Wyniki wyszukiwania - BazTech

1

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

Xinzhe Liu, Mingyang Zhang, Juan Chen, Zhengyu Hu, Shuaifei Xian, Mingxuan Tang, Chenchen Zhang

Polish Journal of Chemical Technology

|

2022

|

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.

2

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

Eri Iva Rustanti, Pramudinta Namira Kholifatul, Nurmayanti Demes

Journal of Ecological Engineering

|

2022

|

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.

3

Low-cost removal of basic red 9 using cow dung ash

Arya Raj Kumar, Meena Ghanshyam, Thapliyal Devyani, Barman Sanghamitra, Halder Gopinath, Shandilya Pooja

Chemical and Process Engineering

|

2022

|

Vol. 43, nr 2

229-–242

EN

In the present study, basic red 9 had been removed from synthetic waste water using animal waste. Cow dung ash had been prepared and characterized by scanning electron microscope. Morphology analysis shows very fine particles of less than 1 μm. The pH analysis study favours a pH of 8.5 for maximum dye removal. The removal of basic red 9 was very fast on cow dung ash. Percentage dye removal was 80.24% and 95.24 in 5 minutes and 90 minutes, respectively at initial dye concentration of 10 ppm.

4

Adsorption of reactive dyes and their mixtures on activated carbon. Kinetics, equilibrium and thermodynamic evaluation

Kouhail Meriem, Elahmadi Zakia, Benayada Abbes, Dewil Raf

Environment Protection Engineering

|

2020

|

Vol. 46, nr 2

5--24

EN

The adsorption of three reactive dyes (Reactive Bezactiv Yellow (RBY), Reactive Bezactiv Blue (RBB) and Reactive Bezactiv (RBR)) on a commercially available activated carbon (CAC) has been evaluated. It was shown that CAC is capable to effectively remove these dyes from a solution. The adsorption increased with higher contact time, adsorbent dose, and initial dye concentration. The data indicated that the adsorption kinetics of dyes on CAC followed a pseudo-second order model. The adsorption isotherms followed the Langmuir isotherm model. Evaluation of thermodynamic parameters revealed that the adsorption process is endothermic for all dyes and spontaneous in a single system and became spontaneous in mixture systems at high temperature, expect RBY and RBB in the ternary mixture. Adsorption was higher for RBY, followed by RBB, and was lowest for RBR. The total adsorption efficiency was confirmed by chemical oxygen demand (COD) measurements.

5

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

You Xiaofang, Ma Chuandong, Li Zhihao, Lyu Xianjun, Li Lin

Physicochemical Problems of Mineral Processing

|

2019

|

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.

6

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

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

Physicochemical Problems of Mineral Processing

|

2018

|

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.

7

Adsorption of hexane and cyclohexane vapours at the water drop surface

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

Physicochemical Problems of Mineral Processing

|

2018

|

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.

8

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

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

Polish Journal of Chemical Technology

|

2017

|

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.

9

Adsorption kinetics of fluoride on bone char and its regeneration

Hu J., Wu D., Rao R., Liu R., Lai W.

Environment Protection Engineering

|

2017

|

Vol. 43, nr 3

93--112

EN

The adsorbent of bone char (BC), produced from the pyrolysis of crushed animal bones, was dominated by the mesopores of the Brunauer Emmett Teller (BET) surface area. The optimal condition for defluoridation with BC was a pH level near 5.0. Chloride and nitrate ions could increase fluoride adsorption capacity in contrast with the effect of sulfate and carbonate ions. The interchangeability between fluoride and hydroxyl groups on BC sorbent was proved by the Fourier transform infrared spectroscopy. Langmuir equation had a better correlation coefficient than the Freundlich equation at various temperatures. Thermodynamic parameters such as Delta G degrees, Delta H degrees, Delta S degrees, Ea and S*, have been calculated to describe the nature of fluoride adsorption onto BC. Negative Delta G degrees and Delta H degrees values at various temperatures indicate a spontaneous process, and its exothermic effect, respectively. However, a positive Delta S degrees value represents an increasing process for entropy. The E-a and S* values ranging from 5 to 40 kj.mol-1 and 0 to 1, respectively, demonstrated that the adsorption is dominated by physical process, although the adsorption kinetic process was involved external diffusion, intraparticle diffusion and chemical reaction equilibrium stage. A high concentration of NaOH solution increases efficiency of removing adsorbed F- ions from the BC surface.

10

Waste Plant Material as a Potential Adsorbent of a Selected Azo Dye

Tomczak E., Tosik P.

Chemical and Process Engineering

|

2017

|

Vol. 38, nr 2

283--294

EN

This paper discusses the adsorption of Direct Orange 26 azo dye on sunflower husk - an agricultural waste product. During the study, sorption kinetics and equilibrium as well as sorption capacity of the husk were investigated. The adsorption kinetics was analyzed using pseudo-first and pseudo-second order equations, which indicated a chemical sorption mechanism. The sorption equilibrium was approximated with the two-parameter Freundlich and Langmuir equations and the three-parameter Redlich-Peterson equation. The main experiments were carried out in a laboratory adsorption column under different process conditions. Experimental data were interpreted with the Thomas model, based on the volumetric flow rate, initial composition of the feed solution and mass of the adsorbent. The results of modeling the adsorption equilibrium, adsorption kinetics and adsorption dynamics were evaluated statistically.

11

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

Czubaszek M., Choma J.

Ochrona Środowiska

|

2016

|

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.

12

Zachowanie się metazachloru i chlomazonu immobilizowanych w alginianowej matrycy w układach woda/gleba i woda/osad denny

Włodarczyk M., Buchwał A.

Przemysł Chemiczny

|

2015

|

T. 94, nr 6

989-993

PL

Badano kinetykę adsorpcji metazachloru i chlomazonu immolilizowanych w alginianowej matrycy w układach woda/gleba i woda/ osad denny. W czasie 48 h zaadsorbowaniu uległo 36,64%–66,31% w przypadku metazachloru, a w przypadku chlomazonu 52,01%–82,66% substancji uwolnionej z matrycy. Czynnikiem determinującym proces adsorpcji obu herbicydów była zawartość węgla organicznego w zastosowanych adsorbentach. Zastosowano model kinetyki pseudo drugiego rzędu do opisu procesu adsorpcji. Na podstawie danych eksperymentalnych wyznaczono szybkość początkową (V0), stałą szybkości adsorpcji (k2) i adsorpcję równowagową (aeq) dla obu herbicydów. Stwierdzono, że szybkość adsorpcji herbicydów bardziej zależy od dostępności miejsc adsorpcyjnych (właściwości fizykochemicznych adsorbentów) niż od ich stężenia w roztworze.

EN

The adsorption kinetics of alginate matrix-immobilized metazachlor and clomazone herbicides were studied in water/soil and water/bottom sediment systems. The adsorption of both herbicides depended on org. C content in the systems. Initial adsorption rate, rate const. of adsorption and the equil. adsorption were calcd. for both herbicides by using the pseudo second-order kinetics model.

13

Adsorption of copper ions from aqueous solutions on natural zeolite

Zendelska A., Golomeova M., Blazev K., Krstev B., Golomeov B., Krstev A.

Environment Protection Engineering

|

2015

|

Vol. 41, nr 4

17--36

EN

The adsorption of copper ions from synthetic aqueous solutions on natural zeolite (clinoptilolite) was examined. In order to determine the rate of adsorption and the copper uptake at equilibrium, a series of experiments were performed under batch conditions from single ion solutions. Equilibrium data were evaluated based on adsorption (Langmuir and Freundlich) isotherms. The adsorption kinetics is reasonably fast. In the first 20 min of the experiment, approximately 80% of Cu2+ ions is adsorbed from the solutions. Data obtained from the kinetic experiments have been described by the pseudo-second order kinetic model as well as by the Weber–Morris and Furusawa–Smith models.

14

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

Kuśmierek K., Świątkowski A.

Ecological Chemistry and Engineering. S

|

2015

|

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.

15

Modeling of adsorption in a mixing tank

Gwadera M., Kupiec K.

Czasopismo Techniczne. Chemia

|

2015

|

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.

16

Halloysite as Mineral Adsorbent of CO2 – Kinetics and Adsorption Capacity

Lutyński M., Sakiewicz P., Gonzalez M. A. G.

Inżynieria Mineralna

|

2014

|

R. 15, nr 1

111--117

EN

Physical adsorption of carbon dioxide on various mineral adsorbents is becoming extremely interesting in the field of energy and environment where CCS technology is an option for CO2 emission reduction. In the article the halloysite from Dunino deposit was assessed in terms of its potential use as a CO2 adsorbent. Results of tests indicate that modified halloysite (i.e. calcinated or modified by acid treatment) has a relatively low adsorption capacity which should be easily increased by other surface modification methods. Sorption kinetic is rather fast and over 85-89% of CO2 adsorption is accounted by a rapid sorption step i.e. 7 to 16 seconds.

PL

Procesy adsorpcji fizycznej CO2 na różnego rodzaju adsorbentach mineralnych są istotne z punktu widzenia technologii wychwytywania i separacji tego gazu z dużych źródeł stacjonarnych (CCS). W artykule przedstawiono wyniki adsorpcji CO2 na haloizycie ze złoża Dunino, który może mieć potencjalne zastosowanie w technologiach adsorpcyjnych. Rezultaty badań wskazują, że adsorpcja CO2 na modyfikowanym haloizycie tj. kalcynowanym oraz kwasowanym jest relatywnie niska w porównaniu z innymi adsorbentami mineralnymi, jednakże odpowiednia metoda jego modyfikacji może zwiększyć znacznie jego chłonność sorpcyjną. Przeanalizowano również kinetykę sorpcji, gdzie oszacowano iż 85-89% CO2 adsorbuje się w czasie 7-16 sekund.

17

Preparation of titanium dioxide/attapulgite composites and their application in treating Reactive Black KN-B wastewater

Xie A., Luo S., Chaoyao Y.

Environment Protection Engineering

|

2014

|

Vol. 40, nr 1

45--56

EN

Removal of water soluble Reactive Black KN-B from aqueous media by means of titanium dioxide/attapulgite (TiO2/ATP) composites was studied in a batch system. The composites were investigated using X-ray diffraction and surface area analysis. Under UV irradiation, the photocatalytic effect of TiO2/ATP composites, pH and reaction temperature on the decolorization rate of Reactive Black KN-B were investigated in detail. The adsorption experiments of TiO2/ATP composites showed that the isotherms and adsorption kinetics were well followed by the Langmuir model and the zero order equation, respectively. The maximum adsorption capacity of TiO2/ATP composites for Reactive Black KN-B calculated by the Langmuir model was 20.08 mg g-1. It can be concluded that the TiO2/ATP composites could be good photocatalysts/adsorbents for treating Reactive Black KN-B wastewater.

18

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

Gwadera M., Kupiec K.

Czasopismo Techniczne. Chemia

|

2014

|

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.

19

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

Otrembska P., Gega J.

Physicochemical Problems of Mineral Processing

|

2013

|

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.

20

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

Kuśmierek K., Świątkowski A.

Ochrona Środowiska

|

2013

|

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.