Beech sawdust based adsorbents for solid-phase extraction of pesticides and pharmaceuticals

Abstract

Carbonaceous solid-phase extraction (SPE) sorbent, efficient in isolation and enrichment of multiclass pesticides and pharmaceuticals from water, was synthesized starting from cheap waste beech sawdust and using KOH as the activated agent. The first step in carbon material preparation was hydrothermal carbonization of the waste beech sawdust. Following hydrothermal treatment, the obtained material was activated, using different amounts of KOH. It was found that applied activation leads to changes in material structure, an increase in specific surface area, and a decrease in the number of surface oxygen groups compared to carbonized sample. SPE procedure of multiclass pesticides and pharmaceuticals from water using activated carbonized beech sawdust (AcSD) was optimized by selecting the appropriate elution solvents, the sample pH, and the sample volume to obtain the highest enrichment efficiency. The optimized SPE procedure was applied for water analysis using different AcSD samples as a sorbent for analyte preconcentration. Activated carbon sorbent, obtained with the highest amount of KOH, showed the highest recoveries regarding the most analytes, which were comparable with the recoveries obtained by commercial cartridges.