Removal of boron in aqueous solution by magnesium oxide with the hydration process

Abstract

Excessive boron in an aqueous solution will endanger the growth of animals and plants and the normal operation of industrial production. To solve the problem of boron pollution, magnesium oxide (MgO) was prepared by precipitation, hydrothermal and calcination to remove boron from aqueous solution. The change of MgO before and after adsorption was analyzed by SEM, BET, XRD, FT-IR, and XPS characterization and calculation methods. Surface hydration of MgO and its transformation to magnesium hydroxide (Mg(OH)2) may be the main process of adsorption on boron. In addition, the adsorption of boron by MgO is an exothermic process and has relatively mild adsorption conditions (pH: 7–9). The maximum adsorption amount could reach 202.43 mg/g within 6 h (pH ≈ 9, T = 25 °C), higher than most boron adsorbents. Moreover, MgO has a certain anti-interference to competitive ions and can be renewable in alkaline solutions. Therefore, MgO is a potential low-cost boron adsorbent.