Chemical Enhanced Oil Recovery Using Ionic Liquid-Based Surfactants

Critical challenges have forced the oil industry to improve chemical enhanced oil recovery (CEOR) processes using more effective materials. In this regard, ionic liquid-based surfactants (IL-based surfactants) with noteworthy features such as good interfacial activity, recyclability, environmentally friendliness, and stability at high temperatures and salinity can be considered as a significant option. While IL-based surfactants have been of interest in various fields, their applications in CEOR have not been systematically reviewed. In this frame, this chapter overviews the performance of IL-based surfactants in different portions of oil production. For this purpose, a brief explanation of the characteristics of the IL-based surfactants and their applicability in CEOR is first provided. Then, the performance of the IL-based surfactants in surfactant flooding, micellar flooding, and wettability alteration are surveyed in detail. Also, the activity of IL-based surfactants in all three regions has been monitored with the effect of the chemical structure, as well as comparing the performance of different types of IL-based surfactants. Relevantly, a comparison with conventional surfactants is also included. The crucial challenges and possible directions for the use of IL-based surfactants and the conclusions are summarized in the final section

Organic Pollutants Removal from Petroleum Refinery Wastewater with Nanotitania Photocatalyst and UV Light Emission

A real petroleum refinery wastewater, containing a range of aliphatic and aromatic organic compounds, was treated using nanotitania particles, as the photocatalyst in UV/TiO2 process. Samples were collected from the inlet point of the biological treatment unit. A conic-shape, circulating, and upward mixing reactor, without dead zone, was employed. The light source was an immersed mercury UV lamp (400 W, 200–550 nm). Optimal suspended catalyst concentration, fluid pH, and temperature were obtained at amounts of near 100 mg·L−1, 3 and 45°C, respectively. A maximum reduction in chemical oxygen demand (COD) of more than 78% was achieved after about 120 min and, hence, 72% after only 90 min. Significant pollutant degradation was also relevant under other conditions. The identification analysis of the organic pollutants, provided by means of a GC/MS, equipped with headspace injection technique, showed that different petroleum compounds were degraded with high efficiencies

Optimization of Cr(VI) Photocatalytic Reduction by UV/TiO2 : Influence of Inorganic and Organic species and Kinetic Study

Background & Aims of the Study: Chromium is widely detected in surface waters and underground waters, which usually appear as Cr(VI), and Cr(III), at sites associated with industrial activities. Cr(VI), in effluent streams with a high level of mobility and notorious mutagenic and carcinogenic toxicity; thus Cr(III) does not have much mobility in soil. So, converting it into less harmful species could be beneficial. Materials & Methods: Cr(VI) photocatalytic reduction in aqueous media was analyzed using desperately low dosages of nanoparticles of commercial titania. A directly imposed irradiation photoreactor equipped with a supersonic source was applied. The optimization of the reduction process was done using the central composite design (CCD) experimental. The residual concentration of Cr(VI) ion was determined by colorimetrically method. In addition, the impact of other factors, including water matrix and hole scavengers, also reduction kinetics were studied. Results: A quadratic equation for reduction efficiency was proposed, and the adequacy of it was evaluated by a variety of statistical methods. A maximum of 80.6% reduction in aqueous samples containing an initial concentration of Cr(VI) within the investigated optimum operating condition (TiO2 dose of 33 mg/L; pH of 2.5, T=35 and t=120 min) was obtained. Results indicate that UV irradiation alone is an acceptable method for Cr(VI) reduction maybe due to H2O2 photolytic generation. The results show Cr(VI) photoreduction was greatly enhanced by about 88.2% when NO3− was used in comparison with SO42− anion. The photoreduction enhancements with the scavengers are appeared in the following order ethylene glycol > formic acid > citric acid with relevant. Maximum reduction of 96.5% for Cr(VI) was obtained in the presence of ethylene glycol hole scavenger. The results indicated that the process rate can be presented with a pseudo-first-order kinetic model. Conclusion: The results showed, the CCD design was approximately adequate in Cr(VI) reduction, so it can be a suitable option for water quality improvement. The addition of inorganic or organic species can act as scavenging hydroxyl radicals- which are photo-generated- and valanceband holes that are on the photocatalysts of the semiconductor, and consistently, enhance the photocatalytic reduction of Cr(VI) ion

Catalytic Activation of Hydrogen Peroxide Using Highly Porous Hydrothermally Modified Manganese Catalysts for Removal of Azithromycin Antibiotic from Aqueous Solution

Hydrogen peroxide catalytic activation holds great promise in the treatment of persistent pollutants. In this study, the novel Mn-Acacair/Al, Mn-Acacarg/Al and Mn-BTCarg/Al catalysts, supported on Al2O3, were applied for rapid hydrogen peroxide activation and azithromycin antibiotic removal. The catalysts were prepared by the calcination-hydrothermal method under air or argon atmosphere. The characterization confirmed that the modification of manganese with acetylacetonate and benzene-1,3,5-tricarboxylic acid (H3BTC) O-donor ligands highly improves the catalyst porosity, amorphousity, and abundance of coordinately unsaturated sites, which facilitate the generation of reactive oxygen species. The hydrogen peroxide activation and azithromycin removal reached 98.4% and 99.3% after 40 min using the Mn-BTCarg/Al catalyst with incredible stability and reusability. Only a 5.2% decrease in activity and less than 2% manganese releasing in solutions were detected after five regeneration cycles under the optimum operating conditions. The removal intermediates were identified by LC-MS/MS analysis, and the pathways were proposed. The hydroxylation and decarboxylation reactions play a key role in the degradation reaction

Binary mixtures of HMIMPF₆ ionic liquid and n-butyl acetate cosolvent in the extraction of acetone from aqueous solutions

<p>A remarkable disadvantage of pure ionic liquids, to be used as a solvent in different processes, is their high viscosity and density. Here, n-butyl acetate was used as a cosolvent in the liquid–liquid system of {water + acetone + 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF₆) ionic liquid}. Mixtures of the ionic liquid and the cosolvent were used as the organic phase to extract acetone from aqueous phase. A drastic decrease in viscosity and a significant decrease in density of the ionic liquid were achieved in the presence of cosolvent. Accordingly, the liquid–liquid equilibrium of different provided systems was studied under temperature of 298.2 K and atmospheric pressure of 81.5 kPa. Binary phase regions and corresponding tie-lines and binodal curves were obtained for ternary and quaternary systems. Results show the extension of the binodal solubility region as well as enhancements up to 41.8% in the acetone separation factor. The tie-line data consistency was confirmed by the Othmer–Tobias and the Hand equations. Moreover, the nonrandom two-liquid model of activity coefficient was applied satisfactorily to reproduce the equilibrium data with a root-mean-square deviation of only 1.95%.</p