A robust viologen and Mn-based porous coordination polymer with two types of Lewis acid sites providing high affinity for H2O, CO2 and NH3.

A novel porous coordination polymer [Mn(pc3)(H2O)2]·xH2O (3 < x < 4) is synthesized in water at pH = 7 using the anionic viologen-carboxylate ligand 4,4'-bipyridinium,1,1'-bis-(2,4-dicarboxyphenyl) (pc32-). Dehydration of the material results in the formation of open pores containing two types of accessible Lewis acid sites: exposed Mn2+ cations and N+ atoms of viologen units. Due to this property the PCP shows high affinity and capacity in the adsorption of H2O, CO2 and NH3. Despite the presence of strong adsorption sites this material is stable in liquid water and in gaseous NH3.

The elimination of selenium(IV) from aqueous solution by precipitation with sodium sulfide.

In this study, the removal/precipitation of selenium with sodium sulfide from initially weakly acidic sulfate solutions containing 300 mg/L of selenium(IV) at 23 °C was studied. The results showed that, below a pH of approximately 7.0, the precipitation reaction was complete at a sulfide to selenium ratio above 1.8 and less than 11 with less than 0.005 mg/L of soluble selenium remaining in solution. When the pH rose between 7.0 and 9.5 the precipitation of selenium was incomplete. Above pH 9.5 the solution turned dark red but no precipitation was apparent. The precipitation reaction started as soon as the sodium sulfide was added in the selenium-bearing solution and was completed in less than 10 min. The orange "selenium sulfide" precipitates, characterized using X-ray diffraction, scanning electron microscopy and chemical analysis, were crystalline in the form of aggregated dense particles with their sulfur/selenium molar ratio varying from 1.7 to 2.3. The precipitate was deduced to be a Se-S solid solution consisting of ring molecules of the following Se(n)S(8-n) formula, where n = 2.5-3. Long term leachability tests (>2 month equilibration) under ambient conditions at pH 7 showed the produced precipitate to be essentially insoluble (<0.005 mg/L).

[Extracorporeal circulation for warming in severe accidental hypothermia. 3 cases]. / Circulation extra-corporelle de réchauffement pour hypothermies accidentelles sévères. 3 observations.

BACKGROUND: Severe accidental hypothermia with central temperature below 28 degrees C can result from prolonged cold exposure and lead to a fatal outcome by spontaneous or provoked ventricular fibrillation. CASE REPORT: Three patients were referred for central temperature below 24 degrees C. At admission, the patients had major ventricular rythm disorders (two were in a state of circulatory arrest and the third had auricular fibrillation and circulatory collapse). Emergency care associated internal warning using extracorporeal circulation via the femoro-femoral route with a centrifuge pump. Outcome was favorable in 2 cases. DISCUSSION: Prognosis is very poor in patients who experience severe accidental hypothermia (< 28 degrees C) with circulatory collapse. Death often results from major rhythm disorders. Optimal emergency rewarming and oxygenation using extracorporeal circulatory assistance can be successful.