Abstract

This work reports on the ability of Clitoria ternatea aqueous flower extract to prepare biogenic silver nanoparticles (AgNPs). The obtained AgNPs were used as efficient nanocatalysts for the elimination of methyl orange, a carcinogenic azo dye, from an aqueous solution. Several parameters that affected the AgNPs formation were examined. The prepared AgNPs were characterised by UV-Vis spectroscopy, FTIR, SEM-EDX, XRD, TEM, and zeta potential. The formation of AgNPs was confirmed by the development of yellowish-brown colour which was further proved by a surface plasmon peak at 430 nm in UV-Vis spectroscopy. FTIR analysis revealed that anthocyanin present in the extract might be responsible for the reduction of Ag⁺ to AgNPs and capping the particles. Production of stable, well-dispersed face centred cubic spherical crystalline particles with diameters in the range of 10–30 nm was obtained from XRD and TEM studies. SEM-EDX result affirmed the silver content of 73.7%, and zeta potential measurement showed excellent stability of AgNPs with high negative values of −27.77 ± 1.51 mV. Further, the AgNPs catalyst exhibited the excellent catalytic performance in the degradation of methyl orange dyes by NaBH<inf>4</inf>. The degradation process was completed within 10 min, together with a constant rate value of 0.3285 min⁻¹. The results show strong potential of the biosynthesised AgNPs as a candidate for use in environmental remediation.