Different ferrosilicate samples have been prepared with varying degrees of crystallinity, porous texture, and speciation of the Fe sites by both hydrothermal and sol-gel procedures: Fe-silicalite-1 with microcrystals (2-10 mu m) and nanocrystals (180nm), Fe-containing composite material consisting of silicalite-1 and amorphous silica, and two samples of mesoporous Fe-containing amorphous silica Fe-SiO2. The resulting solids have been tested for their potential as organic pollutants removal under Fenton-like conditions in heterogeneous catalytic wet peroxide oxidation of phenol and clarithromycin lactobionate. Our results indicate that the three aforementioned parameters show a strong interplay towards the abatement of pollutants in liquid phase. Thus, samples with high crystallinity show an improved performance in the oxidation of organic contaminants over amorphous samples in which the Fe speciation is very well controlled. [GRAPHICS] .