Abstract: Layered double hydroxide pillared by Paratungstate Aion, Mg₁₂ Al₆(OH)₃₆ (W₇O₂₄ )·4H₂O, was prepared via anion exchange reaction of the synthetic precursor, Mg₄Al₂(OH)₁₂ TA·x H₂O(TA^2-=terephthalate), and W₇O₂₄^6- ion. Trace aqueous organochlorine pesticide, hexachlorocyclohexane, was totally degraded and mineralized into CO₂ and HCl by irradiating a suspension of Mg₁₂ Al₆(OH)₃₆ (W₇O₂₄ )·4H₂Oand HCHin the near UVarea. The model and pathway for the photocatalytic degradation of HCHon the Mg₁₂ Al₆(OH)₃₆ (W₇O₂₄ )·4H₂Owere proposed, indicating that the interlayer space is the reaction field, and that photogeneration of OH ·radicals are responsible for degradation pathway.

Key words: Heterogeneous photocatalysis, Layered double hydroxide, Paratungstate A, Organochlorine pesticide, Anion exchange reaction