Adsorption of boron on calcined AlMg layered double hydroxide from aqueous solutions. Mechanism and effect of operating conditions Article uri icon

abstract

  • The adsorption of boron from an aqueous solution on layered double hydroxide (LDH) was investigated in detail in this work. The LDH was synthesized by a co-precipitation method using carbonate as an exchangeable anion; the LDH was calcined at 550. °C and denoted as LDH-550. Experimental adsorption equilibrium data were obtained in a batch adsorber and were interpreted reasonably well using the Langmuir isotherm. The solution pH considerably affected the adsorption capacity of LDH-550 toward boron due to electrostatic interactions between the surface of LDH-550 and the boron species in solution. The adsorption capacity of LDH-550 was independent of temperature when the temperature was increased from 15 to 25. °C but decreased when the temperature was increased from 25 to 35. °C. The reversibility of the adsorption was shown to be dependent on the desorption pH. Boron can be adsorbed on LDH-550 as boric acid and borate. The adsorption of borate on LDH-550 was due to anion exchange and electrostatic attraction, whereas boric acid was adsorbed by an acid-base reaction. The mechanisms were elucidated by evaluating and interpreting the surface charge of LDH-550 before and after boron adsorption, FTIR analysis and the equivalents of anions exchanged during the adsorption of boron. © 2014 Elsevier B.V.

publication date

  • 2014-01-01