Nanocasted PANI/SBA-16 Mesoporous Composite for Trace-Level Adsorption of Perfluoroalkane Sulfonates

High Resolution Image Download MS PowerPoint Slide Three nanocasted polyaniline/mesoporous silica composites (PANI/SBA-16), denoted as PS-25, PS-50, and PS-75, were synthesized by incorporating 25, 50, and 75 wt % of PANI (emeraldine salt form), respectively, into the ordered mesoporous SBA-16. Increasing PANI loading systematically reduced the specific surface area and pore volume from 646 m 2 g –1 and 0.52 cm 3 g –1 for SBA-16 to 404 m 2 g –1 and 0.39 cm 3 g –1 for PS-25, 260 m 2 g –1 and 0.29 cm 3 g –1 for PS-50, and 126 m 2 g –1 and 0.19 cm 3 g –1 for PS-75. At a 20 mg L –1 PS-50 dosage, orbital shaking enabled >99% removal of perfluorooctanesulfonate (PFOS) and >95% removal of individual perfluoroalkane sulfonates (PFSAs) from a mixture containing perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS), perfluoroheptanesulfonate (PFHpS), perfluorooctanesulfonate (PFOS), and perfluorodecanesulfonate (PFDS) within 60 and 120 min, respectively, at initial PFSA concentrations ∼1 μg L –1 each. The log equilibrium distribution coefficient (K D ) values of PFSAs in the mixture were found to be in the range of ∼6.52–7.91 L kg –1 . Adsorption of short-chain PFSAs was relatively more strongly suppressed by competing anions than that of long-chain analogues. Computational analyses further highlighted the contribution of H-bonding in the adsorption mechanism. This sustainable and facile nanocasting strategy provides guidance for designing composites for water purification applications.