Nanostructured carbons for solid phase extraction

Nanostructured carbons have been obtained by the template method using zeolite NaY and silica gels (SG60, Fluka and ZK, POCh) as structure directing agents. Texture and porous structure of carbons were characterized by TEM, XRD and nitrogen adsorption. Surface chemistry was investigated by the potentiometric titration method. It has been shown that all carbons show developed and uniform porous structure with mean size in the micropore range (1.1 nm) for zeolite derived carbon and in the mesopore range (3.4 and 4.8 nm) for silica gel derived carbons. The BET surface area of silica gel derived carbons is in the range 1230–1280 m2/g whereas zeolite derived carbon possesses very high BET surface area, 3000 m2/g. Potentiometric titration showed that carbons obtained by the template method contain significant amount of acid surface groups (carboxylic, lactone/enol and phenolic) with the total amount 1.1–1.5 mmol/g. To study adsorption–desorption properties of nanostructured carbons towards phenol and chlorophenols the solid phase extraction method was used. High recoveries of chlorophenols were obtained (80–93%) at the breakthrough volumes 1700–3000 mL. The recoveries are much higher than that obtained with commercially available carbon ACC (Supelco).