The purpose of this research was to improve the adsorption properties of montmorillonite (MMT) using graphene oxide (GO) and CoFe2O4 magnetic nanoparticles for methyl violet (MV) removal. The surface analyses were done on the fresh and used composite. The Langmuir isotherm had more ability to describe data than other studied models (Freundlich, Redlich-Peterson, and Toth). The maximum adsorption capacity of MV by MMT, MMT/CoFe2O4, and MMT/GO/CoFe2O4 was computed to be 59.61 mg/g, 91.27 mg/g, and 97.26 mg/g, respectively. Obtained data for all adsobers were more consistent with the pseudo-second-order kinetic model (R-2 > 0.92). The thermodynamic study showed that the MV adsorption by MMT, MMT/CoFe2O4, and MMT/GO/CoFe2O4 is spontaneous and exothermic. The ad(de)sorption of MV pollutant was studied up to 10 stages. A textile wastewater sample was treated by using the adsober. The MMT/GO/CoFe2O4 magnetic composite demonstrates the high adsorption capacity and suitable reusability toward the MV removal from aqueous media. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.