One of the tertiary methods for enhanced oil recovery (EOR) is the injection of chemicals into oil reservoirs, and surface active agents (surfactants) are among the most used chemicals. Surfactants lead to increased oil production by decreasing interfacial tension (IFT) between oil and the injected water and to the wettability alteration of the oil reservoir rock. Since surfactants are predomin...

Classic methods of biosurfactant separation are difficult and require large amounts of organic solvents, thus generate high amounts of waste. This work presents and discusses in detail an original procedure to separate rhamnolipid from fermentation broth using high performance membrane techniques. Due to the unique properties of surface active agents, such as capability of forming aggregates ab...

The surfactants cesium, tetramethylammonium, tetraethylammonium, tetrapropylammonium and tetrabutylammonium dodecyl sulfates (CsDS, TMADS, TEADS, TPADS, and TBADS) have been synthesized by ion-exchange. The critical micellization concentration in the absence of added salt (cmc) has been determined at 10, 25, and 40 °C using the electrical conductivity method. The cmc was found to decrease in th...

Intradiffusion coefficients of sodium alkylsulfonates [CH3-(CH2)n-1SO-3 Na+, CnSNa] (n = 5-9, 11) in mixtures with heavy water were measured by the PGSE-NMR technique at 25 degrees C. A slope change in the experimental trends permits the determination of the critical micelle concentration (CMC). In the micellar composition range, solubilized TMS molecules were used to determine the micelle intr...

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solu...

been characterized quite well using a variety of techniques individually and in combination over the last decade. Interest in these surfactant systems stems from a broad application base. These surfactant systems, or “detergents” have found application in oil recovery due to enhanced solubility, higher cloud points, and lower Krafft points than the corresponding pure surfactant in solution. The...

The mixed micellization behaviour of amitriptyline hydrochloride (AMT) with ionic liquid (IL) 1-methyl-3-octylimidazolium hydrochloride, [C8mim][Cl], have been investigated using electrical conductivity, at different temperatures. The non-ideal behaviour (i.e., synergistic interaction) of AMT-[C8mim][Cl] binary mixtures, explained by the deviations in critical micelle concentration (cmc) from i...