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  • Author: T. Segeda x
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Preparation of nanostructured carbons for solid phase extraction

Preparation of nanostructured carbons for solid phase extraction

Nanostructured carbons have been obtained by the template method using silica gel and zeolite as structure directing agents. Carbons were characterised by nitrogen adsorption, acid-base titration, XRD and TEM, thermogravimetric analysis and IR spectroscopy. All carbons show developed and uniform porous structure with the mean size range mesopore 3.4 and 4.8 nm for silica gel derived carbons and in the micropore range 1.1 nm for zeolite derived carbon. The BET surface area of silica gel derived carbons is in the range 1230-1280 m2/g while zeolite derived carbon possesses very high BET surface area 3000 m2/g. Acid-base titration shows that carbons obtained by the template method contain a significant number of surface groups. Silica gel derived carbons possess mainly carboxylic and phenolic groups with small contribution of lactone/enol groups which totals 1.1-1.5 mmol/g. Extremely high number of surface groups (mainly phenolic) demonstrates carbon derived from zeolite - 11.3 mmol/g. The presence of phenolic groups was confirmed by IR spectroscopy. To study adsorption-desorption properties of nanostructured carbons towards phenol and chlorophenols a solid phase extraction method was used. High recoveries of chlorophenols were obtained (75-93%) at the breakthrough volumes 1200-1400 mL. The recoveries are much higher these that obtained with commercially available carbon ACC (Supelco).

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