Comparison of the Microporous Properties of an Alumina Pillared Montmorillonite and an Activated Carbon from Nitrogen Adsorption at 77 K

Langmuir ◽  
1997 ◽  
Vol 13 (16) ◽  
pp. 4483-4486 ◽  
Author(s):  
A. Gil ◽  
P. Grange
2021 ◽  
Vol 16 (1) ◽  
pp. 136-147
Author(s):  
Allwar Allwar ◽  
Asih Setyani ◽  
Ulul Sugesti ◽  
Khusna Afifah Fauzani

Oil palm shell was used as a precursor for preparation of activated carbon using different chemical activations (potassium hydroxide (KOH), zinc chloride (ZNCl2), and phosphoric acid (H3PO4)). Each activated carbons (AC) was mixed with nano-zinc oxide to form a composite. From the gas sorption analyzer, it is showed that nitrogen adsorption isotherms show Type II for ZnO/AC-KOH and ZnO/AC-ZnCl2 corresponding to the micro- and mesoporous structures, respectively. However, the nitrogen adsorption isotherm of ZnO/AC-H3PO4 exhibits the Type I with predominantly microporous structures. The SEM micrographs produced unsmooth surface and different pore sizes. The XRD patterns at 2θ of 25.06° and 26.75° were come from amorphous activated carbon. The peak intensity of ZnO was weak due to low concentration of zinc precursor. However, the ZnO of ZnO/AC-ZnCl2 showed strongly peak intensity. The effectiveness of the composites was examined for phenol removal determined by UV-Vis Spectrophotometer method. The equilibrium adsorption follows the Langmuir and Freundlich models according to the best correlation coefficient (R2). The kinetic model was only obtained for the pseudo-second-order with the best linearity of the correlation coefficient (R2). The results of this study showed that the oil palm shell has a great potential for ZnO/AC with excellent adsorptive property. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


2021 ◽  
Vol 1162 ◽  
pp. 65-73
Author(s):  
Rakhmawati Farma ◽  
Ona Lestari ◽  
Erman Taer ◽  
Apriwandi ◽  
Minarni ◽  
...  

Heavy metal such as Cu, Fe, and Zn are the most serious contributers to environmental problems. The removal of heavy metal from the environment is the research interest nowdays. The adsorption of Cu, Fe and Zn from wastewater was investigated with various activated carbons as adsorbents. The activated carbons were produced from oil palm leaves by using multi-activation methods. The H3PO4, NaOH, ZnCl2 and KOH were chosen as chemical activating agents. Batch adsorption experiment was used to test the ability of activated carbon to remove Cu, Fe, and Zn from wastewater. The surface characteristics of activated carbon were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption-desorption isotherms. The Activated carbons were able to purify wastewater with a maximum turbidity level of 2.83 NTU. The AC-H3PO4 activated carbon showed the highest absorbability of Cu metal as 91.540%, while the highest absorbabilities of Zn and Fe metals were indicated by AC-KOH activated carbon of 22.853% and 82.244% absorption respectively. Therefore, these results enable the oil palm leaves to become a high potential for activated carbon as removal the heavy metals.


Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 855 ◽  
Author(s):  
Azry Borhan ◽  
Suzana Yusup ◽  
Jun Wei Lim ◽  
Pau Loke Show

Global warming due to the emission of carbon dioxide (CO2) has become a serious problem in recent times. Although diverse methods have been offered, adsorption using activated carbon (AC) from agriculture waste is regarded to be the most applicable one due to numerous advantages. In this paper, the preparation of AC from rubber-seed shell (RSS), an agriculture residue through chemical activation using potassium hydroxide (KOH), was investigated. The prepared AC was characterized by nitrogen adsorption–desorption isotherms measured in Micrometrices ASAP 2020 and FESEM. The optimal activation conditions were found at an impregnation ratio of 1:2 and carbonized at a temperature of 700 °C for 120 min. Sample A6 is found to yield the largest surface area of 1129.68 m2/g with a mesoporous pore diameter of 3.46 nm, respectively. Using the static volumetric technique evaluated at 25 °C and 1.25 bar, the maximum CO2 adsorption capacity is 43.509 cm3/g. The experimental data were analyzed using several isotherm and kinetic models. Owing to the closeness of regression coefficient (R2) to unity, the Freundlich isotherm and pseudo-second kinetic model provide the best fit to the experimental data suggesting that the RSS AC prepared is an attractive source for CO2 adsorption applications.


1997 ◽  
Vol 15 (10) ◽  
pp. 803-814 ◽  
Author(s):  
A.M. Youssef ◽  
M.R. Mostafa ◽  
E.M. Dorgham

Zinc chloride-activated carbons and steam-activated carbons were prepared from Maghara coal. The textural properties were determined from low-temperature nitrogen adsorption. Zinc chloride activation is usually associated with the creation of new micropores while steam activation involves pore widening particularly when the percentage burn-off is high. The adsorption of SO2 on steam-activated carbon is high compared with ZnCl2-activated carbons. Steam activation develops surface basic groups which provide chemisorption sites for SO2. The adsorption of SO2 is enhanced in the presence of O2 and water vapour and involves the formation of sulphuric acid in this case. Sulphur dioxide adsorption is related to the chemistry of the carbon surface rather than to the extent of the surface area of the activated carbon.


Author(s):  
Sandeep Kumar Thaligari ◽  
Vimal Chandra Srivastava ◽  
Basheswar Prasad

Abstract In the present study, simultaneous removal of the dibenzothiophene (an aromatic refractory sulfur compound) and quinoline (an aromatic refractory nitrogenous compound) from model fuel was performed using the zinc impregnated granular activated carbon (Zn-GAC). Textual properties of the adsorbent were determined by liquid nitrogen adsorption technique. Binary isotherm study revealed that the quinoline adsorption onto Zn-GAC was more favored in comparison to dibenzothiophene. Various multi-component isotherm models were used for representing the isotherm data from binary solution. Modified Redlich-Peterson model best represented the isotherm data.


1992 ◽  
Vol 9 (1) ◽  
pp. 48-53 ◽  
Author(s):  
D.R. Mehandjiev ◽  
R.N. Nickolov

The dependence of the C constant in the BET equation on the amount of pre-adsorbed water has been investigated by low-temperature nitrogen adsorption on activated carbon containing different amounts of water pre-adsorbed at the same relative water vapour pressure. It is suggested that the rapid decrease in the surface area as determined by the BET method in comparison with the C value in cases of low degrees of sorption volume filling is associated with blocking of part of the carbon texture and the parallel formation of extremely narrow micropores.


2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Huan Huang ◽  
De-Zhi Yi ◽  
Yan-Nan Lu ◽  
Xiao-Lin Wu ◽  
Yun-Peng Bai ◽  
...  

AbstractSamples of activated bentonite and activated bentonite modified with CuCl and CuCl2, separately, were tested as dimethyl sulfide (DMS) adsorbents. The adsorption and desorption behaviours of DMS on the adsorbents were studied systematically. The adsorbents were characterised by nitrogen adsorption, XRD, and DMS-TPD tests. The addition of CuCl and CuCl2 to the activated carbon significantly enhanced the adsorption capacity of DMS, despite a notable decrease in the specific surface area and total pore volume of the activated bentonite. It is presumed that copper cation species may act as an adsorption site for DMS. The adsorption capacity of Cu(II)-bentonite was better than that of Cu(I)-bentonite. The DMS-TPD patterns indicate that the stronger electrophilicity of Cu(II) compared to that of Cu(I) caused it to interact with the DMS molecules more strongly, thus contributing to a better adsorptive performance. The Cu(II)-bentonite calcined at 150°C had the best DMS removal performance with a high sulphur capacity of 70.56 mg S g−1 adsorbent. The DMS removal performance became much lower with the increase in the calcination temperature, which appeared to be due to the decrease in the CuCl2·2H2O phase and the formation of the monoclinic Cu(OH)Cl phase.


2018 ◽  
Vol 9 ◽  
pp. 364-378 ◽  
Author(s):  
Mikhail F Butman ◽  
Nikolay L Ovchinnikov ◽  
Nikita S Karasev ◽  
Nataliya E Kochkina ◽  
Alexander V Agafonov ◽  
...  

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Nurgul Ozbay ◽  
Adife Seyda Yargic

Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C). The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.%) on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW), and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG), Fourier transform-infrared (FT-IR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, point of zero charge measurements (pHPZC), particle size analyzer, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g) was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.


Author(s):  
N. P. Shabelskaya ◽  
M. A. Egorova ◽  
G. M. Chernysheva ◽  
A. N. Saliev ◽  
A. N. Yatsenko ◽  
...  

Scientific interest in the processes of forming the structure of magnetic spinels and composites based on them is due to the possibility of synthesis of materials with multifunctional properties. The process of formation of cobalt (II) nanocrystalline ferrite and CoFe2O4/C composite material is studied. The mechanism of formation of structure of materials including a stage of formation of hydroxides of transition elements, precursors on the basis of complex connections of cations of iron and cobalt with citric acid and their subsequent destruction at heating is offered. The synthesized materials were characterized by x-ray phase analysis, electron microscopy, low-temperature nitrogen adsorption, Debye-Scherrer methods. It is shown that cobalt (II) ferrite has a developed surface, the value of the surface area according to the BET method is 16 m2/g, the average size of the crystallites determined by the Debye-Scherrer equation is 4.0 nm. Activated carbon with a specific surface area of 685 m2/g was used to prepare the composite material. The resulting composite material has a surface area of 222 m2/g, the average crystallite size of 1.1 nm. Cobalt (II) ferrite, included in the composition of the composite material CoFe2O4/C, has a slightly higher value of the lattice parameter, compared with pure cobalt (II) ferrite, which is associated with a decrease in the degree of spinel inversion. The synthesized composite material was tested in the process of adsorption of copper (II) cations from an aqueous solution. It is shown that CoFe2O4/C exhibits an increased adsorption capacity for copper (II) cations in comparison with pure activated carbon, despite a decrease in the specific surface area. The result is explained by the involvement of cobalt (II) ferrite in the adsorption process. The obtained materials may be of interest as catalysts, adsorbents.


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