Adsorption of p-dihydroxybenzene from single, binary and ternary aqueous systems onto activated charcoal

摘要

The adsorption of para-dihydroxybenzene (p-DHB) from aqueous multi-component systems onto activated charcoal was investigated. The study involved the adsorption of p-DHB from systems containing all combinations of p-DHB, phenol and 4-ammo-1-naphthalene sulphomic acid sodium salt (ANSA) in aqueous solutions. Equilibrium isotherms were generated at three temperature values (30 degrees C, 40 degrees C and 55 degrees C). As expected for exothermic physical adsorption, the adsorption of p-DHB from the single-component system and from the binary system containing ANSA decreased with increasing temperature. However, the adsorption of p-DHB; from the binary system containing phenol increased with temperature.The effect of KCl and NaCl (at a concentration of 0.05 M) at 30 degrees C was also investigated. The adsorption of p-DHB varied from one system to another. Both salts reduced the adsorption of p-DHB from the single and binary systems. The reduction in adsorption capacity (relative to the adsorption capacity in a salt-free system) attained only ca. 35% in the case of single-solute adsorption and ca. 20% and 33% from the binary systems containing p-DHB and phenol or ANSA, respectively. In contrast, the presence of KCl or NaCl had no appreciable effect on the adsorption of p-DHB from the ternary system.