纳米铁用于饮用水中As(Ⅲ)去除效果

主要考察实验室合成制得的纳米铁对毒性高,迁移能力强,在厌氧地下水中作为砷的主要存在形式的As(Ⅲ)去除效果.通过批实验探讨吸附动力学,以及pH和纳米铁投加量对As(Ⅲ)的去除影响.反应1 h时,0.25 g纳米铁对起始质量浓度为910μg·L-1 As(Ⅲ)的去除率高达99%以上;反应遵循准一级反应动力学方程,标准化后的速率常数ksA为1.64mL·m-2·min-1.研究结果表明,具有高反应活性的纳米铁将成为饮用水中砷去除非常有效的吸附材料.     

Carbon Budget for Basic Needs:Implications of International Equity and Sustainability

The fundamental way of satisfying the basic needs of human development is to secure the basic needs,limit luxurious and wasteful emissions,and ensure the fulfillment of climate targets,so as to achieve intra-and intergenerational equity.In this paper,the author discusses and analyzes a series of challenges that the development has to face,such as poverty elimination,urbanization,and industrialization,and the problems of increased consumption that is brought about by the improvement of living standards;the author distinguishes the stock emission,which does not need annual updating,and the flow emission of regular consumption;the author also defines the standards of energy consumption and carbon emissions that can meet the basic needs.On this basis,the author proposes the concept and method of carbon budget,compares this method with other means,and in particular,studies and analyzes the implications of international equity and sustainability of carbon budget as part of the international climate regime design.     

The Concept and Theoretical Implications of Carbon Emissions Rights Based on Individual Equity

Climate change has become a hot topic in international environmental negotiations.For post-Kyoto international climate regime negotiations,many countries have proposed a variety of frameworks to share the emission reduction responsibilities and allocate carbon emission rights,and have tried to quantify the emission reduction obligations of all countries based on the perspectives of international equity and individual equity.In this paper,the authors have distinguished the concepts of carbon emissions rights based on these two perspectives respectively,have analyzed the relationship between carbon emissions per capita and economic development,and have calculated and compared the proportion of cumulative emissions per capita of different countries in history and future,and then authors conclude that emission reduction obligations should be allocated based on each country’s conditions,including historical emissions,development stage,and future demands.Developed countries should take the initiative to significantly reduce their emissions because they have already accomplished their industrialization process.However,developing countries are still in the process of industrialization,which requires more emission rights to meet their development needs.For China,the concept of carbon emissions based on individual equity can be used as a theoretical tool for the allocating the international carbon emissions rights.     

Methane–benzene binary mixture destruction in a reverse flow catalytic reactor

An experimental study of methane–benzene binary mixture purification in a bench-scale reverse flow reactor is carried out. Results for catalytic oxidation of the two hydrocarbons with remarkably discrepant chemical properties show that autothermal catalytic combustion of very lean combustible concentration can be achieved with periodic feed reversal. Benzene is well removed, but methane conversion is relatively low and mainly determined by the thermal level of the reactor. If methane is added as auxiliary fuel to maintain autothermal operation when the volatile organic compound (VOC) concentration in the contaminated air is too low, an excess amount is needed. The influences of gas superficial velocity, cycle period, and methane-to-benzene ratio are discussed. A mathematical model is developed and solved using a FORTRAN code, with good correspondence being observed between the two approaches. Results of experimental and numerical study indicate that, during catalytic oxidation of lean VOCs in reverse flow reactor, the mutual inhibition effect between different kinds of hydrocarbon can be neglected.     

Eld’s Deer Translocated to Human-Inhabited Areas Become Nocturnal

As human populations expand and nonhuman animals decline, understanding the interactions between people and wildlife is essential. For endangered species, appreciating the effect of human disturbance can be important for their conservation. However, a human disturbance angle is often absent from ecological research, despite growing evidence of the negative impact of nonfatal human interference. Here, we monitored Hainan Eld’s deer living within a reserve and translocated animals living amongst villagers. We show that translocated deer deviated from a crepuscular activity pattern and became increasingly nocturnal, and most active when villagers were not. It appears that translocated deer adapted over time to human disturbance and this pattern is similar to that of other species during periods of hunting. People do not pose an actual threat to Eld’s deer, but their presence triggered a response akin to predator avoidance and may be interfering with broader aspects of their biology and conservation.     

电解絮凝法处理老龄垃圾渗滤液的实验研究

为考察简便低耗的电解材料处理效果,采用铸铁阳极电解絮凝法对老龄垃圾渗滤液进行了处理,通过正交实验和单因素实验考察了电解液浓度、电流密度、pH、极板间距对处理效果的影响.结果表明,电解絮凝法对该老龄垃圾渗滤液有较好的处理效果,当电流密度为50 mA/cm2、pH值为9、极板间距为2 cm、电解75 min后,COD和NH...     

二级活性炭生物流化床深度处理有机胺废水研究

采用二级活性炭生物流化床工艺深度处理有机胺废水,研究了有机容积负荷、NH3-N容积负荷以及曝气间歇对COD、NH3-N去除效果的影响.结果表明:当有机容积负荷为0.94～2.38 kg COD/(m3·d)时,二级流化床对COD的去除率为80.6%～95.5%,比一级流化床的抗有机负荷冲击的能力更强;当NH3-N容积负...     

有氧垂直折流式反应池处理煤矿酸性废水

为了使实验研究成果更好应用于工程实际,在野外建立了一套有氧垂直折流式反应池来处理贵阳市久安乡废弃煤窑产生的煤矿酸性废水.工程实验研究显示,在有氧垂直折流式反应池中,进水pH值可由2.45～2.95提高到5.91～7.76,单位面积铁的平均去除速率为44.63 g/(d·m2),反应池中铝、铜的去除率均分别在98.44%...     

淀粉改性纳米四氧化三铁的制备及其除磷效能的研究

以可溶性淀粉为改性剂,采用氧化沉淀法分别制备了可溶性淀粉改性Fe3O4以及纯Fe3O4,并研究了2种Fe3 O4粒径、表面性质以及除磷效能的差异。实验结果表明,淀粉改性使得纳米Fe3 O4粒径减小,粒径由60 nm减小到10nm左右;红外和Zeta电位结果表明淀粉在Fe3 O4粒子表面是化学吸附;2种纳米Fe3 O4对...     

Distribution of perfluorochemicals between sera and milk from the same mothers and implications for prenatal and postnatal exposures

The levels of six perfluorocarboxylates (PFCAs), four perfloroalkylsulfonates (PFASs), and one sulfonamide were measured in paired samples of maternal serum, umbilical cord serum, and breast milk. The maternal and cord sera were strongly correlated with each other for all measured compounds (r > 0.5 and p < 0.01). Nevertheless, there was a significant difference in compound composition profile between the two sera matrices, with a more depletion of the longer chain compounds in cord serum. The transfer efficiency values from maternal to cord serum (TF_CS/MS) decreased by 70% with each increasing unit of -CF₂ chain within a PFCA group, and for perfluorooctanesulfonate (PFOS), by a half compared to perfluorooctanoate (PFOA). In contrast to the strong correlation in concentrations between the two sera matrices, the pattern of compounds in breast milk differed considerably with those in sera. Accordingly, compound- and matrix-specific transfer must be considered when assessing prenatal and postnatal exposure.