Highly efficient and selective extraction of strontium by N,N,N′,N′-tetracyclohexyl diglycolamide (TCHDGA) in o-nitrophenyl hexyl ether as a diluent

Efficient separation of Sr²⁺ from HNO₃ solution was achieved by using N,N,N′,N′-tetracyclohexyl diglycolamide and o-nitrophenyl hexyl ether as extractant and diluent, respectively. The experimental variables, i.e., contact time, HNO₃ concentration, NO₃⁻ concentration, extractant concentration and temperature were investigated. Loading capacity, stripping and selectivity were also examined. A further batch simulation of multistage countercurrent extraction recovered above 99.9% Sr²⁺ and gave decontamination factors as high as the magnitude of 10³ between Sr²⁺ and co-existing ions. Combined with the results from ESI-MS, FT-IR, ITC, SC-XRD, and slope analysis, the composition of extracted complex was determined, and the extraction mechanism was also presented.