Preparation and characterization of nano-structured modified montmorillonite for dioxidine antibacterial drug removal in water

An inexpensive nano-structured modified adsorbent was prepared from natural montmorillonite. The optimum and significant parameters were Al3+:Co2+(11:2) with ion exchange, drying and calcination temperatures, respectively 75, 85 and 450 °C. The material was characterized by EDX, SEM, TEM, XRD and low-temperature nitrogen adsorption. The adsorbent was used for removing dioxidine antibiotics in water. The adsorption approximated by Langmuir, Freundlich, Tyomkin, Flory-Higgins, Dubinin-Radushkevich isotherms and kinetics pseudo-first-order, pseudo-second-order, Elovich-Chen-Clayton, Boyd, and Vebber-Morris models. The pseudo-second-order and Freundlich models most adequately describe the adsorption process. The maximum adsorption of dioxidine (96.5%) was achieved with 60 min of contact time, pH 7, dioxidine concentration 30 mg/L and adsorbent dose 5 g/L. The regeneration of the adsorbent was achieved by catalytic oxidative destruction of dioxidine with hydrogen peroxide. The reported adsorbent has shown an exceptional capability to remove dioxidine in water with the loss of about 8–10% adsorption capacity after running 5–6 times. The reported process may be assumed as an effective method for the removal of dioxidine from water with the economy due to the absence of wastewater during the regeneration of the adsorbent.