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Removal of chromium(III) from aqueous solutions by chitosan impregnated with a microemulsion was investigated. The modified chitosan showed a remarkable increase in chromium sorption capacity as compared to an untreated sample. Dynamic column experiments were performed to study the influence of pH, concentration, and the presence of others metal ions (copper and nickel) in the chromium solutions. The adsorption process is pH-dependent, and the amount of Cr(III) retained increases with increasing heavy metal initial concentration. It can be observed that the best bed efficiency was for copper, followed by chromium and then nickel. The nature of chromium(III) adsorption equilibrium at different temperatures (30, 40, and 50 °C) was investigated, and the Freundlich and Langmuir isotherm models were applied to fit the experimental data. The uptake process obeys the Langmuir isotherm. Following the adsorption step, the desorption process was carried out using several eluant solutions. The best results were obtained using strongly acidic solutions as eluants.

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In this study, the biosurfactant produced by Pseudomonas aeruginosa was evaluated in view of its ability to be used in Microbial-Enhanced Oil Recovery (MEOR). This microorganism was isolated from a soil artificially contaminated with crude oil and used to produce rhamnolipid using glycerol as the carbon source. The biosurfactant efficiently reduced water surface tension from 72 to 35.26 mN/m at its critical micelle concentration of 127 mg/L and emulsification rate (E 24) of 69% for the crude oil. Furthermore, it was demonstrated that the rhamnolipid can recover oil, even 2 months after its production, which shows that its biodegradability is not a disadvantage to the application in MEOR. The best result, for a biosurfactant concentration of 100% above the Critical Micelle Concentration (CMC) and petroleum with API gravity of 21.90, showed that the total recovery factor was 50.45 ± 0.79%, of which 11.91 ± 0.39% corresponds to MEOR.

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