Ecosafety Screening of Photo-Fenton Process for the Degradation of Microplastics in Water

Abstract

Microplastic pollution is receiving increased attention due to the realization of its hazards to aquatic and human life. Researchers across the globe are attempting to remove microplastics before its entry into the ecosystem. Therefore, the present work focused on the removal of microplastic from water and studied the potential risks for marine organisms and the ecosystem. The removal of model microplastics, polypropylene (PP) and polyvinyl chloride (PVC), has been studied by using photo-Fenton process. ZnO nanorods coated with SnOx(x < 2) layer and decorated with zero valent iron (Fe0) nanoparticles was used as heterogeneous catalyst for the removal of the microplastics in continuous water flow device. The obtained results demonstrated that high degradation efficiency of PP and PVC microplastics was achieved in a relatively short time and more than 95% of the average particle volume was reduced after 1 week of irradiation. The environmental impact of the photo-Fenton process of the microplastics degradation was investigated by using an ecotoxicological approach. An ecosafety screening has been performed through a series of experiments (bioassays) under controlled conditions, testing water samples after the photo-Fenton degradation of microparticles using a lab scale device. The ecotoxicological impact has been investigated by applying a battery of certified bioassays (UNI EN ISO/EPA standardized techniques) on aquatic organisms at different trophic levels (bacteria, algae, invertebrates). The results obtained on the three model organisms (A. fischeri, P. subcapitata, and D. magna) revealed no toxic effect for samples collected both before and after the photo-Fenton process, thus showing the absence of toxic by-products development during the degradation process.

Insights into the removal of microplastics and microfibres by Advanced Oxidation Processes

“…sand filtration), the application of AOPs for MPs degradation is recent. Recent works have reported advances in the identification of factors that play important roles in the degradation efficiency of MPs by AOPs (Hu et al, 2022b;Llorente-García et al, 2020;Miao et al, 2020;Nabi et al, 2020;Piazza et al, 2022). These factors are described in the following sections.…”

“…The photo-Fenton process was evaluated for the degradation sulfonated PS beads (experimental conditions of UV irradiation from a 250 W Hg (Xe) light, volume of the reaction mixture of 25 mL, Fe 3+ = 0 to 0.63 mM, H 2 O 2 = 0 to 176 mM, and initial pH = 2) (Feng et al, 2011). After such work, photo-Fenton studies attempting MP degradation were carried out (Liu et al, 2020;Piazza et al, 2022). The photo-Fenton process led to almost complete removal of PS MPs after 300 min of UV irradiation (Feng et al, 2011).…”

“…Recently, heterogeneous photo-Fenton using Fe 0 nanoparticles/zinc oxide nanorods coated with ZnO/SnOx was assessed (Piazza et al, 2022). The degradation of PP and PVC MPs was carried out in a continuous flow system (with [H 2 O 2 ] 0 = 35 mM) for up to 30 days and achieved a reduction of the volume of PVC and PP MPs of 94 % and 96 %, respectively after one week of treatment.…”

Microplastics in aquatic systems, a comprehensive review: origination, accumulation, impact, and removal technologies

“…solid iron on a supporting matrix) with photocatalysis resulted in signicant reduction in size of PVC and PP particles aer 7 days. 235 Ozone and peroxide based treatment. Ozone has been applied either on its own, 236,237 or in combination with radical generating hydrogen peroxide 238 to degrade MP.…”

“…solid iron on a supporting matrix) with photocatalysis resulted in significant reduction in size of PVC and PP particles after 7 days. 235 …”