Authors:E. Hallaba, A. Al-Suhybani, S. Al-Khowaiter, and A. El-Sadik
Phosphate treatment of carbonaceous clays increased the uptake capacity for uranium and thorium. Heat treatment up to 400°C
improved enormously the uptake property of the treated clay. These treatments failed to improve the uptake quality of argileous
clays. Strontium exchanges weakly with clays of high Ca and Mg contents but strongly with a silicoaluminium clay of low Ca
and Mg contents. A mixed bed of these two clays was found adequate for decontamination of actinides and fission products.
The thermal behaviour of wool, untreated and chlorinated to various extents, was investigated. The kinetic parameters of the water loss and pyrolysis processes were computed and, based on their values, the way chlorination treatment affects wool fibre is discussed. As it appears, the chlorination process affects the fibre only superficially and not its internal chemical composition, as the values of the kinetic parameters of the thermal decomposition of wool fibre do not seem to be influenced at all by the treatment.
Authors:H. Oudadesse, A. C. Derrien, and M. Lefloch
In biomaterial field, the introduction of new types of composites presents a great interest for orthopaedic surgeons. In this work, geopolymers which are a family of aluminosilicates were synthesised and mixed with biphasic mixture (hydroxyapatite and of tricalcic phosphate). The optimised thermal treatment causes the reduction of pH to 7 units and favours the expansion of composites. Consequently, the increasing of porosity percentage was induced. These properties offer a good opportunity for applied composite as potential osseous biomaterial. To study the consequences of thermal treatment in the initial amorphous structure of composites some physico-chemical techniques like SEM, MAS-NMR and FTIR were employed. These methods permitted to evaluate the porosity, different links in composites and contributions of different groups of Si and Al before and after thermal treatment.
Treatment of an aqueous radioactive waste solution to remove radium prior to discharge was conducted at a laboratory scale. The actual solution is mainly composed of combined radium (226Ra and228Ra) with high concentrations of manganese, iron and calcium, which are present as chlorides in dilute hydrochloric acid. Direct precipitation by sulfate anions was selected to be the more viable treatment technique. Sulfate anion concentration, free acidity, temperature and aging of the sulfate precipitate in the supernate prior to filtration are factors that were investigated for their effect on the separation efficiency. The data obtained are discussed in detail.
Sand granule are used as a filter bed in many ground water treatment stations to remove particulate matter from untreated water. A build up of radioactivity may take place on the granules. The disposal of those granules poses a significant problem. A batch technique was used to test the possibility of removing radioactivity from actual samples of the loaded sands. The study was limited to combined radium (226Ra and228Ra). Acidity, temperature, contact time and liquid-to-solid ratio were thoroughly investigated as factors affecting the treatment process. The data obtained are discussed on the basis of the experimental results.
Authors:N. Kallithrakas-Kontos and P. Maravelaki-Kalaitzaki
Energy dispersive X-ray fluorescence (EDXRF) was employed for the identification of pigments decorating Hellenistic figurines, and the assessment of the efficiency of a treatment with barium hydroxide applied to stone. Elements present in the colored areas of the figurines, as well as the treated stone was identified by EDXRF. These data together with complementary information obtained by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) led to the identification of several precious pigments. As far as the treatment efficiency is concerned, EDXRF analysis revealed that barium is unevenly distributed on the treated surface and reaches a maximum depth of 2.5 mm.
Authors:E. Park, H. Jo, H. Kim, K. Cho, and J. Jung
In order to reduce the toxicity of both raw wastewater and effluent from a rubber products factory, γ-ray treatment was applied
at different dose levels. The γ-ray treatment did not completely removed the toxicity, suggesting that there were major toxicants
other than destroyable organic compounds. Toxicity identification evaluation (TIE phase 1) was conducted to characterize major
toxicants using Daphnia magna. The suspected toxicants in both raw wastewater and effluent were mostly filterable materials and EDTA chelatable metals
and, to some degree, non-polar organic compounds. Anion-exchange removable compounds, most likely organics, were found only
in raw wastewater. Metal analyses showed that zinc and copper concentrations were above levels causing toxicity to D. magna. After 20 kGy γ-ray treatment of raw wastewater, filtrations both at pH 3 and at the initial pH (pH 3.6) showed dramatic
change (9 to 77% and 29 to 85%, respectively) in toxicity reduction, suggesting the formation of toxic filterable materials
which are stable even at acidic conditions. Unlike raw wastewater, there was no significant change in TIE results after γ-ray
treatment at 20 kGy for rubber effluent.
Authors:B. Pacewska, A. Klepańska, P. Stefaniak, and D. Szychowski
Attempt was made to evaluate the usefulness of thermoanalytical methods, combined with X-ray phase analysis and chemical analyses,
for the study of thermal decomposition of waste materials to be subjected to thermal treatment.
The object of the studies were petrochemical waste materials intended to be decomposed in a rotary furnace. Results are given
of the studies of five selected waste materials.
A direct curve simulation treatment has been worked out for the evaluation of the kinetic curves of heterogeneous isotope exchange. Based on the data obtained by a personal computer some considerations have been made on the transport processes in the fully and half exchanged sodium forms of crystalline zirconium phosphate.
Transition metal montmorillonites were saturated with benzidine (BEN) and heated gradually to 200°C, in a vacuum cell supported
by KBr windows. IR spectra were recorded before and after the thermal treatment and at various temperatures during this treatment.
X-ray diffractions were recorded before and after the thermal treatment. Hg clay shows properties similar to those of Mg and
Ca clays. In the interlayer BEN is bound to Hg through a water molecule bridge, either by proton accepting (typeA) or by proton donation (typeB). Some BEN is also protonated (typeD). Initially typeA predominates, but after the thermal treatment, when the film is rehydrated, the amounts of typesB andD increase. With Mn-, Co-, Ni-, Zn- and Cd-montmorillonite a direct coordination of the benzidine by the dehydrated metallic
cation is obtained (typeC), in addition to small amounts of typesA,B andD. During the thermal treatment water is evolved and associationsA andB are completely transformed toC. At elevated temperatures the following associations were identified in trace amounts, ammonium-amine, BEN bound to non-structured
water, hydrophobic adsorbed BEN and BEN bound to the oxygen plane (typesE, F, H andJ, respectively). During the thermal treatment of Co and Cd clays some of the benzidine was oxidized, probably to semiquinone
and quinoidal cation.