ENHANCED PHOTOCATALYTIC DECOLORIZATION OF ORANGE II AND RHODAMINE B DYES IN AQUEOUS SOLUTION WITH G-C3N4 OBTAINED FROM UREA AND 1,3,5-TRIHYDROXYBENZENE

Journal: Acta Chemica Malaysia (ACMY)
Author:  Bin Guoa, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata, Ahmed H. A. Dabwan, Satoshi Kaneco
ISSN: 2576-6732
e-ISSN: 2576-6724

This is an open access journal distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/acmy.01.2026.28.31

Graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized via thermal polymerization of urea in the presence of 1,3,5-trihydroxybenzene (THB) as a molecular modifier. The incorporation of 10 mg THB resulted in enhanced visible-light-driven photocatalytic performance for dye decolorization in aqueous solution. Under 450 nm irradiation, the modified g-C₃N₄ (T10) achieved over 90% degradation of Orange II within 60 min, with a pseudo-first-order rate constant approximately five times higher than that of pristine g-C₃N₄. Kinetic analysis based on the Langmuir–Hinshelwood model confirmed improved charge transfer efficiency and reduced electron–hole recombination. In contrast, Rhodamine B degradation exhibited substrate-dependent behavior, indicating that surface modification influences adsorption characteristics and interfacial reaction pathways. The enhanced performance toward Orange II is attributed to extended π- conjugation, improved visible-light absorption, and surface hydroxyl functionalities introduced by THB, which promote dye adsorption and reactive oxygen species formation. These findings demonstrate that molecular-level modification of g-C₃N₄ using aromatic hydroxyl compounds provides an effective strategy to tailor photocatalytic selectivity and improve visible-light-driven wastewater treatment performance.