The catalytic and photocatalytic oxidation of organic substances using heterogeneous Fenton-type catalysts

Abstract

This paper deals with catalytic and photocatalytic oxidation of organic substances using H202 over heterogeneous Fenton-type catalysts. In the study a series of Fe-containing catalysts was experienced. A zeolite named as FeZSM-5 was selected as the most active heterogeneous Fenton-type catalyst. The FeZSM-5 reported was prepared by hydrothermal crystallization in the presence of iron salt. In contrast to the homogeneous Fenton system the catalyst prepared had minimal, if any, leaching of iron ions, was stable during 30 catalytic runs and didn't lose its activity in the presence of complexing agents, e.g. P2O7(4-). The catalyst was active in oxidation of organic substances at pH from 1.5 to 8, maximum activity was observed at pH = 3. The FeZSM-5 effectively oxidized a simulant of the warfare agent, diethylnitrophenil phosphate, which is hardly detoxified by other methods. It appeared that the rate of oxidation of formic acid, ethanol and benzene over FeZSM-5 increased under the action of visible light (lambda > 436 nm), quantum efficiency being 0.06-0.14.

PHOTO-FENTON REACTION OF DYES WITH Fe(III)-TREATED HYDROXYAPATITES AS HETEROGENEOUS CATALYSTS IN WATER

“…Pore diameter distribution of HAP-300-Fe, HAP-400-Fe, Fe 2 O 3 , FePO 4 •2H 2 O, and FeOOH by a N 2 -adsorption method. …”

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Photo-Fenton reaction is one of advanced oxidation processes, 19 which are essentially used for removal of natural organic matter from drinking water.…”

“…9 From a viewpoint of smoothing and recycling usage, or running cost in future water purification plants, a heterogeneous system must be superior to homogenous one. As heterogeneous catalysts, iron oxides (Fe 2 O 3 , FeOOH), 3,13 Fe(III)-immobilized zeolites, 4,11,12 Fe(III)-immobilized silica, 5,16 Fe(III)-immobilized clay, [6][7][8][9]14,17 Fe(III)-immobilized Al 2 O 3 , 10 Prussian blue colloids, 15 and tungstate salt 18 were employed so far.…”

Photocatalytic Activity of the Iron-Containing Natural Composites in the Reaction of Oxidative Destruction of Oxalic Acid and Phenol

“…However, the use of heterogeneous iron-containing catalysts in the aqueous medium considerably eliminates the mentioned drawbacks. Thus, to purify waters from phenol, ethanol, and different dyes, some previous studies [15][16][17] used iron-containing synthetic zeolite FeZSM-5; other studies [18,19] used iron-containing metal-ceramic composites. The mentioned catalysts manifested high photocatalytic activity in reactions of oxidative destruction of organic pollutants.…”

“…The latter showed high photocatalytic activity in reactions of oxidative destruction of organic substances in water [15][16][17]. However, there are not enough data in the literature on obtaining cheap composites based on natural peat and zeolites with photoactive components for SOS degradation in aqueous media.…”