Chemical stability of caesium iodide deposits in air/steam atmosphere.

Iodine compounds that may be released in case of severe nuclear accident will have important radiotoxicity if they are disseminated in air. One of the most important iodine species is CsI that is deposited on the surfaces of the reactor coolant system. However, depending on the conditions, CsI can volatilize or react with oxidants to produce I2(g). Theoretical and experimental studies demonstrate that the oxidation of iodide depends on the temperature and in the presence of oxidants in the gas. It is also slightly influenced by the crystallinity of the CsI particles and the nature of the support. In case of a high temperature deposition, the iodine release started at temperature lower than 300 °C. For the CsI vapour and aerosol depositions, the iodine is detected only at temperature above 450 °C and become very important above 550 °C.

Experimental data on the characterization of hydroxyapatite synthesized from biowastes.

The purpose of the dataset is to present the morphological features, elemental composition and functional groups of hydroxyapatite (HAp) synthesized from non-separated biowastes (animal bones) by a modified facile heat treatment method up to a maximum temperature of 1100 °C. The synthesized powders were characterized using scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). These evaluations were to reveal the surface features, elemental composition and identify the functional groups of the synthesized powders. After heat treatment of the raw biowastes to 900 °C, 1000 °C, and 1100 °C (regime of heat treatment), the morphological features of the samples exhibited a more densely packed microstructure at the highest sintering temperature (1100 °C). The elemental composition as evaluated by EDX on a weight and atomic basis for all samples provided information on the calcium to phosphate transforms into apatite with a Ca/P ratio of 3.60, 2.04, 2.50 and 2.32 wt % and 2.79, 1.58, 1.94 and 1.78 at. % respectively for raw biowastes (RB) to sintered samples (HA-900, HA-1000 and, HA-1100 °C). The FTIR data showed phosphate and hydroxyl peaks in the thermally treated samples and all the samples produced characteristic stretching modes of O-H bands at about 3417 cm-1 which are noticed in all FTIR spectra of HAp.

Catalytic abatement of CO species from incomplete combustion of solid fuels used in domestic cooking.

This study reveals a first time approach to catalytic based interventions primarily on indoor air pollution emanating from commercial and household solid fuel burning in a region in Nigeria. An intensive survey of the temperatures at different locations in the common stoves used for cooking was conducted so as to ascertain temperatures suitable for catalyst efficiency and stability. Furthermore, cobalt and iron based catalysts were prepared using ultra stable Y type zeolite as supports. The synthesized catalysts were characterized for its physico-chemical properties. The catalytic efficiency of the supported catalysts was tested using simulated exhaust gases in a fix bed reactor. The study further explored real time testing of the catalyzed ceramic monolith using two different wood species. First, the best catalyst in terms of simulated exhaust testing was selected. Consequently, a small layer of zeolite Y was deposited at 3% of the monolith weight to enhance the subsequent adhesion of the best catalyst powder to the structured monolith. Then to catalyze the zeolite Y wash-coated monolith with the cobalt precursor, the dip coating technique was used. From the results, the average values of temperatures observed from the surveyed cook stoves using wood and plant residue as fuel were confirmed to be in the range of 203-425 °C which is considered suitable for catalysts activity. The Co/ZY catalyst showed approximately 100% CO conversion (T100) at 250 °C for initial CO concentration of 1000 ppm, making it the most effective, while T100 was increased to 275 °C and 325 °C for Fe/ZY and Co-Fe/ZY catalyst respectively at an exhaust residence time of 20000 h-1. The catalytic converter in real time testing for CO abatement performed well for both wood species. Only minor differences have been noticed.

Dataset on the comparison of synthesized and commercial zeolites for potential solar adsorption refrigerating system.

The purpose of this dataset is to provide a comparison between synthesized and commercial 4A and 13X type zeolites. Metakaolin produced from the calcination of beneficiated kaolin at 750 °C for 4 h was dealuminated using sulphuric acid to get the required silica to alumina ratio for the zeolite synthesis. Zeolite 4A and 13X samples were characterized along-side with the commercial variants using X-ray fluorescence (XRF), X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) and scanning electron microscopy (SEM) techniques. These analyses revealed that, the zeolites synthesized are of comparatively acceptable quality. The pore size of 120.859 nm, pore volume of 0.0065 cm3/g and surface area of 22 m2/g were obtained from BET analyses for zeolite 4A synthesized from kaolin, while the commercial zeolite 4A used as control gave pore size of 58.143 nm, pore volume of 0.2462 cm3/g and surface area of 559.13 m2/g. In the same vein, the pore size of 10.5059 nm, pore volume of 0.135847 cm3/g and surface area of 324.584 m2/g were obtained from BET analyses for zeolite 13X synthesized from kaolin, while the commercial zeolite 13X gave pore size of 7.2752 nm, pore volume of 0.135951 cm3/g and surface area of 310.0906 m2/g.