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Journal of Thermal Analysis and Calorimetry
Authors: D. Wyrzykowski, E. Hebanowska, G. Nowak-Wiczk, M. Makowski, and L. Chmurzyński

Introduction Citric acid, 2-hydroxypropane-1,2,3-tricarboxylic acid, is a natural compound occurring in human organisms and in plant and animal cells, generated during initial transformations in the Krebs cycle [ 1 – 3 ]. Since

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216 222 Atapattu, N. S. B. M. and Nelligaswatta, C. J. (2005): Effects of citric acid on the performance and the utilization of phosphorus and crude protein in broiler chickens

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-life, Δ sol H m , Δ sol G m , and Δ sol S m of the dissolution process were obtained. The authors also determined the half-life period of oxymatrine in citric acid solution (0.15 M) and normal saline (0.9%).This study provide a potent reference for the

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Abstract  

This study deals with an efficiency of a low dose of citric acid soil application on phytoextraction of uranium. Willow (Salix spp.) and sunflower (Helianthus annus L.) were tested in this experiment with contaminated soil. The enhancing of uranium bioaccumulation was confirmed, but in contrast to previous studies, the highest quantity of uranium was accumulated in leaves. After 5 weeks of citric acid treatment, willow was more efficient in the uptake and translocation of uranium than sunflower. The transfer coefficient calculated for leaves increased from 0.033 (control) to 0.74, or 0.56 after five doses of 5 mmol of citric acid per 1 kg of soil for willow or sunflower, respectively. The uptake characterized by the total U content achieved 88 and 108 mg kg−1 in relation to the above ground parts of sunflower and willow, respectively. Even though both plants accumulated U in their above ground parts in significant rate, they employed diverse ways to achieve it. At the end of the treatment, the physiological condition of the plants enabled us to continue this method.

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Legisa M, Gradisnik-Grapulin M: Sudden substrate dilution induces a higher rate of citric acid production by Aspergillus niger. Appl. Environment. Microbiol. 61 , 2732 (1995). Sudden substrate dilution induces a higher rate of

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Pickled cabbage in brine is one of the traditional fermented products in Turkey. The effects of salt content (6, 8, 10 or 12%) and citric acid concentration (0 or 1%) on the production of biogenic amines in Turkish type pickled cabbage were investigated. Concentrations of putrescine, cadaverine, tryptamine, spermidine, spermine, tyramine and histamine were determined in 8 pickled cabbage samples, 4 of them contained citric acid and the remaining 4 samples contained no citric acid. Numbers of LAB (lactic acid bacteria), enterobactericeae and halophilic microorganisms of samples were determined during fermentation. Amounts of biogenic amines in samples containing 6, 8 or 10% salt and 1% citric acid were found lower than those in samples without citric acid. On the other hand, the highest concentrations of biogenic amines were observed in the sample containing 10% salt and no citric acid (P<0.05). There was a correlation between amounts of biogenic amines and numbers of LAB. Pickled cabbages supplied from the markets had small amounts of biogenic amines.

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Abstract  

In the present work the LaCoO3 formation from gel precursors obtained by water-based sol–gel method with citric acid was studied. As precursors La and Co nitrates were used. The obtained gels were analyzed by TG/DTA and TG/AGE. The decomposition of the gels takes place in two main steps with the evolution of the same volatile compounds (H2O, CO2 si NO2) leading to the conclusion that two types of bonding of the components in the gels occurred. The decomposition of the gels takes place up to 400 °C. The gels thermally treated at 600 °C lead to single pure perovskite rhombohedral phase of lanthanum cobalt oxide (LaCoO3).

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Abstract  

High-level liquid waste from fast reactor fuel reprocessing stream contains significant quantities of lanthanides and trivalent minor actinides. The lanthanides and minor actinides (MA) have been separated from the fast reactor high-level liquid waste (FR-HLLW) using TRUEX solvent, which is a mixture of 0.2 M octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO)-1.2 M tri-n-butylphosphate (TBP) in n-dodecane. A new stripping composition, 0.1 M HNO3 and 0.1 M citric acid (CA), has been employed for back extraction of them from the TRUEX solvent. In order to separate lanthanides from actinides present in the strip solution, the extraction behavior of 241Am(III) and (152+154)Eu(III) from CA–HNO3 medium by a solution of bis-2-ethylhexylphosphoric acid (HDEHP) in n-dodecane has been studied. Separation factors (SF = D Eu/D Am) has been reported as a function of various parameters such as pH, concentrations of HDEHP, diethylenetriamine-N,N,N′,N′′,N′′′-pentaaceticacid (DTPA), 1-octanol and TBP in this paper.

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Abstract  

This study described adsorption of uranium(VI) by citric acid modified pine sawdust (CAMPS) in batch and fixed-bed column modes at 295 K. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Koble–Corrigan and Dubinin–Radushkevich isotherm models. The results indicated that the Langmuir and Koble–Corrigan models provided the best correlation of the experimental data. The Elovish model was better to fit the kinetic process, which suggested that ion exchange was one of main mechanism. The effective diffusion parameter D i values indicated that the intraparticle diffusion was not the rate-controlling step. In fixed-bed column adsorption, the effects of bed height, feed flow rate, and inlet uranium (VI) concentration were studied by assessing breakthrough curve. The Thomas, the Yan and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The results were implied that CAMPS may be suitable as an adsorbent material for adsorption of uranium (VI) from an aqueous solution.

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Abstract  

Behavior of cadmium(II) in aqueous solutions irradiated by accelerated electrons was studied. A concentration of 8.8 × 10−4 mol L−1 of cadmium dissolved from Cd(NO3)2 requires dose of 15 kGy to be effectively removed from the system containing 1 × 10−2 mol L−1 of HCOOK as a scavenger of OH radicals. The positive effect of deaeration with N2O or N2 was observed in the range of lower doses. The addition of solid modifiers (bentonite, active carbon, zeolite, Cu2O, NiO, TiO2 and CuO) reduced the effectivity of radiation removal of cadmium. Product of irradiation is CdCO3. On the contrary, in the system with cadmium dissolved from CdCl2 radiation reduction takes place. Systems contained organic complexants (ethylene diamine tetraacetic acid–EDTA, citric acid) were also studied. The solutions of Cd(NO3)2 containing initial concentration 2.37 × 10−4 mol L−1 of CdII were mixed with 3 × 10−4 mol L−1 EDTA. In this system the efficient degradation proceeds up to 90% at a dose of 45 kGy with addition of 5 × 10−3 mol L−1 carbonate (pH 10.5). The product of irradiation is CdCO3. The presence of 1 × 10−2 mol L−1 of HCOOK in the solution is necessary for radiation removal of cadmium complexed with citric acid (1 × 10−3 mol L−1) at pH 8. With increasing concentration of HCOOK (up to 5 × 10−2 mol L−1) decreases the pH value necessary for the radiation induced precipitation of cadmium. The best result was obtained in the system containing zeolite as a solid modifier.

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