Characterization of activated carbon precursors prepared by dry-air oxidant and its effects on the adsorptions of activated carbons

Abstract

In order to get activated carbon precursors with rich pore size content, coal samples with different degrees of metamorphism were selected, compared and analyzed by means of FTIR and pore size test. By the comparative analysis of the FTIR structure parameters of coal samples, it was found that under the condition of dry-air atmosphere, when the temperature ranges among 100–300 °C, the oxidation degree of coal texture are closely corelated with the increase of temperature. At 200 °C, the methyl and methylene groups in the coal molecule present the highest oxygen binding ability, resulting in more oxygen-containing functional groups and a decrease in alkyl group numbers. The molecular group of the pre-oxidized sample is more active, and it is easier to combine with the activator during the activation process. After the pre-oxidation treatment, the pore size of micropores would be highly developed, and the average pore sizes of the three samples are reduced by about 53.71%, 31.69%, and 52.87%, respectively. Based on the adsorption experiments, it can be seen that the dry-air oxidized precursors activated by KOH would perform excellent adsorption properties.