Efficient removal of acetic acid by a regenerable resin-based spherical activated carbon

Carboxylic acids are the main pollutant of industrial wastewater during the advanced oxidation process (AOPs). In this study, a resin-based spherical activated carbon (RSAC, AF₅) as an adsorbent was examined and acetic acid was used as a model substrate for adsorption investigation. The pH = 3, temperature = 298 K were fixed by batch technique. The pseudo-second-order kinetic model, the intraparticle and external models are fitted well, and it was found that the adsorption of acetic acid onto AF₅ was controlled by liquid film diffusion. A Freundlich model indicated that the adsorption process was heterogeneous multimolecular layer adsorption on the surface. AF₅ shows good regenerative ability; the recovery rate of adsorption capacity was ∼88% after five cycles. Chemical oxygen demand (COD) adsorption removal rate could be maintained at 100% for over 35 h in an actual AOPs effluent, and could be eluted for 100% after 8 h by 0.8wt% NaOH. Characterizations, including XRF, XRD, TG/DSC,FTIR, SEM and N₂ adsorption, showed that the excellent adsorption performance was mainly due to the microporous structure and large specific surface area (1,512.88 m²/g), the adsorption mechanism mainly included pore filling effect and electrostatic attraction. After five adsorption recycles, AF₅'s pore characteristic did not change significantly. This study provides a scientific basis for the wastewater standard discharge process of AOPs coupled adsorption.