Elimination of nanoplastics from water by by Photocatalytic process: a preliminary study

, Robert Didier, Alle Paul-Henri, Garcia Munoz Patricia, Keller Nicolas.

Many household wastewaters contain Microplastics (MPs) and nanoplastics (NPs). Most of this type of pollution is not stopped by current wastewater treatment plants provoking their entrance into the global aquatic systems. This is an emerging issue and potential threat to marine life and human health. However, advanced technologies for efficient MPs and NPs control and elimination remain largely underdeveloped. Heterogeneous photocatalysis represents an attractive and efficient decomposition technique for the nanoplastic particle degradation. The first objectives of this work were i) to study the feasibility of nanoplastic degradation by photocatalysis and ii) to determine the influence of certain reaction parameters i.e. the flowrate, the pH0 and the light intensity on the photocatalytic degradation of calibrated polymethylmethacrylate (PMMA) and polystyrene (PS) nanoparticles with TiO2-P25/β-SiC foams under UV-A. The first results are very encouraging, because to our knowledge, we are the first to show that it is possible to mineralize PMMA and PS nanobeads by UV-A photocatalysis. We were able to convert in 7 hours, 50% of an aqueous suspension loaded with PMMA nanobeads (TOC = 12 mg/l) by working at an irradiance of 112 W/m2, with a flowrate of 10 mL/min and at initial pH value of 6.3, using TiO2-P25/β-SiC foams in a flow-through mode. We also showed that the photocatalytic treatment can be applied to various polymers, such as polystyrene and PMMA.

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