Investigation of photocatalytic degradation of reactive textile dyes by Portulaca oleracea-functionalized silver nanocomposites and exploration of their antibacterial and antidiabetic potentials

Abstract

This study investigated a one-pot green and sustainable silver nanoparticles (AgNPs) synthesis by utilizing Portulaca oleracea leaves (PNL) aqueous extract as a reducing agent. The physical and chemical characteristics of the produced AgNPs were studied by employing numerous standard analytical techniques. The analytical outcomes suggest that PNL-AgNPs were crystalline in nature, fabricated with PNL phytochemicals, and circular in shape measuring similar to 20 nm in size. Biosynthesized PNL-AgNPs exhibited a significant photocatalytic activity for degrading various reactive textile dyes without the need of any reducing agent. Particularly, of the reactive textile dyes, PNL-AgNPs exhibited higher photocatalytic degradation of Reactive Green 19A (RG19A), wherein its deterioration was studied by measuring the reduction in chemical oxygen demand (COD; 84%) and total organic carbon (TOC; 75%) within 60 min of incubation. The effects of various influencing operational factors, such as temperature, pH, light condition, photocatalyst amount, and dye concentrations, on the photocatalytic degradation of RG19A were systematically examined. The catalytic activity of PNL-AgNPs remains stable up to three repeated cycles, which upsurges the real-world applicability of PNL-AgNPs in textile wastewater treatment. PNL-AgNPs showed significant antibacterial activity and synergy with commercial antibiotics against human pathogenic bacteria. The mechanism underlying antibacterial activity was determined based on bacterial cell membrane disruption and cytoplasmic content leakage. PNL-AgNPs potentially constrain the activity of alpha-glucosidase and alpha-amylase enzymes, which are marker enzymes of diabetes. The results obtained indicate the potential application of synthesized PNL-AgNPs in environmental and nano-biomedical applications. (C) 2020 Elsevier B.V. All rights reserved.