Immobilization of TBBPA on pyrogenic carbon subjected to natural organic matter under freeze–thawing conditions: insights into surface functionalization, coverage processes and binding affinity†
The long-term environmental effects of pyrogenic carbon have recently raised many concerns in terms of the fate and transport of emerging pollutants. This study explored the surface changes of geometric structure, functional groups, and site-energy distribution on pyrogenic carbon surfaces throughout a long-term physical aging process. Through synchrotron-based FTIR analysis, a homo-functionalization process was found to be the result of the consolidation of oxygen-containing groups with aromatic structures and the antagonization of other active hydroxyl groups in surface formation. Kinetic studies of TBBPA immobilization on pyrogenic carbon surfaces revealed a coverage process where TBBPA–humic acid, pyrogenic carbon–humic acid and pyrogenic carbon–TBBPA interactions can be formed. Isotherm analysis further indicated that the coverage process of natural organic matter (NOM) can enhance the processes of multilayer adsorption and thermodynamic alteration. Moreover, the results exhibited that site energies were dominated by OC–OH⋯OC–OH hydrogen bonds from NOM linkages, and O–H⋯O–H hydrogen bonds for TBBPA interactions were weakened by NOM coverage. Understanding such TBBPA interactions on carbonaceous porous materials will not only enrich the understanding of the transport of ionic pollutants under complex environmental conditions, but also support the evaluation of long-term environmental impacts of both naturally and artificially produced pyrogenic carbons.