Preparation and comprehensive characterization of C₁₆MImCl/MT for adsorbing cationic dyes

Dyeing wastewater in various industries poses a great threat to the environment. Montmorillonite (MT) is widely used in wastewater treatment because of its abundant reserves and strong exchange capacity. However, natural MT has low affinity for organic pollutants and needs to be organically modified. In order to improve the adsorption capacity of MT to cationic dyes [Congo red (CR)], using ionic liquid [1-hexadecyl-3-methylimidazolium chloride (C₁₆MImCl)] as organic modifier, the optimal preparation process of C₁₆MImCl/MT was determined by response surface methodology. The C₁₆MImCl/MT was comprehensively characterized by utilizing the techniques of XRD, FTIR, TG, BET, SEM, and molecular dynamics simulation. All the research results showed that C₁₆MImCl is successfully inserted into the layers of MT, and the basal interplanar spacing and average pore size of MT are obviously increased. The C₁₆MImCl/MT is a mesoporous material, which shows strong adsorption capacity for CR, and its CR unit adsorption capacity (CRUAC) could reach 940.200 mg/g, which is about three times that of magnetic graphene oxide and bentonite/expanded graphite.