Effect of the occurrence state of magnesium in talc on the adsorption of Pb(II)

Abstract It is of great significance in the resource utilization to make full use of the magnesium in the low-grade mineral to prepare new adsorption materials. In this paper, a Mg(OH)2/talc nanocomposite was prepared by migrating part of Mg2+ from the talc internal structure to the outer surface through a facile acid leaching, coprecipitation and hydrothermal method. The maximum adsorption capacity of Mg(OH)2/talc was 483.33 mg/g, which was significantly improved compared with that of Acid-activated Talc (4.79 mg/g) and pristine talc (259.17 mg/g). The main adsorption mechanism of Mg(OH)2/talc for Pb(II) ions involved electrostatic attraction and ion exchange. Adsorption and desorption cycle experiment showed that, although Mg(OH)2/talc provides a large adsorption capacity for the first time, but the second adsorption capacity decreased by 42%, the third to the fifth kept stable adsorption capacity. This results indicated that the surface of magnesium hydroxide was not stable, only used it once. While magnesium hydroxyl in talc was stable, it could provide stable cycle performance. This work can provide reference for efficient utilization of clay minerals and design novel cost-efficient adsorbents.