Photocatalytic degradation of metronidazole and oxytetracycline by novel l-Arginine (C, N codoped)-TiO2/g-C3N4: RSM optimization, photodegradation mechanism, biodegradability evaluation

Parisa Eskandari; Ehsan Amarloo; Hadis Zangeneh; Mashallah Rezakazemi; Tejraj M Aminabhavi

doi:10.1016/j.chemosphere.2023.139282

Photocatalytic degradation of metronidazole and oxytetracycline by novel l-Arginine (C, N codoped)-TiO₂/g-C₃N₄: RSM optimization, photodegradation mechanism, biodegradability evaluation

Chemosphere. 2023 Oct:337:139282. doi: 10.1016/j.chemosphere.2023.139282. Epub 2023 Jun 20.

Authors

Parisa Eskandari¹, Ehsan Amarloo², Hadis Zangeneh³, Mashallah Rezakazemi⁴, Tejraj M Aminabhavi⁵

Affiliations

¹ School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
² Department of Chemical Engineering, Sharif University of Technology, Tehran, 11155, Iran.
³ Department of Chemical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran. Electronic address: aminabhavit@gmail.com.
⁴ Faculty of Chemical and Materials Engineering, Shahrood University of Technology, Shahrood, Iran. Electronic address: mashalah.rezakazemi@gmail.com.
⁵ Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, Karnataka, 580 031, India.

PMID: 37348615
DOI: 10.1016/j.chemosphere.2023.139282

Abstract

Removal of Metronidazole (MNZ) and Oxytetracycline (OTC) from wastewater by the prepared (C, N codoped)-TiO₂/g-C₃N₄ (Graphitic carbon nitride) was examined. l-Arginine (C, N codoped)-TiO₂ and l-Arginine (C, N codoped)-TiO₂/g-C₃N₄ photocatalysts were successfully synthesized through the sol-gel method, and optimal ratio of l-arginine:TiO₂, as well as l-arginine/TiO₂:g-C₃N₄, was determined by a kinetic study of photodegradation process. The maximum photocatalytic removal rate (0.062 min^-1 for MNZ removal) was observed using 1% l-Arginine-TiO₂/g-C₃N₄ (1:1) under visible light illumination, 2.2 and 12.4 times greater than those of 1% l-Arginine-TiO₂ and pure TiO₂, respectively. l-Arginine (1%)-TiO₂/g-C₃N₄ (1:1) (co-doped-TCN) was investigated using X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), Photo-luminescence (PL), and Differential Reflectance Spectroscopy (DRS) as the best-performing photocatalyst. Response surface methodology (RSM) was used to study the effect of co-doped-TCN dosage (0.5-1.0 g/L), pH of simulated wastewater (4-10), initial concentration of MNZ and OTC (50-100 mg/L), and irradiation time (30-90 min for MNZ and 20-40 min for OTC) on removal efficiency of the antibiotics. Also, their optimum values were determined by RSM. The treated pharmaceutical wastewater showed high biodegradability features with 5-day biological oxygen demand/chemical oxygen demand (BOD₅/COD) of 0.51 and 0.46 after 40 and 100 min reaction for OTC and MNZ, respectively. The order of reactive species responsible for the photodegradation of pollutants was •O₂^─> •OH > h⁺>¹O₂. The effect of inorganic anions showed that all anions decreased the removal efficiency of both antibiotics in order of NO₃^─> Cl^─ >SO₄^2─>HPO₄^2─ >HCO₃^─ for MNZ and NO₃^─> SO₄^2─ > Cl^─ >HPO₄^2─ >HCO₃^─ for OTC. Also, introducing different oxidants improved the photocatalytic removal efficiency with the order of H₂O₂>K₂S₂O₈> KBrO₃.

Keywords: Co-doping; Heterostructures; Metronidazole; Oxytetracycline; Response surface methodology (RSM); g-C(3)N(4).

MeSH terms

Anti-Bacterial Agents / chemistry
Catalysis
Hydrogen Peroxide
Light
Metronidazole
Oxytetracycline*
Photolysis
Wastewater

Substances

Oxytetracycline
Metronidazole
titanium dioxide
Hydrogen Peroxide
Wastewater
Anti-Bacterial Agents