Wyniki wyszukiwania - Biblioteka Nauki

1

Wysokoefektywne uzdatnianie wód podziemnych z zastosowaniem mas katalitycznych

100%

Włodarczyk M. , Wybieralski J.

Ekologia i Technika

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2006

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tom R. 14, nr 1

16-22

PL

W pracy badano kinetykę adsorpcji atrazyny i flufenacetu w preparacie Aspect 500 SC na trzech glebach o różnej zawartości węgla organicznego i różnym składzie granulometrycznym.

EN

The adsorption kinetics of two herbicides atrazine and flufenacet (main ingreadients of Aspect 500 SC) was investigated in three soils of different organic carbon contents and granulometric composition.

2

Modeling of adsorption in a mixing tank

80%

Gwadera M. , Kupiec K.

|

2015

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tom R. 112, z. 1-Ch

3--16

EN

Computational models for adsorption in a tank are presented. The approximate model provides the same results as the exact model. The diffusion coefficient of a dye in an adsorbent pellet and the mass transfer coefficient in a fluid phase were determined on the basis of the measurements of dye adsorption on the activated carbon. It was determined how the fraction of the resistance to mass transfer in the fluid to the overall mass transfer resistance changes during adsorption. It was found that, for the examined system, the main resistance to mass transfer is located in the liquid phase.

PL

Przedstawiono modele obliczeniowe adsorpcji w zbiorniku. Stwierdzono, że model przybliżony daje identyczne wyniki z modelem ścisłym. Na podstawie przeprowadzonych pomiarów adsorpcji barwnika na węglu aktywnym określono wartość współczynnika dyfuzji w ziarnie oraz współczynnika wnikania masy w fazie ciekłej. Wyznaczono czasowe zmiany udziału oporu wnikania masy w fazie ciekłej w sumarycznym oporze przenoszenia masy w trakcie adsorpcji. Stwierdzono, że dla badanego układu główny opór przenoszenia masy jest zlokalizowany w fazie ciekłej.

3

Kinetic research of quinoline, pyridine and phenol adsorption on modified coking coal

80%

Sun X. , Xu H. , Wang J. , Ning K. , Huang G. , Yu Y. , Ma L.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 3

965--974

EN

Adsorption is widely used in wastewater treatment. In this work, the removal of quinoline, pyridine and phenol from coking wastewater by using modified coking coal, which was treated by four different modification methods i.e. acidification sodium hydroxide (5 mol/dm3), hydrochloric acid (5 mol/dm3) and acetic acid (5 mol/dm3) and low-temperature (105 oC) oxidation, was investigated. The modified coal was characterized by the surface area analysis, SEM, total acidity and basicity and FT-IR. The results showed that the surface area from high to low follows the order: modification with acetic acid, modification with hydrochloric acid, raw coal, modification with sodium hydroxide and modification with low-temperature. Experimental data were fitted to pseudo-first-order, pseudo-second-order and intra-particle diffusion. The adsorption of all followed pseudo-second-order kinetics. The result showed that the removal efficiency of coal modified by hydrochloric acid and acetic acid are higher than raw coal, while modified by sodium hydroxide and low-temperature are lower than raw coal., The coal modified by hydroxide acid had the best adsorption capacity.

4

Batch adsorption in a finite volume reservoir – application of an approximate kinetic model

80%

Gwadera M. , Kupiec K.

Czasopismo Techniczne. Chemia

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2014

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tom R. 111, z. 1-Ch

3--13

EN

The paper refers to the kinetics of batch adsorption in a perfect mixing reservoir. Systems with a linear adsorption equilibrium, spherical adsorbent pellets and mass transfer resistance in both phases are considered. An approximate kinetic model, based on approximation with the use of continued fractions, was used in calculations. It was found that the model gives results consistent with the exact solution.

PL

Artykuł dotyczy kinetyki adsorpcji okresowej w zbiorniku z idealnym mieszaniem. Rozważono układy z liniową równowagą adsorpcyjną, kulistymi ziarnami adsorbentu i z oporami przenoszenia masy występującymi w obu fazach. W obliczeniach wykorzystano przybliżony model kinetyczny oparty na aproksymacji ułamkami łańcuchowymi. Stwierdzono, że model ten daje wyniki zgodne z rozwiązaniem ścisłym.

5

Adsorption of hexane and cyclohexane vapours at the water drop surface

80%

Miller R. , Aksenenko E. V. , Kovalchuk V. I. , Tarasevich Y. I. , Fainerman V. B.

Physicochemical Problems of Mineral Processing

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2018

|

tom Vol. 54, iss. 1

54--62

EN

The dependence of the dynamic surface tension of water at the interface with saturated hexane and cyclohexane vapours was measured by the drop profile analysis method. The surface tension for the adsorption layers of cyclohexane at different temperatures was compared with the results reported earlier for the adsorption of hexane and other alkanes from the vapour phase on water drops. It is shown that cyclohexane is adsorbed significantly slower than the adsorption of hexane occurs, and is characterised by a much larger induction time. The error in the drop radius measurements at 40 ºC attains 45 m. The experimental rheologic characteristics of the adsorbed layers are studied and the results are compared with the model developed to describe an adsorption process governed by a kinetic mechanism.

6

Adsorption of CO2 by surface modified coal-based activated carbons: kinetic and thermodynamic analysis

80%

Xinzhe L. , Mingyang Z. , Juan C. , Zhengyu H. , Shuaifei X. , Mingxuan T. , Chenchen Z.

Polish Journal of Chemical Technology

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2022

|

tom Vol. 24, nr 3

19--28

EN

The effects of different surface modifiers on the CO2 adsorption capacity of coal-based activated carbons were studied, and the diffusion behavior, adsorption kinetics and thermodynamic parameters of CO2 in activated car-bons were analyzed. The results show that compared with ethylene glycol, 1,2-propylenediamine and zinc chloride, potassium hydroxide and sodium hydroxide can greatly improve CO2 adsorption capacity. The adsorption rate is faster, and the adsorption capacity is larger, with the maximum CO2 adsorption capacity being 33.54 mL/g. Fick’s law can well describe the diffusion behavior of CO2 in activated carbon. The addition of a surface modifier can increase the diffusion coefficient. The diffusion of CO2 in activated carbon falls into the category of crystal diffusion. The adsorption kinetics of CO2 before and after surface modification follow the Bangham equation. During the adsorption process, δ H < 0, δ G < 0, δ S < 0. Surface modification can reduce adsorption heat and promote adsorption, and the adsorption process is dominated by physisorption.

7

Sorption of the acid dyes onto strongly basic anion exchanger: Kinetic and equilibrium studies

80%

Greluk M. , Hubicki Z. , Wołowicz A.

Challenges of Modern Technology

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2011

|

tom Vol. 2, no. 1

74--78

EN

The strong base acrylic anion exchangers, Amberlite IRA-458, was used as an adsorbent for the investigation of acid dyes (Acid Orange 7, Acid Orange 10 and Acid Red 88) adsorption kinetics and isotherms. The pseudo-fi rst order and pseudo-second order kinetic models were used to analyze the kinetic data and good agreement between the experimental and calculated amounts of dye adsorbed at equilibrium were obtained for the pseudo-second order kinetic models for the entire investigated concentrations domain in the case all three investigated dyes. The adsorption equilibrium data were analyzed by the Langmuir and Freundlich isotherm models with the best fitting being the first one.

8

Adsorption Kinetics of Edamame Soybean Peel Activated Carbon in Reducing the Level of Phosphate

80%

Eri I. R. , Pramudinta N. K. , Nurmayanti D.

Journal of Ecological Engineering

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2022

|

tom Vol. 23, nr 2

97--107

EN

Domestic wastewater, such as detergent wastewater, causes the increase of the phosphate level that strongly contributes to eutrophication. Adsorption is a method that can be used to reduce the levels of phosphate. The natural ingredients that can be made as activated carbon include edamame soybean peel, because it contains a lot of celluloses. This research aimed to analyze the adsorption kinetics and adsorption capacity of edamame soybean peel activated carbon in reducing the phosphate levels. Adsorption was carried out with batch method with various concentrations of adsorbate (2 mg/L, 4 mg/L, and 6 mg/L) and stirring time (3 hours, 6 hours, 9 hours, and 12 hours). The results showed that the highest adsorption capacity was found in 6 mg/L of adsorbate concentration and 6 hours of stirring time. The results were validated by the Langmuir isotherm and pseudo-second-order adsorption kinetics model. The Langmuir isotherm indicated that adsorption occurred in monolayer. The maximum adsorption capacity was 0.43509 mg/g and the constant of adsorption kinetics was 1.5558 g/mg•min. Activated carbon from edamame soybean peel successfully reduced the levels of phosphate. The increase of adsorption capacity was correlated with the increasing concentration of adsorbate and stirring time until the equilibrium.

9

Kinetic studies on sorption of ni(ii) and cd(ii) from chloride solutions using selected acidic cation exchangers

70%

Otrembska P. , Gega J.

|

tom Vol. 49, iss. 1

301--312

EN

Sorption of nickel(II) and cadmium(II) ions from chloride solutions was tested. Three different strongly acidic cation exchangers, i.e. Lewatit MonoPlus SP 112, Amberlite 200C and Amberlyst 15, were used. Effects of phase contact time, pH and initial concentration of metal ions on equilibrium and kinetics of sorption by batch methods were studied. It was showed that sorption of Ni(II) and Cd(II) could be described by the pseudo-second order equation. Experimental results data were analyzed using the Langmuir and Freundlich isotherms. Sorption of Ni(II) and Cd(II) onto investigated resins followed the Langmuir isotherm.

10

Removal of lead(II) ions by an adsorption process with the use of an advanced SiO2/lignin biosorbent

70%

Klapiszewski Ł. , Bartczak P. , Szatkowski T. , Jesionowski T.

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2017

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tom Vol. 19, nr 1

48--53

EN

We demonstrate here that lignin can be successfully combined with silica to create a multifunctional material with considerable sorption capabilities. Experiments were carried out in which a silica/lignin hybrid was used for the removal of lead(II) ions from water solutions. Adsorption kinetics were also determined and preliminary regeneration tests were performed. The effectiveness of the adsorption process depends on the following parameters: contact time of adsorbent and adsorbate (equilibrium times: 5 min for concentration 25 mg/L, 10 min for 50 and 75 mg/L, 60 min for 100 mg/L), pH (optimal pH = 5) and adsorbent mass. The kinetics of the adsorption of lead(II) ions on the SiO2/lignin biosorbent are best described by a pseudo-second-order model. Adsorption isotherms of lead(II) ions were also determined. The experimental data were found to be in agreement with the Langmuir model, and the maximal sorption capacity of the adsorbent with respect to lead(II) was 89.02 mg/g.

11

Adsorption behavior and XPS analysis of nonylphenol ethoxylate on low rank coal

70%

You X. , Ma C. , Li Z. , Lyu X. , Li L.

|

2019

|

tom Vol. 55, iss. 3

721--731

EN

In this work, low rank coal was used for the removal of nonylphenol ethoxylate with fifteen ethylene oxide groups (NPEO15) from aqueous solutions at different contact times, temperatures, and initial adsorbent concentrations. The adsorption isotherms showed good fit with the Langmuir equation. Maximum adsorption capacities calculated at 308, 318, and 328 K were 23.64, 29.41, and 35.71 mg g–1, respectively. The changes in the free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were calculated in order to predict the nature of adsorption. The results of the thermodynamic analysis indicated that a spontaneous process took place, driven synergistically by both enthalpy and entropy. The adsorption kinetics of NPEO15 were consistent with a pseudo-second order reaction model. XPS results showed that the oxygen functional groups on the low rank coal surface were significantly covered by NPEO15. Furthermore, while the content of C–C/C–H functional groups increased significantly, that of C–O functional groups decreased after absorption. These results clearly indicate that low rank coal is more hydrophobic and displays better floatability.

12

Influence of pH on adsorption kinetics of monochlorophenols from aqueous solutions on granular activated carbon

60%

Kuśmierek K. , Świątkowski A.

Ecological Chemistry and Engineering. S

|

2015

|

tom Vol. 22, nr 1

95--105

EN

Adsorptive removal of 2-, 3- and 4-chlorophenol from aqueous solutions by granular activated carbon was studied. The influence of different experimental parameters like initial concentration, carbon dosage and pH on the adsorption of monochlorophenols were evaluated. The influence of type of acid and base used for water acidification or alkalization was also tested. The results indicate that acidic pH is favorable for the adsorption of chlorophenols; however the type of acid or alkali used for the change of pH has a little influence and did not significantly affect the adsorption efficiency. The pH played an important role in the adsorption kinetics of chlorophenols at pH values above the pKa values of the compounds, while little influence on adsorption rate was observed if pH was decreased below the pKa values.

PL

Zbadano absorpcję 2-, 3- i 4-chlorofenolu z wody na granulowanym węglu aktywnym. Sprawdzono wpływ różnych parametrów na adsorpcję, takich jak stężenie początkowe adsorbatów, ilość węgla aktywnego czy pH roztworu, jak również wpływ rodzaju kwasu i zasady użytych do zakwaszenia lub alkalizacji środowiska. Uzyskane rezultaty pokazują, że adsorpcja chlorofenoli zachodzi o wiele lepiej w kwaśnym środowisku, natomiast rodzaj zastosowanego kwasu lub zasady do zmiany pH nie wpływa znacząco na efektywność adsorpcji. pH odgrywa natomiast istotną rolę w przypadku kinetyki adsorpcji chlorofenoli na węglu aktywnym zwłaszcza w pH powyżej wartości ich pKa, natomiast w środowisku o pH poniżej wartości pKa chlorofenoli wpływ ten jest znikomy.

13

Badanie kinetyki adsorpcji wody na zeolitach z gazowych mieszanin etanol-woda

60%

Kupiec K. , Rakoczy J. , Mirek R. , Zieliński Ł.

Inżynieria i Aparatura Chemiczna

|

2004

|

tom Nr 3s

87-88

EN

The kinetic curves of water adsorption on 3A zeolite have been determined. Water has been adsorbed from gaseous ethanol- -water mixture. It has resulted in estimating the diffusion coefficient in an adsorbent pellet. Water adsorption from ethanol mixtures has a practical application in adsorptive ethanol dehydration.

14

Synthesis, Characterization and Cr(VI) Adsorption Properties of Modified Magnetite Nanoparticles

60%

Çıftçı H. , Ersoy B. , Evcın A.

Acta Physica Polonica A

|

2017

|

tom 132

|

nr 3

564-569

EN

In this study, magnetite (Fe₃O₄) nanoparticles were synthesized by chemical co-precipitation method, coated with silica, and then the surface of silica coated magnetite (Fe₃O₄@SiO₂) nanoparticles was modified with (3-aminopropyl)triethoxysilane (APTES) at first. Secondly, attained nanoparticles were characterized by the Fourier transform infrared, X-ray diffraction, transmission electron microscopy, the Brunauer-Emmett-Teller, vibrating sample magnetometer, and zeta-sizer devices/methods. Finally, detailed adsorption experiments were performed to remove hexavalent chromium (Cr(VI)) from aqueous media by synthesized nanoparticles. Mean size and specific surface area of synthesized nanoparticles were about 15 nm and 89.5 m²/g, respectively. The highest adsorption capacity among used adsorbents (Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@L) was attained by Fe₃O₄ nanoparticles and it was determined that adsorption capacity of the other two adsorbents was too low when compared to the Fe₃O₄ nanoparticles. Optimum conditions for Cr(VI) adsorption by Fe₃O₄ nanoparticles were: pH, 3; temperature, 55°C; contact time, 90 min; adsorbent concentration, 0.5 g/l and initial Cr(VI) concentration 10 mg/l. Under these conditions, adsorption capacity and removal percentage of Cr(VI) were found to be 33.45 mg/g and 88%, respectively.

15

Badania kinetyczne adsorpcji wybranych barwników z roztworów wodnych na nanoporowatych węglach aktywnych otrzymanych z prekursorów polimerowych

60%

Czubaszek M. , Choma J.

Ochrona Środowiska

|

2016

|

tom Vol. 38, nr 4

3--12

PL

Badano kinetykę adsorpcji wybranych barwników (oranż kwasowy 7, oranż kwasowy 52 i błękit zasadowy 9) z roztworów wodnych na trzech porowatych adsorbentach. Dwa z nich stanowiły proszkowe węgle otrzymane laboratoryjnie z prekursorów polimerowych, natomiast trzeci – zastosowany w celach porównawczych – był handlowym węglem aktywnym firmy Chemviron Carbon. Pierwszy adsorbent laboratoryjny był węglem aktywnym ze znaczną objętością mikroporów, otrzymanym z sulfonowej żywicy styrenowo-dwuwinylobenzenowej. Drugi był natomiast uporządkowanym mezoporowatym węglem otrzymanym z żywicy fenolowo-formaldehydowej metodą miękkiego odwzorowania. Do opisu kinetyki procesu adsorpcji barwników wykorzystano równania pseudo I i pseudo II rzędu. Stwierdzono, że adsorpcja wybranych barwników na badanych węglach aktywnych przebiegała zgodnie z modelem pseudo II rzędu, o czym świadczyły wartości współczynnika korelacji bliskie 1. Wykazano, że kinetyka adsorpcji na poszczególnych węglach różniła się istotnie – stan równowagi adsorpcyjnej osiągany był najszybciej (kilka minut) na węglu aktywnym z sulfonowej żywicy styrenowo-dwuwinylobenzenowej, natomiast najwolniej (kilka godzin) na węglu handlowym. Badane węgle także istotnie różniły się pojemnością adsorpcyjną – najlepszą charakteryzował się węgiel aktywny otrzymany z sulfonowej żywicy styrenowo-dwuwinylobenzenowej. Wymagana dawka tego węgla w celu usunięcia 100% barwnika z roztworu o stężeniu 150 mg/dm3 wynosiła 400 mg/dm3, natomiast w przypadku pozostałych dwóch węgli była pięciokrotnie większa.

EN

Adsorption kinetics of the selected dyes (Acid Orange 7, Acid Orange 52 and Basic Blue 9) from aqueous solutions were studied on three porous materials. Two of them were laboratory powdered carbons obtained from polymeric precursors, while the third one was a commercial micro-mesoporous activated carbon from Chemviron Carbon, used for reference purposes. The first laboratory adsorbent was an active carbon with a high micropore volume, synthesized from the sulfonated styrene-divinylbenzene resin. The second one was an ordered, mesoporous carbon obtained from phenol-formaldehyde resin by soft-templating. The adsorption kinetics data was illustrated using the pseudo-first and pseudo-second order models. The correlation coefficient values close to unity proved that adsorption of selected dyes on the studied active carbons proceeded according to the pseudo-second order model. It was demonstrated that the adsorption kinetics differed significantly between the studied materials. The active carbon obtained from the sulfonated styrene-divinylbenzene resin was the quickest (minutes) to reach the adsorption equilibrium, while the commercial one was the slowest (hours). Additionally, the studied carbons displayed significantly different adsorption capacities. The activated carbon obtained from the sulfonated styrene-divinylbenzene resin was the best adsorbent and 400 mg/dm3 was a dose sufficient to remove 100% of the dye from 150 mg/dm3 solution. For the remaining two carbons that dose was five times higher.

16

Influence of Ph on Adsorption Kinetics of Monochlorophenols From Aqueous Solutions on Granular Activated Carbon / Wpływ Ph Na Kinetykę Adsorpcji Monochlorofenoli Z Roztworów Wodnych Na Granulowanym Węglu Aktywnym

60%

Kuśmierek K. , Świątkowski A.

|

nr 1

95-105

EN

Adsorptive removal of 2-, 3- and 4-chlorophenol from aqueous solutions by granular activated carbon was studied. The influence of different experimental parameters like initial concentration, carbon dosage and pH on the adsorption of monochlorophenols were evaluated. The influence of type of acid and base used for water acidification or alkalization was also tested. The results indicate that acidic pH is favorable for the adsorption of chlorophenols; however the type of acid or alkali used for the change of pH has a little influence and did not significantly affect the adsorption efficiency. The pH played an important role in the adsorption kinetics of chlorophenols at pH values above the pKa values of the compounds, while little influence on adsorption rate was observed if pH was decreased below the pKa values

PL

Zbadano absorpcję 2-, 3- i 4-chlorofenolu z wody na granulowanym węglu aktywnym. Sprawdzono wpływ różnych parametrów na adsorpcję, takich jak stężenie początkowe adsorbatów, ilość węgla aktywnego czy pH roztworu, jak również wpływ rodzaju kwasu i zasady użytych do zakwaszenia lub alkalizacji środowiska. Uzyskane rezultaty pokazują, że adsorpcja chlorofenoli zachodzi o wiele lepiej w kwaśnym środowisku, natomiast rodzaj zastosowanego kwasu lub zasady do zmiany pH nie wpływa znacząco na efektywność adsorpcji. pH odgrywa natomiast istotną rolę w przypadku kinetyki adsorpcji chlorofenoli na węglu aktywnym zwłaszcza w pH powyżej wartości ich pKa, natomiast w środowisku o pH poniżej wartości pKa chlorofenoli wpływ ten jest znikomy

17

Modelowanie kinetyki sorpcji z zastosowaniem pochodnych ułamkowych dla układu barwnik azowy - sorbent roślinny

51%

Tomczak E. , Kamiński W.

Inżynieria i Aparatura Chemiczna

|

2013

|

tom Nr 4

376--377

PL

W pracy przedstawiono za pomocą równań różniczkowych ułamkowych opis kinetyki sorpcji barwnika azowego Direct Orange 26 na słomie żytniej. W procedurze obliczeniowej wykorzystano metodę numeryczną rozwiązywania równań różniczkowych. Proponowane równanie kinetyki ma trzy parametry: ułamek pochodnej a, stałą kinetyczną K i rząd równania n. Stwierdzono, że sorpcja barwnika dla najwyższego stężenia wynosi 22 mg/g suchego produktu. Można zatem ten odpadowy produkt polecić jako tani sorbent mogący służyć do separacji substancji barwnych z roztwo¬rów wodnych.

EN

The description of sorption kinetics of Direct Orange 26 azo dye on rye straw by means fractional differential equations was presented in the paper. The numerical method for solving differential equations was used in calculations. The proposed kinetics equation represents a three-parameter equation: a - derivative fraction, K - kinetic constant, and n - equation order. It was found that the dye sorption for the highest concentration is equal to 22 mg/g of dry product. Therefore, this waste product can be recommended as inexpensive sorbent that could be used for the separation of colored substances from aqueous solutions.

18

Uptake of phenol from aqueous solution by burned water hyacinth

51%

Uddin M. T. , Islam M. S. , Islam M. A. , Abedin M. Z.

Polish Journal of Chemical Technology

|

2008

|

tom Vol. 10, nr 2

43-49

EN

The potential of burned water hyacinth (BWH) for phenol adsorption from aqueous solution was studied. Batch kinetic and isotherm studies were carried out under varying experimental conditions of contact time, phenol concentration, adsorbent dosage and pH. The pH at the point of zero charge (pH(PZC)) of the adsorbent was determined by the titration method and the value of 8.8 š 0.2 was obtained. The FTIR of the adsorbent was carried out in order to find the potential adsorption sites for the interaction with phenol molecules. The Freundlich and Langmuir adsorption models were used for the mathematical description of adsorption equilibrium and it was found that the experimental data fitted very well to the Langmuir model. Maximum adsorption capacity of the adsorbent was found to be 30.49 mg/g. Batch adsorption models, based on the assumption of the pseudo-first-order and pseudo-second-order models, were applied to examine the kinetics of the adsorption. The results showed that kinetic data closely followed the pseudo-second-order model.

19

Wpływ liczby atomów chloru w cząsteczkach kwasów chlorofenoksyoctowych na ich adsorpcję z roztworów wodnych na węglu aktywnym

51%

Kuśmierek K. , Świątkowski A.

Ochrona Środowiska

|

2013

|

tom Vol. 35, nr 1

47--50

EN

Three phenoxyacetic acids of various number of chlorine atoms in the molecule (PA, 4-CPA, 2,4-D) were selected to adsorption experiments. Adsorption of these compounds from aqueous solutions has been studied using commercial activated carbon F300 (Chemviron). The kinetic data were examined with the pseudo-first-order and pseudo-second-order models, and were found to follow closely the pseudo-second-order kinetic model. With increase in the initial solution concentration rate constants k2 diminish for each adsorbate and with increase in the number of Cl atoms in phenoxyacetic acid molecule rate constants k2 decrease for each initial solution concentration. Adsorption equilibrium data were analyzed and were fitted well using Freundlich isotherm in the studied concentration range. With increase in the number of Cl atoms in phenoxyacetic acid molecules the Freundlich equation constants KF and n decrease. Presence of electrolyte (Na2SO4) in aqueous solutions of phenoxyacids enhances their adsorption.

PL

Do badań adsorpcyjnych wybrano trzy kwasy fenoksyoctowe o różnej liczbie atomów chloru w cząsteczce (PA, 4-CPA, 2,4-D). Adsorpcję tych związków z roztworów wodnych badano stosując handlowy węgiel aktywny F-300 (Chemviron). Dane kinetyczne analizowano z użyciem modeli pseudo-pierwszego i pseudo-drugiego rzędu i stwierdzono, że dobrze spełniają kinetyczny model pseudo-drugiego rzędu. Wraz ze wzrostem początkowego stężenia roztworu wartości stałej szybkości k2 zmniejszały się w przypadku każdego adsorbatu. Także wraz ze wzrostem liczby atomów chloru w cząsteczce kwasu fenoksyoctowego zmniejszały się wartości stałej szybkości k2 przy każdym stężeniu początkowym adsorbatu. Analizowano także dane adsorpcji w funkcji równowagowego stężenia roztworu. Stwierdzono, że w zakresie stosowanych stężeń, adsorpcja była dobrze opisywana przy użyciu izotermy Freundlicha. Wraz ze wzrostem liczby atomów chloru w cząsteczce kwasu fenoksyoctowego wartości stałych równania Freundlicha (KF i n) malały. Stwierdzono też, obecność elektrolitu (Na2SO4) w roztworach fenoksykwasów powodowała wzrost ich adsorpcji.

20

Effect of adjuvants on kinetics of adsorption of atrazine

51%

Włodarczyk M. , Wybieralski J.

|

2006

|

tom Vol. 13, nr 7

703-708

EN

This study investigates the effect of adjuvants on the kinetics of adsorption of model substance atrazine, and the values of water/soil partition coefficients Kd and Koc. Laboratory experiments were conducted on three soils with different organic carbon content (Winna Gora Corg = 0.69 %, Lipnik Corg = 1.65 %, Slawoszewo Corg = 4.83 %). In the experiment two oil adjuvants: Adpros 85 SL, Olejan 85 EC (0.04% v/v) and surfactant Break-Thru S 240 (0.002 % v/v) were used. Two-phase adsorption was clearly observed for all mixtures in all three soils (the first, rapid - non-linear phase and the second, slower - linear phase). The data indicates that the adsorption behavior of atrazine in each soil in the presence of the adjuvants varies. Application of adjuvants resulted in an increase or a decrease in s-triazine adsorption.