Adsorption and electro-assisted method removal of boron in aqueous solution by nickel hydroxide

• The boron adsorbent of nickel hydroxide was prepared by precipitation method and used for conventional adsorption and electro-assisted adsorption without acid desorption. • Electro-assisted adsorption method (57.5 mg/g, 12 h) has a faster adsorption rate and higher adsorption capacity than conventional adsorption (45.4 mg/g, 48 h). • Electro-assisted adsorption method was used to remove boron from aqueous solutions at low voltage (0.2 V), and the mechanism of low-voltage adsorption was explained. Technical research on electrochemical acid-free desorption of boron is imminent, and layered nickel hydroxide is a potential boron-responsive active electrode material. In this paper, nickel hydroxide was used to remove boron from aqueous resources by electro-assisted and conventional adsorption methods. The option of conditions by nickel hydroxide adsorption for boron is mild (pH: 7∼9) with an exothermic process. Interestingly, the synergistic effect of physical and chemical adsorption improves the adsorption rate and adsorption capacity of nickel hydroxide for boron under the action of the electric field, and the adsorption performance is better at low voltage (0.2∼0.4V). The equilibrium time of the electro-assisted method is 4 times shorter than conventional adsorption methods, and the maximum adsorption capacity can reach 57.5 mg/g than conventional adsorption (45.4 mg/g). In addition, the nickel hydroxide has selectivity in high-concentration anion solutions and can be easily regenerated by an alkaline solution. Therefore, it is expected that nickel hydroxide with the electro-assisted method could be a potential approach for the high-efficiency and eco-friendly removal of boron.