Removal of bentazon in water thorough a novel adsorbentprepared by IL@β-cyclodextrin/reduced graphene oxide/multiwall carbon nanotubes

Abstract

A green, simple and catalyst-free ionic liquid@β-cyclodextrin-reduced grapheme oxide-multiwall carbon nanotubes (IL@β-CD-rGO-MWCNTs) was synthesized by hydrothermal reduction and chemical crosslinking without the protection of inert gases and the assistance of energy fields. With the characteristics of large specific surface area, good thermal stability, superior porous structure and rich functional groups, IL@β-CD-rGO-MWCNTs can be used as an effective adsorbent to rapidly remove bentazon from aqueous environments. Under optimal conditions (pH 6.0, solid–liquid ratio of 2:1 and no salt), the maximum adsorption capacity (qm) of IL@β-CD-rGO-MWCNTs to bentazon was 125.00 mg g−1 as corroborated by the Langmuir isotherm model at 40 °C, higher than that of the most commonly used bentazon adsorbent. Many molecular interactions, such as hydrogen bonding and π/π-π interaction, determine its adsorption capacity and selectivity. The adsorption kinetics and isotherm fit well with the pseudo-second-order kinetic model and Langmuir model, and the effective eluting adsorbent can be reused after treatment. The proposed strategy not only provides a valuable reference for the efficient synthesis of IL@β-CD-rGO-MWCNTs, but also provides a new strategy and ideas for the adsorption and removal of pollutants in water environments.