Simultaneous and Synergistic Extraction of Cationic and Anionic Heavy Metallic Species by a Mixed Solvent Extraction System and a Novel Contained Liquid Membrane Device

Abstract

Many wastewaters as well as aqueous solutions used for hydrometallurgical extractions have multiple toxic heavy metals: some are present as cations; others are present as anions. This research is directed toward extracting multiple heavy metallic species simultaneously into an appropriate mixed solvent and then recovering and concentrating such heavy metals into appropriate aqueous stripping solutions. Heavy metals of interest are Cu(II), Cr(VI), Zn(II), Hg(II), etc. Such processes have been carried out in a nondispersive fashion in microporous hydrophobic hollow fiber membrane-based devices containing multiple sets of fibers. The results will be presented, and the basis of the observed synergism will be discussed. The advantages of such extraction-stripping processes will be pointed out.

Desalination by air gap membrane distillation using a two hollow-fiber-set membrane module

“…Song et al [12] studied the performance of such heat exchangers large and small in great detail. We had introduced earlier hollow fiber modules containing two separate sets of hollow fibers: two porous hollow fibers for separation via contained liquid membrane (for gas separation, Majumdar et al [13]; for liquid separation, Sengupta et al [14]); two nonporous hollow fibers for gas separation via internal staging (Sidhoum et al [15]); two porous hollow fibers for synergistic solvent extraction of two separate heavy metals into two separate organic extractants from one aqueous feed solution (Yang et al [16]). Large two fiber set based hollow fiber modules have been built and commercialized following these early studies [17].…”

Extractive removal of chromium (VI) from industrial waste solution

“…This decrease in Cr (VI) extraction may be due to the change in composition of the extracted species. Thus, only a limited number of potential extractant such as, [13][14][15]. Several workers [16,17] studied the Cr extraction with tri-n-octylphosphine oxide (TOPO).…”

Recent advances in supported liquid membrane technology

“…Each aqueous-organic interface is immobilized at the respective fiber by applying the correct pressure difference. Modules with three sets of hollow fibers were introduced to conduct simultaneous separation of cations and anions using two different carriers and two different stripping solutions [9].…”