title: The role of quinone cycle in Fe2+-H2O2system in the regeneration of Fe2.
abstract: The reaction between Fe2+and H2O2generates highly reactive ·OH. However, the weak conversion from Fe3+to Fe2+limits its continuous reaction. Here, the difference between the Fenton system and modified Fenton system for the regeneration of Fe2+was analyzed. A UV-vis spectrometer and redox potential measurements were used to detect Fe2+concentration. Results indicated that Fe2+could be better regenerated in the modified Fenton system. The regeneration of Fe2+was facilitated by the consumption of NH2OH, while in hydroquinone (HQ)- and 1,4-bezoquinone (1,4-BQ)-modified Fenton systems, the quinone cycle could be built up and Fe3+could be converted to Fe2+continuously. However, results showed that HQ and 1,4-BQ reacted with ·OH, which caused a gradual decline in the enhancement effect. In order to keep Fe2+concentration stable for a longer time, the influence of [HQ/1,4-BQ]0/[Fe2+]0on Fe2+concentration was carefully studied. When the mole ratio was 5:1, Fe2+concentration remained nearly 90% of total iron at 40 min. But when the mole ratios were 0.5:1 and 0.1:1, Fe2+concentration decreased to a very low level at 20 min. Oxidation-reduction potential (ORP) results further confirmed the role of quinone cycle.
authors.affiliation: a School of Energy Science and Engineering , Harbin Institute of Technology , Harbin , People's Republic of China.
authors.forename: Wei
authors.identifier: http://orcid.org/0000-0001-5126-0708
authors.initials: W
authors.lastname: Zhou
authors.affiliation: a School of Energy Science and Engineering , Harbin Institute of Technology , Harbin , People's Republic of China.
authors.forename: Jihui
authors.initials: J
authors.lastname: Gao
authors.affiliation: b School of Civil Engineering & Architecture , Northeast Petroleum University , Daqing , People's Republic of China.
authors.forename: Haiqian
authors.initials: H
authors.lastname: Zhao
authors.affiliation: a School of Energy Science and Engineering , Harbin Institute of Technology , Harbin , People's Republic of China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Meng
authors.affiliation: a School of Energy Science and Engineering , Harbin Institute of Technology , Harbin , People's Republic of China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Wu
mesh_terms: D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical; D007501:Iron; D010084:Oxidation-Reduction; D012038:Regeneration
chemical_list: D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Fe2+ regeneration; Fe2+–H2O2 system; hydrogen peroxide; hydroxyl radical; quinone cycle