A sustainable approach for removal of microplastics from water matrix using Colloidal Gas Aphrons: New insights on flotation potential and interfacial mechanism

Microplastics (<5 mm) are becoming one of the most emerging contaminants found in the environment. This study proposes an eco-friendly generation of novel Colloidal Gas Aphrons (CGA) covered flotation technique to remove the microplastics (MPs) from different water matrix. Sapindus mukorossi soap nuts were used to prepare the surfactant solution. Polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP) and polyethylene (PE) MPs were taken as target pollutants. The efficiency of prepared CGA was tested in deionized water (DW), seawater (SW), river water (SW), wastewater (WW) and leachate (LE). The CGA generation, air holdup, half-life, critical-micelle-concentration, stability, kinetic study, and size of CGA microbubbles were studied effectively. The impact of MPs dosages, zeta potential and dissolved organic carbon (DOC) was also examined in a real water matrix. The electrostatic attraction played a major role in removing the target MPs from DW, RW, WW and LE samples whereas ion concentration could be attributed for the removal of MPs in SW. From the experimental results, it can be concluded that the CGA could function as an active agent in removing MPs from the water matrix successfully.