EVALUATION OF SULFANILIC ACID REMOVAL FROM AQUEOUS SOLUTIONS BY ACTIVATED CARBON AND POLYMERIC RESINS

The feasibility of using granular activated carbon (GAC), weakly basic anion-exchanger (D301) and aminated hypercrosslinked polymeric resin (AH-1) to remove sulfanilic acid (SA) from water was investigated. Adsorption isotherms, kinetics, effects of solution pH and coexisting NaCl, as well as regeneration tests were carried out through batch method. Most favorable adsorption was observed at solution pH around 3, and further increase or decrease of solution pH resulted in a reduction of sorption capacity, while the polymeric sorbents AH-1 and D301 were more sensitive to solution pH than GAC. Equilibrium adsorption data fitted well to the Langmuir isotherm, and the maximum uptakes decreased in the following order: D301 > AH-1 > GAC. All the sorption kinetic data followed the pseudo-second-order rate equation well, and AH-1 possessed the fastest sorption rate. Coexisting NaCl exerted a negative effect on the adsorption process, and relatively better salt-resistance property of AH-1 as well as GAC than that of D301 could enable AH-1 and GAC to be used effectively in removal of SA from aqueous solution at a high salinity level. Moreover, AH-1 and D301 were amenable to an entire regeneration by NaOH solution, whereas only about 50% regeneration efficiency was observed for GAC. Results of column adsorption tests reinforced the feasibility of AH-1 for potential industrial application, and SA could be readily recovered by further treatment of the concentrated regenerant solution.