Incorporation of zirconium-based metal-organic framework on kaolin for boosting Rhodamine-B adsorption

This research was focused on the utilization of zirconium-based metal-organic framework (UiO-66) supported kaolin composite (UiO-66@kaolin) for rhodamine-b (RB) adsorption. The proposed composite was prepared via solvothermal method, and the structural properties were characterized by FT-IR, SEM, XRD and BET analyses. The adsorption performances of kaolin and UiO-66@kaolin were compared with equilibrium experiments and the maximum monolayer adsorption capacities calculated from the Langmuir model were found as 2.10 mg g-1 and 17.22 mg g-1, respectively. It was observed that the adsorption capacity of pristine kaolin was significantly increased by UiO-66 incorporation. While kaolin mineral was fitted to monolayer Langmuir isotherm model, the isotherm character of the composite adsorbent was described as multilayer Freundlich model. The equilibrium time for UiO-66@kaolin was 240 min and the adsorption process was determined as pseudo-second-order model. It was observed that RB removal rate decreased in acidic medium and consequently pH had a major effect on adsorption. The thermodynamic parameters demonstrated that RB adsorption was exothermic and spontaneous. The effective removal of RB dye from wastewater systems using the prepared UiO-66@kaolin composite adsorbent was confirmed by extensive adsorption experiments and compared with other studies. For the economic analysis of UiO-66@kaolin as an adsorbent a cost evaluation was carried out. The reported findings may inspire further potential investigations.