scholarly journals Progress in the Characterization of the Surface Species in Activated Carbons by means of INS Spectroscopy Coupled with Detailed DFT Calculations

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Andrea Piovano ◽  
Andrea Lazzarini ◽  
Riccardo Pellegrini ◽  
Giuseppe Leofanti ◽  
Giovanni Agostini ◽  
...  

Activated carbons are materials with relevance in different industrial applications. Due to the inherent complexity and heterogeneity of their structures, an easy assignment of the species present on their surface has a challenging result. Only recently, with the possibility to collect well-resolved inelastic neutron spectra and to simulate by DFT methods more or less extended graphitic clusters, this task is starting to become feasible. Here we report our investigation on a steam activated carbon and we show that different vibrations in the region of out-of-plane C-H bending modes are specifically connected to hydrogen terminations belonging to extended and regular borders or to short and defective ones. Furthermore, simulations including heteroatoms such as oxygen allowed us to point out spectral regions with a contribution from carboxyl species.

2015 ◽  
Vol 74 (11) ◽  
Author(s):  
Riry Wirasnita ◽  
Tony Hadibarata ◽  
Abdull Rahim Mohd Yusoff ◽  
Zainab Mat Lazim

An oil palm empty fruit bunch-derived activated carbon has been successfully produced by chemical activation with zinc chloride and without chemical activation. The preparation was conducted in the tube furnace at 500oC for 1 h. The surface structure and active sites of activated carbons were characterized by means of Fourier transform infrared spectrometry and field emission scanning electron microscopy. The proximate analysis including moisture content, ash content, bulk density, pH, and pH at zero charge was conducted to identify the psychochemical properties of the adsorbent. The results showed that the zinc chloride-activated carbon has better characteristics compared to the carbon without chemical activation.  


2014 ◽  
Vol 9 (1) ◽  
pp. 166-174 ◽  
Author(s):  
Rajeshwar M. Shrestha ◽  
Margit Varga ◽  
Imre Varga ◽  
Amar P. Yadav ◽  
Bhadra P. Pokharel ◽  
...  

Activated carbons were prepared from Lapsi seed stone by the treatment with H2SO4 and HNO3 for the removal of Ni (II) ions from aqueous solution. Two activated carbon have been prepared from Lapsi seed stones by treating with conc.H2SO4 and a mixture of H2SO4 and HNO3 in the ratio of 1:1 by weight for removal of Ni(II) ions. Chemical characterization of the resultant activated carbons was studied by Fourier Transform Infrared Spectroscopy and Boehm titration which revealed the presence of oxygen containing surface functional groups like carboxyl, lactones and phenols in the carbons. The optimum pH for nickel adsorption is found to be 5. The adsorption data were better fitted with the Langmuir equations than Freundlich adsorption equation to describe the equilibrium isotherms. The maximum adsorption capacity of Ni (II) on the resultant activated carbons was 28.25.8 mg g-1 with H2SO4 and 69.49 mg g-1 with a mixture of H2SO4 and HNO3. The waste material used in the preparation of the activated carbons is inexpensive and readily available. Hence the carbons prepared from Lapsi seed stones can act as potential low cost adsorbents for the removal of Ni (II) from water. DOI: http://dx.doi.org/10.3126/jie.v9i1.10680Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 166–174


2017 ◽  
Vol 36 (3) ◽  
pp. 44-53
Author(s):  
G. D. Akpen ◽  
M. I. Aho ◽  
N. Baba

Activated carbon was prepared from the pods of Albizia saman for the purpose of converting the waste to wealth. The pods were thoroughly washed with water to remove any dirt, air- dried and cut into sizes of 2-4 cm. The prepared pods were then carbonised in a muffle furnace at temperatures of 4000C, 5000C, 6000C ,7000C and 8000C for 30 minutes. The same procedure was repeated for 60, 90, 120 and 150 minutes respectively. Activation was done using impregnationratios of 1:12, 1:6, 1:4, 1:3, and 1:2 respectively of ZnCl2 to carbonised Albizia saman pods by weight. The activated carbon was then dried in an oven at 1050C before crushing for sieve analysis. The following properties of the produced Albizia saman pod activated carbon (ASPAC) were determined: bulk density, carbon yield, surface area and ash, volatile matter and moisture contents. The highest surface area of 1479.29 m2/g was obtained at the optimum impregnation ratio, carbonization time and temperature of 1:6, 60 minutes and 5000C respectively. It was recommended that activated carbon should be prepared from Albizia saman pod with high potential for adsorption of pollutants given the high surface area obtained.Keywords: Albizia saman pod, activated carbon, carbonization, temperature, surface area


2020 ◽  
Vol 40 (1) ◽  
pp. 34-44
Author(s):  
Karen L. Martínez-Mendoza ◽  
Juan Manuel Barraza Burgos ◽  
Nilson Marriaga-Cabrales ◽  
Fiderman Machuca-Martinez ◽  
Mariber Barajas ◽  
...  

In this work, activated carbons were produced using coal as raw matter from seven Colombian carboniferous zones. Physical activation was performed in two stages: a carbonization stage with Nitrogen at a temperature of 850 °C and a residence time of 2 h, followed by an activation stage using steam at temperatures of 700 and 850 °C with residence times of 1,5 h and 2,5 h. From the pore volume characterization for the adsorption of gold, two activated carbons from Cundinamarca, obtained at 850 °C (1,5 h), 850 °C (2,5 h), and a commercial carbon (GRC 22) were selected. Gold adsorption tests were performed with those three activated carbons using synthetic aurocyanide solutions and a gold waste solution. The data of the adsorption isotherms were adjusted using the Freundlich adsorption model for the synthetic solution, as well as Langmuir for the waste solution. The results showed that, using a solution of 1 ppm, the activated carbons C-850-2.5 and C- 850-1.5 produced the higher maximum gold loading capacities in the equilibrium (8,7 and 9,3 mg Au/g, respectively) in comparison to the commercial activated carbon (4,7 mg Au/g).  Gold adsorption test using a waste solution (21 ppm of gold) showed that the activated carbon C-850-1.5 had the highest value of adsorption capacity (4,58 mg Au/g) compared to C-850-2.5 (2,95 mgAu /g).


2000 ◽  
Vol 18 (1) ◽  
pp. 1-14 ◽  
Author(s):  
A. Guillot ◽  
F. Stoeckli ◽  
Y. Bauguil

The microporous structure of the activated carbon fibre KF1500 was investigated by applying a new technique as presented here. This was based on a combination of high-pressure CO2 adsorption measurements between 253 K and 353 K with direct measurement of the differential heats of adsorption at 298 K at low and medium coverages. The validity of this approach was tested by using two activated carbons which has been characterized previously by a variety of techniques, including immersion calorimetry. It appears that a combination of high-pressure adsorption and calorimetry with CO2 alone is a useful tool for the characterization of the whole range of microporosity. This approach confirms earlier observations, according to which the initial stage of adsorption by strongly activated carbons corresponds to adsorption on the walls of large micropores rather than to the primary filling of small micropores.


2020 ◽  
Author(s):  
Suryyia Manzoor ◽  
Naseem Abbas ◽  
Javier Fernandez ◽  
Amir Mirza ◽  
Ghazala Yasmin ◽  
...  

Abstract The release of antibiotics to aquatic environment creates aquatic ecotoxicity and their bioaccumulation results in antibiotic resistance. Hence to lessen the risk of ecotoxicity and depletion of natural resources, it is imperative to disclose alternate precursor raw materials that can be successfully employed for the synthesis of new sorbents capable to remove antibiotics from the environment. This research reports the synthesis of activated carbon based sorbents derived from waste biomaterials like coconut shell (CNAC), walnut shell & peach stone (WNAC) and Bombax ceiba fruit capsule (BCAC) and their ability to remove antibiotic Cefpodoxime from the industrial effluents. Activation of carbon was done by HNO3 and H3PO4. FTIR, BET and SEM techniques were used for characterization of sorbents. Langmuir and Freundlich isotherm models were applied to study the adsorption behavior. Moreover, the experimental adsorption capacity (qe) of the three activated carbons was found to be 32 mg/g for CNAC, 40 mg/g for WNAC and 10 mg/g for BCAC. The maximum removal efficiency of the drug was found to be 96% using the WNAC. HPLC analysis was performed to confirm the removal of Cefpodoxime from industrial effluent.


1995 ◽  
Vol 12 (3) ◽  
pp. 247-258 ◽  
Author(s):  
C. Nguyen ◽  
A. Ahmadpour ◽  
D.D. Do

Activated carbon was prepared from nut shells using a conventional two-stage method: carbonization followed by activation. Activation with steam or carbon dioxide as activating agent produced a range of chars of different burn-off. These were characterized for their total and micropore surface areas, and benzene adsorption capacity. Benzene adsorption measurement provided an insight into the effect of porosity development on the adsorptive properties of the adsorbent. It was found that activated carbon products from nut shells were comparable, in terms of adsorption characteristics, with activated carbons from other lignocellulosic precursors. The evolution of porosity of the resulting carbons shows that carbon dioxide is the preferable agent for the production of activated carbon with a narrow micropore size distribution.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. G. Herawan ◽  
M. S. Hadi ◽  
Md. R. Ayob ◽  
A. Putra

Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil-palm shells, as a biomass byproduct from palm-oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO2activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N2adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well-developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced.


2009 ◽  
Vol 6 (4) ◽  
pp. 1221-1227
Author(s):  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján

Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2and CO2isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.


RSC Advances ◽  
2021 ◽  
Vol 11 (14) ◽  
pp. 8025-8032
Author(s):  
Jiaming Zhao ◽  
Lihua Yu ◽  
Feng Zhou ◽  
Huixia Ma ◽  
Kongyan Yang ◽  
...  

A series of micro–mesoporous activated carbons (ACs) were prepared from sugar beet residue by a two-step method including KOH chemical activation and were used for Cr(vi) removal from aqueous solutions.


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