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Membrane Water Treatment Volume 9, Number 6, November 2018 , pages 463-471 DOI: https://doi.org/10.12989/mwt.2018.9.6.463 |
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LLE and SLM studies for Pd(II) separation using a thiodiglycolamide-based ligand |
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Shweta Kumbhaj, Vandana Prabhu and Anand V. Patwardhan
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| Abstract | ||
| The present paper deals with the liquid-liquid extraction and flat sheet supported liquid membrane studies of Pd(II) separation from nitric acid medium using a novel synthesized ligand, namely, N,N,N\',N\'-tetraethyl-2,2- thiodiethanthiodiglycolamide (TETEDGA). The effect of various diluents and stripping reagents on the extraction of Pd(II) was studied. The liquid-liquid extraction studies showed complete extraction of Pd(II) in ~ 5 min. The influence of nitric acid and TETEDGA concentration on the distribution of Pd(II) has been investigated. The increase in nitric acid concentration resulted in increase in extraction of Pd(II). Stoichiometry of the extracted species was found to be Pd(NO3)2 . TETEDGA by slope analysis method. Extraction studies with SSCD solution showed negligible uptake of Pt, Cr, Ni, and Fe, thus showing very high selectivity and extractability of TETEDGA for Pd(II). The flat sheet supported liquid membrane studies showed quantitative transport of Pd(II), ~99%, from the feed (3 M HNO3) to the strippant (0.02 M thiourea diluted in 0.4 M HNO3) using 0.01 M TETEDGA as a carrier diluted in n-dodecane. Extraction time was ~160 min. Parameters such as feed acidity, TETEDGA concentration in membrane phase, membrane porosity etc. were optimized to achieve maximum transport rate. Permeability coefficient value of 2.66 x 10–3 cm/s was observed using TETEDGA (0.01 M) as carrier, at 3 M, HNO3 feed acidity across 0.2 um PTFE as membrane. The membrane was found to be stable over five runs of the operation. | ||
| Key Words | ||
| Pd(II), TETEDGA, liquid-liquid extraction, supported liquid membrane | ||
| Address | ||
| Department of Chemical Engineering, Institute of Chemical Technology, Matunga (East), Mumbai 400019, Maharashtra, India | ||
