Ionic Liquid-Based Process Development for Cobalt Recovery from Aqueous Streams

Abstract

Using the ionic liquid [P 8888 + ][Oleate-], liquid-liquid extraction has been studied to recover Co 2+ from water. Extractionregeneration experiments were followed during five consecutive cycles with Na 2 CO 3 (aq) as regeneration solution. Over 99% of Co 2+ was extracted and using 0.7-1 M Na CO 3 (aq) the extracted Co 2+ was recovered for 99% in the form of CoCO 3 (s). Co 2+ transfer shifted from ion-pair extraction in the first cycle to ion-exchange in the successive cycles. Thus, the measurement of a single extraction-regeneration cycle is not sufficient to perceive conclusive information about the steady-state conditions of the process. In the context of the feasibility of the technology, four key aspects are addressed: extraction efficiency, recovery of the IL, loss of the IL, and the end product.

Kinetic Analysis of an Ionic Liquid-Based Metal Extraction Process Using a Single Droplet Extraction Column

“…All chemicals were used as received, without any further purification. Tetraoctylphosphonium oleate [P 8 8 8 8 ][Oleate] was synthesized according to the procedure described by E.A Othman et al, ( Othman et al, 2019 ). The aqueous phases after each extraction process were analysed by a Metrohm IC Compact 761 ion chromatograph (detection range: 0.1-80 mg/L) and a Perkin Almer Optima 5300 DV inductive coupled plasma optical emission spectrometry (ICP-OES) (detection range: 0.025 -10 mg/L).…”

“…Another important element in this study is understanding the backextraction mechanism which is usually ignored in most studies. An earlier study by Othman et al, emphasized already the necessity of selecting the right regeneration solution and understanding its behaviour since the regeneration of the extractant and the finally obtained product are key drivers for any liquid-liquid extraction process ( Othman et al, 2019 ). In order to investigate the back extraction, experiments were performed using [P 8888 ][Oleate] preloaded with 0.34 M Co.…”

“…This type of investigations is usually performed using ZnSO 4 /D 2 EHPA/Kerosene, which is recommended by the European Federation of Chemical Engineering as a standard test system ( Anari et al, 2018 ;Korb et al, 2018 ). The present study focuses on the extraction of Co due to its significant value in supporting economic growth and development next to reducing environmental impact arising from metallurgical, and mining industries ( Cheng et al, 2019 ;Othman et al, 2019 ). In this study, [P 8 8 8 8 ][Oleate] is used which demonstrates a high and selective extraction efficiency towards Co over several consecutive batch cycles ( Othman et al, 2019 ;Parmentier et al, 2015 ).…”

“…The present study focuses on the extraction of Co due to its significant value in supporting economic growth and development next to reducing environmental impact arising from metallurgical, and mining industries ( Cheng et al, 2019 ;Othman et al, 2019 ). In this study, [P 8 8 8 8 ][Oleate] is used which demonstrates a high and selective extraction efficiency towards Co over several consecutive batch cycles ( Othman et al, 2019 ;Parmentier et al, 2015 ). The presence of bulky, long-chained tetraalkylphosphonium cations and hydrophobic oleate anions minimizes the loss of IL to the aqueous phase.…”