Enhanced photocatalytic treatment using plasmonic Ag@Ag3PO4/Ag@AgCl nanophotocatalyst for simultaneous degradation of multiple parabens and UV-filters in various aquatic environments under visible light irradiation.

In this study, simultaneous photocatalytic degradation of different parabens (methyl-, ethyl-, propyl-, and butyl paraben) and UV filters (benzophenone-3, 4-methylbenzylidene camphor, 2-ethylhexyl 4-(dimethylamino) benzoate, ethylhexyl methoxycinnamate and octocrylene) in water matrices was performed under visible light irradiation using novel double plasmonic Ag@Ag3PO4/Ag@AgCl nanophotocatalyst, synthesized by an easy and fast photochemical conversion and photo-reduction. It was found that the nanophotocatalyst with appropriate mole ratio of Ag@Ag3PO4/Ag@AgCl (1:3) showed superior photocatalytic activity than individual plasmonic nanoparticles. This is because there are two simultaneous surface plasmon resonances (SPR) generated by the metallic Ag nanoparticles, in addition to the hetero-junction structure formed at the interface between Ag@Ag3PO4 and Ag@AgCl. The structures of the synthesized photocatalysts were characterized, and the principal reactive oxygen species in the photocatalytic process were identified via a trapping experiment, confirming superoxide radicals (∙O2-) as the key reactive species of the photocatalytic system. The process of photodegradation of the target pollutants was monitored using an optimized method that incorporated solid-phase extraction in combination with gas chromatography-mass spectrometry. The simultaneous photodegradation process was modeled and optimized using central composite design. The kinetic study revealed that the degradation process over Ag@Ag3PO4 (30%)/Ag@AgCl (70%) under visible light followed a pseudo-first-order kinetic model. The simultaneous degradation of target compounds was further investigated in sewage treatment plant effluent as well as tap water. It was found that the matrix constituents can reduce the photodegradation efficiency, especially in the case of highly contaminated samples.

Investigation of simultaneous multiple UV filters degradation efficiency of plasmonic Ag@AgCl photocatalyst in the aquatic environment under sunlight irradiation.

UV filters as an important class of emerging organic pollutants are continuously released into and transported between the aquatic environments. So, the removal of these compounds from aquatic environments is of great importance. This study was conducted to evaluate the simultaneous photodegradation of three widely used UV filter compounds (4-methylbenzylidene camphor, 2-ethylhexyl 4-(dimethylamino) benzoate, ethylhexyl methoxycinnamate), in an aqueous environment under sunlight and Ag@AgCl photocatalyst integrated with plasmonic effect. The plasmonic Ag@AgCl nanocomposite was constructed via photochemical conversion and photoreduction. The enhanced photocatalytic performance can be attributed to the surface plasmon resonance effect of the silver nanoparticles and the hybrid effect caused by AgCl. For the monitoring of the target compounds' degradation before and after photodegradation, an optimized method based on membrane-protected micro-solid-phase extraction coupled with gas chromatography-mass spectrometry (GC-MS) was employed. The simultaneous degradation of selected UV filters was also further investigated in contaminated real samples (river water) and the results showed that the matrix constituents could diminish the photocatalytic degradation efficiency.