Modification of Lignin-derived Activated Carbon with Surfactants for Removal of Phenol

Abstract

Activated carbon (AC) was prepared from Kraft lignin and was modified with four surfactants of sodium lauryl ether sulfate (SLES), dodecyl benzenesulfonic acid (LABSA), cetyltrimethylammonium bromide (CTAB) and cocoamidopropyl betaine (CAPB). The structure of modified ACs were characterized with BET, SEM and FTIR spectroscopy. Then, the effects of pH, initial concentration, adsorbent dosage, and contact time on adsorption of phenol from aqueous solutions were evaluated. The results showed that the highest percentage of adsorption and resistance to saturation is achieved using batch and continuous systems for AC/CAPB at the optimum pH of 8.0. High recovery percentage was also observed for AC/CAPB when ethanol was used as a regeneration solvent. It was also found that adsorption/desorption of phenol is a pH-dependent process. It is concluded that lignin-derived AC modified with CAPB as an amphoteric surfactant performs well in removing phenol from aqueous solution in comparison with pure AC and ACs treated with cationic and anionic surfactants.