Effect of phosphate on heterogeneous Fenton oxidation of catechol by nano-Fe 3 O 4 : Inhibitor or stabilizer?

Abstract

The effect of phosphate on adsorption and oxidation of catechol, 1,2-dihydroxybenzene, in a heterogeneous Fenton system was investigated. In situ attenuated total reflectance infrared spectroscopy (ATR-FTIR) was used to monitor the surface speciation at the nano-Fe 3 O 4 catalyst surface. The presence of phosphate decreased the removal rate of catechol and the abatement of dissolved organic compounds, as well as the decomposition of H 2 O 2 . This effect of phosphate was mainly due to its strong reaction with surface sites on the iron oxide catalyst. At neutral and acid pH, phosphate could displace the adsorbed catechol from the surface of catalyst and also could compete for surface sites with H 2 O 2 . In situ IR spectra indicated the formation of iron phosphate precipitation at the catalyst surface. The iron phosphate surface species may affect the amount of iron atoms taking part in the catalytic decomposition of H 2 O 2 and formation of hydroxyl radicals, and inhibit the catalytic ability of Fe 3 O 4 catalyst. Therefore, phosphate ions worked as stabilizer and inhibitor in a heterogeneous Fenton reaction at the same time, in effect leading to an increase in oxidation efficiency in this study. However, before use of phosphate as pH buffer or H 2 O 2 stabilizer in a heterogeneous Fenton system, the possible inhibitory effect of phosphate on the actual removal of organic pollutants should be fully considered.

Remediation of an aged PCP-contaminated soil by chemical oxidation under flow-through conditions

“…By analogy, M-β-CD as an organic ligand may sorb to soil constituents and thus blocking catalytical sites for HP decomposition. In contrast to previous reports where decrease in removal extent of organic compounds often accompanies decrease in HP decomposition rate [43,44], no change in removal extent of PCP was observed in the present study.Higher concentrations of M-β-CD have significantly limited the decomposition of HP and so increased the lifetime of HP in reaction medium (Fig. 12).…”

The photocatalytic performance and mechanism of magnetically retrievable Z-scheme Cr2O3–Fe3O4/C hetero-nanostructure polyhedra

“…30,31 Nevertheless, the presented Fe 3 O 4 nanoparticles showed low catalytic performance, leaching of iron ions and the characteristic of being easy to agglomerate in reactions, thereby reducing catalytic activity. 32,33…”

Preparation of Magnetic g-C3N4/Fe3O4 Composite and Its Application in the Separation of Catechol from Water

“…Furthermore, catechol is difficult to degrade, so conventional water treatment technology cannot effectively remove it from polluted water [5]. Currently, the common methods for the removal of catechol include catalytic degradation [6,7], advanced oxidation technology [8,9,10,11], and adsorption [12]. Thereinto, adsorption has become a widely used method for the treatment of catechol due to its simple operation, low cost, and high efficiency.…”