Physico-chemical characterization of activated carbon–metal oxide photocatalysts by immersion calorimetry in benzene and water

Abstract

[EN] From a commercial activated carbon (AC) and Al3?, Fe3?, Zn2?, SnCl2, TiO2 and WO4 2- in water, three series of AC–metal (hydr)oxide (MO) samples prepared by wet impregnation in two successive steps of soaking at 80 ºC and oven-drying at 120 ºC (S1) and subsequent heat treatment at 200 (S2) or 850 C (S3) were characterized texturally by N2 adsorption at -196 C and by immersion calorimetry in benzene and water. The mass changes associated with the preparation of the samples are usually stronger for S1 and S3 than for S2. The incorporation of MO to AC causes a greater decrease in the micropore volume and pore narrowing only for the SnCl2-impregnated sample. The opposite effects on the microporous structure are noted for most S2 and S3, as compared to S1. For AC, -DiH(C6H6) is 114.0 J g-1 and -DiH(H2O) is 30.5 J g-1. For the AC–MO samples, -DiH(C6H6) and Stot(C6H6) are generally lower than for AC and vary by S3[S2[S1. However, -DiH(H2O), Stot(H2O) and [O] are usually lower for S3. Stot(C6H6) is higher for the samples prepared using the metal ions. The results of immersion calorimetry for AC and AC–MO samples provide one with valuable information concerning the dependence of the hydrophobicity and hydrophilicity of the samples on the method used in their preparation.