Wyniki wyszukiwania - Biblioteka Nauki

1

Modeling of experimental data for the adsorption of methyl orange from aqueous solution using a low cost activated carbon prepared from Prosopis juliflora

100%

Kumar M. , Tamilarasan R.

Polish Journal of Chemical Technology

|

2013

|

tom 15

|

nr 2

29-39

EN

This paper presents the feasibility for the removal of methyl orange (MO) dye from aqueous solution using an activated carbon prepared from Prosopis juliflora bark. Batch adsorption experiments were carried out as a function of pH, contact time, adsorbate concentration, adsorbent dosage and temperature. The commonly applicable isotherms namely Freundlich and Langmuir equations are used for the prediction of isotherm parameters. A comparison of linear least-square method and a trial-and-error non-linear method are examined in Freundlich and Langmuir (Four forms) isotherms. The nature of adsorption isotherm feasibility was evaluated with dimensionless separation factors (RL). The dynamics of adsorption process was analyzed with Lagergren’s Pseudo-first order and Pseudo-second order kinetic equations. Thermodynamic parameters like the change in enthalpy (ΔHo), change in entropy (ΔSo) and change in Gibbs free energy (ΔGo) were evaluated and ΔGo shows a negative value whereas ΔHo shows the positive value indicating that the adsorption process was spontaneous and endothermic in nature. The functional group characterization of the adsorbent was done using Fourier transform infrared spectroscopy (FTIR). The thermal stability of activated carbon was analyzed using Thermo gravimetric analysis (TGA) and Differential thermal analysis (DTA).

2

Chemical Capacitor Based on Activated Carbon Powder and Poly(vinyl alcohol)-H2SO4 Proton Conducting Polymer Electrolyte

100%

Lewandowski A. , Galiński M.

|

2001

|

tom Vol. 75, nr 12

1913-1920

EN

A totally solid state electric double layer capacitor was fabricated using a PVA-H2SO4-H2O polymer electrolyte and activated carbon powder (ACP) as an electrode material. The polymer electrolyte served both as a separator as well as a binder of carbon powder. The PVA-H2SO4-H2O (separator) as well as PVA-H2SO4-H20-ACP foils were prepared by the solution cast technique. The electric performance of the capacitors was investigated by cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy. The prototype capacitors were assembled by contacting three foils (electrode + electrolyte + electrode) having a thickness of ca. 1.5-2 mm, a diameter of 1.8 cm and a capacity of ca. 0.6-1.5 F. The specific capacitance of ACP was estimated to be of ca. 130 F/g.

3

Synthesis, Characterization and Photocatalytic Activity of Some TiO2/Carbon Composites

100%

Kulesius Z. , Valatka E.

|

2006

|

tom Vol. 80, nr 2

335-344

EN

Anatase-type TiO2 composites with various allotropic forms of carbon (carbon nanotubes, carbon nanofibers and activated carbon) were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, thermogravimetry-differential scanning calorimetry (TG-DSC), Fourier-transform infrared (FT-IR) and scanning electron microscopy (SEM) analysis. The synthesis of TiO2/carbon composites was carried out by using acid-catalyzed sol-gel method, followed by drying in supercritical 2-propanol. The weight ratio mTiO2/mcarbon was 4 in all prepared samples. In order to compare the photoactivity of different catalysts, the phenol degradation was employed as a test reaction

4

Laboratory and pilot plant performance of novel carbon monolithic catalysts development for selective flue gas d-NOxing at low temperature.

100%

Olivares J. , Kułażyński M. , Salvador L. , Walendziewski J. , Trawczyński J.

|

tom Vol. 10, nr 57

169-176

EN

A new method for monolithic carbon catalyst manufacture for selective catalytic d-NOxing removal of combustion gases at low temperature (180-230C) with ammonia has been developed. The procedure constitutes a very interesting step in the field sorption and catalytic methods using carbonaceous materials. A series of experiments was carried out to test the formation of carbonaceous slip pastes into monolithic thin-wall blocks of "honeycomb" structure, and several factors affecting the formation process were tested at lab and semi-commercial scales. These research studies included drying and carbonization parameters, which influenced the quality (geometric shape and mechanical properties) of the finished carbon monoliths. After the shaping process, the prototypes were dried, carbonized, activated, and impregnated with metal oxides (V and Cu) in order to increase the d-NOxing activity. Very high NOx to N2 conversions at process temperature 190-200C have been obtained at lab and pilot scales.

5

Adsorption of crystal violet from aqueous solution on activated carbon derived from Gölbaşi lignite

100%

Depci T. , Kul A. R. , Onal Y. , Disli E. , Alkan S. , Turkmenoglu Z. F.

|

2012

|

tom Vol. 48, iss. 1

253-270

EN

Activated carbon (AC) was obtained from lignite of the local resource, Gölbaşi - Adiyaman (Turkey) by chemical activation. The Gölbaşi lignite was chosen as the precursor for its availability and low cost. The BET surface area of the activated carbon was found 921 m2/g. The AC was used as an adsorbent for Crystal Violet (CV) in aqueous solution. The adsorption properties of CV onto the activated carbon are discussed in terms of the adsorption isotherms (Langmuir and Freundlich) and the kinetic models (pseudo-first-order, pseudo-second-order and intraparticle diffusion model). It was shown that the experimental results best fitted by the Langmuir model, and the second-order kinetic equation. The thermodynamic parameters show that the adsorption process is endothermic. The experimental results point out that the obtained activated carbon is a viable candidate for sorbent removing CV from aqueous solutions.

6

Kinetic, Equilibrium and Thermodynamic studies on the removal of Cr(VI) by activated carbon prepared from Cajanus Cajan(L) Milsp seed shell

100%

Thamilarasu P. , Kumar G. , Tamilarasan R. , Sivakumar V. , Karunakaran K.

Polish Journal of Chemical Technology

|

2011

|

tom 13

|

nr 4

1-7

EN

This paper presents the feasibility of the removal of hexavalent chromium ions from aqueous solutions by using activated carbon prepared from Cajanus Cajan(L) Milsp. It was carbonized and activated by treating it with concentrated sulfuric acid followed by heating for 5 h at 500°C. Batch adsorption experiments were carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage and temperature. The experimental data fitted well to the Freundlich isotherm. The thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were calculated, which indicated that the adsorption was spontaneous and endothermic in nature. The adsorbent used in this study was characterized by FT-IR and SEM before and after the adsorption of metal ions. The results indicate that Cajanus Cajan(L) Milsp can be employed as a low cost alternative and commercial adsorbents in the removal of chromium (VI) from water and waste water.

7

Adsorption of Binary Mixtures of Organic (n-C6H12 or C6H5Cl) and Water Vapours on Activated Carbon U-03 at 293 K

100%

Sobota R. M.

|

2008

|

tom Vol. 82, nr 12

2309-2322

EN

The adsorption of vapour and liquid mixtures of H2O + c-C6H12 and H2O + C6H5Cl on activated carbon U-03 has been examined at room temperature 293 K. A model of Independent Co-adsorption proposed by Stoeckli et al. [1,2] leads to a good correlation between experimental and calculated mole fractions for each vapour in binary mixtures. This model can improve predicting dynamic systems such as break through curves and PSA (Pressure Swing Adsorption). This model shows Independent Co-adsorption which can describe static or dynamic systems including break through curves and PSA systems of binary immiscible vapour mixtures adsorbed by a typical industrial activated carbon U-03. The model assumes that vapours are adsorbed according to their respective Dubinin-Astakhov isotherms. A good mutual agreement was found between the calculated and experimental data.

8

Estimation of Features of Activated Carbon Materials Used for DrinkingWater Purification

100%

Klymenko N. A. , Savchyna L. A.

|

2008

|

tom Vol. 82, nr 1-2

283-290

EN

The adsorption parameters of the activated carbon (AC) BAU and KAU-TF, which have been used for purification of tap water over a long period of time, are estimated. It is shown, that the AC with the native biofilm is subjected to spontaneous bioregeneration. As a result of this process 68–96% of surface of AC mesopores is restored. To free the porous volume of the AC completely it is necessary to wash out the AC with the solutions of alkali and acid consistently after approximately two years of AC filter work.

9

Study of the Trace Palladium Enrichment Mechanism on Modified Activated Carbons with Respect to Analytical Applications

100%

Dobrowolski R. , Kuryło M. , Reszko-Zygmunt J.

|

2008

|

tom Vol. 82, nr 1-2

255-262

EN

The influence of modification of commercially available carbon on Pd(II) adsorption has been studied.Modified activation carbons are characterized by different palladium sorption capacities. The optimal pH-value for Pd(II) adsorption is 1.5 units. The influence of nitrate on Pd(II) adsorption was also studied. Linear decrease of Pd(II) adsorption with the increasing nitrate concentration was observed. The obtained Pd(II) adsorption isotherms were described by the Freundlich equation. It was stated that the parameter n characterizing heterogeneity of a carbon has the great influence on the sorptionmechanism.

10

Recovery of bis(1-chloro-2-propyl) ether from aqueous solution onto activated carbon

88%

Pełech R.

Polish Journal of Chemical Technology

|

2010

|

tom 12

|

nr 4

11-14

EN

The results of the studies of bis(1-chloro-2-propyl) ether adsorption from aqueous solution onto AG5 activated carbon were presented here. Dynamic adsorptivity, mass transfer zone and the velocity of the adsorption front of the 10cm adsorption bed depth for the velocity of flow 9 and 25 cm/min were determined. For the regeneration of the adsorption bed, acetone rinsing was used. Total washout of adsorbed bis(1-chloro-2-propyl) ether from the bed was obtained. After the regeneration the adsorbent has not shown deterioration of adsorption properties. To isolate bis(1-chloro-2-propyl) ether from acetone, distillation was used.

11

Adsorption of 1,2-dichloropropane from aqueous solution

88%

Pełech R. , Milchert E.

Polish Journal of Chemical Technology

|

2007

|

tom 9

|

nr 2

34-36

EN

In this study dependences of the adsorption equilibrium of 1,2-dichloropropane in aqueous solution for six activated carbons (A, AG, AG5, DTO, WD-ekstra, CWZ-22) and four polymeric adsorbents (XE-563, XE-572, XE-340, XE-348) were presented. All the adsorption isotherms onto activated carbons were described by the Freundlich equation. To analyze the isotherms on the polymeric adsorbents the Langmuir-Freundlich equation was used. It was found that in the low range of the concentrations the adsorptive properties of the activated carbons are reduced in the following direction DTO>WD-ekstra>CWZ-22>AG>A>AG5. Reducing the adsorptive properties of the polymeric adsorbents states was carried out in the following order: XE-340> XE-572>XE-563>XE-348. The adsorbents XE-340, XE-572 and XE-563 have much more higher adsorptive properties than the applied activated carbons. Lower adsorptive properties of XE-348 are the result of its high surface polarity.

12

Gliceryna – produkt uboczny procesu wytwarzania biodiesla

88%

Buczek B. , Kozera P.

Zeszyty Naukowe Uniwersytetu Ekonomicznego w Krakowie

|

2013

|

nr 912

5-16

EN

The paper presents the physical and chemical properties of glycerol and how it is used. It also shows methods of the industrial processing of glycerine fraction – in terms of obtaining and concentrating it – and methods of biodiesel production, of which glycerine is a by-product. The paper evaluates the possibility of concentrating glycerol by removing other compounds of technical glycerine using carbon adsorbents (ARP2) prepared with oxygen active centers. The most important aspect of this approach is to eliminate the energy consuming rectification process. Results of this study show that concentrating glycerol using specially selected carbon sorbents is a valid process.

13

Durability and narrow pore size distribution (PSD) of carbons fabricated fromSalix viminaliswood

88%

Łukaszewicz J. , Zieliński K.

Chemical and Process Engineering

|

2011

|

tom 32

|

nr 3

195-201

EN

Microporous carbon molecular sieves of extremely narrow pore size distribution were obtained by carbonization of a novel raw material (Salix viminalis). The precursor is inexpensive and widely accessible. The pore capacity and specific surface area are upgradable by H3PO4 treatment without significant change of narrowed PSD. The dominating pore size indicates that these molecular sieves are a potential competitor to other nanoporous materials such as opened and purified carbon nanotubes.

14

Mass transfer in the bath reactor of the adsorption process of 1,2-dichloropropane from aqueous solution onto the activated carbon

88%

Pełech R.

Polish Journal of Chemical Technology

|

2007

|

tom 9

|

nr 2

30-33

EN

A pseudo-second order rate equation describing the kinetics of the adsorption of 1,2-dichloropropane from aqueous solution onto the activated carbon at different initial concentrations, adsorbent dose, temperature, particle diameter and the rate of stirring have been developed. The rate constant was calculated. The rate constant correlation in a good mixing conditions was described as a function of the temperature.

15

Modelling of NO adsorption in fixed bed on activated carbon

88%

Kuboňová L. , Obalová L. , Vlach O. , Troppová I. , Kalousek J.

Chemical and Process Engineering

|

2011

|

tom 32

|

nr 4

367-377

EN

Adsorption experiments of nitric oxide in nitrogen carrier gas were held on activated carbon in a fixed bed flow system. Breakthrough curves describing the dependence of exit concentrations of nitric oxide on time were matched with theoretical response curves calculated from the linear driving force model (LDF). The model assumes Langmuir adsorption isotherm for the description of non-linear equilibrium and overall mass transfer coefficient for mass transfer mechanism. Overall mass transfer coefficients were obtained by the method of least squares for fitting numerically modelled breakthrough curves with experimental breakthrough curves. It was found that LDF model fits all the breakthrough curves and it is a useful tool for modelling purposes.

16

Adsorption and desorption kinetics behaviour of methylene blue onto activated carbon

88%

Sarici-Ozdemir C.

|

2012

|

tom Vol. 48, iss. 2

441-454

EN

In the present work investigations on a potential use of activated carbon for the removal of Methylene Blue (MB) from wastewater are presented. Adsorption kinetics of methylene blue has been studied using reaction-based and diffusion-based models. Three kinetic models, namely, pseudo-first-order, pseudo-second-order and the Elovich are analyzed at the temperature of 298 K for the reaction-based model. The kinetic studies showed that the data were well described by the pseudo-second-order kinetic model. Intraparticle diffusion, external-film diffusion, and internal-pore diffusion models characterizing MB were obtained. The results suggested that the activated carbon has a high potential to be used as an effective adsorbent for methylene blue adsorption. Pseudo first-order, pseudo second-order and the Elovich models were employed to describe the desorption mechanism. The experimental results showed that the pseudo second-order equation is the best model. About 99% of activated carbon has been regenerated by desorption.

17

Fixed-bed adsorptive removal of metanil yellow from simulated wastewater in a fixed-bed column by nitric acid-treated-H3PO4-activated carbon (NATPAAC) from oil palm fruit mesocarpfibre

88%

Isiuku B. O. , Ojike C. A. , Akakuru O. U. , Ibe F. C.

World News of Natural Sciences

|

2018

|

tom 17

157-172

EN

We carried out fixed-bed column adsorption of metanil yellow from simulated wastewater on NATPAAC derived from oil palm fruit mesocarpfibre so as to determine the adsorption capacity, qe, of the carbon under the effects of inlet concentration, Co, carbon bed height, H and dye solution flow rate, Q. Our results indicate that the optimum qe was 15.982 mg/g by Co 25 mg/L, H 4.1cm and Q 8 mL/min. In the study, qe was observed to decrease with increase in Co and Q. The optimum bed height was 4.1cm. Our experimental data were modelled by applying Thomas and Yoon-Nelson kinetic models. Correlation coefficient, R2 values (generally above 0.85) show that the two kinetic approaches provide an effective model of the experimental data. We conclude that oil palm fruit mesocarpfibre has potential as a precursor for production of carbon for acid-dye removal from wastewater.

18

Preparation and characterization of coal - based activated carbons supporting TiO2.

88%

Przepiórski J. , Yoshizawa N. , Yamada Y.

|

tom Vol. 9, nr 56

363-368

EN

Detailed preparation procedure and characterization of coal-based activated carbons supporting TiO2 are given. Changes of chemical state of titanium organic complex introduced into three raw coals of a different rank are described and illustrated by XRD patterns taken at defferent stages of the carbons preparation. Influence of coal rank and titanium suppored on the development of microporous and mesoporous structures are discussed. Changes in the Ti content activated carbons is given basing on the TEM observations.

PL

Przedstawiono metodę otrzymywania węgli aktywnych zawierających TiO2 z węgli kamiennych różnych klas. Rezultatami pomiarów XRD zilustrowano zmainy postaci chemicznej wprowadzonego organicznego związku tytanu na różnych etapach przygotowania węgli aktywnych. Pokazany jest wpływ klasy węgla i wprowadzonego tytanu na rozwój syruktury mikro- i mezo-porowatej otrzymywanych węgli aktywnych. Ponadto przedstawiono zależność pomiędzy ilością tytanu w końcowych produktach (oraz ilością tytanu utraconego), a czasem aktywacji. W pracy tej pokazano również jak czas aktywacji węgli wpływana wielkość cząstek TiO2 w nich zawartych.

19

Catalytic conversion 1,2-dichloroethane over carbon catalysts.

88%

Szymański G.

|

tom Vol. 9, nr 56

369-374

EN

Results of catalytic tests on activated carbons with defferent surface chemical nature are reported. The carbons with various amounts of oxygen and/or nitrogen surface functional groups were obtained by modification of commercial activated carbon D43/1 (Carbo Tech, Essen, Germany). As-received carbon as well as deashed carbon samples were subjected to the following modification procedures: annealing at different temperatures (1023-1423 K) in stream of hydrogen (i) or of ammonia (ii), ammoxidation with mixture of ammonia and air (iii), and oxidation with concetrated nitric acid (iv). The carbons were characterized by FTIR spectroscopy and measurements of Ph of water suspensions. Subsequently, the catalytic tests were conducted in a fixed bed flow-type reactor by mmicropulse technique. The conversion of 1,2-dichloroethane was conducted in the temperature range of 573-623 K. The results show that the obtained carbon catalysts effectively promote dehydrochlorination of 1,2-dichloroethane to vinyl chloride. The most catalytically active are carbons treated with ammonia. In contrast, the oxidized carbons reveal the lowest activity. Propably, the nitrogen functional groups, generated during the ammonia treatment, are responsible for the high catalytic activity of the nitrated carbons. The previous XPS [1] measurements indicate that annealing in ammonia results in incorporation of nitrogen into the carbon matrix in the form of pyrrolic and pyridine structures which may play the role of active centers.

PL

Badano aktywność katalityczną modyfikowanego węgla aktywnego 43/1 w reakcji dehydrochlorowania 1,2-dichloroetanu do chlorku winylu w zakresie temperatur 573-623 K. Wyjściowy węgiel poddano procesom modyfikacji poprzez utlenianie stężonym kwasem azotowym bądź wygrzewanie w wysokich temperaturach (1023-1423 K) w atmosferze beztlenowej (w strumieniu wodoru lub amoniaku) lub w mieszaninie amoniaku z powietrzem (amoutlenianie). Wyjściowy węgiel charakteryzuje się niewielką aktywnością katalityczną, która ulega dalszemu obniżeniu po utlenieniu powierzchni węgla kwasem azotowym. proces amoutleniania powoduje tylko niewielki wzrost aktywności badanego węgla. Natomiast wygrzewanie w strumieniu wodoru lub amoniaku prowadzi do drastycznego wzrostu aktywności katalitycznej. Otrzymane katalizatory charakteryzują się wysoką wydajnością i selektywnością tworzenia chlorkuy winylu. Najwyższą aktywność wykazuje węgiel wygrzewany w amoniaku w temperaturze 1023 K przez 6 h. Wysoka aktywnośc katalityczna azotowanych węgli związana jest z obecnością na nich powierzchni struktur pirydonowych i pirolowych wbudowanych w matrycę węglową. Struktury te mogą pełnić rolę dodatkowych centrów aktywnych. Zuwagi na względnie niską cenę oraz łatwość utylizacji węgle aktywne, po procesie azotowania, mogą stanowić efektywne i stosunkowo niedrogie katalizatory procesów katalitycznego oczyszczania gazów odlotowych z chlorowcopochodnych organicznych.

20

Adsorption Behavior of Reactive Dye from Aqueous Phase on Activated Carbon

88%

Khan M. R. , Rahman M. M. , Mozumder M. S. I. , Uddin M. J. , Islam M. A.

|

2009

|

tom Vol. 83, nr 7

1365-1378

EN

The adsorption of a reactive dye (Procion Red) from aqueous solution onto activated carbon was investigated. The effect of contact time, pH, adsorbent dosage and temperature were studied. The equilibrium data were described well by both Langmuir and Freundlich isotherm model. The adsorption kinetics was tested for pseudo-first-order, pseudo-sec - ond order, intraparticle diffusion and unified approach kinetic models. The unified approach model de scribed the kinetic data in accor dance with the experimental data and the forward and backward rate constants were evaluated from the model fittings. The adsorption is highly pH dependent and adsorption efficiency in creases with the decrease in pH. Thermodynamic parameters of the adsorption process suggested that the process was endothermic. The adsorption capacity of regenerated activated carbon showed more than 70 percent recovery of the adsorption efficiency of the initial virgin adsorbent.