Synthesis of silver nanoparticles from microalgae for potential photocatalytic dye removal

Abstract

Silver nanoparticles (AgNPs) with excellent optical and electronic properties is gaining significant attention by researchers for wastewater treatment. In recent years, the production of AgNPs has shifted towards green synthesis approach by using bio-reducing agent (e.g. plant extract). In this study, live cells Chlorella vulgaris were used as the bio-reducing agent to produce AgNPs from precursor (silver nitrate (AgNO3) solution). Two process parameters were investigated, namely incubation time and pH. The results affirmed that the optimum synthesis condition of AgNPs was at 24 hr incubation time and pH 8.4 in the mixture of live cells microalgae and 3 mM AgNO3 (3:1 v/v). The synthesized AgNPs showed Localized Surface Plasmon Resonance (LSPR) peak at 412.5 nm with absorption maxima of 0.81 a.u. as indicated using UV-Vis spectrophotometer. The synthesized AgNPs had shown 80.7% of photocatalytic dye degradation in 5 mg/L MB solution and 32.1% in 25 mg/L MB solution within 9 hr of incubation time. The dye removal rate with the addition of AgNPs was 1.2 times faster in 5 mg/L MB solution and was 3.5 times faster in 25 mg/L MB solution as compared to control set.