 10.1016/j.heliyon.2023.e16450. eCollection 2023 May.

Authors

Smita Gupta¹, Jemi Gandhi¹, Santosh Kokate^{1

2}, Laxman G Raikar¹, Vijayakumar Gupta Kopuri³, Halan Prakash¹

Affiliations

¹ Energy and Environmental Chemistry Laboratory, Department of Chemistry, Birla Institute of Technology and Science, Pilani, K K Birla Goa Campus, NH17B, Zuarinagar, Goa, 403726, India.
² Aditya Birla Science & Technology Co. Pvt. Ltd., Taloja, Mumbai, 410208, India.
³ Kwality Photonics Pvt. Ltd., Kushaiguda, Hyderabad, 500062, India.

Abstract

Photocatalytic degradation of organic pollutants in water using graphitic carbon nitride and persulfate under visible light (g-C₃N₄/PS system) has been studied. Here, we demonstrate augmentation of photocatalytic degradation of Acetaminophen (AAP) using hydrothermally treated g-C₃N₄ and PS under 400 nm LED irradiation (HT-g-C₃N₄/PS system). A pseudo-first-order rate constant (k_obs, 0.328 min^-1) for degradation of AAP using HT-g-C₃N₄/PS system was determined to be 15 times higher compared to g-C₃N₄/PS system (k_obs, 0.022 min^-1). HT-g-C₃N₄ showed a higher surface area (81 m²/g) than g-C₃N₄ (21 m²/g). Photocurrent response for HT-g-C₃N₄ was higher (1.5 times) than g-C₃N₄. Moreover, Nyquist plot semicircle for HT-g-C₃N₄ was smaller compared to g-C₃N₄. These results confirm effective photoelectron-hole separation and charge-transfer in HT-g-C₃N₄ compared to g-C₃N₄. AAP degradation using HT-g-C₃N₄/PS system was significantly inhibited with $O_{2}^{. -}$ and h⁺ scavengers compared to ¹O_2, ${S O}_{4}^{. -}$ and ${H O}^{.}$ scavengers. ESR results revealed $O_{2}^{. -}$ formation in HT-g-C₃N₄/PS system. Moreover, photocurrent measurements reveal AAP oxidation by h⁺ of HT-g-C₃N₄ was effective than g-C₃N₄. HT-g-C₃N₄ was reused for five cycles in HT-g-C₃N₄/PS system. Augmented photocatalytic degradation of AAP by HT-g-C₃N₄/PS system compared to g-C₃N₄/PS is attributed to effective photoelectron hole separation of HT-g-C₃N₄ that generates $O_{2}^{. -}$ and h⁺ for oxidation of pollutant. Importantly, electrical energy per order (E_EO) was 7.2 kWh m^-3 order^-1. k_obs for degradation of AAP in simulated groundwater and tap water were determined as 0.029 and 0.035 min^-1, respectively. Degradation intermediates of AAP were proposed. AAP ecotoxicity against marine bacteria Aliivibrio fischeri was completely removed after treatment by HT-g-C₃N₄/PS system.

Keywords: A. fischeri; Electrical energy per order; Emerging contaminants; Photocatalysis; Photocurrent; Superoxide radical anion.