Carrier mediated transport of Pd(II) from nitric acid medium using Dithiodiglycolamide(DTDGA) across a supported liquid membrane (SLM)

A novel ligand, namely, N,N,N′,N′-tetra-(2-ethylhexyl)dithiodiglycolamide (DTDGA) has been explored as a carrier across a supported liquid membrane (SLM) to study the transport behavior of Pd(II) from nitric acid medium. Almost quantitative transport of Pd(II) was observed in ~2 h time interval using 0.025 M DTDGA in n-dodecane as carrier from 4.0 M HNO3 feed solution with 0.01 M thiourea in 0.2 M HNO3 as strippant. During this time interval almost negligible transport of other fission products present in high level waste (HLW) solution was observed. Various parameters were optimized to achieve maximum transport rate viz., feed acidity, DTDGA concentration in membrane phase, membrane porosity etc. Highest permeability co-efficient value of 2.37×10−3 cm/s was observed for 0.025 M DTDGA as carrier keeping the feed acidity at 4 M HNO3 and using 0.2 µm PTFE as membrane support. The membrane was found to be stable over six cycles of operation.