Biosynthesis of zinc oxide tri-doping selenium (Se), sulfur (S) and silver (Ag) using matoa leaf extract for methyl orange photocatalyst

Abstract

Water pollution caused by synthetic dye waste from the textile industry, particularly methyl orange, is a serious environmental problem due to its carcinogenic properties and difficulty in degradation. This study aims to synthesize tri-doped ZnO nanoparticles with Se, S, and Ag using a biosynthetic method based on matoa leaf extract (Pometia pinnata) with the aid of microwave irradiation and to test their photocatalytic activity. The samples were synthesized with a fixed Se concentration of 4%, S varied from 1% – 2%, and Ag varied from 1-3% at pH 8 using 540 Watt microwave irradiation for 3 × 1 minute. UV-Vis characterization showed a band gap energy of 3.34 – 3.60 eV with absorbance peaks in the range of 344.92 – 372.18 nm. XRD analysis confirmed a hexagonal wurtzite crystal structure with a crystal size of 24.97 – 37.34 nm. FESEM displayed a quasi-spherical morphology with a particle size of 107.69 – 1562.02 nm. EDX confirmed the presence of Zn, O, Se, S, and Ag elements in the sample. BET characterization showed the highest surface area in the (0,1,4)Ag,S,Se/ZnO sample at 16,298 m²/g with a type IV mesoporous structure. Photocatalytic testing against methyl orange under UV-C irradiation showed consistent degradation for 120 minutes. This study proves that the biosynthesis of tri-doped ZnO using matoa leaf extract produces an effective and environmentally friendly photocatalyst material for industrial waste treatment.