A molybdovanadophosphate-based surfactant encapsulated heteropolyanion with multi-lamellar nano-structure for catalytic wet air oxidation of organic pollutants under ambient conditions

A series of surfactant encapsulated heteropolyanions (SEH-n) based on molybdovanadophosphates (MVPs) was prepared. The morphological optimisation of the SEHs was studied by the control of solvent polarity and MVP to surfactant ratio used. Investigation by TEM revealed the formation of particles with multi-lamellar nano-structure in the SEHs. Characterization of the SEHs by XRD, TGA and FTIR indicated the successful encapsulation of the molybdovanadophosphates with the surfactant. The performance of SEHs as catalysts for the removal of bisphenol-A under ambient conditions was evaluated. Factors influencing the performance of the SEH-n are the relative stability of the Keggin structure and electron accepting property. The dissolved oxygen plays a crucial role in improving the BPA removal efficiency. The hydrophobic property of the nano-sized SEHs provides good aqueous stability and allows excellent recoverability of the catalyst from the aqueous solution after treatment.