Application of a mathematical model for copper permeation from a Chilean mine water through a hollow fiber-type supported liquid membrane

Extraction of Cu(II) from aqueous solutions by vegetable oil-based organic solvents

Various types of vegetable oil-based organic solvents (VOS), i.e. vegetable oils (corn, canola, sunflower and soybean oils) with and without extractants (di-2-ethylhexylphosphoric acid (D2EHPA) and tributylphosphate (TBP)), were investigated into their potentiality as greener substitutes for the conventional petroleum-based organic solvents to extract Cu(II) from aqueous solutions. The pH-extraction isotherms of Cu(II) using various vegetable oils loaded with both D2EHPA and TBP were investigated and the percentage extraction (%E) of Cu(II) achieved by different types of VOS was determined. Vegetable oils without extractants and those loaded with TBP alone showed a poor extractability for Cu(II). Vegetable oils loaded with both D2EHPA and TBP were found to be the most effective VOS for Cu(II) extraction and, thus, are potential greener substitutes for the conventional petroleum-based organic solvents.

Di(2-ethylhexyl)phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater

Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconut oil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 x 10(-9) to 8.9 x 10(-9) mol/(m2 x s) within the Cu(II) concentration range 7.8 x 10(-4)-78.6 x 10(-4) mol/L at pH of 4.0 in the feed and 12.4 x 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 x 10(-9) mol/(m2 x s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 x 10(-4) mol/L D2EHPA (membrane) in 0.5 microm pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II).

Description of transport mechanism during the elimination of copper(II) from wastewaters using supported liquid membranes and Acorga M5640 as carrier

The kinetics of copper facilitated transport through a flat-sheet supported liquid membrane is investigated, using the commercially available oxime Acorga M5640 as ionophore, as a function of hydrodynamic conditions, stripping phase composition, concentration of copper(II), and pH of the source phase and carrier concentration in the membrane phase. The performance of the system is also compared using organic diluents of different nature (aliphatic or aromatic) and against other available oxime extractants (LIX 860, LIX 622, LIX 973N and LIX 84-I). A model is presented that describes the transport mechanism, consisting of diffusion through source side aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion carrier and its metal complex through the organic membrane. The organic membrane diffusional resistance (delta(org)) and aqueous diffusional resistances (delta(aq)) were calculated from the proposed model, and their values were 9.3 x 10(-7) and 46565 s/cm, respectively. It was observed that the copper flux across the membrane tends to reach a plateau at high concentration of copper or low concentration of H+ owing to carrier saturation within the membrane and leads to a diffusion-controlled process. The values of the apparent diffusion coefficient (Dorg(a)) and limiting metal flux (Jlim) were calculated from the limiting conditions and found to be 5.2 x 10(-11) and 1.9 x 10(-9) mmol/cm2 s, respectively. The values of the bulk diffusion coefficient (Db,org) and diffusion coefficient (Dorg) calculated from the model were 4.8 x 10(-10) and 1.3 x 10(-10) cm2/s,respectively. The method had proven its feasibility to recover copper(II) from wastewaters.

Removal and recovery of metals and other materials by supported liquid membranes with strip dispersion

This paper reviews recent advances in supported liquid membranes (SLMs) with strip dispersion for removal and recovery of metals including chromium, copper, zinc, and strontium; it also discusses potential applications of SLMs for removal and recovery of other materials, including cobalt and penicillin G. The technology for chromium that we developed, not only removes the Cr(VI) from about 100-1,000 ppm to less than 0.05 ppm in the treated effluent allowable for discharge or recycle, but also recovers the chromium product at a high concentration of about 20% Cr(VI) (62.3% Na(2)CrO(4)) suitable for resale or reuse. In other words, we have achieved the goals of zero discharge and no sludge. The stability of the SLM is ensured by a modified SLM with strip dispersion, where the aqueous strip solution is dispersed in the organic membrane solution in a mixer. The strip dispersion formed is circulated from the mixer to the membrane module to provide a constant supply of the organic solution to the membrane pores. The copper SLM system that we have identified, not only removed the copper from 150 ppm in the inlet feed to less than 0.15 ppm in the treated feed, but also recovered the copper at a high concentration of greater than 10,000 ppm in the strip solution. For the zinc SLM system identified, zinc at an inlet feed concentration of 550 ppm was removed to less than 0.3 ppm in the treated feed, whereas a high zinc concentration of more than 17,000 ppm was recovered in the strip solution. For strontium removal, we synthesized a family of new extractants, alkyl phenylphosphonic acids. The SLM removed radioactive (90)Sr to the target of 8 pCi/L or lower from feed solutions of 300-1,000 pCi/L. The SLM removed cobalt from about 525 ppm to 0.7 ppm in the treated feed solution, concentrating it to at least 30,000 ppm in the aqueous strip solution. Concerning penicillin G recovery, the SLM removed penicillin G from a feed of 8,840 ppm and concentrated it to a high concentration of 41,011 ppm in the aqueous strip solution with a high recovery of about 93%.