Green synthesized nanosilver-biochar photocatalyst for persulfate activation under visible-light illumination

This paper presents a novel eco-sustainable wastewater treatment using silver nanoparticles and biochar ([email protected]) synthesized from an Eriobotryra japonica leaf. A simple green pyrolysis method was chosen to activate peroxydisulfate (PDS) for organic pollutant degradation under the action of visible light. Rhodamine B (RhB) was chosen as a typical containment to assess the photocatalytic performance of the [email protected]/PDS system with visible-light illumination ([email protected]/PDS-vis). When [email protected] (referring to the [email protected] pyrolyzed at 750 °C) was added, the photocatalytic activity of PDS for RhB degradation was enhanced (from kapp = 0.165–2.984 min−1). The result confirmed that 99.9% of the RhB was degraded in the [email protected]/PDS-vis system within 10 min and with a 2.0 g/L photocatalyst, 10 mM PDS and under pH 9.03 (kapp = 6.723 min−1). Over 100 mg/L of RhB could be degraded completely in the [email protected]/PDS-vis system within 30 min mainly attributed to various free radicals. The possible degradation pathways of RhB were illustrated and the recyclability of the [email protected] photocatalyst was confirmed. The findings in this study reveal the virtue of using the [email protected]/PDS-vis process for advanced water disinfection and its provision as an alternative solution in addressing the green way for further water treatment.