Separation of oil from oily wastewater by sorption and coalescence technique using ethanol grafted polyacrylonitrile

Polyacrylonitrile fiber (PANF) was modified by alcoholysis reaction and the efficiencies of the PANF and the modified polyacrylonitrile fiber (MPANF) for oil removal were investigated. Fourier transform infrared (FTIR) spectroscopy revealed that new organophilic functional groups were grafted on the fiber surface. Scanning electron microscopy (SEM) showed that the alcoholysis process made the surface of the MPANF rougher than that of the PANF. Oil sorption tests of the PANF and the MPANF for motor oil SAE 30, motor oil SAE 50, and multigrade engine oil (MEO) were carried out in batch tank (in water and in oil without water), and the MPANF showed higher oil sorption capacity compared to the PANF. Dynamic sorption of diesel oil-in-water emulsion (initial oil concentration of 630 mg/dm(3)) was investigated in coalescing bed. The experiments in the coalescing bed indicated that the MPANF could resist higher interstitial velocity, as compared to the PANF. More than 97% of oil content in the influent stream could be removed by the MPANF bed under the optimum condition. The results indicated that reuse of the PANF as oil sorbent was quite feasible.