The synthesis and characterization of a series of macroporous, strong basic anion exchangers (SBAEs), with an average pore radius higher than 50 nm, and the evaluation of their sorption properties for uranyl chlorocomplexes from HCl solutions are reported. Finely divided macroporous styrene–divinylbenzene (S–DVB) copolymers with a narrow distribution of beads sizes, diameters within the range of 90–200 μm, were prepared for this purpose with 2‐ethyl‐1‐hexanol as a porogen, at a high dilution of monomers (D ≥ 0.55 mL/mL). Chloromethyl groups were introduced with (CH2O)n/Me3SiCl as a chloromethylation agent in the presence of a Lewis acid as a catalyst (TiCl4, SnCl4, and FeCl3) in CHCl3 as a reaction medium. SnCl4 and FeCl3 gave comparable chloromethylation degrees in the same reaction conditions. TiCl4 was not efficient as a catalyst in the chloromethylation with this reagent. Diethyl‐2‐hydroxyethylamine was used as a tertiary amine to prepare SBAEs. Structural and morphological characteristics were determined after every functionalization step of the macroporous network. Both the chloromethylation, in the presence of FeCl3 as a catalyst, and the amination reactions determined a significant decrease of the pore volume, in the whole range of the nominal crosslinking degree, comparative with the starting copolymer. The specific surface area and the average pore radius varied in a different way as a function of the nominal crosslinking degree. Thus, the specific surface area increased and the average pore radius decreased after chloromethylation and amination for copolymers with a DVB content lower than 10 wt %. Small decreases of the specific surface area and the average pore radius were observed after chloromethylation and amination reactions for copolymers with a DVB content higher than 10 wt %. SBAEs were also characterized by thermogravimetric analysis and sorption capacity for uranyl chlorocomplexes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2451–2461, 2004

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One of the most important tributaries of the Danube River in Romania, the Olt River, was characterized in its middle catchment in terms of the isotopic composition using continuous flow-isotope ratio mass spectrometry (CF-IRMS). Throughout a period of 10 months, from November 2010 to August 2011, water samples from the Olt River and its more important tributaries were collected in order to investigate the seasonal and spatial isotope patterns of the basin waters. The results revealed a significant difference between the Olt River and its tributaries, by the fact that the Olt River waters show smaller seasonal variations in the stable isotopic composition and are more depleted in (18)O and (2)H. The waters present an overall enrichment in heavy isotopes during the warm seasons.

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The rate of nitrogen isotrope exchange between NO,;and NOi in aqueous solution has been measured, at low acidity, as a function of pH, [NO,;-], [NOi], and temperature. Exchange does not occur in the absence of NO, and during slow exchange processes NO and NOi remain closely similar in isotopic content. The exchange rate law is shown to be R = k[H+][HN0 2 ][N031, and the measured activation parameters are EA = 74.4±2.6kJ, AH! = 72.0±2.6kJ, AS! = -97.4±8.5JK-1 • It is concluded that there is no direct interaction pathway for nitrate-nitrite exchange, and that this process and NO-HN0 3 exchange both occur via the reversible HN0 2 disproportionation reaction, involving N 2 0. as intermediate.3570

The basic isotopic exchange reaction is responsible for the separation of ISN in the Nitrox system that between gaseous nitrogen oxides and aqueous nitric acid with a single stage separation factor ~= 1.055 for 10M nitric acid, at 25 ~ and atmospheric pressure takes place. In order to know what happens in ~5N separation at higher pressure, when the isotopic transport between two phases is improved, a stainless steel laboratory experimental plant with a 1000 mm long • 18 mm i.d. column, packed with triangular wire springs 1.8• mm 2, was utilised. At 1.5 atm (absolute), and 2.36 mlcm -2 .min -l flow rate HETP was 7% smaller than at atmospheric pressure and 1.5 times smaller flow rate. HETP at 3.14 mlcm-2.min -I flow rate and 18 atm is practically equal with that obtained at atmospheric pressure and 2 times smaller flow rate. The operation of the ISN separation plant at 1.8 atm (absolute), instead of atmospheric pressure, will permit doubling of the 10M nitric acid flow rate and of lSN production of the given column.