Biomass-derived magnetic porous activated carbon for magnetic solid-phase extraction of herbicides from water samples

Abstract

ABSTRACT Highly porous biomass-derived activated carbon was prepared by carbonisation of cherry laurel (Prunus laurocerasus L.) stone followed by chemical activation with zinc chloride (ZnCl2) at 700°C. The resulting activated carbon was magnetised using a thermal process. The physicochemical properties of the magnetic activated carbon (AC/Fe3O4) were characterised by N2 adsorption-desorption, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometer. The magnetic material exhibited a high specific surface area of 959 m2/g and a maximal saturation magnetisation of 28.5 emu/g. The AC/Fe3O4 was then used as an adsorbent for the magnetic solid-phase extraction of target herbicides (hexazinone, propachlor and prometryn) from environmental water samples followed by high performance liquid chromatography-ultraviolet detection. After optimising the main parameters in the extraction procedure, the extraction recoveries and preconcentration factors in the ranges of 71–84% and 18–21 were obtained, respectively. Good linearities were achieved with the coefficients of determination ranging from 0.9978 to 0.9997. The intra- and inter-day relative standard deviations were less than 5.2%. Limits of detection were obtained between 0.05 and 0.28 µg/L. Finally, the proposed method was applied for the determination of the target herbicides in the environmental waters and satisfied recoveries between 71 and 101% were obtained from spiked samples.