Mussel-inspired encapsulation of poly(pyrogallol-tetraethylenepentamine) resin into mesoporous MSU-H matrix and its rapid removal feature for Congo red from aquatic environment

Removing organic dyes from polluted water by mesoporous polymeric composite has recently attracted intensive attentions. Herein, the mesoporous poly(pyrogallol-tetraethylenepentamine)/MSU-H (PPTA/MSU-H) adsorbent was tapped for the capture of Congo red (CR) in aquatic environment via mussel-inspired encapsulation strategy. Many characterizations ( e.g. FT-IR, SEM, BET, etc ) are employed to confirm the successful decoration of PPTA resin. Effects of composite components, initial concentrations, environmental temperatures, adsorbent dosages, initial pH values, and foreign ions on the removal of CR by PPTA/MSU-H- x composites have been investigated successively. At optimal conditions of process variables, PPTA/MSU-H-20 exhibits the highest R % value (94.79 %) and reaches adsorption equilibrium at 180 min. The adsorption behavior of the representative adsorbent is matched well with the pseudo-second-order model, meaning one CR molecule binds with two capture sites. Furthermore, it indicates a monolayer homogeneous adsorption on PPTA/MSU-H-20 with the maximum theoretical capacity of 222 mg g −1 according to the well fitted Langmuir model. The removal mechanism of CR may be ascribed to hydrogen bonding, π-π stacking, electrostatic attraction, pore filling effects, and addition reaction. Overall, results reveal that mesoporous PPTA decorated adsorbent has a rewritable refabrication character and excellent specificity for the anionic dye purification in polluted water.