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1.
本研究用直接法和后处理法合成了不同过渡金属(Fe、Co、Ni)负载的介孔分子筛载体材料MCM-41,并利用Al对分子筛进行了改性,制备了Fe/Al复合催化剂,对上述材料进行了表征.研究了这些非均相催化剂对染料活性艳蓝KN-R的催化氧化脱色,分别研究了催化剂制备方法、过渡金属种类及负载量对KN-R脱色效率的影响,并考察了所制得催化剂的稳定性和重复利用性.结果表明,直接法合成的催化剂具有较高的催化性能及较低的金属溶出量,负载铁(Ⅱ)的催化剂对染料的催化降解性能要远高于钴(Ⅱ)和镍(Ⅱ)负载型催化剂,催化氧化活性随金属负载量的提高而显著升高.Al改性进一步提高了催化剂的活性,在pH=2.5,氧化剂H_2O_2投加剂量为50.0 mmol·L~(-1),催化剂剂量为4.0 g·L~(-1)的条件下,反应30 min,对初始浓度为250 mg·L~(-1)的KN-R染料的脱色率均可达95%以上,矿化率达60%以上.当Al/Si为0.21,Fe负载量为23.6 mg·g~(-1)时,在10 min内可将250 mg·L-1的KN-R完全脱色.经过3次循环使用后,上述催化剂仍能表现出良好的性能,但进一步循环使用,催化活性下降.  相似文献   

2.
采用多针-水电极反应器,研究了直流电晕放电对活性艳蓝KN-R染料废水的脱色,考察了放电电压、初始pH值和初始浓度对活性艳蓝脱色的影响,通过对液相活性物质(O3和.OH)浓度的考察探讨了脱色机理.结果表明,多针-水电极直流电晕放电对活性艳蓝脱色效果明显;放电电压、溶液初始pH值对活性艳蓝脱色效果的影响与其对液相O和.OH浓度的影响一致;.OH和O是促使RBB脱色的主要因素.  相似文献   

3.
采用渗流式电化学反应器,以碳纳米管和活性碳纤维作为反应器的阳极.选取活性艳蓝X-BR模拟废水作为实验对象,计算电化学过程的传质系数,考察电压、pH值和电解质对活性艳蓝脱色的影响,在优化条件下(电压为8V,pH=2,电解质浓度为1g·l-1),对浓度为200mg·l-1活性艳蓝X-BR的脱色率可达90%以上.  相似文献   

4.
固定化无花果曲霉对活性艳蓝KN-R的脱色   总被引:4,自引:0,他引:4  
采用海藻酸钙法固定不同状态无花果曲霉,形成活菌固定化小球和死菌固定化小球。同时考察了不同因素如培养时间、温度、pH、染料浓度对活性艳蓝KN-R的脱色影响。试验结果表明:在33℃、pH为5.0、150r/min的振荡条件下,经66h它对活性艳蓝KN-R的脱色达到最佳效果。两种不同状态固定化小球的脱色率有较大的差别,其中活菌固定化小球的脱色率明显高于死菌固定化小球。其中活菌固定化小球经3次脱色后能重复使用,脱色率仍达79.8%。  相似文献   

5.
微米气泡强化臭氧氧化的作用机理研究   总被引:4,自引:0,他引:4  
采用微米气泡系统(平均粒径约为58 μm)和普通的鼓泡系统进行对比研究微米气泡对臭氧氧化的强化作用机理.在相同的进气流率下,采用微米气泡体系臭氧在水中的传质系数和利用率是鼓泡系统的1.6-2.7倍和2.3-3.2倍.利用臭氧氧化模拟活性艳蓝KN-R废水(100 mg·l-1)的实验结果表明,染料在微米气泡体系中的脱色速率高于鼓泡系统,二者达到99%脱色效率所需的时间分别为30 min和60 min.在同样的脱色速率下,染料在微米气泡系统中的TOC去除率较大,说明微米气泡不仅能够提高臭氧的传质速度,而且可以强化臭氧的氧化能力.  相似文献   

6.
UV-vis/草酸铁/Fenton体系降解蒽醌染料   总被引:2,自引:0,他引:2  
以活性艳蓝KN—R作为研究对象,考察了处理活性艳蓝KN-R的主要影响因素。在固定染料浓度为100 mg/L时,得到氧化体系的最佳用量比值为ρ(Fe2+):ρ(H2O2):ρ(H2C2O4)为1:15:1.5。在最佳条件下,脱色率达到95%以上,COD和TOC去除率分别达到87.7%和66.8%。活性艳蓝KN-R脱色的动力学模型为拟一级反应模型。  相似文献   

7.
纳米TiO_2多孔微粒阳光催化降解活性艳蓝染料   总被引:2,自引:0,他引:2  
首次利用高分子悬浮聚合与溶胶-凝胶法相结合的技术,成功地制备不同孔结构的TiO2多孔微粒,并对其光催化降解活性艳蓝KN-R的染料溶液pH、无机阴离子、光强、通空气等影响因素进行了系统研究。结果表明:强酸性条件有利于染料在催化剂表面的吸附,而强碱性条件有利于催化反应的进行;常见无机阴离子Cl-、SO42-,对染料降解有不同程度的抑制作用;染料降解效率随光强增加而提高;光降解动力学结果表明:TiO2多孔微粒对活性艳蓝KN-R染料的光催化降解反应符合一级反应动力学;降解时持续通空气有利于降解效率的提高。实验证明所制得的微粒具有良好的光催化降解效果和重复使用性能。  相似文献   

8.
微电解对不同结构染料脱色效果的研究   总被引:6,自引:0,他引:6  
采用微电解法研究了染料脱色效率与染料结构的关系.结果表明,脱色的难易程度从染料结构看,依次为偶氮型、蒽醌型>金属络合型>半菁阳型.在pH值为5.7-6.0,铁炭比为2:1时,处理效果最好,对100mg·l-1的摸拟染料废水处理1h后,脱色率达到90%以上.  相似文献   

9.
以多孔陶瓷球为载体,采用溶胶-凝胶法在其表面进行纳米TiO2薄膜负载,制备了多孔陶瓷球负载纳米晶粒二氧化钛光催化剂,经X射线衍射法(XRD)等手段对其表征结果表明,复合载体经500℃焙烧后,TiO2以锐钛矿晶型存在。对催化剂降解活性艳蓝溶液的催化活性进行研究表明,催化剂在5 h内可完全降解活性艳蓝染料。  相似文献   

10.
合成锰钾矿型化合物对偶氮染料的脱色研究   总被引:1,自引:0,他引:1  
利用合成锰钾矿型化合物对酸性橙Ⅱ染料废水进行了脱色研究,讨论了初始溶液酸度、样品投加量、样品粒径大小、反应时间、反应温度等实验条件对脱色率的影响;在最佳脱色条件为:25℃条件下,pH值为2.9,粒径160-200目,锰钾矿投加量0.10g,反应2h,对50ml浓度为400mg·l-1酸性橙Ⅱ模拟废水的脱色率可达到95%以上,处理后废水色度为25倍,完全达到了<纺织染整工业污染物排放标准>(GB4287-1992)中的一级标准.通过反应前后锰钾矿比表面积的测定及Mn(Ⅱ)溶出试验研究结果表明,染料与锰钾矿颗粒物的界面发生了氧化还原反应,使染料的发色基团破坏而导致其脱色;另外锰钾矿会吸附小分子物质.据此推断染料废水的脱色是锰钾矿型化合物的吸附性和氧化性共同作用的结果.  相似文献   

11.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

12.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

13.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

14.
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  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

17.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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