NaCl改性人造沸石去除废水中氨氮的性能及其影响因素

采用NaCl溶液对人造沸石进行改性处理,考察NaCl溶液浓度对改性效果的影响.通过表面特征分析、静态吸附试验及吸附等温分析,进一步比较了人造沸石和改性人造沸石对氨氮的吸附去除性能.由X射线衍射(XRD)分析可知,沸石经改性后表面变粗糙,同时出现NaCl晶体特征衍射峰.试验结果表明,1.0 mol·L-1NaCl溶液对人造沸石的改性效果最佳;在沸石用量为1.0 g(50 mL废水)、氨氮浓度为10 mol·L-1、反应时间为40 min、反应温度为25℃和pH值为6.52条件下,改性人造沸石对氨氮的吸附效果最佳,去除率为96.02％.Langmuir和Freundlich吸附等温方程均可较好地拟合2种沸石对氨氮的吸附过程.改性人造沸石对氨氮的吸附饱和容量(21.46 mg·g-1)远大于人造沸石(9.03 mg·g-1).     

改性沸石(Na-Y型)对Ni2+的吸附行为

将天然沸石熔融制得新型改性沸石(Na-Y型),研究Na-Y型沸石对Ni2 的吸附行为.结果表明,对Ni2 的饱和吸附量,Na-Y型沸石为31.04mg·g-1,而天然斜发沸石和Na型沸石(NaCl改性)仅为3.60mg·g-1和7.64 mg·g-1.Na-Y型沸石对Ni2 的等温吸附行为符合Freundlich方程.对溶液中Ni2 的吸附量在初始阶段(0-5h)快速上升,而后趋于平缓.共存阳离子对Na-Y型沸石吸附Ni2 的影响为:Co2 》Ca2 》Fe3 》 K .     

三种人工湿地填料对低浓度氨氮废水的吸附特性

以沸石、陶粒、火山岩为试验材料,分别考察了不同初始氨氮浓度、pH、共存金属阳离子、温度对填料吸附氨氮的影响,并采用了吸附等温线、动力学和热力学对吸附过程进行解析.结果表明,Langmuir方程与Freundlich方程均能较好地描述氨氮在3种填料上的等温吸附行为.3种填料对氨氮的最大吸附量分别为0.9625 mg·g-1(沸石)、0.8643 mg·g-1(火山岩)和0.6928 mg·g-1(陶粒).Freundlich方程中,1/n0.5,表明3种填料对氨氮的吸附属于优惠吸附.颗粒内扩散不是控制填料吸附NH+4的唯一控速步骤,吸附过程可能受到内扩散和表面吸附的共同影响.pH值介于6—9之间时,对氨氮有较好的去除效果.共存阳离子对氨氮的吸附具有抑制作用,具体表现为Al3+Mg2+Na+Ca2+.等温解吸试验表明,陶粒对氨氮的吸附以物理作用为主,而沸石和火山岩以离子交换为主.     

改性斜发沸石处理高浓度氨氮废水

采用NaOH碱熔法对缙云斜发沸石进行处理,采用正交实验对碱熔法改性沸石的最佳条件进行了选择;并对改性前后的沸石进行粉末X射线衍射(XRD)、电感耦合等离子体发射光谱法(ICP-AES)和扫描电镜(SEM)表征;详细研究了所得改性沸石在氨氮废水处理中的净化性能.结果表明,处理沸石的水热温度对氨氮去除效果的影响最显著;碱熔法处理可使缙云斜发沸石转变为低硅铝比的Na-P型分子筛,它对氨氮废水的NH4+-N具有优异的吸附性能.当改性沸石投加量为5 g,对100 mL浓度为1000 mg.L-1氨氮溶液,氨氮去除率可达77.8%,改性沸石吸附NH4+-N是一快速吸附过程,且能较好地符合Langmuir吸附等温模式,偏向于单分子层的吸附.     

天然斜发沸石的氨氮改性吸附与化学再生

本文采用改性与化学再生方法,探索天然斜发沸石对氨氮吸附的最佳改性及化学再生条件.无机盐改性、热改性、有机改性试验结果表明,最佳改性方法为无机盐NaCl法,改性沸石吸附量较天然沸石提升了近20%,最佳NaCl浓度为1 mol·L~(-1);热改性法不能显著提高沸石的氨氮吸附容量,相反高温会破坏其结构;十二烷基苯磺酸钠改性法可以使改性沸石在其表面形成了新的阳离子吸附点,使其吸附性能提升;而十六烷基三甲基溴化铵改性沸石表面形成的是阴离子吸附点,对带正电的NH_4~+会产生排斥,导致其吸铵性能下降.化学再生试验表明,KCl溶液对铵饱和沸石的再生效果最显著,适宜再生浓度为0.1—0.2 mol·L~(-1).经KCl再生后的沸石再次通过NaCl改性,可延长沸石使用周期以及提高再生沸石的吸附能力.     

改性斜发沸石吸附水中氨氮的研究

研究了改性斜发沸石对水中氨氮的吸附行为，考察了pH值，氨氮初始浓度以及竞争阳离子等对钠型沸石吸附氨氮的影响，同时进行了钠型沸石的吸附动力学研究。结果表明，采用饱和氯化钠改性制备得到的钠型沸石具有较大的饱和吸附容量，受氨氮初始浓度和溶液pH值的影响，钠型沸石吸附氨氮的行为在YNH4^ =0.5时发生偏离，竞争阳离子的存在在不同程度上抑制了钠型沸石对氨氮的吸附。钠型沸石吸附氨氮的行为在YNH4^ ＝0．5时发生偏离。竞争阳离子的存在在不同程度上抑制了钠型沸石对氨氮的吸附。钠型沸石吸附氨氮速度的控制步骤是内扩散步骤，可采用Vermeulen吸附模型加以描述。     

人工湿地不同基质对氨氮的吸附特性研究

过量氮是引发水体富营养化的重要原因之一,氮的去除是控制水体富营养化的关键,其中人工湿地中基质对氨氮的去除是人工湿地处理污水的重要途径。通过基质氨氮吸附动力学、等温吸附以及基质饱和吸附后氨氮解吸实验,研究沸石、红泥、水洗砂、炉渣4种人工湿地基质净化氨氮的效果,评价其饱和吸附后氨氮解吸可能造成的二次污染风险及基质去除氨氮的主要途径。结果表明：4种基质对氨氮的吸附量顺序依次为沸石〉红泥〉炉渣〉水洗砂;沸石去除氨氮的途径以离子交换为主,物理吸附作用很小;炉渣的离子交换作用和物理吸附作用效果相当。从氨氮的解吸率来看,沸石的解吸率最小,红泥次之,炉渣和水洗砂的解吸率较大。综合评价,沸石更适合作为人工湿地污水去除氨氮的基质。     

氨氮弱吸附滤料筛选与基于氮素资源化的沼液悬浮物过滤预处理研究

在去除沼液悬浮物(SS)的同时,最大程度地保留其氮素养分是提高沼液资源化利用价值的关键。通过静态吸附-解吸试验筛选出弱吸附氨氮的过滤介质,然后利用滤料填充柱动态过滤试验分析筛选滤料填充柱对沼液SS和氨氮浓度的影响。结果表明,在海砂(SSD)、沸石(ZLT)、石英砂(QSD)和氧化铝废渣(GRM)4种供试滤料中,QSD对溶液氨氮的吸附能力最低,脱附率接近SSD,且远小于ZLT和GRM。按2.4 L·h~(-1)流量进水,沼液经QSD滤料填充柱动态过滤处理后,SS去除率最高可达86.1%,0.5～1 mm粒径QSD填充柱对SS去除率普遍高于3～5 mm粒径QSD填充柱,两种粒径QSD填充柱对沼液氨氮的去除效果无明显区别;运行24 h时滤料填充柱自进水端开始出现堵塞现象,32 h后3～5 mm粒径QSD填充柱堵塞严重;若要达到沼液SS相同去除效果,0.5～1 mm粒径QSD填充柱较3～5 mm粒径QSD填充柱具有运行时间更持久和滤料层填充高度更小的优势;0.5～1 mm粒径QSD填充柱对SS去除率超过80%,且未显著吸附截留沼液氨氮,适合作为沼液SS过滤预处理单元且有利于后续氮回收。     

镧-四氧化三铁-沸石复合材料制备及去除水中磷酸盐和铵

采用La3+、Fe~(2+)、Fe3+和粉末状天然沸石制备了一种镧-Fe_3O_4-沸石复合材料,通过批量吸附实验考察了该复合材料对水中磷酸盐和铵的吸附作用.结果表明,镧-Fe_3O_4-沸石复合材料对水中磷酸盐和铵的单位吸附量随吸附剂投加量的增加而降低,对磷酸盐和铵的去除率随吸附剂投加量的增加而增加.当溶液pH值由6逐渐增加到11时,镧-Fe_3O_4-沸石复合材料对水中磷酸盐和铵的吸附能力逐渐下降.镧-Fe_3O_4-沸石复合材料对水中磷酸盐的吸附平衡数据可以采用Langmuir、Freundlich和Dubinin-Redushkevich(D-R)等温吸附模型加以拟合,对铵的吸附平衡数据可以采用Langmuir和D-R等温吸附模型加以拟合.根据Langmuir模型计算得到的镧-Fe_3O_4-沸石复合材料对水中磷酸盐和铵的最大单位吸附量分别为12.9 mg·g~(-1)(以磷计)和6.99 mg·g~(-1)(以铵计).镧-Fe_3O_4-沸石复合材料对水中磷酸盐和铵的吸附动力学过程可以采用准二级动力学方程加以描述.升高反应温度增强了镧-Fe_3O_4-沸石复合材料对水中磷酸盐和铵的吸附.溶液存在的氯离子、硫酸根离子和碳酸氢根离子对镧-Fe_3O_4-沸石复合材料吸附磷无负面影响.溶液存在的钾离子对镧-Fe_3O_4-沸石复合材料吸附铵的负面影响最大,其次为钠离子,钙离子的负面影响最小.1 mol·L~(-1)NaOH溶液可以使50%左右吸附到吸附剂上的磷酸盐解吸下来.1 mol·L~(-1)NaCl溶液可以使98%左右吸附到吸附剂上的铵解吸下来.当溶液pH值为7时,镧-Fe_3O_4-沸石复合材料对磷酸盐的吸附机制主要是配位体交换作用.镧-Fe_3O_4-沸石复合材料对铵的吸附机制主要是阳离子交换作用.     

富营养化水体中微囊藻细胞碎屑对氨氮的吸附特性

以微囊藻细胞碎屑作为水体有机质颗粒悬浮物的代表,模拟研究了有机质颗粒悬浮物对无机氮的吸附行为及吸附特性.实验表明,细胞碎屑颗粒对氨氮的吸附在30min内即可接近吸附平衡,吸附符合Henry吸附模式,在吸附剂浓度为10mg·l-1,氨氮初始浓度为1.0mg·l-1,pH7.0的实验条件下,吸附分配系数高达30426L·kg-1.碎屑浓度、pH值和盐度对吸附具有一定的影响.     

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     

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.     

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.     

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.     

What Every Conservation Biologist Should Know about Economic Theory

Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.     

Effects of Coffee Management on Deforestation Rates and Forest Integrity

Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km² around Bonga and 3000 km² in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques     

Globalization of the Cashmere Market and the Decline of Large Mammals in Central Asia

As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central     

The lichen-rich coastal heath vegetation on the isle of Anholt, Denmark — conservation and management

The high conservational value of the lichen-rich vegetation and landscape of the marine foreland Ørkenen on the isle of Anholt is treated from a Danish as well as a European perspective. The sensitivity of the lichen-rich vegetation to physical disturbance is emphasized. The impact of invasive species such asPinus mugo as well as the effect of atmospheric deposition of nutrients on the heaths at Anholt is described. Considerations related to the development of a management plan for Ørkenen are presented.     

Behavior and ecology of Old World Luperini beetles of the genusAulacophora (Coleoptera: Chrysomelidae)

Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.     

Importance of greater interdisciplinarity and geographic scope when tackling the driving forces behind biological invasions

Invasive non-native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non-native species. I carried out a bibliometric analysis of articles published from 2000 to 2020 that address either invasive non-native species or biodiversity and ecosystem services and that also mention 1 or more drivers of ecosystem change. I examined 5 indirect drivers (demographic, economic, governance, sociocultural, and technological) and 6 direct drivers (climate change, invasive non-native species, land-use or sea-use change, natural hazards, pollution, and resource extraction). Using the Web of Science core collection of citation indexes, I undertook searches of article titles and keywords and retrieved 27,462 articles addressing invasive non-native species and 110,087 articles dealing with biodiversity or ecosystem services. Most research to date on biological invasions as well as on biodiversity and ecosystem services has focused on anthropogenic direct drivers of ecosystem change rather than indirect drivers. Yet currently, less than 18% of articles addressing biological invasions examined drivers of ecosystem change, a similar level to that found over 20 years ago for biodiversity or ecosystem services. Knowledge of the drivers of biological invasions is limited, emphasizes tractable drivers over those that require an interdisciplinary approach, and is biased toward developed economies. Drivers generally deemed important for biological invasions, such as governance and resource extraction, accounted for less than 2% of research effort. The absence of a systematic understanding of the forces that drive invasive non-native species and how they interact means that attempts to mitigate or forecast biological invasions are likely to fail. To address biological invasions requires a much better orientation of national and international research on drivers in relation to both their actual importance as well as their policy relevance.