Preparation of a magnetic porous carbon with hierarchical structures from waste biomass for the extraction of some carbamates.

In this study, corn stalk was used to synthesize a magnetic adsorbent by pyrolysis together with KHCO3 as the chemical activator and iron(III) salt as the magnetic reagent. The characterization by scanning electron microscopy, transmission electron microscopy and N2 adsorption-desorption analysis showed that the magnetic carbon adsorbent had a structure of hierarchical pores with a high specific surface area. To evaluate its adsorption performance, the adsorbent was used for the extraction of carbamates pesticides (propoxur, isoprocarb and fenobucarb) from water and zucchini samples before high-performance liquid chromatography analysis. The result showed that the adsorbent had a good adsorption capability for the analytes. Under the optimized conditions, a good linearity for the analytes existed in the range of 0.1-100.0 ng/mL for water samples and 0.5-100.0 ng/g for zucchini samples with the correlation coefficients of 0.9992-0.9998. The limits of detection for the analytes at a signal to noise ratio of 3 were 0.03 ng/mL for water samples and 0.20-0.50 ng/g for zucchini samples.