Preparation of cationic pillar5arene modified bentonite and its adsorption to orange Ⅳ

A new adsorbent material (CP5A/BT) of cationic pillar5arene (CP5A) modified bentonite (BT) was prepared by the hydrothermal method. The CP5A/BT was characterized by infrared absorption spectroscopy (IR), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Nionic dye orange yellow Ⅳ (OIV) was used as the target adsorbate. The adsorption effect of the concentration of CP5A, the amount of adsorbent added, solution pH, contact time and initial OIV concentration were investigated. The adsorption process was studied by adsorption kinetics and adsorption isotherm models. Through the "adsorption-desorption" cycle, the regeneration of CP5A/BT adsorbent was investigated. The results showed that CP5A was successfully loaded on BT, and BT has different surface morphology and structure after CP5A modification. The surface of BT modified by CP5A has a large number of active sites, and the adsorption reached equilibrium within 45 minutes. The adsorption capacity under acidic and weakly alkaline conditions was higher than that of strongly alkaline conditions. According to the analysis of kinetic model, Langmuir and Freundlich model, the theoretical adsorption capacity of CP5A/BT to OIV reached 230.4247 mg·g⁻¹, and the pseudo-second-order kinetics and Freundlich isotherm model could better fit the adsorption process of CP5A/BT to OIV. This adsorption process is mainly chemical adsorption. CP5A/BT adsorbent has excellent adsorption-regeneration properties.