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91.
Traian Buzatu Gabriela Popescu Ionela Birloaga Simona Săceanu 《Waste management (New York, N.Y.)》2013,33(3):699-705
Used batteries contain numerous metals in high concentrations and if not disposed of with proper care, they can negatively affect our environment. These metals represent 83% of all spent batteries and therefore it is important to recover metals such as Zn and Mn, and reuse them for the production of new batteries. The recovery of Zn and Mn from used batteries, in particular from Zn–C and alkaline ones has been researched using hydrometallurgical methods. After comminution and classification of elemental components, the electrode paste resulting from these processes was treated by chemical leaching. Prior to the leaching process the electrode paste has been subjected to two washing steps, in order to remove the potassium, which is an inconvenient element in this type of processes. To simultaneously extract Zn and Mn from this paste, the leaching method in alkaline medium (NaOH solution) and acid medium (sulphuric acid solution) was used. Also, to determine the efficiency of extraction of Zn and Mn from used batteries, the following variables were studied: reagents concentration, S/L ratio, temperature, time. The best results for extraction yield of Zn and Mn were obtained under acid leaching conditions (2 M H2SO4, 1 h, 80 °C). 相似文献
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93.
Metal availability and uptake by sorghum plants grown in soils amended with sludge from different treatments 总被引:6,自引:0,他引:6
Several factors depending on the sludge, the soil, or the combination of both substrates, may affect element availability to plants. In this study, an assessment was done of the effect of two sludges obtained by different processes (activated sludge and facultative stabilization pond) on heavy-metal availability and uptake by sorghum plants in soils with high and low copper contents. Results obtained for DTPA-extractable metal indicated higher metal availability in sludge-amended soils. In addition, sludges caused changes in copper and zinc distribution in soil, indicating in most cases a discrete increase in the more labile metal forms. However, observed changes did not increase heavy metal concentration in plant leaves, indicating that assessment of metal availability by a chemical procedure (single extraction or metal fractionation) would not permit a good prediction of metal bioavailability. On the other hand, sludge application at a rate of 100 t ha−1 to high-copper agricultural soils would not imply greater mobility of this metal on account of a greater sorbing capacity provided by the sludges. Such results would indicate that sludges from wastewater treatment plants, meeting the standards of heavy metal contents, regardless of the process by which they were obtained, may be applied to several kinds of soil, even to high-copper soils, with no risk of increasing heavy metal bioavailability to phytotoxic levels in the short range. 相似文献
94.
95.
Jesus Silva Rodrigo Nardoto Gabriela Bielefeld Schor Tatiana da Silva Marcia Regina Farias Martinelli Luiz Antônio 《Environment, Development and Sustainability》2022,24(1):1010-1030
Environment, Development and Sustainability - Urbanization has threatened rural communities’ livelihoods worldwide, changing their agro-food systems from locally produced traditional items to... 相似文献
96.
Carlos Rosas Gerard Cuzon Cristina Pascual Gabriela Gaxiola Darwin Chay Nelda López Teresita Maldonado Pedro M. Domingues 《Marine Biology》2007,152(2):371-381
The present study was designed to evaluate the effect of a natural prey (the crab Callinectes sp.) and an artificial diet (pellet with squid paste and offered as a paste) on the survival and assimilation efficiency
of subadult octopuses with 486 g of initial live weight. In order to reach this goal, the effects of the type of diet on energetic
balance were assessed by recording ingestion rate (C), respiratory rate (R = R routine, R
rout + R apparent heat increment, R
AHI), ammonia production rate (U = U routine, U
rout + U post-prandial, U
PP) and biomass production (P) of Octopus maya during its growing process. Energy lost from faeces (H) was calculated as H=C−(U+R+P) and assimilated energy (As) as R + P. Octopuses fed an artificial diet had almost five times higher ingestion rate compared to that observed in octopuses fed
crab. However, growth rate and production (P) were high in octopuses fed crab in comparison to octopuses fed artificial diet. An inverse relation between faeces (H) and type of food was observed, indicating that animals lost 77% of the ingested energy when fed artificial diet and only
5% when fed crab. A higher assimilation and production efficiency were obtained in octopuses fed crab (P/As: 61%) than in animals fed the artificial diet (P/As: −5%). The routine O : N ratio for animals in fasting was 9.1 and 2.3 for octopuses being fed crabs and the artificial
diet, respectively. The post-alimentary O : N ratio was 3.6 and 2.2 for animals fed crabs and the artificial diet, respectively.
This indicates that animals fed on both diets rely almost exclusively on protein. Based on energy balance data, a value of
472 kJ week−1 kg−1 of live octopus was estimated as the energy needed to obtain a growth rate near 9 g day−1 (2.8% BW day−1) for O. maya subadults. The total crab biomass needed to obtain 1 kg of fed O. maya biomass was calculated. A comparison with other different energy balance measurements made in other octopus species indicates
that O. maya and Enteroctopus megalocyathus (Pérez et al. 2006) tend to be more efficient by channelling more ingested energy to biomass production (P = 69.5% of C) than O. vulgaris (P = 23% of C; Petza et al. 2006) or Paraledone charcoti (P = 4% of C; Daly and Peck 2000). 相似文献
97.
98.
Ewa M. Bem Bronisław W. Kaszper Czesław Orłowski Jerzy K. Piotrowski Gabriela Wójcik Ewa Żołnowska 《Environmental monitoring and assessment》1993,25(1):1-13
Cd, Zn, Cu, and metallothionein (MT) levels have been determined in the renal cortex and liver of 70 persons who died in Lodz and its surroundings in the years 1985–1989. The mean concentrations were: 44.9±28.6 µg Cd/g, 52.0±16.7 µg Zn/g, 2.4±1.0 µg Cu/g, 0.79±0.40 µmol Hg/g, and 3.5±1.8 µg Cd/g, 66.7±30.5 µg Zn/g, 4.9±2.1 µg Cu/g, 0.50±0.38 µmol Hg/g wet tissue in renal cortex and liver, respectively, with mean age 54.0±13.8. Smokers showed 2.4 times higher levels of Cd in the renal cortex than non-smokers. The mean body burden of Cd was 33.4±17.3 mg. Smoking increases it twofold from 22.0 mg in non-smokers to 41.8 mg in smokers.This work was supported by the grant CPBR 11.12(C-56/86) from the Institute of Rural Medicine, Lublin, Poland.Deceased. 相似文献
99.
Săcărescu Liviu Chibac-Scutaru Andreea-Laura Roman Gheorghe Săcărescu Gabriela Simionescu Mihaela 《Environmental Chemistry Letters》2023,21(1):561-596
Environmental Chemistry Letters - Pollution by toxic metals is a worldwide health issue, yet analytical methods to monitor selectively metal ions in complex media are limited. Fluorescence sensing... 相似文献
100.
dentification of groups that are similar in their floristic composition and structure (habitat types) is essential for conservation
and forest managers to allocate high priority areas and to designate areas for reserves, refuges, and other protected areas.
In this study, the use of indigenous knowledge for the identification of habitat types in the field was compared against an
ecological characterization of habitat types, including their species composition obtained by using classification and ordination
techniques for a tropical landscape mosaic in a rural Mayan area of Quintana Roo, Mexico. Plant diversity data calculated
from 141 sampled sites chosen randomly on a vegetation class’s thematic map obtained by multispectral satellite image classification
were used for this propose. Results indicated high similarity in the categorization of vegetation types between the Mayan
classification and those obtained by cluster and detrended correspondence analysis. This suggests that indigenous knowledge
has a practical use and can be comparable to that obtained by using science-based methods. Finally, identification and mapping
of vegetation classes (habitat types) using satellite image classification allowed us to discriminate significantly different
species compositions, in such a way that they can provide a useful mechanism for interpolating diversity values over the entire
landscape. 相似文献