Caffeine degradation in synthetic coffee wastewater using silverferrite nanoparticles fabricated via green route using Amaranthus blitum leaf aqueous extract

Abstract

Caffeine is a persistent chemical with toxic effects on various biological systems in the environment which initiates the necessity to degrade the caffeine. This study aimed to degrade caffeine using Amaranthus blitum leaf extract mediated silverferrite nanoparticles (AgFeO2-NPs) under compact fluorescent lamp illumination in shake flask by photocatalysis. The AgFeO2 NPs were monodispersed with spherical shape (92 nm in average size and bandgap of 1.9 eV), holds higher photocurrents and surface area of 10.4 μA/cm2 and 145.21 m2/g respectively. The effect of different operating conditions such as initial pH (4, 7and 9), AgFeO2 NPs loading (10, 20, 50, and 100) mg/L, and caffeine concentration (10, 20, 50 and 100) ppm was studied on degradation efficiency. The results showed that optimal conditions led to maximum degradation of 99.9% at pH 9.0, 50 mg/L NPs dose with initial caffeine concentration of 50 ppm in 15 h compared to photolysis and NPs under dark condition. Under optimized conditions, (∼ 120 ppm caffeine in synthetic wastewater, pH 9.3, and 50 mg/L of AgFeO2 NPs), it was found that 95% degradation occurred in 24 h. Also, AgFeO2 NPs found to degrade polyphenols under light conditions suggesting a potential catalyst for treating caffeine wastewater.