Production of biosurfactants through biodesulfurization of spent engine oil – an experimental study

Figures & data

Table 1. Characteristics of spent engine oil.

Properties	Values
I.B.P. (°C)	128
F.B.P. (°C)	352
Specific gravity (basis: density of water = 1000 kg/m^3)	915.5
Sulfur (%)	1.05
Calorific value (Cal/g)	10,878

Figure 1. FESEM view of the treated spent oil–water interface (a) and diesel oil–water interface (b).

Figure 2. Plot of specific growth rate, µ, as a function of the ratio of spent oil to aqueous phase in the small bioreactors.

Figure 3. Double reciprocal plot of inverse of initial specific growth rates against the inverse of corresponding initial sulfur concentration in spent oil.

Figure 4. Plot of the experimental values of concentrations of biomass in the reaction broth against the batch time.

Figure 5. Plot of the experimental values of sulfur concentrations in the oil phase with the batch time.

Figure 6. Plot of the experimental values of surface tension of aqueous and oil phases of bioreactor samples with batch time.

Surface tension of aqueous layer,

surface tension of spent oil layer.

Figure 7. Plots of the experimental values of emulsification index of aqueous and oil phases of bioreactor samples with batch time.

E24 aqueous layer,

E24 of spent oil layer.

Figure 8. Overlaid GC–MS chromatograms of untreated (black line) and treated (red line) spent engine oil.