fulltext.study @t Gmail

Comparison of catalytic decomposition of hydrogen peroxide and catalytic degradation of phenol by immobilized iron oxides

Paper ID Volume ID Publish Year Pages File Format Full-Text
42996 45950 2008 9 PDF Available
Title
Comparison of catalytic decomposition of hydrogen peroxide and catalytic degradation of phenol by immobilized iron oxides
Abstract

Immobilized iron oxides on silica matrixes in fluidized bed reactors, including SiG1, SiG2, C1, and the commercial catalyst FeOOH, were used in the catalytic decomposition of H2O2 and the catalytic degradation of phenol. They were characterized using XRD, SEM, N2-sorption, and elucidation of the kinetics of dissolved iron by oxalic acid in dark surroundings. XRD patterns reveal that SiG1, SiG2, and C1 exhibit amorphous structures, and FeOOH exhibits the poor crystallinity of goethite. The SEM images reveal that the surfaces of all the iron oxides are smooth and that the iron oxides are aggregated by the iron oxide floc. The N2-sorption isotherm indicates that SiG1 and SiG2 are non-porous materials, and that C1 and FeOOH are typical type II and typical type IV materials, respectively. A kinetic model for iron dissolved by oxalic acid is established. The order of apparent first-order dissolution rate constants (kc) is SiG1 > SiG2 > FeOOH ∼ C1. The immobilized iron oxides, SiG1 and SiG2, are weakly bonded to the support (silica sand) in the presence of oxalic acid. The decomposition of H2O2 follows pseudo-first-order kinetics. The number of active sites for the decomposition of H2O2 is similar among all iron oxides at a particular kapp (1.8 × 10−3 min−1). There are no interactions between phenol and iron oxides in the absence of hydrogen peroxide at pH 4. SiG1 and SiG2 exhibit much higher catalytic activities in phenol degradation than either C1 or FeOOH. The reactivity of iron oxides in catalyzing the phenol degradation by H2O2 relates to the tendency of iron to be dissolved by oxalic acid. The intermediates of phenol degradation, such as catechol and oxalic acid, promote the dissolution of iron from SiG1 and SiG2 by reductive and non-reductive pathways and lower the pH values. The catalyses of SiG1 and SiG2 involve heterogeneous and homogeneous reactions.

Graphical abstractImmobilized iron oxides on silica matrixes in fluidized bed reactors, including SiG1, SiG2, C1, and the commercial catalyst FeOOH, were used in the catalytic decomposition of H2O2 and the catalytic degradation of phenol. The iron oxides were characterized using XRD, SEM, N2-sorption, and elucidation of the kinetics of dissolved iron by oxalic acid in dark surroundings. SiG1 and SiG2 exhibit higher catalytic activities in phenol degradation. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Catalyst; Phenol; Iron oxides; Fenton; Fluidized bed reactor
First Page Preview
Comparison of catalytic decomposition of hydrogen peroxide and catalytic degradation of phenol by immobilized iron oxides
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 346, Issues 1–2, 31 August 2008, Pages 140–148
Authors
, ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us