Removal and Recovery of Metals and Other Materials by Supported Liquid Membranes with Strip Dispersion

Abstract

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%.

Au(I) extraction by LIX-79/n-heptane using the pseudo-emulsion-based hollow-fiber strip dispersion (PEHFSD) technique

“…As a result, it has been difficult to scale up the application of this technique for industrial use. In view of this, Hu et al [4b], Ortiz et al [4c,4d] Ho et al [5][6][7][8], Klaassen et al [9] and Sonawane et al [10] developed pseudo-emulsion-based hollow-fiber strip dispersion (PEHFSD), which provided the system with a very good level of stability and also resulted in consistent performance. Ortiz et al [4c,4d] have performed modeling of PEHFSD system under different experimental conditions.…”

Supported liquid membranes with strip dispersion for the recovery of Cephalexin

“…Previous literature on SLM with strip dispersion has focused on the removal and recovery of heavy metals such as chromium [13], copper [14], zinc [14], cobalt [14], strontium [15], uranium [16], gold [17], and cadmium [18]. Studies have ranged from lab to pilot plant scales and have demonstrated that SLM with strip dispersion can efficiently remove metals from aqueous solutions, while also recovering them in high concentrations in the aqueous strip solution.…”

Extraction of cadmium from dilute solution using supported liquid membrane

“…In this context, different liquid membrane processes have been proved to be an effective alternative for treatment of cadmium containing effluents/wastewaters [16][17][18][19][20][21]. The supported liquid membrane (SLM) has edge over other membrane processes with respect to its high selectivity, low energy utilization [18] and has been a subject of number of recent investigations for separation of cadmium and other metal ions from wastewaters/effluents using a variety of extractants [22][23][24][25][26][27][28].…”