Removal of phenol from aquatic environment by SDS-modified alumina: Batch and fixed bed studies

Alumina is a very efficient adsorbent for the removal of anionic surfactant (AS) from aqueous environment even when it is present at a very high concentration. After removal of AS the exhausted surfactant coated alumina hereafter designated as surfactant-modified alumina (SMA) posses the ability to remove organic solutes from aquatic environment through the process called adsolubilization. In this study, SMA was used for the removal of phenol from water environment. In batch study it was seen that the pH < 7 favours the removal. The removal efficiency was increased in the presence of anions and decreased a little in the presence of cations. Temperature had no effect on the removal of phenol. The column having a diameter of 2 cm, with different bed heights such as 10, 20 and 30 cm could treat 1.65, 3.66 and 5.27 l of phenol bearing wastewater with initial phenol concentration 50 mg/l and flow rate 8.5 ml/min. Time required for the bed to become exhausted after the breakthrough occurred was very short. This indicated that the adsorption zone was almost saturated at the time of exhaustion. Different column design parameters like depth of exchange zone, time required for exchange zone to move its own height, adsorption rate, adsorption capacity, etc., were calculated. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. Desorption of phenol from the SMA surface was possible using 0.25 M sodium hydroxide solution, rectified spirit and acetone.