Adsorption and desorption of Pb2+ on magnetic Mn2O3 as highly efficient adsorbent: Isotherm, kinetic and thermodynamic studies

摘要

This article focuses on adsorption and desorption of Pb2+ on a novel adsorbent consisting of Mn2O3 and Fe3O4. The adsorbent was prepared through combining Sol-Gel and precipitation methods to in-situ magnetization. Decreasing preparation time, synthesizing at room temperature, not using organic solvents are advantages of the presented approach. The characterizations were done by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometer and Brunauer-Emmett-Teller. High surface area and strong magnetic property propose the nanocomposite as a magnetic solid phase extraction adsorbent. Under the optimum preconcentration conditions, (a) limit of detection of 0.36 mu g L-1, (b) relative standard deviation (n = 5) of 0.94%, (c) preconcentration factor of 33.33 and (d) linearity of dynamic range of 10-200 mu g L-1 show the applicability of the adsorbent. The adsorbent was found to be durable for 3 months and efficiently applicable during this time but it is not reusable. To understand the adsorption mechanism, isotherm adsorption, kinetic adsorption and thermodynamic adsorption were established. The sorbent was employed to preconcentrate Pb2+ from water and vegetables samples.