Purification of crude oil contaminated water using fly ash/clay

The adsorbent used in this study were characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET)/Barrett-Joyner-Halenda (BJH) and Fourier transform infrared (FTIR) techniques. Filtration experiments were used as the purification technique, while fly ash, clay, and their mixtures (fly ash:clay; 1:1, 1:2 and 2:1 ratios) were used as adsorbents. The fly ash showed higher pore size with lower surface area than clay. Siloxane, silicate, and silanol were the major functional groups that exist in the adsorbents. Clay consisted of muscovite, orthoclase, quartz and kyanite, while fly ash consisted of mullite, sillimanite, quartz and hematite. Contaminated water was simulated and allowed to have contact with the adsorbents at contact times of 10–30 min. Total dissolved solid (TDS), pH, and turbidity of water before and after filtration was determined and recorded. The increase in the composite ratio showed an increase in pH, TDS, conductivity, and a decrease in turbidity removed from the water. The results obtained from the tests further showed that 1:2 ratio was the most efficient with highest turbidity removal of 97.6% in 20 min. Ratio 1:2 also showed an average turbidity removal of 86.9% in 10 min and an optimal pH value of 8. The TDS values for this ratio were lower than 500 mg/L. The composite with 2:1 ratio also had optimum turbidity removal of 96.7% in 15 min with a pH value of 10.45 and TDS value of 763.5 mg/L. Clay was observed to have better purification capacity than fly ash.