基于胡焕庸线波动的长江经济带水资源环境承载力动态演变特征

基于水资源生态足迹模型,对长江经济带2010—2018年131个地区水资源生态足迹与生态承载力进行研究,并用GIS可视化揭示和探讨长江经济带水资源时空特征。研究发现： （1）胡焕庸线假说在长江经济带区域成立;（2）长江经济带人均水资源生态盈余状况在胡焕庸线以西区域最好,胡焕庸线与胡焕庸亚线之间次之,胡焕庸亚线以东最差;（3）长江经济带胡焕庸线以西区域人均水资源承载力均值、水资源承载力均值在三个区域中最大;（4）长江经济带各地区历年万元GDP生态足迹呈减小趋势,水资源利用率逐年提高;（5）长江经济带历年平均水资源负载指数呈上升趋势,水资源压力逐年上升。研究结果有助于长江经济带水资源综合管理,为水资源的调控及使用提供量化依据。     

臭氧-生物活性炭技术在微污染饮用水处理中的应用

通过研究国内外臭氧—生物活性炭工艺的发展现状和应用实践，指出了该项技术在应用中体现出的优越性，并提出了此项技术在应用中存在的问题，部分地介绍了提高此项技术应用水平的措施。研究表明，臭氧—生物活性炭工艺在处理微污染饮用水将会受到重视和广泛地推广应用，同时也对今后的研究方向提出了相应的观点。     

Potential world garbage and waste carbon sequestration

To offset the carbon dioxide released by fossil fuels, a proposed sequestration strategy relies on burying garbage and waste in landfills. This paper roughly estimates the current annual world supply of carbonaceous waste to be 35.5 billion metric tons and to contain about 18 billion metric tons of carbon. If landfills received all of this waste, sequestration of more than 5.6 billion metric tons of carbon seems theoretically possible—an amount well in excess of the 3.3 billion metric tons which the atmosphere is currently gaining.     

Estimation of atmospheric trace metal emissions in Vilnius City, Lithuania, using vertical concentration gradient and road tunnel measurement data

A new approach for the estimation of trace metal emissions in Vilnius city was implemented, using vertical concentration profiles in the urban boundary layer and road tunnel measurement data. Heavy metal concentrations were examined in fine and coarse particle fractions using a virtual impactor (cut-off size diameter 2.5 μm). Negative vertical concentration gradients were obtained for all metals (Ba, Pb, V, Sb, Zn) and both fractions. It was estimated that the vertical concentration gradient was formed due to emissions from an area of about 12 km². Road tunnel measurements indicated that trace metal concentrations on fine particles were lower than those on coarse particles, which suggested that re-emitted road dust was highly enriched in trace metal due to historic emissions within the tunnel. Emission rates of different pollutants in the road tunnel were calculated using pollutant concentration differences at the tunnel entrance and exit and traffic flow data. Heavy metal emission rates from the area of Vilnius city were estimated using the vertical gradient of heavy metal concentrations and the coefficient of turbulent mixing, as derived from meteorological measurement data. The emission values calculated by the two different methods coincided reasonably well, which indicated that the main source of airborne trace metals in Vilnius city is traffic. The potential of the vertical concentration gradient method for the direct estimation of urban heavy metal emissions was demonstrated.     

A simple semi-empirical model for predicting missing carbon monoxide concentrations

Carbon monoxide monitoring using continuous samplers is carried out in most major urban centres in the world and generally forms the basis for air quality assessments. Such assessments become less reliable as the proportion of data missing due to equipment failure and periods of calibration increases. This paper presents a semi-empirical model for the prediction of atmospheric carbon monoxide concentrations near roads for the purpose of interpolating missing data without the need for any traffic or emissions information. The model produces reliable predictions while remaining computationally simple by being site-specifically optimized. The model was developed for, and evaluated at, both a suburban site and an inner city site in Hamilton, New Zealand. Model performance statistics were found to be significantly better than other simple methods of interpolation with little additional computational complexity.     

Recent advances in antimony removal using carbon-based nanomaterials: A review

• The synthesis and physicochemical properties of various CNMs are reviewed. • Sb removal using carbon-based nano-adsorbents and membranes are summarized. • Details on adsorption behavior and mechanisms of Sb uptake by CNMs are discussed. • Challenges and future prospects for rational design of advanced CNMs are provided. Recently, special attention has been deserved to environmental risks of antimony (Sb) element that is of highly physiologic toxicity to human. Conventional coagulation and ion exchange methods for Sb removal are faced with challenges of low efficiency, high cost and secondary pollution. Adsorption based on carbon nanomaterials (CNMs; e.g., carbon nanotubes, graphene, graphene oxide, reduced graphene oxide and their derivatives) may provide effective alternative because the CNMs have high surface area, rich surface chemistry and high stability. In particular, good conductivity makes it possible to create linkage between adsorption and electrochemistry, thereby the synergistic interaction will be expected for enhanced Sb removal. This review article summarizes the state of art on Sb removal using CNMs with the form of nano-adsorbents and/or filtration membranes. In details, procedures of synthesis and functionalization of different forms of CNMs were reviewed. Next, adsorption behavior and the underlying mechanisms toward Sb removal using various CNMs were presented as resulting from a retrospective analysis of literatures. Last, we prospect the needs for mass production and regeneration of CNMs adsorbents using more affordable precursors and objective assessment of environmental impacts in future studies.     

Cracking styrene derivative polymers in decalin solvent with metal-supported carbon catalysts

The cracking of styrene derivative polymers dissolved in decalin was conducted with metal-supported carbon catalysts under an inert gas atmosphere to recover monosubstituted styrene or monosubstituted ethylbenzene in higher yields than is obtained by pyrolysis, and to elucidate the detailed reaction mechanisms in the solvent. Poly-(4-methylstyrene), poly-(4-t-butylstyrene), poly-(α-methylstyrene), and polystyrene were used. In decalin without a catalyst, each polymer was decomposed into the monomer, dimer, and trimer derived from the corresponding polymer except for poly-(α-methylstyrene), which was decomposed into the monomer and styrene. By using metal-supported carbon, the olefinic compounds derived from the corresponding polymer were thoroughly hydrogenated to the saturated form in a nitrogen atmosphere by a hydrogen transfer reaction from decalin, which was simultaneously dehydrogenated to tetralin and naphthalene with the evolution of hydrogen gas. In comparison with metal species, Pd- and Ru-supported carbon catalysts maintained the hydrogenation activity for a longer time and with a lower evolution of hydrogen than Pt or Rh. The dehydrogenation of decalin was mainly observed not on the metal surfaces, but on the carbon surfaces over Pd-supported carbon. Stabilization of the monomers will be able to suppress the coking which occurs with repolymerization in long running process. Received: July 19, 2000 / Accepted: March 16, 2001     

Formation characteristics of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar PCBs in fly ash from a gasification–melting process of municipal solid waste

PCDDs/DF and Co-PCB (dioxin) formations were studied with ash from a newly developed gasification and melting process for municipal solid waste. Ash samples were heated in a laboratory-scale fixed-bed reactor. Emphasis was placed on the effects of the type and composition of ash, temperatures, gas residence time, and gaseous organic precursors. Investigations using macroscopic and homologue distribution analyses led to the following conclusion. The ash from the gasification–melting process had the ability to generate dioxins in flue gas. A possible carbon source is unburned carbon in the ash samples, although this was very low (less than 0.01%). An experimental result that the level of dioxins generated from preheated fly ash obtained from a conventional incinerator was much lower than that from nonheated fly ash supported this conclusion. Dioxin concentrations obviously showed temperature dependence and peaked at 350°C. Dioxins formed in a gasification–melting process ash were readily desorbed from the surface, probably because of the low carbon content of the ash. There was no experimental evidence that gaseous organic precursors fed to the reactor generated dioxins. Therefore, an organic precursor was not essential for the formation of dioxins. A good linear relationship obtained between PCDDs/DFs and gas residence time also supported the assumption. Received: February 14, 2000 / Accepted: June 30, 2000     

The impact of natural and anthropogenic hydrocarbons on the tropospheric budget of carbon monoxide

A method to quantify the relative contributions of surface sources and photochemical production of atmospheric carbon monoxide has been implemented in a three-dimensional chemical-transport model. The impact of biogenic and anthropogenic hydrocarbons has been calculated. The oxidation of isoprene contributes to about 10% of the global tropospheric burden of carbon monoxide, with a maximum contribution over southern America and Africa. Oxidation of methane and terpenes contribute to 28 and 2%, respectively, of the tropospheric burden of CO. The oxidation of the other hydrocarbons, which include ethane, propane, ethylene, propylene and the surrogate hydrocarbon representing other hydrocarbons results in 12% of the CO tropospheric burden, among which 69% results from the oxidation of hydrocarbons of biologic origin. The overall global CO yield from the oxidation of isoprene is estimated to be 23% on a carbon basis. Comparisons between model results and the few available observations of isoprene, terpenes and their oxidation products show that there is no evidence that the current global isoprene emissions proposed in the IGAC/GEIA emissions data base are substantially overestimated, as suggested by previous studies.     

Urban expansion and its contribution to the regional carbon emissions: Using the model based on the population density distribution

The method is used for calculating regional urban area dynamics and the resulting carbon emissions (from the land-conversion) for the period of 1980 till 2050 for the eight world regions. This approach is based on the fact that the spatial distribution of population density is close to the two-parametric Γ-distribution [Kendall, M.G., Stuart, A., 1958. The Advanced Theory of Statistics, vol. 1.2. Academic Press, New York; Vaughn, R., 1987. Urban Spatial Traffic Patterns, Pion, London]. The developed model provides us with the scenario of urbanisation, based on which the regional and world dynamics of carbon emissions and export from cities, and the annual total urban carbon balance are estimated. According to our estimations, world annual emissions of carbon as a result of urbanisation increase up to 1.25 GtC in 2005 and begin to decrease afterwards. If we compare the emission maximum with the annual emission caused by deforestation, 1.36 GtC per year, then we can say that the role of urbanised territories (UT) in the global carbon balance is of a comparable magnitude. Regarding the world annual export of carbon from UT, we observe its monotonous growth by three times, reaching 505 MtC. The latter, is comparable to the amount of carbon transported by rivers into the ocean (196–537 MtC). The current model shows that urbanisation is inhibited in the interval 2020–2030, and by 2050 the growth of urbanised areas would almost stop. Hence, the total balance, being almost constant until 2000, then starts to decrease at an almost constant rate. By the end of the XXI century, the total carbon balance will be equal to zero, with the exchange flows fully balanced, and may even be negative, with the system beginning to take up carbon from the atmosphere, i.e., becomes a “sink”. The regional dynamics is somewhat more complex, i.e., some regions, like China, Asia and Pacific are being active sources of Carbon through the studied period, while others are changing from source to sink or continue to be neutral in respect the GCC.