Citrus sinensis peel waste assisted synthesis of AgNPs: effect of surfactant on the nucleation and morphology

Abstract

Silver nanoparticles (AgNPs) were synthesized by using Citrus sinensis peel waste extract. Optical images and UV-visible spectroscopy reveals the appearance of yellow to brown-red color and surface plasmon resonance (SPR) band at 400–480 nm, respectively, due to the formation of AgNPs. The stable perfect transparent silver sols were formed in presence of cetyltrimethylammonium bromide (CTAB). The brownish precipitates appeared with sodium dodecyl sulphate (SDS) after 3 h. The nucleation, position of SPR band and intensity depends on the head group nature of cationic and anionic micelles of SDS and CTAB. The as-prepared AgNPs were characterized using conventional techniques such as Fourier-transform infra-red, energy dispersed X-ray detector, scanning electron microscope, transmission electron microscope, and X-ray diffractometer. Zeta potential of CTAB-AgNPs was calculated and found to be stable for ca. 1 week. Molar concentration (3.3 × 10−4 mol/L) and aggregation number (607,339.917) of DPE-AgNPs were calculated. Ascorbic acid, citric acid and total reducing sugars were estimated in dry and fresh peel extract. Gram positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria shows excellent antibacterial activities toward DPE-AgNPs.