Sulfonated polyHIPE/nanoclay composites with hierarchically porous structure for efficient removal of...

The objective of this study is the synthesis of macroporous polystyrene-based polyHIPE/nanoclay (p[HIPE]/NClay) monoliths and post-functionalization of the monoliths through sulfonation to improve the structural and textural properties as well as adsorption performances toward bisphenol A (BPA) as an endocrine-disrupting chemical. The adsorption tests were conducted with raw p(HIPE), nanoclay, p(HIPE)/NClay, and sulfonated samples in order to obtain insights in the adsorption mechanism. The synergy between clay embedding and sulfonation resulted in higher BPA removal performance of p(HIPE)/NClay@S sample (96% removal) when compared with the raw polyHIPE (52% removal). The adsorption efficiency was mainly attributed to the functionality, followed by porosity and hydrophilicity of the as-synthesized materials. Considering the roles of hydrophobic, hydrogen-bonding, and π-π stacking interactions, the adsorption mechanism was discussed by using X-ray photoelectron spectroscopy (XPS) analysis. Moreover, the experimental parameters including solution pH, co-existing anions, ionic strength, and temperature were investigated in detail. The adsorption data were fitted to isotherm and kinetic models. The composite adsorbents also displayed excellent regeneration and stability until the fifth cycle. This research provides fresh insights into the effective adsorptive removal of endocrine-disrupting hormones by sulfonated porous nanoclay-polymer monoliths. PRACTITIONER POINTS: Sulfonated p (HIPE)/nanoclay monoliths were prepared. Bisphenol A adsorption mechanism was explored in detail. Nanoclay incorporation and sulfonation greatly enhanced the removal efficiency. The composite could be used until the fifth cycle.