SULFIDE REMOVAL FROM PETROLEUM REfiNERY WASTEWATER BY ADSORPTION ON CHEMICALLY MODIFIED ACTIVATED CARBON

Experiments were carried out to evaluate the batch adsorption of sulfur compounds from petroleum refinery wastewater on a chemically modified activated carbon (MAC). The modification technique enhances the removal capacity of carbon and therefore decreases cost-effective removal of sulfide from refinery wastewater. Different techniques have been used to characterize the modified activated carbon. Adsorption equilibrium and kinetics data were determined for sulphur removal from real refinery wastewater. The data were fitted to several adsorption isotherm and kinetics models. The Freundlich isotherm fitted well with the equilibrium data of sulfur on different adsorbents, whereas, the kinetics data were best fitted by the pseudo-second order model. The MAC adsorbent was found to have an effective removal capacity of approximately three times that of non modified carbon. Using different MAC, sulfides were eliminated with a removal capacity of 52 mg g−1. Several chemical techniques were tested for the regeneration of saturated activated carbon and it was found that HCl showed high regeneration efficiency (86%). Therefore, MAC can be utilized as an effective and less expensive adsorbent for the reduction of sulfur in refinery wastewater.