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S.B. Lyubchik----活性炭

Intercalation as an approach to the activated carbon preparation

from Ukrainian anthracites

S.B.Lyubchik a,*,L.Ya.Galushko a ,A.M.Rego b ,Yu.V.Tamarkina a ,O.L.Galushko a ,

I.M.Fonseca c

a

Institute of Physical-Organic and Coal Chemistry,National Academy of Science,Donetsk,Ukraine

b

Centro de Quimica-Fisica Molecular,Instituto Superior Te

′cnico,Complexo Interdisciplinar,Lisboa,Portugal c

Faculdade de Cie

?ncias e Tecnologia,Universidade Nova de Lisboa,Lisboa,Portugal Abstract

Recently developed approach to the activated anthracites preparation combining a chemical pre-treatment and a physical activation was

applied to Ukrainian anthracites (C daf 92–95%).Anthracites were pre-treated under intercalation-like conditions either with HClO 4or with HNO 3vapours.Chemically pre-treated samples were afterwards submitted to physical activation either with H 2O or CO 2at 8508C for 1–8h.The in?uence of the pre-treatment conditions was analysed by means of X-ray photoelectron spectroscopy,XRD,elemental analysis and gas adsorption techniques.Under the experimental conditions investigated,the optimum conditions for producing of activated carbons from chemically modi?ed anthracites were identi?ed.Chemical pre-treatment with nitric acid of the low rank anthracite of C daf 92%followed by its activation with steam for 2h at 8508C looks like to be the best way for activated anthracites preparation.By abovementioned approach the high microporous activated carbon of 0.7cm 3/g and extended surface area of 1600m 2/g was obtained from Ukrainian anthracite.q 2003Elsevier Ltd.All rights reserved.

Keywords:A.Microporous materials;B.Chemical synthesis;C.Photoelectron spectroscopy;D.Surface properties

1.Introduction

Chemical pre-treatment followed either by physical (H 2O,CO 2)or chemical (KOH)activation is widely used for improving the textural properties of activated carbons.For this purpose different oxidants (O 2[1],HNO 3in aqueous solutions [2]or mixtures with HClO 4[3],Ac 2O [4])were http://www.wendangku.net/doc/fa56543f192e45361066f58a.htmlst years we have studied in detail the in?uence of different kinds of coals pre-treatment,either with HNO 3or HClO 4[5–7]under conditions like the ones used for graphite intercalation compound (GIC)synthesis.It was observed that there is a strong in?uence on the pore size distribution of resulted activated carbons and on the activation process in whole.

In the present study our developed approach to the activated carbon preparation,combining a chemical pre-treatment via intercalation-like reactions and a physical activation,has been applied to Ukrainian anthracites from the main coal region of Ukraine,i.e.Donbass region.The optimization of the synthesis conditions and of the textural parameters of the resulted activated anthracites has been

done under control of the standard solid-state physics background.According to our recent studies,the resulted activated carbons from Ukrainian anthracites were found to be suitable for the liquid phase application,namely for the selective adsorption of precious metals [11].2.Experimental

Representative group of the anthracites in a wide range of carbon content,i.e.C daf 92–95%,with 0.4–1mm particle sizes were chosen for the investigation (Table 1).Sample of Ceylon graphite was used as a reference.Chemical pre-treatment was carried out either with HClO 4or with HNO 3vapour.The HClO 4pre-treatment was performed by ‘step by step’heating (up to 1608C),the details are described elsewhere [6,7].The HNO 3pre-treatment was carried out by exposure of dried anthracite in HNO 3vapour at room temperature during different soaking time (1–72h).After accomplishing the contact time,samples were evacuated from the reactor and weighted.Then they were washed to remove nitric acid,dried,and weighted again.

The kinetics experiment was carried out to evaluate the effective constants of weight loss of the chemically

0022-3697/$-see front matter q 2003Elsevier Ltd.All rights reserved.

S.B. Lyubchik----活性炭

doi:10.1016/j.jpcs.2003.10.006

Journal of Physics and Chemistry of Solids 65(2004)127–132

http://www.wendangku.net/doc/fa56543f192e45361066f58a.html/locate/jpcs

*Corresponding author.Fax:t380-622-558425.

E-mail address:s_lyubchik@http://www.wendangku.net/doc/fa56543f192e45361066f58a.html (S.B.Lyubchik).