Black carbon (BC) is a promising sediment amendment, as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility, but its reliability when used for the removal of pollutants in natural sediments still needs to be evaluated. For example, the ageing process, resulting in changing of surface physicochemical properties of BC, will decrease the adsorption capacity and performance of BC when applied to sediment pollution control. In this study, how the ageing process and BC proportion affect the adsorption capacity of BC-sediment systems was modelled and quantitatively investigated to predict their adsorption capacity under different ageing times and BC additions. The results showed that the ageing process decreased the adsorption capacity of both BC-sediment systems, due to the blockage of the non-linear adsorption sites of BC. The adsorption capacity of rice straw black carbon (RC)-sediment systems was higher than that of fly ash black carbon (FC)-sediment systems, indicating that RC is more efficient than FC for nonylphenol (NP) pollution control in sediment. The newly established model for the prediction of adsorption capacity fits the experimental data appropriately and yields acceptable predictions, especially when based on parameters from the Freundlich model. However, to fully reflect the influence of the ageing process on BC-sediment systems and make more precise predictions, it is recommended that future work considering more factors and conditions, such as modelling of the correlation between the adsorption capacity and the pore volume or specific surface area of BC, be applied to build an accurate and sound model. 相似文献
Water pollution is a global environmental problem that affects the ecosystem severely. Treatment of oily wastewater and organic pollutants is a major challenge that waits to be solved as soon as possible. Adsorbing is one of the most effective strategies to deal with this problem. Three-dimensional (3D) porous adsorbents made of graphene or graphene-based nanomaterials skeletons had attracted more attention in wastewater treatment because of their large surface area, high porosity, low density, high chemical/thermal stability, and steady mechanical properties, which allow different pollutants to easily access and diffuse into 3D networks of adsorbents. This work presents an extensive summarization of recent progress in the synthesis methodologies and microstructures of 3D graphene foams and 3D graphene-based foams and highlights their adsorption performance for oils and organic solvents. Advantages and disadvantages of various preparation strategies are compared and the corresponded structures of these skeletons are studied in detail. Furthermore, the effects of the structures on oil-adsorption properties are analyzed and some data and parameters of the oil-adsorption properties are listed and studied for easier comparison. At last, the future research directions and technical challenges are prospected, which is hoped that the researchers will be inspired to develop the new graphene-based adsorbents.
Electronic tags were used to examine the biology of Atlantic bluefin tuna (Thunnus thynnus L.) on their breeding grounds in the Gulf of Mexico (GOM). The hypothesis that movement patterns, diving behavior, and thermal
biology change during different stages of the breeding migration was tested. Mature Atlantic bluefin tuna tagged in the western
Atlantic and the GOM, were on their breeding grounds from February to June for an average of 39 ± 11 days. The bluefin tuna
experienced significantly warmer mean sea surface temperatures (SSTs) within the GOM (26.4 ± 1.6°C) than outside the GOM (20.2 ± 1.9°C).
As the bluefin tuna entered and exited the GOM, the fish dove to daily maximum depths of 568 ± 50 and 580 ± 144 m, respectively,
and exhibited directed movement paths to and from the localized breeding areas. During the putative breeding phase, the bluefin
tuna had significantly shallower daily maximum depths (203 ± 76 m), and exhibited shallow oscillatory dives during the night.
The movement paths of the bluefin tuna during the breeding phase were significantly more residential and sinuous. The heat
transfer coefficients (K) were calculated for a bluefin tuna in the GOM using the recorded ambient and body temperatures. The K for this fish increased rapidly at the high ambient temperatures encountered in the GOM, and was significantly higher at
night in the breeding phase when the fish was exhibiting shallow oscillatory dives. This suggests that the fish were behaviorally
and physiologically thermoregulating in the Gulf of Mexico. This study demonstrates that the movement patterns, diving behavior,
and thermal biology of Atlantic bluefin tuna change significantly at different stages of the breeding migration and can be
used to define spawning location and timing.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
ABSTRACT: Game-theoretic models are developed for describing and analyzing the inspection and enforcement process, especially as it relates to environmental laws and regulations in North America. Based on these models, systems using irrevocable control orders can be compared to those relying on court determination of guilt and punishment. The cost-effectiveness of environmental enforcement can be systematically assessed in terms of factors such as the private gains for violators, the costs of inspection, penalties, and the social value of deterring violations. The policy implications of the analysis, especially with reference to environmental protection, are emphasized. 相似文献