Removal of methomyl from aqueous solutions using thermal regenerated carbon microspheres

Methomyl is a widely used carbamate pesticide, which has been extensively used over the past 60 years, primarily as an insecticide, but also as an herbicide and fungicide. Methomyl pro-duction involves a series of complex reactions. During its synthesis, wastewater from pesticide manufacturing plants can contaminate aqueous media. This study provides the results of investi-gation of effectiveness of methomyl removal from aqueous solutions by adsorption using the ther-mally regenerated microspheres of activated carbon (RAC). The microstructure of the adsorbent surface was examined by scanning electron microscopy (SEM). The change in the relative concen-tration of the pesticide in the aqueous solution was monitored using UV-Vis spectrophotometry. Methomyl adsorption kinetics and isotherms of regenerated activated carbon microspheres fit the pseudo-first-order and Freundlich models. The pseudo-first-order rate constant is 0.0105 min-1 at a temperature of 25 °C. By determinig the thermodynamic parameters of adsorption, it can be concluded that the process is spontaneous and exothermic.