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2774. Adsorbents for iron removal obtained from vermiculite

Creator:
Węgrzyn, Agnieszka, Chmielarz, Lucjan, Zjeżdżalka, Paweł, Andrzej Kowalczyk, Jabłońska, Magdalena, Baldrich Tolosa, Xavier, and Michalik, Marek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, vermikulit, adsorpce, vermiculite, adsorption, acid treatment, iron removal, 7, and 551
Language:
English
Description:
In presented work, raw, expanded and acid treated vermiculites were used as low-cost and active adsorbents for reducing of environmental pollution with heavy metals. Acid treatment was performed at elevated temperature (95°C) for 2 and 24 h in solution of HNO3. Adsorption capacity towards Fe3+ was studied in column, semi-batch and batch mode. It was shown that all samples are effective in removal of heavy metals; however adsorption mechanism is based not only on ion exchange of interlayer cations but also precipitation/deposition processes. Starting material and modified samples as well as spent adsorbents were characterized with respect to the vermiculite structure using X-ray diffraction method., Agnieszka Węgrzyn, Lucjan Chmielarz, Paweł Zjeżdżalka, Andrzej Kowalczyk, Magdalena Jabłońska, Xavier Baldrich Tolosa and Marek Michalik., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2775. Adsorpcia arzeničnanov na pôdach: štúdium rýchlosti adsorpcie a adsorpčných izoteriem

Creator:
Hiller, Edgar
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
adsorption, freundlich isotherm, arsenates, kinetic equation, adsorpcia, Freundlichova izoterma, arzeničnany, and rýchlostná rovnica
Language:
Slovak
Description:
Kinetic and equilibrium studies of adsorption of arsenates As(V) were investigated in four soils from Slovakia. Using experimentally obtained adsorption isotherms of arsenates, the effect of selected soil properties on its adsorption was studied. The rate of As(V) adsorption was evaluated by three simple kinetic models: Elovich equation, modified Freundlich isotherm and pseudo-second order equation. It can be stated from experimentally obtained and calculated data that an increase in the initial As(V) concentration in solution resulted in a drop in the rate of As(V) adsorption and an increase in the time necessary for an attainment of the adsorption equilibrium. Results from equilibrium studies of As(V) adsorption fitted well to the Freundlich isotherm. The comparison of Freundlich coefficient kF with selected soil properties showed that capacity of particular soil for As(V) retention increased with increasing calcium carbonate content in given soil. The relation between CaCO3 content and kF coefficient was supported by highly positive correlation of dependence kF vs CaCO3, with R2 = 0.868. and Na štúdium rýchlosti adsorpcie arzeničnanov As(V) a ich adsorpčných izoteriem boli použité štyri vzorky pôd. Pomocou experimentálne získaných adsorpčných izoteriem As(V) bol sledovaný aj vplyv niektorých pôdnych vlastností na rozsah adsorpcie As(V). Rýchlosť adsorpcie As(V) bola zhodnotená použitím troch jednoduchých rýchlostných rovníc: Elovichovej rovnice, modifikovanej Freundlichovej izotermy a kinetickej rovnice pseudo-druhého poriadku. Namerané a vypočítané výsledky zo štúdia rýchlosti adsorpcie dokumentujú, že s rastúcou počiatočnou koncentráciou As(V) vo vodnom roztoku sa adsorpčná rýchlosť znížila a čas potrebný na dosiahnutie adsorpčnej rovnováhy sa zvýšil. Experimentálne získané adsorpčné izotermy As(V) veľmi dobre vyhovovali Freundlichovej adsorpčnej izoterme. Zo sledovaných chemických a fyzikálnych vlastností pôd mal na koeficient kF najväčší vplyv obsah uhličitanu vápenatého (CaCO3). Vzťah medzi obsahom CaCO3 a koeficientom kF sa potvrdil vysoko pozitívnou koreláciou (R2 = 0,868).
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2776. Adsorption of phenol and aniline by original and quaternary ammonium salts-modified montmorillonite

Creator:
Kostelníková, Hana, Petr Praus, and Turicová, Martina
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, adsorpce, montmorillonit, fenoly, anilin, adsorption, montmorillonite, phenols, aniline, intercalation, quaternary ammonium salts, 7, and 551
Language:
English
Description:
Adsorption of phenol and aniline onto original and with quaternary ammonium salts (QASs)-modified montmorillonite was described by sorption isotherms of type III and II, respectively. For the montmorillonite (MMT) modification - hydrophobisation, cetyltrimethyl- ammonium (CTMA) and tetramethylammonium (TMA ) cations were used. In comparison with phenol, aniline was adsorbed largely on original MMT but less on modified one. XRD pa tterns indicated that both aromatic compounds were intercalated in the MMT interlayer be ing perpendicularly oriented to silicate sheets. Alkyl chains of CTMA and TMA probably act as organic "pillars" stabilising the MMT tabular structure against exfoliation due to the intercalation with phenol and aniline of high concentrations., Hana Kostelníková, Petr Praus and Martina Turicová., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2777. Adsorptive removal of aromatic compound by montmorillonite: application of factorial design analysis

Creator:
Geyikçi, Feza and Çoruh, Semra
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, montmorillonit, montmorillonite, factorial design analysis, phenol adsorption, 7, and 551
Language:
English
Description:
Phenolic compounds are common pollutants found particularly in the effluents from petroleum and petrochemical, coal conversion, and phenol producing industries. Due to their toxicity and carcinogenity, water and wastewater containing phenolic compounds must be treated before being used and discharged for receiving water bodies. There is a growing interest in using low-cost and commercially available materials for the adsorption of organic compounds. Clay minerals have great potential to remove phenols in water due to efficient sorbents which can be used as alternative adsorbents to replace the costly activated carbon. They are widely applied in many fields of adsorption technology including the removal of amines, metals, ketones, phosphates, chlorophyll, non-ionic contaminants, and organic pigments/dyes. Montmorillonitic smectites, {(Na,Ca)0.33(Al,Mg)2(Si4O10)-(OH)2.nH2O} are one of the natural clay minerals that have specific surface chemical properties. In this study, a factorial experimental design technique was used to investigate the adsorption of phenol from water solution on montmorillonite. Factorial design of experiments is employed to study the effect of three factors: pH (2.0 and 8.0), montmorillonite dosage (0.1 and 1.0 g/L) and initial low and high concentration (10 and 100 mg/L). The efficiency of phenol adsorption was determined after 60 min of treatment. Main effects and interaction effects of three factors were analyzed by using statistical techniques. A regression model was found to fit the experimental data very well. Through using the Student’s t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage phenol adsorption., Feza Geyikçi and Semra Çoruh., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2778. Adult demography, dispersal and behaviour of Brenthis ino (Lepidoptera: Nymphalidae): how to be a successful wetland butterfly

Creator:
Zimmermann, Kamil, Fric, Zdeněk, Filipová, Ladislava, and Konvička, Martin
Type:
article, model:article, and TEXT
Subject:
Argynnini, Nymphalidae, Brenthis ino, behaviour, butterfly ecology, dispersal, habitat quality, grasslands, host plant range, and metapopulation
Language:
English
Description:
Continent-wide loss of traditionally managed humid meadows is raising concern for associated butterfly specialists across Europe. However, not all species associated with this biotope are threatened, and the Lesser Marbled Fritillary (Brenthis ino) has even spread locally. We employed mark-recapture and transect walks to study its population structure and patterns of landscape occupancy in a hilly region of western Bohemia, Central Europe, to determine which life history or demography traits might be responsible for its success. A population studied by mark-recapture harboured more than 1000 individuals and was interconnected with other populations. This was further supported by a fit of the inverse power function to dispersal data. Observations of adult behaviour revealed a broad host plant range: at least three species of plants were used by the single population. On a landscape scale, the butterfly exhibited an aggregated distribution matching its host plants. It was associated with the distribution of characteristic plants and butterflies of semi-natural humid meadows, but its frequency exceeded those of other humid grasslands specialists. The relatively broad host range coupled with varying biotope requirements of individual host plant species results in a wide biotope range for the butterfly, explaining its persistence in fragmented Central European landscapes.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2779. Adult demography, spatial distribution and movements of Zerynthia polyxena (Lepidoptera: Papilionidae) in a dense network of permanent habitats

Creator:
Čelik, Tatjana
Type:
article, články, model:article, and TEXT
Subject:
Zoologie, zoologie, entomologie, Lepidoptera, Papilionidae, Zerynthia polyxena, Southern Festoon, mark-release-recapture, demography, resource distribution, movement, home range, butterfly conservation, 2, and 59
Language:
English
Description:
1_The adult demographic parameters, mobility, nectar choice and how the spatial distribution of males and females of Z. polyxena is affected by the distribution and abundance of host-plants, and adults of the opposite sex was studied in a population of this species inhabiting a dense network of permanent habitats (totalling 8.7 ha). The population size was estimated to be ca. 300 individuals. The average adult lifespan was 4.4 days and the maximum 23 (male) and 20 (female) days. The capture probability was higher for males than females due to the more conspicuous behaviour and bounded area of activity of males. A slow increase was followed by a slow decrease in the sex specific parabolic recruitment curve, indicating slight protandry and long emergence period, probably due to habitat heterogeneity. The spatial distribution of host plants (Aristolochia lutea) is the key factor determining the spatial distribution of adults. There was a strong positive correlation between male and female density at each patch, both of which were dependent on the cover of host plants growing in sunny conditions. In searching for A. lutea plants suitable for oviposition, females fly greater distances and move more frequently between patches than males. The size, shape and orientation of the male home range were influenced by the size, shape and orientation of stands of host-plants in sunny positions, but not by patch area. Such adult fidelity to stands of host-plants in sunny positions indicates that the spatial distributions of oviposition sites, mate-locating sites and larval habitats of Z. polyxena overlap. The better statistical fit and much lower probabilities for long-distance movements generated by a negative exponential function than an inverse power function are probably due to the small size and high habitat connectivity of the site studied. Adults were opportunistic in their use of nectar plants., 2_Traditional management is the key factor for maintaining permanent habitats for this species in a grassland biotope., Tatjana Čelik., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2780. Adult feeding increases fecundity in female Helicoverpa armigera (Lepidoptera: Noctuidae)

Creator:
Song, Zeng-Ming, Li, Zhe, Li, Dian-Mo, Xie, Bao-Yu, and Xia, Jing-Yuan
Type:
article, model:article, and TEXT
Subject:
Noctuidae, Helicoverpa armigera, adult feeding, fecundity, and lifespan
Language:
English
Description:
The availability and quality of nectar for adults are thought to affect fecundity of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Experiments were conducted to analyze the effect of adult feeding on the fecundity, and oviposition pattern of moths, and larval performance (egg hatch). The moths were fed either on distilled water, honey solution, or one of a range of concentrations of sucrose solution. The results showed that diets with sugars significantly increased fecundity and adult lifespan. Lifespan, total numbers of eggs and egg mass were significantly higher for females that fed on sugar during adult life. Egg hatch (a measure of offspring fitness) decreased over time regardless of sucrose concentration, but had always higher levels in the groups fed sugars. The peak of the ovipositing period was delayed and prolonged, with more eggs deposited, when moths were fed on sugar solution. In conclusion, adult feeding increases the fecundity of female moths and plays an important role in enhancing the fitness of individual cotton bollworm offspring.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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