Reactivation of Spent Activated Carbon Using Sodium Hydroxide for Industrial Wastewater Treatment at the Mellitah Oil and Gas Complex, Libya

Abstract

This study aimed to evaluate the effectiveness of reactivating spent activated carbon and reusing it in industrial wastewater treatment at the Mellitah Oil & Gas Complex in western Libya. The significance of this study lies in its potential to reduce the operational costs associated with purchasing new activated carbon and disposing of spent carbon, thereby enhancing the economic and environmental sustainability of industrial processes. Spent activated carbon was regenerated using sodium hydroxide (NaOH) solutions at concentrations of 10% and 15% under various temperature conditions with a contact time of 30 min. The adsorption performance of the regenerated carbon was assessed by analyzing key industrial wastewater quality parameters, including oil and grease (O&G), pH, and chemical oxygen demand (COD). The results demonstrated that reactivation with a 15% sodium hydroxide solution achieved higher oil removal efficiency than the 10% concentration. The reactivated carbon treated at 50°C exhibited the highest removal efficiency, reaching 98.60%. In contrast, the activated carbon reactivated with 10% sodium hydroxide showed superior performance in pH adjustment, with an average pH value of approximately 6.1. Regarding COD removal, the results indicated comparable performance between the activated carbon reactivated with 10% and 15% sodium hydroxide, with no significant differences observed in the removal efficiency of organic pollutants. The study concludes that the reactivation of spent activated carbon using sodium hydroxide represents a promising approach for its reuse in industrial wastewater treatment, achieving high efficiency in oil removal. The study further recommends conducting a comprehensive economic and environmental assessment to compare different reactivation techniques while considering the entire life cycle of activated carbon, from production and utilization to reactivation and final disposal.