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1.
R. Periáñez A. Absi M. Villa H. P. Moreno G. Manjón 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):293-299
The Odiel and Tinto rivers, southwest Spain, form a fully mixed estuary. An industrial area that includes a complex dedicated
to the production of phosphate fertilizers is located by the Odiel River. This complex released phosphogypsum wastes directly
to the Odiel River and also disposed them on open air piles located by the Tinto River. Due to new EU regulations, wastes
are not directly released to the Odiel from 1998 on, although they are still disposed on the open air piles. The behavior
of 226Ra in a system like this estuary is complex, since radionuclides are affected by tidal actions and interactions with sediments
through adsorption/desorption reactions and erosion/deposition processes. A numerical 2D depth-averaged model of the estuary
has been developed, including processes mentioned above. It has been applied to reproduce experimental data measured after
a release from the industrial complex in the Odiel River and after an accidental release in the Tinto River from the gypsum
piles. The model has also been applied to simulate the self-cleaning process observed in the estuary after the direct releases
from the fertilizer complex were stopped. 相似文献
2.
J. E. Martín A. Martínez-Aguirre M. A. Respaldiza M. F. da Silva 《Journal of Radioanalytical and Nuclear Chemistry》1997,223(1-2):33-40
The studied marsh area is located at the southwest of Spain in an estuarine system formed by the confluence of the Odiel river and the Atlantic ocean. 23 samples collected in the marsh have been analysed by Thick Target Proton Induced X-ray Emission using 2 MeV protons from the 3 MV Van de Graaff accelerator of the ITN. Elemental concentrations in the samples are affected by the Atlantic ocean, the materials transported by the Odiel river and the wastes discharged by the factories of a nearby industrial area. The study has shown that certain areas of the estuary present high concentrations of P, Cu, Zn, As and Pb, which were attributed to the operation of a phosphate fertilizer factory and a Cu extraction factory. The mining activity carried out near the source of the river could be also responsible of part of this contamination. Finally, the spatial distribution of the contamination has reflected the dinamic of the Odiel river waters, due to tidal movements, into the marsh area. 相似文献
3.
H. P. Moreno A. Absi I. Vioque G. Manjón R. García-Tenorio 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(2):309-315
Experiment procedures have been developed for the determination of 226Ra and 224Ra activity concentration in solid and liquid samples collected around a non-nuclear industrial area, by liquid scintillation counting. The different radiochemical procedures developed in this work, have been adaptations of a radiochemical procedure previously used, for 226Ra and 224Ra determinations by LSC in drinking water, which was improved, refined up and adapted to the type of sample to be applied. These improved radiochemical methods have been applied to waste samples (phosphogypsum) produced by two factories which are engaged in phosphoric acid production, and to waters collected from the Odiel river, where during the sampling period a fraction of these wastes were released. 226Ra activity concentrations in the phosphogypsum ranged from 673 to 1178 Bq/kg dry weight, indicating that the wastes are particularly enriched in this radionuclide. Consequently, high 226Ra levels were easily found in the river waters analysed, especially in the neighbouring zones of the waste discharges. 相似文献
4.
Metals occur naturally in the environment and as constituents of the Earth’s crust. They have many uses, and metals such as iron, copper, and zinc are widely used in industries. Elevated levels of metals in the environment also occur as a result of human activities (municipal, residential, and traffic–related activities). A list of 15 metals chosen for this study included priority substances and those listed in the European Union Water Framework Directive 2000/60/EC. The concentrations of heavy metals in the environment are affected by several factors that must be taken into account when monitoring heavy metals released into the environment through wastewater treatment plants (WWPTs). This work examines the concentrations of metals found in WWPTs and the effects of treatment type on dissolved metal concentrations. Effluent samples were collected from the outflow of nine WWPTs in Dublin and Cork, Ireland from July 2009 to June 2011. All samples were found to contain priority metals that exceeded environmental quality standards in several cases. We present the frequency of occurrence and concentrations of metals in effluents of studied WWPTs and discuss relationships between the occurrence of heavy metals, the influence of factors such as industrial inputs, levels of treatment at WWPTs, and percentage urban area in an agglomeration. The results of this study are an indication that WWPTs may be contributing to the high levels of heavy metals found at discharge points back into river systems. 相似文献
5.
T. Nakanishi H. Fukuda M. Hirose 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):887-891
Polonium-210 in phosphoric acid has been recognized as a significant source of alpha contamination of processed Si-wafers
for memory devices of computer. In the present work, a convenient method was developed for the determination of trace210Po in phosphoric acid of high purity. For the determination,209Po was used as a yield tracer. The present method consists of (1) addition of the tracer to 5 ml aliquot of phosphoric acid
sample, (2) pH adjustment (to 2) of the sample solution to make up electrolytic solution, (3) electrodeposition for the simultaneous
achievement of Po separation and preparation of counting source on stainless-steel disc, and (4) alpha-ray spectrometry. By
the developed method, more than 95% of Po was separated from phosphoric acid sample onto counting disc. The minimum detectable
radioactivity of210Po in 5 ml of phosphoric acid was about 0.03 mBq by counting the electrodeposited alpha-activity for 10 days under a counting
efficiency of ≈30%. 相似文献
6.
Cristal Fernández-Gómez Josep M. Bayona 《International journal of environmental analytical chemistry》2013,93(15):1689-1698
The diffusive gradient in the thin films (DGT) technique was tested to measure dissolved mercury (Hg) both in laboratory aqueous solutions and in situ in river water. For this purpose, a commercial ready-to-use and specific-for-Hg DGT device was used. Each sampler consisted of a filter membrane-agarose gel as the diffusive layer and a Spheron-Thiol resin in polyacrylamide gel as the binding agent. Basic performance assays at the laboratory with this type of DGT unit confirmed the applicability of Fick's first law for DGT measurements. The diffusion coefficient of MeHg in the agarose diffusive gel was 8.50?×?10?6?cm2 s?1 at 25°C. Several field studies were also carried out in two different rivers of the Ebro River basin (NE Spain) affected by Hg wastes released by the chlor-alkali industry. Hg concentrations determined by DGT were generally much lower than the results obtained through direct measurements of the river water. In addition, the results of a time series experiment also performed in the field show that the amount of Hg accumulated in the resin does not increase at all with the exposure time. This may be explained by the underestimation of the truly dissolved Hg fraction due to the formation of a biofilm layer on the surface of the samplers, thus clogging the filter and preventing Hg species from diffusing through it. Consequently, it was demonstrated that the DGT technique presents important limitations for measuring Hg in polluted rivers characterised by a high biomass load (eutrophic), whereas its performance was demonstrated to be correct in oligotrophic waters. 相似文献
7.
D. Yalcin O. Ozcalik E. Altiok O. Bayraktar 《Journal of Thermal Analysis and Calorimetry》2008,94(3):767-771
Tartaric acid is mainly used in food, pharmaceuticals and cosmetics industries. In this study, the waste samples, which contain
tartaric acid, from the wastes of wine and grape juice industries were characterized by using TG, DSC, FTIR and XRD techniques.
HPLC was used to determine tartaric acid content of samples. The decomposition temperatures of waste samples were found to
be relatively higher compared with that of pure tartaric acid. This difference in decomposition temperatures was attributed
to the presence of potassium tartrate since high potassium content was detected with ICP-AES. 相似文献
8.
Slow pyrolysis experiments of China fir (Cunninghamia lanceolata) wood were performed in a vertical tubular furnace at various heating rates. The raw material was pretreated by impregnation with phosphoric acid solutions of various concentrations for given times. The evolution of the gaseous products CO, CO2, H2 and CH4 was analyzed online by using gas spectrometry to investigate the effect of phosphoric acid on the pyrolytic gaseous products of biomass. The addition of phosphoric acid was shown to significantly reduce the pyrolysis temperature necessary for the production of CO, CO2 and H2 gases, and the pyrolysis variables exerted an influence on the amount of the gases released. Moreover, phosphoric acid appreciably depressed the CO, CO2 and CH4 production, and promoted H2, especially when a higher heating rate was employed. This suggested that phosphoric acid catalyzed both the primary thermal decomposition of biopolymers and the secondary reactions that took place among the pyrolytic vapor products. 相似文献
9.
The acquisition of data relevant to gaseous fluoride wastes in Slovenia was started in our laboratory four years ago with the intention to find out the quantities of particular fluoride wastes and the best way for their treatment or disposition.From the collected data it is obvious that brick and ceramic industry are among the worst pollutants. The clay from the majority of Slovenian clay pits was characterized. The concentrations of fluoride wastes released from the raw bricks during the firing were measured in different temperature regions. The large fluctuations of fluoride emission values, observed in chimney gases from brick-kilns are discussed and explained. 相似文献
10.
The 235.48 nm non-resonance line of tin gives a sensitivity for AAS determination equal to that given by the most sensitive resonance line. Vaporization from a platform improves some twofold the sensitivities of all lines investigated. The atomization temperature has only slight influence on the relative sensitivities given by the non-resonance tin lines studied. Phosphoric acid shows a rather peculiar interference pattern, low concentrations (0.05%) depressing the signal, but high concentrations (1%) enhancing it. Contrary to expectation, the resonance and non-resonance lines are affected to the same extent by phosphoric acid. Platform-vaporization does not change the interference pattern of phosphoric acid. Calibration can be done by injecting various volumes of a single standard solution onto a platform coated with tantalum carbide. This method yields calibration graphs that are just as linear as those obtained with identical volume of standards of various concentrations. Some suggestions are made for further improvement of the analytical potential of non-resonance lines. 相似文献
11.
Denise M. G. Freire Geraldo L. Sant'Anna Jr. Tito Livio M. Alves 《Applied biochemistry and biotechnology》1999,79(1-3):845-855
This work presents a mathematical model that describes time course variations of extracellular lipase and protease activities for the batch fermentation of the fungus Penicillium restrictum, a new and promising strain isolated from soil and wastes of a Brazilian babassu coconutoil industry. The fermentation process was modeled by an unstructured model, which considered the following dependent variables: cells, fat acid, dissolved oxygen concentrations, lipase and protease activities, and cell lysate concentration. The last variable represents the amount of cells that has been lysed by the shear stress and natural cell death. Proteases released to the medium, as consequence of this process, enhance lipase inactivation. The model is able to predict the effects of some operation variables such as air flow rate and agitation speed. The mathematical model was validated against batch-fermentation data obtained under several operating conditions. Because substrate concentration has antagonistic effects on lipase activity, a typical optimization scheme should be developed in order to minimize these deleterious effects while maximizing lipase activity. 相似文献
12.
Raman spectroscopy of the system iron(III)-sulfuric acid-water: an approach to Tinto River's (Spain) hydrogeochemistry 总被引:1,自引:0,他引:1
Sobron P Rull F Sobron F Sanz A Medina J Nielsen CJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(4):1138-1142
Acid mine drainage is formed when pyrite (FeS(2)) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Tinto River (Huelva, Spain) is an example of this phenomenon. In this study, Raman spectroscopy has been used to investigate the speciation of the system iron(III)-sulfuric acid-water as an approach to Tinto River's aqueous solutions. The molalities of sulfuric acid (0.09 mol/kg) and iron(III) (0.01-1.5 mol/kg) were chosen to mimic the concentration of the species in Tinto River waters. Raman spectra of the solutions reveal a strong iron(III)-sulfate inner-sphere interaction through the nu(1) sulfate band at 981 cm(-1) and its shoulder at 1005 cm(-1). Iron(III)-sulfate interaction may also be facilitated by hydrogen bonds and monitored in the Raman spectra through the symmetric stretching band of bisulfate at 1052 cm(-1) and a shoulder at 1040 cm(-1). Other bands in the low-frequency region of the Raman spectra are attributed to the hydrogen-bonded complexes formation as well. 相似文献
13.
《Arabian Journal of Chemistry》2023,16(5):104699
Pharmaceuticals are a unique class of emerging contaminants owing to their intrinsic ability to induce physiological effects on man and animals at low concentrations. Pharmaceuticals are released into the environment via diverse routes; human and animal wastes are the major sources. The persistence and mode of action of pharmaceuticals in the environment make them a major concern. Among methods available for wastewater treatment, the adsorption technique is found to be effective and easy to operate. The expensive nature of commercial activated carbons, however, created a limitation to the adsorption technique; hence the exploration for low-cost and sustainable adsorbents for the removal of different categories of water contaminants. Agricultural wastes offer such advantages as low-cost, abundance and eco-friendly materials in adsorbent preparation. Herein presented are the category and classes of pharmaceuticals cum the risks associated with pharmaceuticals released into the environment. The chemistry of activated carbon/agro wastes viz-a-viz suitability and potency in adsorption of different pharmaceutical waste removal were reviewed; the benefits associated with agricultural wastes usage in pharmaceutical removal have also been presented. Various challenges, gaps cum research prospects in the current field of discussion are herein presented. This work will serve as a tool for public education and enlightenment, help environmentalists make plans for envisaged threats and serve as a guide for policy makers. 相似文献
14.
The determination of 210Po in phosphoric acid reagent by alpha-ray spectrometry using extraction chromatographic resin is presented. The decontamination factors of interference elements were measured. It was observed that HCl, HNO3, ascorbic acid, thioacetamide and Cu were free from 210Po but Pb contain small amounts of 210Po. 210Po in phosphoric acid samples was ranged from <8 to 2.4 Bq/l. The detection limit of 210Po in 50 ml of phosphoric acid is 8 mBq/l with a counting time of 1 day undercounting efficiency of 30%. 相似文献
15.
Studies have been carried out on the solubility of Pu(III) oxalate by precipitation of Pu(III) oxalate from varying concentrations of HNO3/HCl (0.5–2.0M) solutions and also by equilibrating freshly prepared Pu(III) oxalate with solutions containing varying concentrations of HNO3/HCl, oxalic acid and ascorbic acid. Pu(III) solutions in HNO3 and HCl media were prepared by reduction of Pu(IV) with ascorbic acid. 0.01–0.10M ascorbic acid concentration in the aqueous solution was maintained as holding reductant. The solubility of Pu(III) oxalate was found to be a minimum in 0.5M–1M HNO3/HCl solutions containing 0.05M ascorbic acid and 0.2M excess oxalic acid in the supernatant. 相似文献
16.
Vanadium(IV) can be accurately titrated with potassium dichromate in media containing phosphoric acid of 3-12M concentration: the change in absorption of vanadium(IV) is followed in the region 660 mmicro using a red filter. It is more convenient to carry out the titration in 3M phosphoric acid because at higher concentrations chloride, nitrate, cerium(III) and manganese(II) may interfere. Photoelcetric titration is more convenient than potentiometric because the former can be made in a 3M phosphoric acid medium, whereas the latter is possible only in 12M phosphoric acid. The simultaneous differential photometric titration of iron(II) and vanadium(IV) is also possible. Conditions have been found for the photometric titration of cerium(III) and of cerium(III) plus iron(II). The titration is carried out (at 450 mmicro or with a blue filter) in about 10.5M phosphoric acid. Application of the method to a cerium mineral is considered. 相似文献
17.
R. A. Pacer 《Journal of Radioanalytical and Nuclear Chemistry》1990,139(2):255-262
The radioactive boric acid wastes generated from the nuclear power plants have been solidified with cement. One of the properties required for solidified radioactive wastes is resistance to leaching. The leachability of137Cs from solidified waste specimens prepared by various formulation has been studied according to the proposed ANS 16.1 Standard Leach Test. For the evaluation of radiological safety in the solidified radioactive waste disposal, the leachability indices have been determined from the leaching test data. The results have turned out to be 5.97–7.60, depending on formulation and solidifying matrix. 相似文献
18.
El Naggar Ahmed M. A. Ali Mohsen M. Abdel Maksoud Samir A. Taha Mohamed H. Morshedy Asmaa S. Elzoghby Amir A. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(3):741-755
Journal of Radioanalytical and Nuclear Chemistry - The ultimate usage of phosphoric acid is declared in food and fertilizers industries. Therefore, purification of commercial phosphoric from their... 相似文献
19.
Ping Zhou Z. L. Wang Y. Z. Xu Lei Zhang Y. B. Wang 《Journal of Radioanalytical and Nuclear Chemistry》1993,175(2):81-94
Uranyl luminescences in phosphoric acid system has been studied. Uranyl excited by a nitrogen laser shows single or biexponential luminescence decays in the phosphoric acid system. When the uranyl ion or phosphoric acid concentration are lower, a single exponential luminescence decay appears, whereas at higher uranyl ion or phosphoric acid concentrations, biexponential decay is observed. Time-resolved spectra of uranyl in this system are measured. The reasons of the phenomena are tentatively established. 相似文献
20.
Taiwan monazite is a unique mineral obtained from the heavy sand found in the river floor of Tzuo-suei river and En-suei river. Both rivers are flowing parallel with separated narrow area into the sea at southwestern coast of Taiwan. The characteristic of monazite is that it contains considerable rare earth elements (REEs). REEs are considered very useful elements in the local industries and scientific researches such as ceramic, semiconductors, and glass optics. In this study, chemical neutron activation analysis (CNAA) was used to determine the contents of REEs in Taiwan monazite. A few milligram of monazite was digested in the microwave oven for 25 minutes with mixed acid (conc. HNO3 and HClO4). REEs were preconcentrated by hydrated magnesium oxide and CNAA was performed. 相似文献