Removal of aromatic sulfonates from aqueous media by aminated polymeric sorbents: Concentration-dependent selectivity and the application

Sorption of aromatic sulfonates onto two aminated polystyrene sorbents with different pore structures (M-101 and D-301) was investigated for optimization of their potential application in chemical wastewater treatment. Sodium benzenesulfonate (BS), sodium 2-naphthalene sulfonate (2-NS) and disodium 2,6-naphthalene disulfonate (2,6-NDS) were selected as reference solutes and sodium sulfate was as a competitive inorganic salt. Sorption selectivity of both sorbents is dependent upon the concentration levels of aromatic sulfonates in solution coexisting with sodium sulfate at a high level. However, both sorbents exhibit different characters. D-301 presents more favorable sorption for the solutes at relatively high levels (e.g., higher than 5 mM for BS, 0.7 mM for 2-NS and 0.05 mM for 2,6-NS), while M-101 removes aromatic sulfonates more completely when the solute concentration kept at relatively low levels. Based on the experimental results, we proposed an integral process of sorption onto D-301 followed by secondary-sorption onto M-101 to remove aromatic sulfonates from industrial wastewater completely and economically. Furthermore, the satisfactory performance revealed from large-scale application further demonstrated the feasibility of extending this process to dispose of other associated chemical wastewaters.