Synthesis of magnetic multiwalled carbon nano tubes and investigation of isotherm and kinetic models for cleanup of carbaryl pesticide

Water is the main factor of movement and transport of pesticides and contamination of water by these pollutants is one of the most important challenges due to their widespread use and increased concentrations. Moreover, these compounds are on the U.S.EPA Priority Pollutant list because of the potential of accumulation and the property of damaging effects. In this study, multiwalled carbon nanotube-based magnetic nanoparticles were synthesized and used as an affective adsorbent for carbaryl pesticide. The properties of the synthesized Fe3O4@MWCNTs were characterized by TEM images and XRD analysis. The obtained data were studied by isotherm and kinetic models. Carbaryl adsorbed onto the synthesized adsorbent was compatible with the Langmuir isotherm (R-2 = 0.993). The maximum adsorption capacity (q(max)) of the pesticide onto the Fe3O4-MWCNTs was obtained at 68.2 mg/g. The kinetic studies of the reactions showed that the adsorption process followed the pseudo-second order model with R-2 >= 0.99 for all initial carbaryl concentrations. The adsorbent was extracted by magnet reused several times (six rounds) with a reasonable efficiency. The Fe3O4-MWCNTs have great potential for adsorption of carbaryl from water and wastewater due to high efficiency, easy separation and reusability.