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103.
采用改性活性炭粉末对用纯净水加氟化钠配制而成的含氟水溶液进行动态电吸附去除实验.研究不同电压、电吸附时间,以及Cl-和SO2-4对氟离子去除的影响,并探讨吸附动力学和吸附方程.实验结果表明:活性炭对氟离子的吸附等温方程符合Freundlich方程,吸附动力学符合一级动力学方程;活性炭对氟离子去除与所施加的电位、吸附时间等因素有关,施加的电位越大,去除效果越好;随着吸附去除时间的延长,氟离子浓度下降趋缓;Cl-对氟离子去除影响很小,而SO2-4对氟离子去除有显著的不利影响. 相似文献
104.
Loss of grassland species resulting from activities such as off-road vehicle use increases the need for models that predict
effects of anthropogenic disturbance. The relationship of disturbance by military training to plant species richness and composition
on two soils (Foard and Lawton) in a mixed prairie area was investigated. Track cover (cover of vehicle disturbance to the
soil) and soil organic carbon were selected as measures of short- and long-term disturbance, respectively. Soil and vegetation
data, collected in 1-m2 quadrats, were analyzed at three spatial scales (60, 10, and 1 m2). Plant species richness peaked at intermediate levels of soil organic carbon at the 10-m2 and 1-m2 spatial scales on both the Lawton and Foard soils, and at intermediate levels of track cover at all three spatial scales
on the Foard soil. Species composition differed across the disturbance gradient on the Foard soil but not on the Lawton soil.
Disturbance increased total plant species richness on the Foard soil. The authors conclude that disturbance up to intermediate
levels can be used to maintain biodiversity by enriching the plant species pool. 相似文献
105.
Summary The balance of evidence suggests a perceptible human influence on global ecosystems. Human activities are affecting the global
ecosystem, some directly and some indirectly. If researchers could clarify the extent to which specific human activities affect
global ecosystems, they would be in a much better position to suggest strategies for mitigating against the worst disturbances.
Sophisticated statistical analysis can help in interpreting the influence of specific human activities on global ecosystems
more carefully. This study aims at identifying significant or influential human activities (i.e. factors) on CO2 emissions using statistical analyses. The study was conducted for two cases: (i) developed countries and (ii) developing
countries. In developed countries, this study identified three influential human activities for CO2 emissions: (i) combustion of fossil fuels, (ii) population pressure on natural and terrestrial ecosystems, and (iii) land
use change. In developing countries, the significant human activities causing an upsurge of CO2 emissions are: (i) combustion of fossil fuels, (ii) terrestrial ecosystem strength and (iii) land use change. Among these
factors, combustion of fossil fuels is the most influential human activity for CO2 emissions both in developed and developing countries. Regression analysis based on the factor scores indicated that combustion
of fossil fuels has significant positive influence on CO2 emissions in both developed and developing countries. Terrestrial ecosystem strength has a significant negative influence
on CO2 emissions. Land use change and CO2 emissions are positively related, although regression analysis showed that the influence of land use change on CO2 emissions was still insignificant. It is anticipated, from the findings of this study, that CO2 emissions can be reduced by reducing fossil-fuel consumption and switching to alternative energy sources, preserving exiting
forests, planting trees on abandoned and degraded forest lands, or by planting trees by social/agroforestry on agricultural
lands. 相似文献
106.
Asymmetric regulation of a global pollutant between countries can alter the competitiveness of industries and lead to emissions leakage, which hampers countries’ welfare. In order to limit leakage, governments consider supporting domestic trade-exposed firms by subsidizing their investments in abatement technology. The suppliers of such technologies tend to be less than perfectly competitive, particularly when both emissions regulations and advanced technologies are new. In this context of twin market failures, we consider the relative effects and desirability of subsidies for abatement technology. We find a more robust recommendation for upstream subsidies than for downstream subsidies. Downstream subsidies tend to increase global abatement technology prices, reduce pollution abatement abroad and increase emission leakage. On the contrary, upstream subsidies reduce abatement technology prices, and hence also emissions leakage. 相似文献
107.
A. Joseph Berkmans M. Jagannatham S. Priyanka Prathap Haridoss 《Waste management (New York, N.Y.)》2014,34(11):2139-2145
Upcycling polymer wastes into useful, and valuable carbon based materials, is a challenging process. We report a novel catalyst-free and solvent-free technique for the formation of nano channeled ultrafine carbon tubes (NCUFCTs) and multiwalled carbon nanotubes (MWCNTs) from polyethylene terephthalate (PET) wastes, using rotating cathode arc discharge technique. The soot obtain from the anode contains ultrafine and nano-sized solid carbon spheres (SCS) with a mean diameter of 221 nm and 100 nm, respectively, formed at the lower temperature region of the anode where the temperature is approximately 1700 °C. The carbon spheres are converted into long “Y” type branched and non-branched NCUFCTs and MWCNTs at higher temperature regions where the temperature is approximately 2600 °C, with mean diameters of 364 nm and 95 nm, respectively. Soot deposited on the cathode is composed of MWCNTs with a mean diameter of 20 nm and other nanoparticles. The tubular structures present in the anode are longer, bent and often coiled with lesser graphitization compared to the nanotubes in the soot on the cathode. 相似文献
108.
K.H. Roucoux I.T. Lawson T.R. Baker D. Del Castillo Torres F.C. Draper O. Lähteenoja M.P. Gilmore E.N. Honorio Coronado T.J. Kelly E.T.A. Mitchard C.F. Vriesendorp 《Conservation biology》2017,31(6):1283-1292
Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development. 相似文献
109.
Hannah Fraser Kylie Soanes Stuart A. Jones Chris S. Jones Matthew Malishev 《Conservation biology》2017,31(3):540-546
The objectives of conservation science and dissemination of its research create a paradox: Conservation is about preserving the environment, yet scientists spread this message at conferences with heavy carbon footprints. Ecology and conservation science depend on global knowledge exchange—getting the best science to the places it is most needed. However, conference attendance from developed countries typically outweighs that from developing countries that are biodiversity and conservation hotspots. If any branch of science should be trying to maximize participation while minimizing carbon emissions, it is conservation. Virtual conferencing is common in other disciplines, such as education and humanities, but it is surprisingly underused in ecology and conservation. Adopting virtual conferencing entails a number of challenges, including logistics and unified acceptance, which we argue can be overcome through planning and technology. We examined 4 conference models: a pure‐virtual model and 3 hybrid hub‐and‐node models, where hubs stream content to local nodes. These models collectively aim to mitigate the logistical and administrative challenges of global knowledge transfer. Embracing virtual conferencing addresses 2 essential prerequisites of modern conferences: lowering carbon emissions and increasing accessibility for remote, time‐ and resource‐poor researchers, particularly those from developing countries. 相似文献
110.
锆-十六烷基三甲基氯化铵改性活性炭对水中硝酸盐和磷酸盐的吸附特性 总被引:3,自引:3,他引:0
采用锆(Zr)和阳离子表面活性剂十六烷基三甲基氯化铵(CTAC)对活性炭进行联合改性,考察了所制备的Zr-CTAC改性活性炭对水中硝酸盐和磷酸盐的吸附去除作用,并探讨了相关的吸附去除机制.结果表明,Zr-CTAC改性活性炭对水中硝酸盐和磷酸盐均具备较好的吸附去除能力.Zr-CTAC改性活性炭对硝酸盐和磷酸盐吸附动力学过程满足准二级动力学模型.Langmuir、Freundlich和Dubinin-Radushkevich(D-R)等温吸附模型可以较好地描述Zr-CTAC改性活性炭对水中硝酸盐的等温吸附过程,Langmuir和D-R等温吸附模型可以较好地描述Zr-CTAC改性活性炭对水中磷酸盐等温吸附过程,通过Langmuir模型计算得到吸附剂对硝酸盐和磷酸盐的最大单位吸附量分别为7.58 mg·g-1和10.9 mg·g-1.高的p H会抑制Zr-CTAC改性活性炭对水中硝酸盐和磷酸盐的吸附.水中共存的Cl-、HCO-3和SO2-4等阴离子均会抑制Zr-CTAC改性活性炭对硝酸盐和磷酸盐的吸附,且对吸附硝酸盐的抑制作用较强而对吸附磷酸盐的抑制作用较弱.水中共存的磷酸盐对Zr-CTAC改性活性炭吸附硝酸盐的抑制作用较强,而水中共存的硝酸盐对Zr-CTAC改性活性炭吸附磷酸盐的抑制作用较弱.1 mol·L-1Na Cl溶液可以使90%左右被吸附到Zr-CTAC改性活性炭表面上的硝酸盐解吸下来.1 mol·L-1的Na OH溶液可以使78%左右被吸附到Zr-CTAC改性活性炭表面上的磷酸盐解吸下来.Zr-CTAC改性活性炭对硝酸盐的吸附机制主要包括阴离子交换作用和静电吸引作用,对磷酸盐的吸附机制主要包括配位体交换作用、阴离子交换作用和静电吸引作用.上述结果说明Zr-CTAC改性活性炭适合作为一种吸附剂去除废水中的硝酸盐和磷酸盐. 相似文献