Sorption of pesticides on carbon sorbent obtained by microwave-assisted carbonization of lignosulfonates in the presence of phosphoric acid

Abstract Carbon sorbents derived from natural waste materials were tested for the preconcentration of pesticides from water. These carbons were obtained during the carbonization of lignosulfonates with the use of microwave irradiation in the presence of phosphoric acid as an activator. Phosphoric acid also plays role of antipirene protecting the carbon precursor against burning and also acts as an effective microwave absorber, which causes higher temperatures to be reached more quickly and improves the development of the pore structure. The effect of the activator addition on the chemical and porous structures of the obtained carbons was investigated. To study their applicability in the solid-phase extraction (SPE), the recoveries and breakthrough volumes of pesticides: chlorpropham, chlorsulfuron, thiophanate-methyl were determined. The results indicate that chlorpropham has the greatest affinity for the surface of the obtained carbons. SPE tests showed that the sorption capacity of the sorbent towards the studied pesticides was approximately 2 mg g −1 .