The role of adsorbent pore size distribution in multicomponent adsorption on activated carbon

Abstract

The impact of adsorbent pore size distribution (PSD) on adsorption mechanism for the multi solute system was evaluated in this study. Anoxic and oxic adsorption equilibrium for the single solute (phenol), binary solute (phenol/2-methylphenol) and ternary solute (phenol/2-methylphenol/2-ethylphenol) systems on one granular activated carbon (GAC) F400 and two types of activated carbon fibers (ACFs), namely, ACC-10 and ACC-15, were determined. F400 has a wide PSD, while ACC-10 and ACC-15 have narrow PSD and their critical pore diameters are 8.0 Å and 12.8 Å, respectively. In single solute adsorption, the increase of adsorptive capacity under oxic conditions as compared to anoxic ones was related to the PSD of the adsorbent. Binary solute adsorption on ACC-10 and ternary solute adsorption on ACC-15 indicated no impact of the presence of molecular oxygen on the adsorptive capacity and the adsorption isotherms were well predicted by the ideal adsorbed solution theory (IAST). Significant differences between oxic and anoxic isotherms were noticed for other multicomponent adsorption systems. The narrow PSD of ACFs was effective in hampering the oligomerization of phenolic compounds under oxic conditions. Such a phenomenon will provide accurate predictions of fixed bed adsorbers in water treatment systems.