Emulsion ionic liquid membranes (EILMs) for removal of Pb(ii) from aqueous solutions

Abstract

Ionic liquids (ILs) are playing increasingly important roles in the membrane separation processes. The present manuscript discusses the removal of Pb(II) ions from aqueous solution using an emulsion ionic liquid membrane (EILM) process. Initially, the emulsion liquid membrane (ELM) was prepared by stirring strip phase (sulphuric acid) and organic phase (surfactant: span 80, extractant: D2EHPA, diluent: hexane) together under high speed agitation. Note that, the parameters of the ELM process such as emulsification speed, pH of the feed phase, treat ratio, extractant and surfactant concentrations were studied for the maximum removal of Pb(II) ions. The role of IL was explored by adding hydrophobic IL, octylmethylimidazole hexafluorophosphine ([OMIM][PF 6 ]), in the organic phase. The performance of ELM with and without IL was compared on the basis of stability, enrichment factor and the removal efficiency for Pb(II). The results showed that the percentage of Pb(II) extraction was complete by the emulsion membrane with IL (EILM) in comparison to the 97% achieved by neat ELM. Further, the stability and the enrichment factor of the EILM were found to be 2-3 times greater than that of the ELM. The FT-IR spectroscopic analysis revealed that bond interactions between IL and membrane phase components avoided the coalescence of internal phase droplets and enhanced the emulsion stability. The results obtained in this work support the use of the IL [OMIM][PF 6 ] as both a stabilizer and carrier for the overall improvement of the ELM process.

Extraction of Ce(iv) from sulphuric acid solution by emulsion liquid membrane using D2EHPA as carrier

“…It has been reported that various ions can be successfully extracted by ELM. [18][19][20][21][22][23] Few papers have been reported on the extraction of lanthanides by ELM. [24][25][26] Teramoto et al 27 and Tang and Wai 28 explored the extraction and transport of trivalent lanthanides by liquid membrane systems.…”

Preparation and in vitro evaluation of hydrophobic‐modified montmorillonite stabilized pickering emulsion for overdose acetaminophen removal

“…A multiple emulsion with an internal phase (NaOH; MgSO 4 ), organic phase (Parleam 4; Abil EM90), and external phase (Lutrol F127) has been reported as a relatively efficient and safe treatment in vitro for paraquat poisoning . In fact, in view of the large specific surface areas and high selectivity, the technique of emulsion with organic surfactants has been investigated in many fields such as (i) the removal of metal ions and recovery of organics in waste, (ii) the controlled release of drugs, and (iii) the removal of toxins from organisms . Nevertheless, because of the poor thermodynamic stability, probable toxicity, and low biocompatibility, such emulsions containing organic surfactants have limited applications, especially in pharmacy and food industries.…”

Optimization of Emulsion Liquid Membrane for Lead Separation from Aqueous Solutions

“…Lead contamination in an environment is a very important problem worldwide due to its highly toxic and nonbiodegradable nature [1]. The industrialized activities using lead such as batteries, photographic materials, pigments, fuels and explosives have contaminated the environment.…”

“…Various destructive effects have been found as a result of heavy metal pollution. Therefore, a limit of 0.01 ppm for Pb in the surface water was recognized by WHO and USEPA [1]. There are several methods for treating Pb discharges such as smelting [2], adsorption [3], ion exchange [4], and liquid-liquid extraction [5].…”

“…Moreover, the interfacial film of the surfactant molecules will expand over a higher number of water droplets causing a decrease in density. The interfacial film will be no longer resistant against collisions, and hence, increasing coalescence rate [1]. Taguchi technique is a unique and powerful optimization tool that allows optimization with minimum number of experiments.…”