Reusable, few-layered-MoS2 nanosheets/graphene hybrid on cellulose paper for superior adsorption of methylene blue dye

Abstract

In this study, we report for the first time few-layered MoS₂ nanosheets grown onto graphene dipped cellulose filter paper (M-G-CFP) using a simple hydrothermal method towards efficient adsorption of cationic methylene blue (MB) dye. Detailed morphological and chemical characterization studies of M-G-CFP are performed using FESEM, TEM, XRD and Raman spectroscopy that reveal micro flower-like MoS₂ grown onto graphene modified paper with few layers of MoS₂ nanosheets and its high purity nature. Due to electrostatic interactions between cationic dye and the anionic adsorbent surface, the hybrid M-G-CFP exhibits ultrafast removal of MB within 2 min with a maximum adsorption capacity of 485.4 mg g⁻¹ which is superior in comparison to other reported MoS₂ based adsorbents. This high adsorption capacity is attributed to large accessible active sites on the surface of the hybrid M-G-CFP structure. The adsorption mechanism of MB dye on the MoS₂ nanosheets are well described using kinetic and isotherm models with the effects of parameters like pH, contact time and temperature. The kinetic and isotherm study reveals that the adsorption of MB dye follows a pseudo-second order model, indicating the chemisorption and Langmuir model of monolayer adsorption, respectively. Furthermore, this hybrid structure can be efficiently reused for subsequent dye adsorption without compromising on its dye removal efficiency suggesting it is a feasible and promising material towards wastewater treatment applications.