Insights into the removal of microplastics and microfibres by AdvancedOxidation Processes br

Water treatment plants' effluents are hotspots of microplastics (MPs) and microfibres (MFs) released into the aquaticenvironment because they were not designed to capture these particles. Special attention should be given to MFs,since they mainly come from laundry and are related to one of the main MP shapes detected in water and wastewatertreatment plants. In this sense, Advanced Oxidation Processes (AOPs) could be a feasible solution for tackling MP andMF pollution, however, it is still premature to extract conclusions due to the limited number of studies on the degra-dation of these particles (specifically MFs) using AOPs. This review addresses the impacts of AOPs on MPs/MFs, focus-ing on their degradation efficiency, toxicity, and sustainability of the processes, among other aspects. The reviewpoints out that polyamide MFs can achieve mass loss>90% by photocatalytic system using TiO2. Also, the low oxida-tion of MPs (<30 %) by conventional Fenton process affects mainly the surface of the MPs. However, other Fenton-based processes can provide better removal of some types of MPs, mainly using temperatures>100 degrees C, reactiontime >= 5 h, and initial pH <= 3, achieving MP weight loss up to 96 %. Despite these results, better operating conditionsare still required for AOPs since the ones reported so far are not feasible for full-scale application. Additionally, ozon-ation in treatment plants has increased the fragmentation of MPs (including MFs), leading to a new generation of MPs.More attention isneededon toxicity effects ofintermediates andmethods of analysis employed for theanalysis ofMPs/MFs in wastewater effluent should be standardized so that studies can be compared effectively. Future research shouldfocus on the sustainability of the AOP for MP removal in water treatment (power consumption, chemicals consumedand operational costs) for a better understanding of full-scale applicability of AOP adapted to MP treatment.

Automated summary

Water treatment plants' effluents are a major source of microplastics (MPs) and microfibres (MFs) in aquatic environments. Advanced Oxidation Processes (AOPs) show promise in degrading these particles, but more research is needed. This review highlights the impacts of AOPs on MPs/MFs, focusing on degradation efficiency, toxicity, and sustainability. It also suggests the need for standardized analysis methods and further investigation into the operational feasibility of AOPs for MP removal.