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951.
Removal of Copper and Cadmium Ions from Diluted Aqueous Solutions by Low Cost and Waste Material Adsorbents 总被引:2,自引:0,他引:2
Ulmanu Mihaela Marañón Elena Fernández Yolanda Castrillón Leonor Anger Ildiko Dumitriu Daniela 《Water, air, and soil pollution》2003,142(1-4):357-373
The sorption of copper and cadmium ions using activated carbon,kaolin, bentonite, diatomite and waste materials such as compost,cellulose pulp waste and anaerobic sludge as sorbents is reported. Equilibrium isotherms were obtained for the adsorption of these metals in single and binary solutions. Bentonite presented the highest adsorption capacities for both copper and cadmium. A competitive uptake was observed when both metals are present; copper being preferentially adsorbed by all materials with theexception of anaerobic sludge. Equilibrium data were fitted toLangmuir and Freundlich models, with satisfactory results for most of the adsorbent-metal systems studied.Of all the adsorbents studied, bentonite and compost presentedthe highest removal efficiencies, reaching 99% for copper whencadmium is also present, for initial solution concentrations ofup to 100 mg L-1. Anaerobic sludge has a greater preferencefor cadmium, even in the presence of copper, with removal efficiencies of 98% for similar concentrations to those mentioned above. 相似文献
952.
Achilli M. Zoboli A. Gács I. De Robertis U. Bianchi A. 《Water, air, and soil pollution》1997,93(1-4):285-302
This study is focused on the speciation of selected elements in oil ash. Our efforts were directed primarily to obtain information on the various forms of vanadium, chromium and nickel. One sample was characterized via its total composition and via its capacity for releasing various elements. The latter was estimated by hot water and nitric acid extractios. A rapid cold water extraction technique has been developed and utilized for sample preparation prior to aqueous speciation by high pressure ion chromatography (HPIC). Results of the HPIC measurements, in agreement with electron spin resonance (ESR) investigations performed on the solid sample, indicate that 38% of the vanadium is present as VOSO4, 58% of the chromium is Cr2(SO4)3 and 30% of the nickel is NiSO4. The pH and the redox potential values of the cold water extract support the existence of these forms. Results of a generic study with successive fractionation extractions show the probable existence of oxides, associations with organic matter and aluminosilicate minerals. 相似文献
953.
The time-course of 14CO2 formation in chernozem soil samples enriched with 1- or 2-14C-2, 4-dichlorophenoxyacetic acid (50 μg g g?1 air-dry soil) was determined during incubation at 28°C. Except for the initial phase of decomposition, when the conversion of carboxyl carbon to 14CO2 predominated over that of carbon in position 2, the rates of mineralization of the two carbon atoms of the side chain of the herbicide molecule exhibited no significant difference. The exponential phase of 14CO2 evolution lasted from the 3rd to the 21st day of incubation; a semilogarithmic plot of its time dependence was strictly linear. The mineralization activity doubling time in this phase was 89.1 ± 3.6 h with 1-14CO-2, 4-D and 85.4 ± 5. l h with 2-14CO-2,4-D. An exponential decrease in mineralization activity was observed after 21 days, probably due to substrate exhaustion. The total proportion of radioactive carbon introduced into the soil in the form of 1- or 2-14CO-2,4-D and converted into 14CO2 during 31 days of incubation was about 33%. Plate counts of bacteria increased during 35 days of incubation from 2.14 × 108 to 2.8 × 108 g?1. The proportion of bacteria capable of producing 14CO2 from the labelled herbicide increased in this period from 4.1 to 86.1%. This increase is probably directly responsible for the immediate onset of mineralization of the herbicide in soil treated previously with it or in soil inoculated with a suspension prepared from a sample previously incubated with the herbicide. 相似文献
954.
Carmen G. Méndez-García Mayra Y. Luna-Porres Maria E. Montero-Cabrera Marusia Renteria-Villalobos Bernardo Pérez-Cázares Rafael García-Tenorio 《Journal of Soils and Sediments》2016,16(7):1970-1985
Purpose
The El Granero reservoir is the last reservoir of the Rio Conchos before it joins the Rio Grande at the Mexico–USA border. This reservoir, together with the San Marcos reservoir, is located in the arid region of Chihuahua, Mexico. High, naturally occurring radioactivity levels, as well as high arsenic (As) concentrations, have been found in both reservoirs. The main goal of this research was to establish the spatial and temporal distribution of trace and radioactive elements in surface sediments and cores collected from these reservoirs.Materials and methods
Sediment cores were dated using 210Pb and 137Cs measurements and applying the constant rate of supply (CRS) model. Major, trace, and radioactive elements were determined in surface samples and three sediment cores. Radioactive elements were determined by both alpha and gamma spectrometry. Major and trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using the EPA 3051a method. Enrichment factors (EF), contamination factors (CF), and pollution load indexes (PLI) were calculated in order to identify the human impact in both reservoirs, whereas the chemical index weathering (CIW) was used to assess differences in the degree of weathering.Results and discussion
High uranium (U) enrichment (EFs?=?24.9–54.7) was observed in core layers at the San Marcos reservoir, while in surface sediments, this enrichment was lower. The high variability of lead (Pb) and As in sediment cores from the Granero reservoir was attributed to human influence. Arsenic and Pb enrichment differences between entry and exit sediment cores were explained by the filtering capabilities of the elongated shape, the topography, and the presence of plants on the reservoir’s bed. The highest PLI was found at the entrance core of the Granero reservoir.Conclusions
The natural element concentration levels of As, Pb, and U were established at the Granero reservoir. High EFs for As and Pb suggest an anthropogenic origin of these pollutants at specific time intervals. High U concentrations in the San Marcos area are explained as naturally occurring. The concentrations of As in most of the studied sediments could pose a risk to human health by As ingestion, since they are above the probable effect level (PEL).955.
J. Aguilar C. Dorronsoro E. Fernández J. Fernández I. García F. Martín M. Sierra M. Simón 《Water, air, and soil pollution》2007,180(1-4):109-118
In 1998, the pond containing the ore wastes from a pyrite mine in Aznalcóllar (SW, Spain) broke open, spilling some 36×105 m3 of acidic waters and 9?×?105 m3 of tailings containing high concentrations of As and heavy metals. The affected area was around 55 km2 of predominantly agricultural soils. After the clean-up of the tailings, many remediation actions were undertaken and the use of blocking agents to immobilize the As was one of the most extended measure. The first experiment performed was to determine the most important soil components in As adsorption under acidic conditions. A second experiment was conducted to neutralize the acidity caused by the solution coming from the tailings undergoing oxidation; an adequate liming material (sugar-refinery scum) was selected and the application rates were established. After the remediation measures, the zone was monitored for three years. A detailed study in four experimental plots located in the most polluted sector was carried out to test the influence of iron oxides in the As immobilization. The use of red soils of the area (rich in free-iron oxides Fed) was established as an appropriate material in the remediation of the area. 相似文献
956.
Fermentation of white wines in the presence of wood chips of American and French oak 总被引:2,自引:0,他引:2
Pérez-Coello MS Sánchez MA García E González-Viñas MA Sanz J Cabezudo MD 《Journal of agricultural and food chemistry》2000,48(3):885-889
Must obtained from Airén grapes was fermented in the presence of wood chips (4 and 7 g/L) of either French oak (from Vosges, central France, and Allier zones) or American oak. Fermentation yields were higher than in the control fermentations carried out in the absence of wood, and production of volatile substances during fermentation (alcohols, esters, and acetates) was also higher. The volatile substances that leached out of the wood were analyzed by GC-MS-SIR. The results showed that their concentrations depended on the type and amount of the oak; some of these substances were consumed in part by the yeasts during fermentation. A taste panel favorably assessed the wines produced by fermentation in the presence of oak chips, which retained part of the must original fruity aroma. 相似文献
957.
Improvement of table grapes quality and safety by the combination of modified atmosphere packaging (MAP) and eugenol, menthol, or thymol 总被引:1,自引:0,他引:1
Valverde JM Guillén F Martínez-Romero D Castillo S Serrano M Valero D 《Journal of agricultural and food chemistry》2005,53(19):7458-7464
Table grape is a nonclimacteric fruit that shows a rapid loss of quality during storage and is very susceptible to colonization by fungi, especially Botrytis cinerea, which is considered the most important disease of this commodity. To solve this problem, synthetic fungicides have been used, although legal restrictions and consumer's concern demand the search of other safe means. In the present paper, and as an alternative of synthetic fungicides, an active packaging to improve MAP effectiveness on preserving table grape (cv. Crimson Seedless) quality and safety was developed by the addition of 0.5 mL of eugenol, thymol, or menthol inside the packages. Packages were stored at 1 degree C for 35 days. The final gas composition inside the packages was 1.4-2.0 and 10.0-14.5 kPa of CO(2) and O(2), respectively, with no significant slight differences among treatments. Results showed that the addition of eugenol, thymol, or menthol improved the beneficial effect of MAP in terms of delaying weight loss and color changes, retarding degrees Brix/acidity ratio evolution, and maintaining of firmness. Thereafter, these treatments showed additional benefit in terms of delayed rates of rachis deterioration and berry decay. Finally, the total viable counts for both mesophilic aerobics and especially yeast and molds were significantly reduced in the grapes packaged with the natural antimicrobial compounds. All of the above effects led to maintenance of table grape quality and safety for longer storage periods (3 additional weeks as compared to controls under MAP only). 相似文献
958.
Jakub Horecký Evžen StuchlÍk Pavel Chvojka David W. Hardekopf Martin Mihaljevič Jan Špaček 《Water, air, and soil pollution》2006,173(1-4):261-272
We performed a comparative study of strongly acidified mountain streams covering 10 sites in the Czech Republic in the season 1999/2000. The aim of the study was to determine how acidification influenced macroinvertebrate community structure within a relatively narrow pH range. We focused on strongly acidified, non-humic running waters with low ionic content (pH < 4.6, total organic carbon < 10 mg l?1, specific conductivity < 100 μS cm?1) and minimum human influence in the catchment. The actual pH values ranged from 3.98 to 4.65, and concentrations of reactive aluminium ranged from 0.2 to 2.0 mg l?1. Characteristic macroinvertebrates were the stoneflies Leuctra nigra, Nemurella pictetii, and Protonemura spp.; the chironomids Corynoneura spp.; and the caddisfly Plectrocnemia conspersa – the former two stoneflies formed together 46% of total organisms. The sites were divided into three groups with use of divisive classification. Individual groups reflected similarity in water chemistry, catchment characteristics, and geographical proximity. The largest biotic difference detected by PCA was in the abundance of stoneflies, mainly Diura bicaudata and Leuctra major. The strongest correlation with this gradient was shown by pH (and associated heavy metals), followed by the distance from source. The results show that even in such narrow pH range, the number of taxa is determined by the low pH value and related high concentrations of aluminium and heavy metals. 相似文献
959.
Chemical composition and antifungal activity of essential oil of Chrysactinia mexicana gray 总被引:1,自引:0,他引:1
Cárdenas-Ortega NC Zavala-Sánchez MA Aguirre-Rivera JR Pérez-González C Pérez-Gutiérrez S 《Journal of agricultural and food chemistry》2005,53(11):4347-4349
The chemical composition of the essential oil of Chysactinia mexicana was analyzed by gas chromatography-mass spectrometry. Seventeen compounds were characterized; eucalyptol (41.3%), piperitone (37.7%), and linalyl acetate (9.1%) were found as the major components. The essential oil of leaves and piperitone completely inhibited Aspergillus flavus growth at relatively low concentrations (1.25 and 0.6 mg/mL, respectively). 相似文献
960.
Araújo CL Bezerra IW Oliveira AS Moura FT Macedo LL Gomes CE Barbosa AE Macedo FP Souza TM Franco OL Bloch-J C Sales MP 《Journal of agricultural and food chemistry》2005,53(11):4381-4387
A proteinaceous inhibitor with high activity against trypsin-like serine proteinases was purified from seeds of the tamarind tree (Tamarindus indica) by gel filtration on Shephacryl S-200 followed by a reverse-phase HPLC Vidac C18 TP. The inhibitor, called the tamarind trypsin inhibitor (TTI), showed a Mr of 21.42 kDa by mass spectrometry analysis. TTI was a noncompetitive inhibitor with a Ki value of 1.7 x 10(-9) M. In vitro bioinsecticidal activity against insect digestive enzymes from different orders showed that TTI had remarkable activity against enzymes from coleopteran, Anthonomus grandis (29.6%), Zabrotes subfasciatus (51.6%), Callosobruchus maculatus (86.7%), Rhyzopertha dominica(88.2%), and lepidopteron, Plodia interpuncptella (26.7%), Alabama argillacea (53.8%), and Spodoptera frugiperda (75.5%). Also, digestive enzymes from Diptera, Ceratitis capitata (fruit fly), were inhibited (52.9%). In vivo bioinsecticidal assays toward C. capitata and C. maculatus larvae were developed. The concentration of TTI (w/w) in the artificial seed necessary to cause 50% mortality (LD50) of larvae was 3.6%, and that to reduce mass larvae by 50.0% (ED50) was 3.2%. Furthermore, the mass C. capitata larvae were affected at 53.2% and produced approximately 34% mortality at a level of 4.0% (w/w) of TTI incorporated in artificial diets. 相似文献