Efficient mineralization of phenol by a temperature-responsive polyoxometalate catalyst under wet peroxide oxidation at lower temperatures

Abstract

Herein, a temperature-responsive polyoxometalate (POM) catalyst [C16H33(CH3)3N]3[PO4{WO(O2)2}4]/poly(N-isopropylacrylamide) (abbreviated as (C16PW(O2)2/PNIPAM) was prepared and used in the catalytic wet peroxide oxidation (CWPO) of phenol under mild conditions. The POM catalyst C16PW(O2)2/PNIPAM showed a higher degradation efficiency and mineralization of phenol with H2O2 at room temperature or even at lower temperature (0 °C) within a short time (120 min). The high efficiency at lower temperature was attributed to its temperature-responsive property, wherein the lattice of the temperature-sensitive polymer relaxed at lower temperature and then wrinkled at higher temperature. These characteristics also permitted C16PW(O2)2/PNIPAM to be easily separated for recycling. The leaching test indicated that the POM catalyst exhibited excellent stability and little leaching and can be used as a thermosensitive catalyst for about six times. C16PW(O2)2/PNIPAM has potential application in the CWPO of phenol without the limitation of temperature and pH conditions.