English abstract
Oil wastewater (OWW) is separated from oil during transport from the field to Mina Al Fahl for exportation. OWW is partially treated using gravity separation. Two samples of OWW were received from PDO (Mina Al Fahl), one after the gravity separation treatment called 'outlet' and one before that treatment called 'inlet' for treatment using adsorption. Activated carbon (AC) was prepared from date palm leaflets using phosphoric acid activation. AC was oxidized using nitric acid to produce oxidized activated carbon (OAC). OAC was functionalized via amide coupling to produce lipophilic activated carbons (LACs) using n-alkyl amine surfactants: n-ethyl amine (LACE), n-butyl amine (LACB) and n-octyl amine (LACO). AC possesses high surface area (361 m2/g). It possesses less carbon-oxygen functional groups on its surface with slightly higher mesoporosity. Upon oxidation and surface functionalization, the surface area tremendously decreased and microporosity diminished. Total organic carbon (TOC) and chemical oxygen demand (COD) of both samples were tested for their removal on the different carbons at different initial pH, time and carbon mass. pH 7, the pH of OWW, was selected for the removal of organics from OWW in kinetic and equilibrium studies. Equilibrium time was found to be ~ 10 hours for LACs, however for AC more than 24 hours was required for reaching equilibrium. Dissolved organics diffusion on LACs was faster than on AC. Adsorption data were found to follow the pseudo second order kinetic model. By increasing the amount of carbon mass, removal percentage of both TOC and COD for both samples of OWW has increased. The adsorption of TOC and COD follow the order: LACE > LACB > AC> LACO >OAC. As the n-alkyl chain increases the adsorption decreases and this is probably because the long chains attract each other and can be entangled together limiting the access for active sites on the surface. From this study, LACs, particularly with short immobilized n-alkyl chains, show better performance for dissolved organics removal than activated carbons.
