Photocatalytic Degradation of Methylparaben Using Green Nanosilver Supported on Reduced Graphene Oxide

Methylparaben (MeP) is one of the most serious water pollutants found in cosmetic industry effluents. It interferes with various organisms' endocrine or hormonal systems and has been increasingly accumulating in water bodies because of its widespread use and high chemical stability, prompting the need for its mitigation. Plasmonic nanoparticles offer a promising pathway for pollutant removal in water treatment due to their ability to perform direct visible light-driven photocatalysis. In this regard, a hybrid catalyst of silver nanoparticles on reduced graphene oxide (rGO/AgNPs) was fabricated using biobased in situ reduction process and was employed as a visible light photocatalyst to treat MeP. The use of green reducing agents reduces the overall cost and environmental impact of the process. The synthesized catalyst exhibits significantly enhanced adsorption and photocatalytic degradation efficiency of MeP (97.6%) than rGO or AgNPs, individually. The conditions that influence the kinetics of the photocatalytic degradation by rGO/AgNPs were comprehensively studied using response surface methodology, including solution pH, catalyst dose, persulfate concentration, MeP initial concentration, and time. The nanocomposite showed high stability and could be used for several cycles without reducing the activity. Additionally, the mechanism of the photocatalytic reaction was investigated by scavenger tests and the density functional theory study. This approach provides new insights into the future research and development of low-cost photocatalysts for cosmetic wastewater treatment utilizing visible light irradiation.

Automated summary

Methylparaben (MeP) is a serious water pollutant in cosmetic industry effluents, but a hybrid catalyst of silver nanoparticles on reduced graphene oxide (rGO/AgNPs) fabricated using a green reducing agent showed significantly enhanced photocatalytic degradation efficiency of MeP. The conditions influencing the degradation kinetics were comprehensively studied using response surface methodology. The nanocomposite exhibited high stability and potential for multiple cycles of use, providing new insights into the development of low-cost photocatalysts for cosmetic wastewater treatment.