Competitive Vs. Synergistic Surfactant Adsorption

The adsorption behavior of both nonionic and charged surfactants onto minimally charged nanoplastic surfaces holds potential for advancing the comprehension of antibiotics’ removal onto the nanoplastic present in post-cleaned water systems. The aim of this ongoing research is to measure the adsorption of hexadecyltrimethylammonium bromide (CTAB) and varying nonionic ethoxylated surfactants such as tetra- (C12E4) and hexa-methylene glycol monododecyl ether (C12E6) onto polystyrene. Employing the quartz crystal microbalance with dissipation (QCM-D) apparatus, the adsorption behavior of these surfactants onto polystyrene quartz crystal was evaluated to create isotherms as the concentration of the surfactants exceed the critical micelle concentration (CMC). CTAB, a cationic surfactant, caused desorption onto the polystyrene quartz crystal, facilitated by the electrostatic repulsion driven by the slight negative charge the polystyrene surface. This makes it a good cleaning solution. Conversely, the C12E6 isotherm illustrates adsorption onto the crystals surface. Subsequent investigations will encompass more surfactants to facilitate a further understanding of the underlying relationships.