Modeling of gadolinium recovery from nitrate medium with 8-hydroxyquinoline by emulsion liquid membrane.
The extraction equilibrium of Gd(III) from nitrate medium by 8-hydroxyquinoline (HOX) in toluene was studied. Liquid-liquid investigations were first carried out. Based on the equilibrium results, the extraction of Gd(III) from aqueous nitrate medium into an emulsion liquid membrane system (ELM) containing 8-hydroxyquinoline in toluene as extractant, HNO(3) as stripping solution, Span-80 as surfactant was studied. The stability of the prepared ELM was studied in terms of the degree of membrane breakage. The different parameters affecting the permeation of gadolinium (III) were also studied. A general permeation model for the recovery of Gd(III) by the selected membrane is presented. The internal mass transfer in the water in oil (W/O) emulsion drop, the external mass transfer around the drop, the rates of formation and decomposition of the complex at the external aqueous-organic interface were considered.
Synergistic extraction and separation of Dysprosium and Europium by supported liquid membrane
Synergistic extraction and separation of Dysprosium (Dy) and Europium (Eu) via supported liquid membrane (SLM) were investigated using mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and Bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex272). The results showed that separation of Dy and Eu was highly dependent on the pH of feed solution. Dy can be extracted more than Eu, because the equilibrium constant for Dy using the mixture of D2EHPA and Cyanex272 was greater than that for Eu. Various parameters were optimized to achieve maximum separation factor, namely feed phase pH, carrier concentration and stripping phase concentration. The membrane was stable at six cycles of operation.
Right coronary artery stenosis associated with tricuspid valve ring annuloplasty
A 70-year-old man with severe symptomatic functional mitral valve regurgitation underwent successful mitral valve repair combined with tricuspid valve ring annuloplasty. Pre-operative coronary angiography (CAG) showed no significant stenosis. One-and-a-half years later, the patient presented with an acute exacerbation of heart failure. Repeat CAG demonstrated tight stenosis in the right coronary artery (RCA) with arterial kinking that corresponded to the same point as the stenosis where the RCA is the closest to the tricuspid valve ring. The new lesion probably occurred as a consequence of the tricuspid valve ring annuloplasty.