Effect of copper loadings on product selectivities in microwave-enhanced degradation of phenol on alumina-supported copper oxides

Alumina-supported copper oxides catalysts were prepared using impregnation method and characterized using XRD, SEM and BET. Catalytic activities in phenol removal from its aqueous solution (200 ppm) were studied using hydrogen peroxide as an oxidant under microwave irradiation. Effects of copper loadings, reaction temperatures (50 and 70 °C) and pH (5 and 9) were studied. The high loading samples (9–14 wt%) exhibited 97% phenol removal efficiency corresponding to 90% total organic carbon (TOC) value. Lower loading samples (1 wt%) showed significantly lower phenol removals and inferior catalyst stability. At similar levels of phenol degradations, there was higher proportion of high molecular weight products or intermediates on 14 than on 1 wt% copper/Al2O3.