Sol-gel Mediated by Extract of Santang Orange Peel in Synthesis of TiO2 Nanoparticle for Photocatalytic Degradation of Methyl Orange

Abstract

TiO₂ nanoparticle (TiO₂-NPs) was successfully synthesized through green-synthesis approach, sol-gel mediated by santang orange (Citrus sp.) peel extract. The use of Citrus sp. peel extract as media is a promising method in synthesizing TiO₂-NPs due to low-cost processes, environmentally friendly, and effective as a bio-mediator in chemical reaction. The synthesized TiO₂-NPs were characterized by XRD, DRS UV-Vis, FESEM, HRTEM, PSA, and zeta potential. The diffractogram confirmed that anatase phase was formed with nanocrystalline size. The calculated band-gap energy in the Kubelca-Munk equation was 3.3 eV. The spherical particle size is approximately 6 – 17 nm with agglomeration size about 50 – 90 nm. HRTEM and SAED analysis confirmed the formation of anatase phase from synthesized TiO₂-NPs. The photocatalytic activity of TiO₂-NPs was examined for methyl orange (MO) as artificial wastewater. About 92% of MO dye solutions were degraded within 240 min which followed the pseudo-first order kinetic reaction. The photocatalytic mechanism was studied by analyzing the scavengers of reactive oxygen species effect in photocatalytic degradation of MO. The results revealed that hydroxyl radical (•OH) was the key in the photocatalytic process using TiO₂-NPs.