ZnO薄膜光电催化降解乙酰甲胺磷

采用溶胶-凝胶法制备了ZnO薄膜,并通过光电流响应、EIS、SEM、XRD等分析方法对其光电化学性能、表面形貌和结构进行表征.以制备的ZnO薄膜为工作电极对乙酰甲胺磷进行光电催化降解.实验表明,ZnO薄膜电极在UV照射下能够有效地光电催化降解乙酰甲胺磷,加入适量H2O2后具有一定的协同作用.在H2O2浓度为9.908 mmol.L-1,外加电压为1.2 V,支持电解液Na2SO4浓度为0.01 mol.L-1,溶液pH值为5.4的条件下,对0.1 mmol.L-1的乙酰甲胺磷180 min的降解率可达到89.6%.     

Fe（0）/H_2O_2协同降解亚甲基蓝的研究

进行了Fe（0）和H2O2协同催化降解亚甲基蓝的研究,分析了Fe（0）投加量、H2O2投加量、溶液初始pH值和染料初始质量浓度等因素的影响。研究表明：Fe（0）和H2O2协同可有效催化降解亚甲基蓝;在pH为4.5,Fe（0）用量为2.0 g.L-1,H2O2用量为3.0 mmol.L-1时对10 mg.L-1亚甲基蓝的去除率在60 min内达到90%以上。MB的降解去除率随着Fe（0）投加量与H2O2用量的增加而增加,但随着其初始质量浓度的增大而降低。研究结果还表明,Fe（0）和H2O2可在接近中性条件下有效协同催化降解亚甲基蓝。UV-Vis光谱在反应过程的变化说明亚甲基蓝降解生成了一些小分子物质。     

g-C3N4-MoS2/WSe2自偏压系统构建与不同类型污染物同时去除性能研究

由于工业化进程的不断推进,染料与重金属废水被非法排入自然水体,水体污染问题日益严峻.为实现两种污染物的同时去除,本文通过调控合成MoS₂/WSe₂（MW）异质结复合催化材料,提高其催化活性.黑暗条件下,以MoS₂、WSe₂以及MW为阳极材料,g-C₃N₄为阴极材料组建自偏压燃料电池系统,实现在降解有机染料的同时,去除水体中的重金属离子.通过调控参数,探究影响染料与重金属去除的因素.研究表明,影响重金属和有机染料去除效果的因素有pH、电解质溶液浓度、重金属溶液浓度.当溶液pH=5,电解质溶液浓度为0.1 mol·L^-1,铜离子浓度为4 mg·L^-1时,重金属的去除率为64.3%.当溶液pH=5,电解质溶液浓度为0.2 mol·L^-1,铜离子浓度为2 mg·L^-1时,有机染料罗丹明B的去除率为99.5%.该系统在无外加光照条件下,实现不同类型污染物同时去除,并产生约240 ...     

Ce/TiO_2/Fe_3O_4粒子电极光电催化降解藏红T模拟染料废水

采用化学共沉淀-超声辅助法,制备出磁性纳米材料Fe3O4,利用溶胶-凝胶法在Fe3O4表面包裹Ce/TiO2,得到磁性复合材料Ce/TiO2/Fe3O4.用XRD、SEM、BET等对其结构和性能进行了表征,催化剂主要以催化活性较高的锐钛矿相存在,Ce/TiO2包覆在纳米Fe3O4的表面形成多孔结构,复合材料具有LangmuirⅣ吸附-脱附等温线,比表面积76.68m2·g-1,平均孔径8nm,主要分布在4.5—15.4nm之间.通过电助光催化降解藏红T溶液研究了Ce/TiO2/Fe3O4的光电催化活性.在催化剂的加入量为6g·L-1,降解时间为60min,外加电压为5V,50mg·L-1的藏红T溶液的降解率可达到90%以上,COD去除率达84.7%.所制备的Ce/TiO2/Fe3O4在重复使用5次后仍能保持较好的光电催化活性.     

水热法制备PbMoO4微晶体及其光催化降解灭幼脲

以水热法合成的PbMoO4微晶体为催化剂,考察了反应溶液pH、污染物初始浓度和催化剂用量对光催化降解灭幼脲的影响,研究了光催化降解过程的反应动力学和作用机理.结果表明,最佳反应溶液pH 6.0、污染物初始浓度20 mg.L-1、催化剂用量0.4 g.L-1.反应4 h灭幼脲降解率达99.96%,矿化率达66.4%,降解反应符合一级动力学.通过加入自由基清除剂对比实验发现,PbMoO4微晶体主要通过空穴和.OH的氧化作用使灭幼脲降解,其中空穴起主要作用.     

Fe_3O_4@Graphite电极中性条件下电Fenton降解有机污染物

制备了Fe3O4复合石墨电极(Fe3O4@graphite),通过循环伏安测定,对自制电极的电化学特性进行了表征.在外加电压无隔膜反应池中,基于Fe3O4@graphite为阴极,铂网为阳极,在pH7.0中性条件下,探讨了降解有机染料罗丹明B(Rhodamine B,RhB)及无色小分子2,4-二氯苯酚(2,4-dichlorophenol,DCP)的电Fenton反应特性,结果表明,对1.0×10-5mol.l-1RhB在外加电压6 V和支持电解质Na2SO410 g.l-1条件下,电Fenton反应120 min,RhB降解率达100%.采用过氧化物酶催化反应吸光光度法和苯甲酸荧光分析法跟踪测定RhB降解反应过程中H2O2和羟基自由基(.OH)的变化,表明RhB降解过程涉及.OH历程.采用红外光谱分析和TOC测定RhB降解过程中深度氧化变化,表明电Fenton反应条件下,RhB反应过程中其分子结构被破坏,生成羧酸或者胺类小分子化合物,同时180 min矿化率达59.2%,对2,4-DCP而言,240 min降解率为98.6%,14h矿化率为86.8%.     

胶束电动毛细管色谱法测定水中的毒死蜱含量

利用胶束电动毛细管色谱（MEKC）建立了测定水中毒死蜱含量的方法,研究了检测波长、运行缓冲液的种类、浓度以及pH、有机添加剂、脱氧胆酸钠（NaDCh）的浓度和分离电压等实验条件对毒死蜱测定的影响.实验结果表明,以25 mmol.L-1硼砂（pH 9.0,含20%（V/V）乙腈和50 mmol.L-1NaDCh）作为缓冲...     

吸附-电氧化法降解气态乙二醇乙醚乙酸酯(EGEA)的研究

采用吸附-电氧化两步联动降解VOCs,结果表明,相同电压下以铁作为阳极时的CODCr脱除率达到80%以上,比用不锈钢阳极时高40%左右.电解质溶液的pH值和CODCr值随时间有规律地变化,也验证了反应器中所发生的反应.     

连续流微生物电解池处理有机废水同步生产甲烷北大核心CSCD

为进一步提高有机废水的厌氧处理效率,同时实现能源物质的回收,采用微生物电解池并结合连续流工艺处理有机废水并同步回收甲烷,系统地研究不同水力停留时间、有机负荷、外加电压对微生物电解池内基质浓度的降解、甲烷生产速率等方面的影响.结果表明,在同一有机负荷下,随着外加电压(0.6 V,1.0 V,1.2 V)的升高,微生物电解池COD的去除效率和甲烷生产率也同时提高.在进水COD浓度为1 178 mg L-1、水力停留时间为8 h、外加电压为1.2V的条件下,其COD去除率、甲烷浓度、甲烷产生速率分别为97.7%、96%、1 071 m L L-1 d-1,较普通厌氧发酵(对照组)分别提高了31.5%、13.6%、123%;当进水COD浓度为4 812 mg L-1、水力停留时间为20 h、外加电压为1.2 V时,甲烷的产生速率达1 888 m L L-1 d-1,达理论产率的98.0%,而此条件下对照组甲烷产生速率仅为理论值的64.9%.说明连续流微生物电解池能够明显提高有机废水的处理效率,并实现处理过程中稳定回收甲烷的目的.高通量分析结果显示:微生物电解池阳极碳毡优势菌群为methanogens与Geobacter sp.,其丰度分别占总菌群的53.3%和7.5%,而对照组碳毡相应丰度仅为25.2%和0.7%.此外,研究发现有机负荷与电解池能量的消耗呈负相关,当外加电压为0.6 V时,有机负荷由3.5 kg m-3d-1提升至5.7 kg m-3d-1时,电解池能量消耗降低了79.3%.据此认为,通过优化水力停留时间和外加电压来处理有机废水并同步生产甲烷是可行的.     

太阳光/电-Fenton法降解H-acid的表观动力学研究

进行了太阳光/电-Fenton法降解染料中间体H-acid模拟废水的表观动力学研究,通过对不同初始H-acid浓度和Fe2+浓度体系以及不同初始电压浓度体系反应的分析,确定该反应的表观动力学方程和动力学参数,为该技术降解H-acid废水优化反应条件提供了依据.结果表明,在固定初始pH值、支持电解质Na2SO4为0.10...     

Achieving Open Access to Conservation Science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Threats to intact tropical peatlands and opportunities for their conservation

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.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.