Fabrication of hydrophilic and hydrophobic site on polypropylene nonwoven for removal of bisphenol a from water: explorations on adsorption behaviors, mechanisms and configurational influence

Abstract

In this study, hydrophilic and hydrophobic site was fabricated onto the surface of polypropylene (PP) nonwoven for removal of bisphenol A (BPA). The adsorption behaviors as well as the adsorption driving forces were systematically analyzed. It is revealed that the amphiphilic PP nonwoven (PP-g-GMA-OA) had strong affinity towards BPA molecules and the predominant driving forces were hydrophobic interaction and hydrogen bonding. The hydrophobic site acted as adsorption site to provide hydrophobic interaction. The hydrophilic site accelerated the diffusion and adsorption process. In addition, the detailed connections between grated layer configuration and adsorption behaviors were observed and systematically elucidated. To ascertain the configurational transformation of grafted layer on PP surface, a microparticle grafting experiment was designed based on stimuli-responsive material measurement and the results indicated that the grafted layer had extended and contracted configuration with the variety of pH. Surface zeta potential measurement revealed that the configurarational transformation was mainly controlled by electrostatic interaction. On the basis of specially designed adsorption isotherm experiment, it is observed that extended configuration could offer more sites and slightly increased the adsorption capacity compared with contracted configuration.

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