Removal Of Chromium Research Articles

Molecular Identification of Potent Chromium Reducing Bacteria Isolated from Hydrocarbon-Contaminated Soil within Sokoto Metropolis

Study’s Novelty/Excerpt This study investigates chromium reduction potential of bacteria isolated from hydrocarbon-contaminated soils in the Sokoto metropolis, a specific environment previously underexplored in this context. It uniquely identifies Brucella intermedia and Bacillus sp. as potent chromium-tolerant isolates with significant reduction efficiencies, providing new insights into the bioremediation capabilities of these strains. Additionally, the research demonstrates a high chromium removal efficacy at various concentrations, highlighting the potential application of these isolates for effective bioremediation of chromium-polluted soils and water bodies. Full Abstract Hydrocarbon-contaminated soils are recognised as reservoirs for heavy metal-utilizing bacteria due to the phenomenon of co-selection. These bacteria can have a potential in the biosorption of chromium heavy metal. This research aimed to screen the chromium reduction potential of bacteria isolated from hydrocarbon-contaminated soils. The soil samples used in this study were collected from hydrocarbon-affected sites in the Sokoto metropolis; additionally, a control sample was collected from non-polluted soil. Bacteria were isolated using standard protocols. Variable amounts of chromium were prepared using potassium monochromate (K2CrO4) and then incorporated into a nutrient broth medium. The most potent, molecularly-identified hydrocarbonoclastic bacteria were screened for chromium tolerance, and the percentage reduction in chromium content was also measured. Mean colony counts from the hydrocarbon-contaminated soil ranged from1.00×106 to 1.30×106 CFU/g while the control soil had 2.30×105 CFU/g. From the 14 strains, two, molecularly identified using NCBI BLAST as Brucellaintermedia and Bacillus sp., were shown to be the most potent chromium tolerant isolates. B. intermedia reduced Cr from an initial value of 350 mg/L to 198 mg/L within 72 hours (44 % removal efficiency). At the lowest concentration used in this study (50 mg/L), a removal efficacy of 96% was achieved. Bacillus sp. recorded the highest chromium reduction compared to Brucellaintermedia at the tested concentrations (50, 150, 250, and 350 mg/L). A 100% reduction in Cr was obtained at the 50 mg/L concentration. This study demonstrated that Bacillus sp. and Brucellaintermedia are particularly effective at reducing chromium from chromium metal solutions of different concentrations. These isolates can be used for bioremediation of chromium-polluted soils or water bodies.

Efficient removal of Chromium(VI) from wastewater based on magnetic multiwalled carbon nanotubes coupled with deep eutectic solvents

Industrial wastewater containing heavy metal Cr(VI) seriously affects the health of organisms and may even lead to cancer. Developing efficient adsorbents that can quickly separate heavy metals is crucial for treating wastewater. In this study, magnetic multiwalled carbon nanotubes (MMWCNTs) with moderate particle size and abundant surface active sites were prepared by coating multiwalled carbon nanotubes with magnetic nanoparticles. The results of FTIR, XRD, TG, VSM, BET, and EDS showed MWCNTs completely encapsulated on the surface of the magnetic nanoparticles, with a particle size of approximately 30 nm. Oxygenated groups provided abundant surface active sites and formed numerous mesopores. The response surface methodology was used to optimize the adsorbent dose, adsorption contact time and adsorption temperature, and the removal rate of Cr(VI) was more than 95%. The quasi-second order kinetics and Freundlich adsorption isotherm model explained the adsorption process to Cr(VI). MMWCNTs interacted with Cr(VI) through electrostatic attraction, reduction reactions, complexation, and other means. The extensive hydrogen bonding of the green solvent deep eutectic solvent (DES) was employed to desorb the MMWCNTs and desorption rate exceed 90%. Even after five adsorption-regeneration cycles, the adsorbent maintained a high capacity. In conclusion, these novel MMWCNTs, as efficient adsorbents paired with DES desorption, hold broad potential for application in the treatment of Cr(VI)-contaminated wastewater.

Simultaneous removal of tetracycline hydrochloride and hexavalent chromium by heterogeneous Fenton in a photocatalytic fuel cell system

In this work, a novel double-chamber system (PFC-Fenton), combined photocatalytic fuel cell (PFC) with Fenton, was constructed for tetracycline hydrochloride (TCH) and hexavalent chromium (Cr(VI)) removal and electricity production. Therein, Zn5(OH)6(CO3)2/Fe2O3/BiVO4/fluorine-doped SnO2 (ZIO/BiVO4/FTO) and carboxylated carbon nanotubes/polypyrrole/graphite felt (CCNTs/Ppy/GF) were served as photoanode and cathode, respectively. Under light irradiation, the removal efficiencies of TCH and Cr(VI) with the addition of H2O2 (2 mL) could reach 93.1% and 80.4%, respectively. Moreover, the first-order kinetic constants (7.37 × 10−3 min−1 of TCH and 3.94 × 10−3 min−1 of Cr(VI)) were 5.26 and 5.57 times as much as the absence of H2O2. Simultaneously, the maximum power density could be obtained 0.022 mW/cm2 at a current density of 0.353 mA/cm2. Therein, the main contribution of TCH degradation was ·OH and holes in anode chamber. The synergistic effect of photoelectrons, generated ·O2−, and H2O2 played a crucial role in the reduction of Cr(VI) in cathode chamber. The high-performance liquid chromatography-mass spectrometry indicated that TCH could be partially mineralized into CO2 and H2O. X-ray photoelectron spectroscope and X-ray absorption near-edge structure spectra showed that Cr(VI) could be reduced to Cr(III). After 5 times of cycling, the removal efficiencies of TCH and Cr(VI) were still greater than 70%, indicating the remarkable stability of the PFC-Fenton system. Overall, this system could remove TCH/Cr(VI) and generate power simultaneously without iron sludge formation, demonstrating a promising method to further develop PFC-Fenton technology.

Desulfovibrio-induced gauzy FeS for efficient hexavalent chromium removal: The influence of SRB metabolism regulated by carbon source and electron carriers

Biosynthetic metal sulfides showed great application prospects in the environmental treatment against high-valence metal pollutants. However, the efficiency of biosynthesis, agglomeration during the reaction process, and the formation of the passivation layer during the reduction process were always the important factors restricting its development. This study explored the composition of the culture medium to promote the growth of highly corrosive sulfate-reducing bacteria (SRB) and its metabolism to produce FeS nanoparticles (NPs). The results showed that reducing the carbon source (CS) and adding electron carriers in the culture medium effectively promoted the production of small, dispersed, and loose FeS NPs in cells. At pH = 7, 24 °C and 10 min reaction time, 0.1 g/L FeS NPs produced by SRB under the conditions of 10 % CS with 10 ppm cytochrome c medium could achieve 100 % removal efficiency of 1 mM hexavalent chromium (Cr(VI)). Under this condition, FeS NPs could be produced by intracellular metabolism in SRB cells, and environmental factors such as pH, metal cations, and Cl− had little effect on the removal of Cr(VI) by this FeS NPs. The surface proteins of FeS NPs significantly enhanced their antioxidant properties. After 7 days of natural environment exposure, the Cr(VI) removal efficiency of FeS NPs was only reduced by 16 % compared with the initial sample. This work provided an in-depth understanding of Cr(VI) removal by SRB biosynthesis of FeS and contributes to the widespread application of FeS in the future.

Removal of Chromium from Aqueous System Using Nanocellulose Prepared from Defoliated Terminalia Catappa Leaves

Nanocellulose is considered as a sustainable and renewable nanomaterial due to its abundant availability, biodegradability and biocompatibility characteristics. The study demonstrates the synthesis of nanocellulose from defoliated leaves of the Tropical Almond (Terminalia catappa) plant, abundantly available residual plant biomass and its subsequent use in eliminating Cr(VI) from the water system. The study demonstrates the preparation of nanocellulose by chemical means, employing NaOH and H2SO4 as chemical agents. Characterization techniques like FTIR, SEM, and XRD were used to study the chemical composition and morphology of the resulting nanocellulose. The characterization studies confirm the formation of nanocellulose from the plant biomass. The Cr(VI) adsorption study of the produced nanocellulose is carried out through fitting different adsorption isotherm models and kinetic models. According to the study, Cr(VI) adsorption gradually increases as time period of treatment increases. A maximum adsorption of 98.4% is attained for time period of treatment of 75 min. Overall, the study proposes mixed types of adsorption (chemisorption and physisorption) of Cr(VI) on nanocellulose. This comprehensive research contributes in developing affordable, sustainable nanobiomass from plentiful bio-waste for use in the removal of heavy metals from water streams.

Efficient chromium removal from leather industrial wastewater in batch experimental study: Green synthesis and characterization of zinc oxide nanoparticles using Ficus benghalensis extracts

The urgent need to address the severe environmental risk posed by chromium-contaminated industrial wastewater necessitates the development of eco-friendly cleanup methodologies. Utilizing the Ficus benghalensis plant extracts, the present study aims to develop green zinc oxide nanoparticles for the removal of Cr metal ions from wastewater. The leaves of Ficus benghalensis, often known as the banyan tree, were used to extract a solution for synthesizing ZnO NPs. These nanoparticles were developed with the goal of efficiently eliminating chromium (Cr) from industrial effluents. Batch studies were carried out to assess the efficiency of these synthesized ZnO NPs in treating leather industrial effluent, with aiming for optimal chromium removal. This involved measuring the nanoparticles' capacity to adsorb Cr ions from wastewater samples by comparing chromium levels before and after treatment. Removal efficiency for Cr was estimated through the batches such as optimization of pH, contact time, initial Cr concentration and sorbent dose of ZnO NPs were of the batches. These synthesized ZnO NPs were found to be successful in lowering chromium levels in wastewater to meet permissible limit. The nanoparticles exhibited their highest absorption capacity, reaching 94 % (46 mg/g) at pH 4, with a contact time of 7 hours with the optimum sorbent dose of 0.6 g/L. Hence, the excellent adsorption capabilities of these nanoparticles, together with their environmentally benign manufacturing technique, provide a long-term and efficient solution for chromium-contaminated wastewater treatment. Its novel nature has the potential to significantly improve the safety and cleanliness of water ecosystems, protecting the both i.e. human health and the environment.

Microwave-assisted magnetic biochar for removal of hexavalent chromium from aqueous solution

ABSTRACT In this study, biochars were prepared by pyrolysis of tea waste and rice husk and hexavalent chromium (Cr(VI) sorption was obtained after post-modification of biochars with magnetic iron nano/micro-particles. The maximum sorption of Cr(VI) by magnetic tea waste biochar (MTWB) was 99.9% followed by 97.36% for magnetic rice husk biochar (MTRHB) at pH 5.2. Among studied competing ions, sulfate ions (SO4 2-) considerably reduced the sorption of Cr(VI) up to ~66.5% for both biochars. The surface functional groups such as – OH, C-H, Fe-O and porous biochars structure loaded with iron nanoparticles helped in Cr(VI) adsorption by ion exchange and electrostatic interactions as indicated by FTIR, XPS and SEM-EDS data. Both Cr(III) and Cr(VI) species were observed on biochars surface confirming the Cr(VI) removal process by reduction and direct adsorption of Cr(VI) ions. Hence, this study provides an excellent option for the application of magnetic biochars to treat Cr(VI) containing wastewater.

Tailored Euler-Lagrange modelling of microfluidic solid/liquid reactive separations

Micro- and nano- sized particles display an outstanding performance in the selective capture or release of molecules after the target species is contacted. Microfluidics can hugely benefit the performance of these systems given the remarkable features it presents. In this work, to the best knowledge of the authors, the microfluidic solid/liquid selective interfacial mass transfer is tackled for the first time in a Computational Fluid Dynamics (CFD) model based on the Euler-Lagrange framework. To gain insight on the effect of describing the particles as discrete entities, another model with the same purpose has been developed under the Euler-Euler approach. To experimentally validate and test the performance of the models, the microfluidic capture of chromate ions employing amino-functionalized particles in a Y-Y shaped microdevice has been selected as case study. Both models have been successfully validated, providing a relative root-mean-square error (RRMSE) of 9.86% for the Euler-Lagrange model and 22.62% for the Euler-Euler one. The performance of both models has been tested through a set of simulations in which the residence time and the load of particles are varied. The Euler-Euler option overestimates the hexavalent chromium removal in the kinetic region up to 27.94%, although both provide equally precise equilibrium data. The prediction difference between models is more significant when higher particle loads are used. Therefore, it is concluded that the Euler-Lagrange model proves to be a reliable and highly resourceful tool to predict the behavior of microfluidic multiphasic systems in a wide range of conditions.

One-pot anchoring BaBi2O6/Bi2O3 nanoparticles on oxygen vacancy rich TiO2: Double Z-scheme nanocomposites with QDs size for elimination of wastewater pollutants

The emergence of nanostructured photocatalysts with high activity offers facile solutions for removing water pollutants. In this study, a novel double Z-scheme TiO2-x/BaBi2O6/Bi2O3 nanocomposite with QDs size of about 5.52 nm was prepared by a facile one-pot hydrothermal procedure, and its activity was studied in the photocatalytic degradation of pharmaceutical and dye pollutants. The optimized nanocomposite showed a significant efficiency in the removal of tetracycline, rhodamine B, fuchsine, methylene blue, and chromium (IV), which was 12.4, 7.38, 11.1, 10.2, and 12.1 times higher than pure TiO2-x, respectively. The presence of oxygen deficiency in the crystal lattice of TiO2-x/BaBi2O6/Bi2O3 nanocomposite played a significant role in the effectual separation of photoexcited charges, increasing reactive active sites, and capturing charge carriers. Besides, providing a short distance for the rapid migration of charges to the surface of the nanocomposite was possible with the quantum size of the catalyst particles. Enforced by the established double Z-scheme heterojunctions, the charge segregation was considerably enhanced along with maintaining their redox capability. Finally, biocompatibility tests showed the harmlessness of the treated solution for agricultural use.

Efficient removal of hexavalent chromium from wastewater using a novel sodium alginate-biochar composite adsorbent

Discharging hexavalent chromium (Cr(VI))-containing wastewater has become a critical environmental and ecological concern. Coffee grounds biochar (CGB), rich in oxygen-containing functional groups, can reduce Cr(VI) to the less toxic trivalent chromium (Cr(III)) without secondary contamination. This study developed a composite adsorbent by incorporating sodium alginate (SA) into CGB, exploiting their synergistic adsorption and ion exchange reduction effects for efficient Cr(VI) removal. The maximum adsorption capacity of SACGB, fitted by the Langmuir isotherm model, was 30.66 ± 1.89 mg/g. Under optimal conditions (pH = 2, SA: CGB mass ratio = 3:2, Cr(VI) concentration = 50 mg/L), SACGB achieved 99.79 % Cr(VI) removal from synthetic wastewater. Significant Cr(VI) reduction to Cr(III) (58.97 % removal) occurred at an SA:CGB ratio of 1:1. The adsorption mechanism involved hydrogen bonding, electrostatic interactions, and ion exchange reduction. Removal of Cr(VI) retained 93 % removal despite interference from coexisting Cu(II), Zn(II), and Ni(II) ions, and the ions promoted Cr(VI) adsorption onto SACGB. In actual wastewater, SACGB exhibited excellent Cr(VI) removal (99.26 %), meeting the Chinese industrial effluent discharge standard (0.2 mg/L). After 6 recycling cycles, SACGB demonstrated stable removal performance and contained no biotoxic components. The cost of preparation and adsorption process was analyzed and also compared with earlier studies to evaluate and highlight the economic feasibility of the adsorbent for a truly green removal method. This study highlights SACGB as an economical and efficient adsorbent with practical application potential for Cr(VI) removal from industrial wastewater.

Phytoremediation potential of duckweed (Lemna minor L.) for hexavalent chromium removal in synthetic wastewater: unveiling physiological response and defense mechanisms against excessive heavy metal uptake

Phytoremediation potential of duckweed (Lemna minor L.) for hexavalent chromium removal in synthetic wastewater: unveiling physiological response and defense mechanisms against excessive heavy metal uptake

Quaternary nitrate and chloride molten salts for the next concentrating solar power plants: Corrosion considerations for the use of AISI 304L steel

The study addresses the advancement in concentrating solar power (CSP) plants by transitioning from binary nitrate salts to nitrate and chloride quaternary salts, focusing on the corrosivity of four salts as evaluated by immersion testing of AISI 304L stainless steel. Four compositions of salts were evaluated, from solar salt to equimolar NaNO3‐KNO3‐NaCl‐KCl, up to 21 days (500 h) at 500 °C in an open atmosphere, determining the corrosion kinetics using gravimetry. The morphology, chemical composition, and microstructure of the corrosion products were characterized using XRD, FESEM-EDS, and GD-OES. Exposure to the molten salt with 0 mol% Cl‐ (Solar Salt) resulted in negligible corrosion kinetics, consistent with previous studies. The salt with 14 mol% Cl‐ caused a stable corrosion product with a corrosion rate 30 times higher than without chloride. All quaternary salts exhibited a multilayer structure of the top surface with selective chromium (Cr) removal. Specimens exposed to salts with more than 29 mol% Cl‐ displayed a similar structure with Cr and iron (Fe) removal, resulting in more brittle layers and corrosion rates 90 to 250 times higher than the salt without chloride. GD-OES analysis confirmed Cl diffusion into the oxide layer, highlighting the role of pCl2(g) and pO2(g) in driving corrosivity. Based on the results, using in salts with 29 mol% Cl‐ at 500 °C is discouraged, while using 304L with 14 mol% Cl‐ in a cold tank may be considered.

Fungus-mediated preparation of porous carbon based on wheat straw: Efficient removal of chromium and enhanced electrochemical properties

Herein, a lignocellulose-degrading fungus (Irpex lacteus) was used to solidly ferment wheat straw to enhance its performance by improving its native structure and introducing an additional nitrogen source. Subsequently, the fungal-mediated wheat straw porous carbon (IL-WSPC-700) was prepared by the NaOH-activated etching method. The results of the characterization confirmed that the fungal treatment could successfully disrupt the natural structure of the wheat straw, resulting in better etching during the subsequent alkali activation process. The IL-WSPC-700 exhibited a larger specific surface area (3452.42 m2 g−1) with more micropores, which positively impacted the adsorption of heavy metal Chromium (Cr, the oxidation number was 6) by the material, and the highest adsorption capacity (678.41 mg g−1) was observed at pH value = 1. In addition, the electrode prepared by IL-WSPC-700 had a high specific capacitance of 310.7 F g−1 at 1 A g−1 current density and maintained 95.83 % of the specific capacitance after 5000 cycles in the two-electrode system. The above experiments confirmed the success of the fungal treatment strategy, IL-WSPC-700 had excellent adsorption and electrochemical performances. This study is an attempt to design and prepare adsorbents and electrode materials using microbial hypha and agricultural wastes. It could provide a reference for the preparation of high-performance materials via the synergistic effect of microbial assistance and alkali etching.

Adsorption potential of native, acid, and ionic liquid-treated biochar derived from Prosopis juliflora towards chromium removal from simulated solutions: isotherm, kinetics, and characterization

Adsorption potential of native, acid, and ionic liquid-treated biochar derived from Prosopis juliflora towards chromium removal from simulated solutions: isotherm, kinetics, and characterization

Effects of humic acid, nitrate and sulfate on hexavalent chromium removal by abiotic and biotic zero-valent iron

Effects of humic acid, nitrate and sulfate on hexavalent chromium removal by abiotic and biotic zero-valent iron

Application of natural earth-based materials as adsorbents for the treatment of chromium (VI)-contaminated tannery wastewater: Box-Behnken and fixed-bed column optimization

This study focuses on the application of earth materials (gravel, clay, zeolite, lime rock, sea shell (Diplodonta)) as adsorbents for the removal of chromium (VI) from tannery wastewater. The removal efficiencies and adsorption capacities of chromium (VI) followed this order: pristine lime rock (63.59 %, qe: 65.5 mg/g)> pristine gravel (48.88 % and 50.4 mg/g)> pristine sea shell (39.03 %, qe: 40.2 mg/g)> pristine zeolite (38.5 %, qe: 39.7 mg/g) > pristine clay (33.55 %, qe: 34.5 mg/g). Lime rock and gravel gave the highest chromium (VI) adsorption capacities and hence, were used in subsequent experiments. Employing Box-Behnken design through response surface methodology, gravel exhibited the highest adsorption capacity (40.7 mg/g) at pH 4, and lime rock (56.1 mg/g) at pH 2, with initial chromium (VI) concentration of 150 mg/L and 11-hour contact time. Scanning electron microscopy and Brunauer–Emmett–Teller analysis showed a lack of pores on both adsorbents suggesting electrostatic attraction as the primary removal mechanism. Best-fitted models were Dubinin-Radushkevich and Temkin isotherms for lime rock and gravel, respectively, while pseudo-first-order kinetics suited both. Thermodynamics calculations showed adsorption is exothermic for lime rock and endothermic for gravel. Application of lime rock in fixed-bed column study showed the highest removal percentage and adsorption capacity (16.64 %, qe: 2.3 mg/g). Applying optimum conditions from column study to synthetic tannery wastewater achieved 63.61 % removal and adsorption capacity (qe: 12.7 mg/g) at 150 mg/L initial chromium (VI) concentration. Regeneration of the adsorbents after 3 cycles maintained strong adsorption capacity. The cost-effective, easily-prepared adsorbent underscores its potential for large-scale wastewater treatment.

Determination of parameters and kinetic evaluation for chromium (VI) removal using four resins

This research aimed to identify optimal studied variables for chromium (VI) removal using four resins (IRA 96, IRA 400, DOWEX 1x8, and LEWATIT). A 1,5-diphenylcarbazide method was used for the quantification of chromium (VI). A factorial design with triple replication at the center point was used to evaluate pH, resin dose (g/100 mL), and initial chromium (VI) concentration. The optimal values for the four resins were a pH of 3, a resin concentration of 0.15 g/100 mL of solution, and an initial concentration of 10 mg/L of chromium. Then, an ANOVA study was done to compare the resins results using a p-value <0.05. The DOWEX resin presented the highest removal percentage (98.39%) for a reaction period of 45 minutes, with an exponential model that fits a pseudo-first-order kinetics with a coefficient of determination equal to 0.967.

Efficient removal of hexavalent chromium from aqueous solutions by lanthanum crosslinked chitosan/polypyrrole composite

In this work, in order to improve the adsorption capacity of chitosan for Cr(VI), a chitosan-based composite co-modified with lanthanum and polypyrrole (CS-La-PPy) was prepared and its effectiveness in removing Cr(VI) from aqueous solution was investigated. CS-La-PPy was characterized by FT-IR, XRD, BET, SEM, EDS and XPS. The successful synthesis of CS-La-PPy was confirmed by the presence of C=C (pyrrole ring) and La-O in the FT-IR spectrum. The effects of different adsorbent materials, dosage, initial pH, coexisting ions, adsorption time and temperature on the removal of Cr(VI) were investigated by batch experiments. The removal efficiency of 50 mL Cr(VI) with concentration of 150 mg L−1 by CS-La-PPy is 95.28 % at pH=2.0, T = 298 K. The adsorption process is spontaneous, which is consistent with pseudo-second-order kinetic model and Freundlich adsorption isotherm model. The maximum adsorption capacity is 321.96 mg g−1. XPS analysis showed that the removal mechanism of Cr(VI) by CS-La-PPy was mainly based on the electrostatic adsorption between Cr(VI) and lanthanum, -NH2+, and -NH3+, the ion exchange between Cr(VI) and Cl−, the reduction of Cr(VI) to Cr(III) by PPy0 and -OH groups, and the complexation between Cr(III) ions and COO- groups. This work provides a reference for the design and preparation of efficient chitosan-based adsorption materials.

Optimization of Zeolite LTA Synthesis Parameters for Chromium Removal From Tannery Wastewater

Optimization of Zeolite LTA Synthesis Parameters for Chromium Removal From Tannery Wastewater

Non-Dispersive Extraction of Chromium(VI) by Cyphos IL102/Solvesso 100 Using the Pseudo-Emulsion-Based Strip Dispersion Membrane Operation.

The removal of chromium(VI) from an acidic (HCl) medium through non-dispersive extraction with strip dispersion (NDXSD) was investigated using a microporous PVDF membrane support in a permeation cell. The ionic liquid Cyphos IL102 (phosphonium salt) in Solvesso 100 was used as an organic phase. In NDXSD, the stripping phase (NaOH) is dispersed in the organic phase on the cell side with an impeller stirrer adequate to form a strip dispersion. This pseudo-emulsion phase (organic + strip solutions) provides a constant supply of the Cyphos IL102/Solvesso 100 to the membrane phase. Various hydrodynamic and chemical parameters, such as variation in the feed and pseudo-emulsion stirring speeds, HCl and Cr(VI) concentrations in the feed phase, and carrier concentration, were investigated. Results indicated that the best chromium(VI) transport was obtained under the following conditions: feed and pseudo-emulsion stirring speeds of 1000 min-1 and 600 min-1, respectively; an HCl concentration in the feed phase of 0.1 M; a chromium concentration of 0.01 g/L in the same phase; and carrier concentration in the organic phase in the 2-5-10% v/v range. From the experimental data, several mass transfer coefficients were estimated: a bulk diffusion coefficient of 3.1·10-7 cm2/s and a diffusion coefficient of 6.1·10-8 cm2/s in the membrane phase and mass transfer coefficients in the feed (5.7·10-3 cm/s) and membrane phases (2.9·10-6 cm/s). The performance of the present system against other ionic liquids and the presence of base metals in the feed phase were investigated.