Application of the graphene oxide/chitosan nanocomposite in the removal of methyl orange from aqueous solutions: a mechanism study

Abstract

Graphene oxide (GO) and the functionalized graphene oxide with chitosan (GO-C) has been used for the removal of methyl orange from aqueous solutions. Batch experiments such as solution pH, amount of adsorbents, contact time, concentration of the methyl orange and temperature are carried out to study the sorption process. Kinetic studies are well described by pseudo-second-order kinetic model for both adsorbents. Isotherm studies have shown that Langmuir isotherm for GO and GO-C are the best to represent the measured sorption data. Negative ∆G^◦ values indicate the nature of spontaneous adsorption process. Physical sorption is suggested for the adsorption process. In addition, methyl orange molecules can be desorbed from GO-C up to 79.2% at pH =11 and that the consumed GO-C can be reutilized up to 5th cycle of regeneration.