We report on a facile and rapid microwave-assisted method for preparing a sodium-cadmium metal-organic framework (having coordinatively unsaturated sodium ions) that considerably shortens the conventional synthesis time from 5 days to 1 hour. The obtained (Na,Cd)-MOF showed an excellent volumetric CO2 adsorption capacity (5.2 mmol cm(-3) at 298 K and 1 bar) and better CO2 adsorption properties than those shown by the same metal-organic framework when synthesized following a more conventional procedure. Moreover, the newly prepared material was found to display high selectivity for adsorption of carbon dioxide over nitrogen, and good regenerability and stability during repeated CO2 adsorption-desorption cycles, which are the required properties for any adsorbent intended for carbon dioxide capture and sequestration (CSS) from the post-combustion flue gas of fossil fuelled power stations.

Functionalization of the MIL-100(Cr) metal–organic framework with alkylamines (ethylenediamine and N,N′-dimethylethylenediamine) improves carbon dioxide sorption properties, especially in the case of ethylenediamine.

Interaction between carbon dioxide and the coordinatively unsaturated Cr(III), V(III) and Sc(III) cationic centers in MIL-100(Cr), MIL-100(V) and MIL-100(Sc), respectively, was studied by means of variable-temperature infrared (VTIR) spectroscopy, a technique that affords determination of standard adsorption enthalpy (Delta H-0) and entropy (Delta S-0) from analysis of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. Delta H-0 was found to be -63, -54 and -48 kJ mol(-1) for MIL-100(Cr), MIL-100(V) and MIL-100(Sc), respectively, which are among the highest values so far reported for CO2 adsorption on metal-organic frameworks containing open metal sites. Corresponding values for Delta(0) resulted to be -210, -198, and -178J mol(-1) K-1, thus showing a positive correlation between Delta H-0 and Delta S-0. The observed values of standard adsorption enthalpy are discussed in the broader context of corresponding data reported in the literature for the adsorption of carbon dioxide on other MOFs, as well as on zeolites. (C) 2014 Elsevier Inc. All rights reserved.

Natural zeolite samples from northern Niger were studied by X-ray diffraction (XRD). The obtained results, completed with scanning electron microscopy/energy dispersive X-ray microanalysis spectrometry (SEM/EDAX) revealed the presence of analcime within the samples. Typical analcime diffraction patterns have been identified. The studied samples were found heterogeneous and contained variable amounts of quartz. No trace of other types of zeolite has been detected.

Two new flow methods, flow injection analysis (FIA) and sequential injection analysis (SIA), for the spectrophotometric determination of Cu(II) in water at trace levels have been developed and optimised. Both methods are based on the reaction with oxalic acid bis(cyclohexylidene hydrazide) (cuprizone) in alkaline media. The two procedures have been developed for the final aim to compare their performances and to offer new rapid heavy metals analysis tools, avoiding the use of extraction steps. A detailed study of the physico-chemical parameters affecting the systems performances has been carried out. The reversed FIA and sandwich SIA approaches offered the best sensitivity. In both cases, an extremely good linearity has been obtained within the range 0.06–4μgml−1 (correlation coefficient r=0.9999), whereas the observed detection limits were 0.013 and 0.004μgml−1, for FIA and SIA, respectively. Furthermore, due to the great similarity of the diffusion zones in the reaction slugs, our approach offers the opportunity to compare the two methods in analogous conditions. This SIA method, besides keeping its typical reagent saving features, offered analytical performances equivalent to those of FIA. To obtain these results, an original “stop-flow like” method was successfully employed in the SIA approach. Both methods were validated by analysis of real water samples, after copper addition, and certified reference samples of fortified and waste waters.

Pd-loaded Ce0.6Zr0.4O2 solid solutions supported on Al2O3 are investigated as catalysts for the reduction of NO by CO. The attention is focused on the role of the Ce0.6Zr0.4O2 and of the Pd dispersion on the catalytic activity. The system shows a very high activity below 500 K, which is almost independent on the Pd dispersion. The high activity is attributed to a promoting effect of the Ce0.6Zr0.4O2 on the NO conversion. Investigation of the influence of high temperature treatments disclosed a thermal stabilisation of both Ce0.6Zr0.4O2 and Al2O3 in the Ce0.6Zr0.4O2/Al2O3 system.