Adsorption of Inorganic Arsenic As(Ⅲ), As(Ⅴ) and F- on MgAl-NO₃-LDH in Water

NO₃-type layered double hydroxide (MgAl-NO₃-LDH) was prepared via an ion exchange method, and its adsorption capacity toward As(Ⅲ), As(Ⅴ) and F^- with trace amount in water was investigated. The materials after the adsorption were desorbed using acid-salt method and the adsorption capacity was further tested. The results showed that the adsorption capacity toward As(Ⅲ)，As(Ⅴ) and F^- was 0.026, 0.11 and 3.8 mg/g-LDH, respectively, and the main adsorption mechanisms of MgAl-NO₃-LDH were the ion exchange. After regeneration the uptake amount toward As(Ⅲ) was found to be reduced to 0.014 mg/g-LDH, but that toward As(Ⅴ) was still high (0.099 mg/g-LDH).