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1.
A previously reported acute temperature dependency for the effective removal of tarry residue from feather clusters, utilising magnetic particles, has also been demonstrated to occur for the plumage of whole birds, whereby a maximum removal of up to 96% may be achieved. The experimental design allows an approximate equilibrium constant, for the distribution of contaminant between the residue and the magnetic particles, to be estimated at each temperature. This allows the thermodynamics of the process to be examined via application of the van't Hoff equation, suggesting an explanation for the phenomenon.  相似文献   

2.
A pilot-scale anaerobic ammonia oxidation (ANAMMOX) reactor was used to treat mixed wastewater resulting from a chlortetracycline and starch production process. The results, collected over the course of 272 days, show that the ratio of influent ammonium to nitrite, pH, and temperature can all affect the efficiency of nitrogen removal. The ratio of influent ammonium to nitrite was maintained at about 1:1 at a concentration below 200 mg·L-1 for both influent ammonium and nitrite. The total nitrogen (TN) loading rate was 0.15–0.30 kgN·m-3·d-1, pH remained at 7.8–8.5, and temperature was recorded at 33±1°C. The rate of removal of ammonia, nitrite, and TN were over 90%, 90%, and 80%, and the effluent ammonium, nitrite and TN concentrations were below 50, 30, and 100 mg·L-1.  相似文献   

3.
This study evaluated the feasibility of integrating amorphous magnesite and bentonite clay (composite) as an alternative technology for removing arsenic from industrial effluents. The removal of arsenic from industrial effluents by using magnesite–bentonite clay composite was carried out in batch mode. The effects of equilibration time, adsorbent dosage, adsorbate concentration, and pH on removal of arsenic were investigated. The experiments demonstrated that ≈100% arsenic removal is optimum at 30 minutes of agitation, 2 g of adsorbent dosage (2 g: 100 mL, S/L ratio), and 20 mg L?1 of arsenic concentration. The adsorption data fitted well to both Langmuir and Freundlich adsorption models, hence proving monolayer and multilayer adsorption. The kinetic studies revealed that the data fitted better to a pseudo-second-order reaction than to a pseudo-first-order reaction, hence proving chemisorption. At optimized conditions, the composite was able to remove arsenic to below World Health Organization water quality guidelines, hence depicting that the composite is effective and efficient in removing arsenic from contaminated water. Based on that, this comparative study proves that the composite is a promising adsorbent with high adsorption capacity for arsenic and can be a suitable substitute for the conventional treatment methods.  相似文献   

4.
以有机氯农药生产企业工业场地污染土壤为对象,研究Tween80、TritonX-100和SDS这3种表面活性剂对土壤中氯丹(α-氯丹和γ-氯丹)、灭蚁灵、七氯、硫丹(α-硫丹和β-硫丹)的增溶洗脱效应.结果表明,3种表面活性剂对土壤中的有机氯农药均具有一定的增效洗脱作用,且洗脱去除率随表面活性剂添加量升高而逐渐增加.3种表面活性剂对土壤中氯丹、硫丹和七氯的去除率明显高于灭蚁灵,TritonX-100对灭蚁灵的去除率明显高于SDS和Tween80.Tween80和TritonX-100添加量为10g·L-1、SDS添加量为8.50g·L-1时,对土壤中4类有机氯农药的总去除率最高,分别为32.8%、59.7%和60.1%.对于该类污染场地土壤,选择10g·L-1 TritonX-100溶液在50℃条件下振荡5min时洗脱效果最好.  相似文献   

5.
It was long thought that the colour of bird feathers does not change after plumage moult. However, there is increasing evidence that the colour of feathers may change due to abrasion, photochemical change and staining, either accidental or deliberate. The coloration of plumage due to deliberate staining, i.e. with cosmetic purposes, may help individuals to communicate their quality to conspecifics. The presence of carotenoids in preen oils has been previously only suggested, and here we confirm for the first time its presence in such oils. Moreover, the carotenoids in the uropygial secretions were the same specific pigments found in feathers. We show not only that the colour of feathers of greater flamingos Phoenicopterus roseus became more colourful due to the application of carotenoids from uropygial secretions over the plumage but also that the feathers became more colourful with the quantity of pigments applied over them, thus providing evidence of cosmetic coloration. Flamingos used uropygial secretions as cosmetic much more frequently during periods when they were displaying in groups than during the rest of the year, suggesting that the primary function of cosmetic coloration is mate choice. Individuals with more colourful plumage initiated nesting earlier. There was a correlation between plumage coloration before and after removal of uropygial secretions from feathers’ surfaces, suggesting that the use of these pigmented secretions may function as a signal amplifier by increasing the perceptibility of plumage colour, and hence of individual quality. As the cosmetic coloration strengthens signal intensity by reinforcing base-plumage colour, its use may help to the understanding of selection for signal efficacy by making interindividual differences more apparent.  相似文献   

6.
利用碳还原剂和氯化钙熔盐药剂在1100℃下还原污泥焚烧灰中的磷酸盐为气态磷单质并去除,采用X射线衍射分析(XRD)残渣的组成和热重质谱(TGA-MS)分析反应过程.结果表明,添加氯化钙可显著提高污泥焚烧灰除磷效率,氯化钙的最优添加量为25%质量分数,此时污泥焚烧灰除磷效率为82%.XRD结果显示,污泥焚烧灰经熔盐处理后形成了氯磷灰石(chlorapatite),珍珠云母(margarite)等物质,其中氯磷灰石的形成有利于焚烧灰中磷的还原.对TGA-MS结果进行热解动力学反应拟合,结果显示,污泥焚烧灰除磷反应在添加少量氯化钙添加时为均相反应;污泥焚烧灰除磷反应在添加较多氯化钙时为固相扩散反应.固相反应的发生有利于降低磷酸盐还原反应温度并提高去除效率.  相似文献   

7.
To determine whether stable isotope measurements of body feathers can be used to investigate the isotopic niche of moulting (inter-nesting) adult seabirds, we examined the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of body feathers of breeding wandering albatrosses (Diomedea exulans) from Crozet Islands, southern Indian Ocean. First we showed that the isotopic composition of body feathers was not significantly different from that of wing feathers, being thus a safe alternative to flight feathers whose collection impairs the birds’ flying ability. Second, we looked at the variances in δ13C and δ15N values resulting from the isotopic measurement of a single feather, four different feathers, and a pool of four feathers per bird, to delineate the best isotopic analytical procedure. A two-step protocol is proposed that allows investigating both the intra- and inter-individual components of the niche width of the species. In a first step, isotopic measurements on a single feather per bird are used to define isotopic specialist from isotopic generalist populations. In a second step and for generalist populations only, measurements on additional (three) feathers per bird are used to delineate type A from type B isotopic generalists (Bearhop et al. in J Anim Ecol 73:1007–1012, 2004). Third, from a biological point of view, our data showed different moulting isotopic niches for adult males and females, and also within female wandering albatrosses. Since the isotopic composition of body feathers in this species reflects that of wing feathers, our results suggest that, after validation, body feathers have the potential for investigating the foraging ecology of other Procellariiforms and seabirds during the poorly known inter-nesting period.  相似文献   

8.
研究凤眼莲(Eichhornia crassipes)盖度对不同水流模式下的净化效果,分别对生长有凤眼莲的流动和静止水体进行长期监测,结果表明:流动水体中,随凤眼莲盖度增加,水体TN、TP、BOD5去除率均有提高,其中以盖度〉80%最为显著,去除率分别为44.35%、45.46%、56.98%。静止水体中,随凤眼莲盖度增加,水体DO显著降低;凤眼莲对TN、NH4+-N、NO3-N、NO2-N有显著吸收作用,尤其以盖度〈50%时效果较好,较对照水体分别低出36.60%、88.84%、36.74%、79.39%,远高于其他盖度时期;当盖度〉50%时,虽有一定的吸收作用,但吸收率较低;有凤眼莲水体TP含量显著上升,而PO43--P含量有所降低,尤其当盖度低于95%时,凤眼莲对水体PO43-P吸收显著,一旦盖度达100%,凤眼莲对PO43--P吸收作用减弱。故利用凤眼莲对污染水体进行生态修复时,要区别水体性质,控制其盖度。  相似文献   

9.
Stable isotopes of growing feathers and blood both represent assimilated diet, and both tissues are used to study the diet and foraging distribution of marine and terrestrial birds. Although most studies have assumed that both tissues represent a difference of one trophic level to diet, the enrichment factors of blood and feathers may differ, especially where endogenous reserves are used as precursors during feather synthesis. In this study, we compare carbon and nitrogen stable isotopes of blood and simultaneously growing feathers of five species of Procellariiformes, representing five genera, different geographical regions and different life stages (chicks and adults). In all species, feathers were enriched in 15N and 13C compared with blood. Isotopic values of carbon and nitrogen were correlated in different tissues growing simultaneously for most species analyzed, suggesting that mathematical corrections could be used to compare different tissues. Our results imply that more care needs to be taken when comparing stable isotope signatures across studies assuming different tissues are equivalent indicators of trophic ecology.  相似文献   

10.
The aim of this work is to investigate the application of fly ash adsorbent for removal of arsenite ions from dilute solution (100–1,000 ppm). Experiments were carried out using material from the “Turów” (Poland) brown-coal-burning power plant, which was wetted, then mixed and tumbled in a granulator to form spherical agglomerates. Measurements of arsenic adsorption from aqueous solution were carried out at room temperature and natural pH of fly ash agglomerates, in either a shaken flask or circulating column, to compare two different methods of contacting solution with adsorbent. Adsorption isotherms of arsenic were determined for agglomerated material using the Freundlich equation. Kinetic studies indicated that sorption follows a pseudo-second-order model. Preferable method to carry out the process is continuous circulation of arsenite solution through a column.  相似文献   

11.
Magnetic ion-imprinted polymers (IIPs) were prepared by precipitate polymerization and leached with HCl to remove uranium. Their ability to remove hexavalent uranium from wastewater effluents was studied. Batch adsorption studies to determine the optimum conditions of U(VI) removal were conducted at different levels of sample pH, sorbent amount, agitation time, and initial uranium concentration. It was observed that, under optimum conditions (i.e. pH 4, adsorbent amount of 50 mg, 45 min agitation time, and initial U(VI) concentration of 2 mg L?1), the maximum removal of U(VI) cations was >98% and 80% for the magnetic IIP and the corresponding magnetic non-imprinted polymers (NIP), respectively. Langmuir and Freundlich isotherms were used to describe the adsorption of U(VI) onto magnetic IIP and NIP. The adsorption capacity of U(VI) was determined to be 1.06 and 0.85 mg g?1 for the two isotherms, respectively. The order of selectivity was found to be U(VI) > Fe(III) > Pb(II). For six cycles of regeneration and reuse, the magnetic polymers maintained their stabilities with only a 4% loss in the extraction efficiency. The average extraction efficiencies of the magnetic polymers for the spiked acid mine drainage and sewage wastewater effluents were 71% and 58% for the magnetic IIP and NIP, respectively. From powder X-ray diffraction analysis, application of the Scherrer equation yielded magnetic nanoparticles of an average mean diameter of 11.9 nm. Thermo-gravimetric analysis revealed that the HCl-leached magnetic polymers had a magnetite residual weight of 5%.  相似文献   

12.
初步实验证实螯台球菌(Chelatococcus daeguensis)TAD1在高温下具有异养硝化-反硝化的能力,为验证其可应用性,采用曝气生物滤池工艺,研究了TAD1在温度为50℃的异养硝化-反硝化性能.结果表明,TAD1在曝气生物滤池中可同时进行好氧反硝化和异养硝化.当分别以硝氮、氨氮及硝氮和氨氮为氮源时,12 h的氮去除率均达到100%,氮的去除能力分别为12.67 mg.L-.1h-1、3.62 mg.L-.1h-1及16.53 mg.L-.1h-1.虽然在脱氮过程中,亚硝盐在6 h迅速积累到76 mg.L-1(硝氮为氮源)和52.6 mg.L-1(硝氮和氨氮为氮源),但在随后的几个小时内又快速降低至0(检测限之外).因而,TAD1具有应用于高温生物脱氮工艺的能力和优势.  相似文献   

13.
? The Cu–Ni/γ-Al2O3 catalyst was prepared to study HCN hydrolysis ? On catalyst calcined at 400°C, the HCN removal efficiency reaches a maximum. ? HCN removal is the highest at 480 min at a H 2 O/HCN volume ratio of 150 ? The presence of CO facilitates HCN hydrolysis and increases NH 3 production. ? O 2 increases the HCN removal and NOx production but decreases NH 3 production GRAPHIC ABSTRACT To decompose efficiently hydrogen cyanide (HCN) in exhaust gas, g-Al2O3-supported bimetallic-based Cu–Ni catalyst was prepared by incipient-wetness impregnation method. The effects of the calcination temperature, H2O/HCN volume ratio, reaction temperature, and the presence of CO or O2 on the HCN removal efficiency on the Cu–Ni/g-Al2O3 catalyst were investigated. To examine further the efficiency of HCN hydrolysis, degradation products were analyzed. The results indicate that the HCN removal efficiency increases and then decreases with increasing calcination temperature and H2O/HCN volume ratio. On catalyst calcined at 400°C, the efficiency reaches a maximum close to 99% at 480 min at a H2O/HCN volume ratio of 150. The HCN removal efficiency increases with increasing reaction temperature within the range of 100°C–500°C and reaches a maximum at 500°C. This trend may be attributed to the endothermicity of HCN hydrolysis; increasing the temperature favors HCN hydrolysis. However, the removal efficiencies increases very few at 500°C compared with that at 400°C. To conserve energy in industrial operations, 400°C is deemed as the optimal reaction temperature. The presence of CO facilitates HCN hydrolysis andincreases NH3 production. O2 substantially increases the HCN removal efficiency and NOx production but decreases NH3 production.  相似文献   

14.
Discharge of refinery effluents containing phenanthrene (Phe) may exert carcinogenic effects on aquatic organisms. The aim of the current investigation was to investigate electrochemical removal of Phe from urban drinking water using a batch reactor. Phe removal efficiency was examined under different operating conditions including current density (1–8 mA/cm2), electrode composition materials such as aluminum (Al), copper (Cu), iron (Fe), steel (AS), or zinc (Zn), pH (4–10), and duration (20–60 min). Phe concentration was determined utilizing standard techniques. Steel–Steel (AS–AS) as anode–cathode electrodes resulted in the least Phe removal (not detected), while Zn–Cu anode–cathode electrodes produced the highest Phe removal (100%) under similar experimental conditions. The increase in current density from 1 to 8 mA/cm2 at optimum electrode and pH enhanced Phe removal from 56% to 100%. The rise in duration from 20 to 60 min at optimum electrode and pH increased Phe removal from 32% to 100%. These findings indicated that Phe removal efficiency was elevated with increasing current density, electrolysis time, and pH. Batch experiments indicated that the electrochemical reactor might be effective in removing Phe from drinking water.  相似文献   

15.
三种表面活性剂对高浓度DDTs污染土壤的洗脱作用   总被引:1,自引:0,他引:1  
以高浓度滴滴涕(DDTs)污染场地土壤为研究对象,采用表面活性剂洗脱试验,比较研究了聚氧乙烯山梨糖醇酐单硬脂酸酯(Tween60)、辛基酚聚氧乙烯醚(TritonX 100)、十二烷基硫酸钠(SDS)对污染土壤中DDTs的洗脱效率.试验结果表明,三种表面活性剂对污染土壤中DDTs均具有一定的洗脱作用,去离子水对DDTs几乎没有洗脱效果.随着洗脱液中Tween60和SDS质量浓度的逐渐升高,土壤中DDTs的总洗脱效率逐渐增大,一次性洗脱时最大洗脱效率分别为43.60%和34.62%.随着洗脱液中TritonX 100质量浓度的逐渐升高,土壤中DDTs的总洗脱效率出现先增大后降低再升高的变化现象,最大为15.46%.土壤中六种DDT组分的洗脱效率不完全一样,其中Tween60对2,4'-DDD的洗脱效率可达55.12%,对4,4'-DDD的洗脱效率为54.09%;SDS对2,4'-DDD的洗脱效率为59.99%,对4,4'-DDD的洗脱效率为57.10%.试验结果可为筛选适宜的表面活性剂及质量浓度,研发高浓度DDTs污染场地土壤表面活性剂洗脱修复技术的工程应用提供理论依据.  相似文献   

16.
Summary Explanations of delayed plumage maturation (DPM) in passerines have focused on potential breeding season advantages for non-definitive (subadult) plumage. In contrast, the molt constraint hypothesis (Rohwer and Butcher 1988) proposes that subadult plumage is a winter adaptation, increasing winter survivorship by decreasing intraspecific aggression (the winter status signaling hypothesis) or predation (the winter crypsis hypothesis). Under the molt constraint hypothesis, nondefinitive breeding plumage is non-adaptive, resulting from species-specific constraints on the number of feathers replaced during the pre-alternate (spring) molt. In studies conducted on an overwintering population of orchard orioles in Panama, I tested predictions of both the winter status signaling and molt constraint hypotheses. Contrary to predictions of winter status signaling, I found no evidence that subadult plumage reduces adult male aggression toward subadults. Agonistic encounters occurred at random with respect to plumage and the intensity of adult male/subadult male encounters was not lower than the intensity of encounters occurring within age classes. Contrary to the molt constraint hypothesis, I found no evidence that the number of feathers exchanged by subadults in their pre-alternate molt is the sole constraint on the development of subadult breeding plumage. The majority of feathers grown by molting subadult orioles during January and February were of non-definitive coloration. These results, together with results of earlier breeding season experiments which tested summer communication hypotheses for DPM in this species, suggest that subadult plumage in the orchard oriole may be non-adaptive and the result of constraints on plumage development. They also indicate, however, that the extent of the pre-alternate molt is not the sole source of that constraint.  相似文献   

17.
Quantification of animal colors is important to a variety of fields of research, especially those dealing with visual communication and sexual selection. Most animal colors are easily measured using well-established spectrophotometric techniques. However, the unique characteristics of iridescent colors present particular challenges and opportunities to quantify novel color metrics. Due to the fine-scale angle dependence of iridescent coloration, color metrics, such as hue and brightness, must be measured using methods that allow for repeatable comparison across individuals (e.g., by carefully controlling and measuring viewing geometry). Here, we explain how the optical characteristics of iridescent colors should be considered when developing measurement techniques, describe the pitfalls of some commonly used techniques, and recommend improved methods and metrics (angular degree of color change and breadth of reflectance) for quantifying iridescent color. In particular, most studies of iridescent birds to date have used less than ideal procedures and have not provided repeatability estimates for their methods. For example, we demonstrate here that measuring coloration from overlapping patches of iridescent feathers may be problematic, and we argue against methods that do not carefully control viewing geometry. We recommend measuring iridescence at maximal reflectance angles using an apparatus that allows for sample rotation, and we compare this technique to some other commonly used methods using iridescent gorget and crown feathers from Anna’s hummingbirds (Calypte anna). Our apparatus allows for the quantification of angular color change, and we found that maximal reflectance measurements using single feathers are highly repeatable both within feather samples and among samples within an individual.  相似文献   

18.
In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Activated carbon was obtained from pine cone chemically activated using ZnCl2 and modified by H3PO4. Natural zeolite of clinoptilolite was modified by acid treatment with HCl, while nano-ceria was synthesized via redox method. Mixed supports of carbon-zeolite and carbonceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller surface area (BET), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation of nano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts (~1000 m2·g?1). FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100° C-250°C. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds (VOCs), representing high catalytic performance of 98% for the abatement of xylene at 250°C. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocatalysts.  相似文献   

19.
甲基对硫磷降解菌DLL-1的分离、鉴定及降解性研究   总被引:13,自引:0,他引:13  
从长期施用甲基对硫磷的污染土壤中分离到一株能以甲基对硫磷为唯一碳源生长且能将其完全矿化的细菌 D L L- 1 ,经鉴定,为邻单胞菌( Plesiomonas sp .) .该菌株3 h 内对50 mg/ L甲基对硫磷的降解率为93 % ,24h 内对50 mg/ L甲基对硫磷的降解率为95 % 以上.在葡萄糖铵盐培养基中, D L L1 对甲基对硫磷的耐受浓度和降解速度均增大.降解曲线表明延滞期内,菌体依靠上一生长阶段分泌的酶类对甲基对硫磷进行降解,一旦菌体开始生长,则检测不到中间代谢产物对硝基苯酚的存在.生长情况和粗酶液试验均显示 D L1 优良的降解性状  相似文献   

20.
Renewable energy production is expanding rapidly despite mostly unknown environmental effects on wildlife and habitats. We used genetic and stable isotope data collected from Golden Eagles (Aquila chrysaetos) killed at the Altamont Pass Wind Resource Area (APWRA) in California in demographic models to test hypotheses about the geographic extent and demographic consequences of fatalities caused by renewable energy facilities. Geospatial analyses of δ2H values obtained from feathers showed that ≥25% of these APWRA‐killed eagles were recent immigrants to the population, most from long distances away (>100 km). Data from nuclear genes indicated this subset of immigrant eagles was genetically similar to birds identified as locals from the δ2H data. Demographic models implied that in the face of this mortality, the apparent stability of the local Golden Eagle population was maintained by continental‐scale immigration. These analyses demonstrate that ecosystem management decisions concerning the effects of local‐scale renewable energy can have continental‐scale consequences.  相似文献   

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