A promising sustainable green nanosilver formula for p-nitrophenol and methylene blue remediation from wastewater

In an attempt to create wastewater treatment “green” techniques that are both economically feasible and sustainable without using any dangerous chemicals, barley grain (Hordeum vulgare L.) water extract was used to phyto-synthesize silver nanoparticles (Ag°). Barley grains served as a natural reductant and stabilizer at the same time. The role of different synthesis conditions and their effect on the efficiency of the green synthesis process were studied and confirmed with characterization using several techniques (UV–vis, SEM, EDX, sizing distribution, and FTIR). The Ag°9 formula catalytic reduction was inspected against p-nitrophenol (PNP) and methylene blue (MB) as a model of nitroaromatic components and dyes, respectively. The removal studies were conducted using the target pollutants in a single or mixed liquid state. Remarkably, the Ag°9 particle size was around 20 nm, and its final concentration in the current formula was 2.2 × 10⁻⁷ mol L⁻¹. The adsorption mechanism of the PNP and MB was pseudo-second order. The good fit with the pseudo-second-order kinetic model suggests that chemisorption occurs in the sorption process. The formula catalytic activity to remove PNP and MB was 99 and 66% at levels 60 and 500 µL from the Ag°9 formula, respectively, within less than 5 min.