Efficient degradation of organic pollutants with ferrous hydroxide colloids as heterogeneous Fenton-like activator of hydrogen peroxide.

Ferrous hydroxide colloids were prepared and characterized as an activator of H(2)O(2) for decomposing organic pollutants, such as Rhodamine B, sulfamonomethoxine (SMM) and 4-nitrophenol (4-NP). As major reactive oxygen species, hydroxyl radicals were confirmed to be generated in the activation of H(2)O(2) by using fluorescent probe technique and electron spin resonance technique. The highly-dispersed colloidal nanoparticles with large specific surface area combined the merits of both homogeneous and heterogeneous activator, leading to fast degradation of organic contaminants. Almost complete decolorization of added RhB (0.02 mM), along with a removal of 64.3% of total organic carbon, was achieved within only 1 min by adding 0.30 mM ferrous hydroxide colloids and 1.20 mM H(2)O(2) at pH 7.0. Based on the contributions from the redox activation and the caged activation, a new mechanism was proposed to explain the enhancing effect of the colloids.