Preparation of mesoporous ferrisilicate with high content of framework iron by pH-modification method and its catalytic performance

The mesoporous ferrisilicates (MFS) with high iron content were synthesized by pH-modification method, and the iron content could be up to 10.5 wt.% (Si/Fe=8). The pH was kept less than 2 at pre-hydrothermal synthesis step and was adjusted to 11 during hydrothermal step. The samples were characterized by XRD, HRTEM, N(2)-sorption, XRF, FTIR, DRUV-vis, Fe K-edge EXAFS, EPR, and DSC. The results suggested that the MFS materials were ordered 2D hexagonal mesophase of MCM-41, and the iron atoms were tetrahedral coordinated in the silica framework. This material could efficiently catalyze the hydroxylation of phenol in water medium using H(2)O(2) as an oxidant, and the phenol conversion could be up to 52% under the optimal experimental conditions.