Use of membrane contactors as an efficient alternative to reduce effluent ecotoxicity

Urtiaga, Ane; Abellán, María José; Irabien, Ángel; Ortiz, Inmaculada

doi:10.1016/j.desal.2005.08.011

Cited by 7 publications

(1 citation statement)

References 21 publications

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“…However, the lack of long-term stability, the need of extra emulsification and de-emulsification steps, and the higher inventory of organics are shortcomings of this configuration. ,, EPT with hollow fiber contactors was introduced as a clean alternative to perform the separation and recovery of metals present at low concentration (such as Zn, Cr, Hg, Fe, etc.) from aqueous industrial effluents − as well as in the remediation of polluted ground water from heavy metals and organic matter. − …”

Section: Introductionmentioning

confidence: 99%

Separation of Rare-Earth Elements Using Supported Liquid Membrane Extraction in Pilot Scale

Alemrajabi

Ricknell

Samak

et al. 2022

Ind. Eng. Chem. Res.

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The use of supported liquid membrane extraction for recovery and separation of rare-earth elements (REEs) has been investigated. Experiments have been carried out using the different configurations: (1) standard hollow fiber supported liquid membrane operation (HFSLM), (2) renewal liquid membrane operation (HFRLM), and (3) emulsion pertraction technology (EPT). The experiments were performed in pilot scale using a hollow fiber module with a mass transfer surface area of 8 m2. Synthetic feed solution was used with compositions based on a process for recovery of REE from an apatite concentrate. The total concentration of REE in the feed was varied from 1 to 22 mM REE and the pH was varied in the range 1.5–3.2. Di(2-ethylhexyl) phosphoric acid (D2HEPA) diluted in kerosene, 10% (v/v), was used as the organic membrane solution, and 3 M HCl was used as stripping solution. In supported liquid membrane extraction, the extraction performance is governed by both the kinetics of REE transport through the membrane and by thermodynamics. The effect of feed composition on the selectivity and transport of REE through the liquid membrane have been investigated. The results show that the liquid membrane is more selective toward the heavy REE at lower pH values and higher REE concentration. HFRLM shows a higher transport rate than HFSLM, while the HFSLM configuration gives a higher selectivity toward individual REE. The membrane performance in HFSLM configuration rapidly decays with time, while in the HFRLM and EPT configurations, the performance is much more stable. Possible mechanisms for decaying membrane performance are discussed, and gel formation is identified as being of significant importance. Gel formation is observed at an organic loading above ∼46% for Nd, 38% for Y, 46% for Dy, and 65% for Er. The work performed in this study serves as an initial step to demonstrate that HFRLM and EPT can provide stable operation and be feasible options for processing of REE liquors. A process flow diagram for the recovery of the REE, present in the apatite concentrate, in three fractions is proposed based on the results from this study.

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