Study On Synthesis And Adsorption Of As(V) Behavior Of Anionic Clays

Anionic clays (LDH) have peculiar structure and properties, so they have become an important class of inorganic functional materials with applications in the fields of adsorption, ion exchange and catalysis.Systematic study was carried out on the preparation of Mg/Al-LDH and on the adsorption of As(V). A preliminary investigation has also been carried out on the mechanism of adsorption.Systematic investigation was carried out on the dependence of the synthesis LDH on such reaction conditions as Mg/Al molar ration, pH value, time and temperature by some experiments. The results show that, when Mg/Al molar ratio is 2:1, pH value is 9.0, time of reaction is 5h and temperature is 30 ℃, a series of well crystal Mg/Al-LDHs can be successfully obtained. When pH value is 5.0, oscillating rate is 150r/min, temperature is 30℃ and time of reaction is 1h, the maximal removal efficiency of As(V) can be reached using synthetical LDH. The diluted Na₂CO₃ solution is an efficient agency for regeneration of anionic clay after loaded As(V).The adsorption enthalpy is 2.85kJ.mol^-1 and adsorption entropy is 29.38J.mol^-1.K^-1, Gibbs free energy is in the range of-5.90^-6.64kJ.mol^-1.The dynamic adsorption data are well followed the Lagergren pesudo-second rate equation. The adsorption activation energy is 14.40kJ.mol^-1.