Heterogeneous degradation of precipitated hexamine from wastewater by catalytic function of silicotungstic acid in the presence of H2O2 and H2O2/Fe2+

Iron-glutamate-silicotungstate ternary complex as highly active heterogeneous Fenton-like catalyst for 4-chlorophenol degradation

“…However, in the presence of both Fe Ш GluSiW and H2O2, H2O2 can oxidize SiW12O40 5− to SiW12O40 4− , producing additional HO • species (Eq. (10)) [25]. This proposal is supported by the fact that the redox potential of H2O2 to HO • and H2O (+0.71 V versus the normal hydrogen electrode [36]) is more positive than that of SiW12O40 4-to SiW12O40 5-(+0.057 V versus the normal hydrogen electrode [37]).…”

“…Sedlak's group [24] showed that addition of PW12O40 3− to the Fe 3+ /H2O2 homogeneous system extends the working pH range up to pH = 8.5. Taghdiri et al [25] reported that silicotungstic acid catalyzes the oxidation of hexamethylenetetramine in the presence of H2O2 or H2O2/Fe 2+ . These studies suggest potential synergies between iron and POM for catalytic oxidation of pollutants by H2O2.…”

Highly active iron-containing silicotungstate catalyst for heterogeneous Fenton oxidation of 4-chlorophenol

“…Most recently, Taghdiri et al reported enhanced degradation of hexamine by addition of silicotungstic acid into Fe 2+ /H 2 O 2 system, in which a precipitate was firstly formed by hexamine and silicotungstic acid, and then hexamine in the precipitate was oxidized with silicotungstic acid released into aqueous phase. The high oxidation efficiency was attributed to synergetic effect of Fe 2+ and silicotungstate, which resulted in increased production of hydroxyl radicals and direct oxidation of hexamine by silicotungstate [36].…”

Degradation process and kinetics study of actual urotropine wastewater by Fenton method

“…Urotropine is a very stable molecule with a cyclic symmetric structure like adamantine [3], which makes the molecule recalcitrant to oxidation via methylotrophic pathway reactions so that minimum soil microbes can degrade it for utilization [4], In addition, the urotropine is a commonly used insecticide and hexamine is resistant to biodegradation, even when sludge has been acclimated for a long period. Previous studies reported that brevundimonas diminuta and a phyllobacterium sp.…”