Cathleen SimatupangVinod K JindalRanjna JindalMahidol University. Faculty of Engineering. Department of Civil and Environmental EngineeringMahidol University. Faculty of Engineering. Department of Chemical Engineering2021-12-242021-12-242021-12-242021Environment and Natural Resources Journal. Vol. 19, No. 6 (Nov-Dec 2021), 468-480https://repository.li.mahidol.ac.th/handle/20.500.14594/63936Interest in the biosynthesis of silver nanoparticles (AgNPs) has been steadily increasing primarily due to their numerous applications in various fields, low-cost, use of non-toxic environmentally-friendly materials and easy implementation. This study focused on the biosynthesis of AgNPs using orange peel extract (OPE), optimization of process conditions, and application in catalytic degradation of methylene blue (MB) dye used in the textile industry. A central composite design in response surface methodology resulted in optimum conditions of 0.0075 g dry peel/mL for OPE concentration, pH of 11 and 1.5 mM silver nitrate concentration. The optimum conditions for the response variables corresponded to the peak absorbance of 0.79 and SPR wavelength of 403.8 nm in UV-vis spectra, and minimum particle size of 12.9 nm. In addition, peak absorbance and SPR wavelength appeared to be related to the size of the AgNPs. A full-factorial design for the catalytic degradation of MB dye by the biosynthesized AgNPs for 1 h indicated the maximum influence of AgNPs compared to the concentrations of MB dye and NaBH4 in decreasing order. The MB dye was reduced rapidly with NaBH4 in the presence of AgNPs due to their catalytic action. The findings of the study show the potential of OPE for the biosynthesis of AgNPs with excellent catalytic activity for the treatment of MB dye in industrial effluent.engMahidol UniversityBiosynthesisOrange peel extractSilver nanoparticlesCentral composite designMethylene blue dyeEnvironment and Natural Resources Journalวารสารสิ่งแวดล้อมและทรัพยากรธรรมชาติResearch ArticleFaculty of Environment and Resource Studies Mahidol University