Degradation of marine humic acids by ozone-initiated radical reactions

Imai, Daizo; Dabwan, Ahmed H. A.; Kaneco, Satoshi; Katsumata, Hideyuki; Suzuki, Tohru; Kato, Tadaya; Ohta, Kouji

doi:10.1016/j.cej.2008.09.013

Cited by 37 publications

(17 citation statements)

References 27 publications

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“…Additionally, k was calculated as 8 Á 4 9 10 -1 , 5.1 9 10 -1 , 3.6 9 10 -1 , 3 9 10 -1 , and 1.5 9 10 -1 min -1 , for the HCOBC at concentrations of 15, 30, 50, 75, and 100 mg/L, respectively. Iami et al reported similar results for HA from Sigma-Aldrich, but at a different initial concentration [35].…”

Section: Resultssupporting

confidence: 71%

Degradation of humic acids through heterogeneous catalytic ozonation with bone charcoal

Mortazavi

Asgari

Hashemian

et al. 2010

Reac Kinet Mech Cat

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Catalytic ozonation has recently been used as a new means of contaminant removal from water and wastewater. In this study, bone charcoal (BC), a new catalyst prepared under laboratory conditions, was used to catalyze the ozonation of humic substances (HS) in aqueous solutions. The catalytic effect of bone charcoal and the relevant parameters of this ozonation process (solution pH, temperature, scavenger effect, humic acids concentration and BC dosage) were investigated. In the catalytic ozonation experiments, the degradation kinetics was investigated. The reaction rate and the rate constant were determined. The results showed that using a BC catalyst in the ozonation of HS produced a 1.43-and 1.56-fold increase in reaction rates compared to the sole ozonation processes (SOP) under acidic and alkaline conditions, respectively. Furthermore, the applicability of heterogeneous catalytic ozonation with bone charcoal (HCOBC) to humic acid degradation was evaluated by performing comparisons with H 2 O 2 , O 3 , O 3 /H 2 O 2 and O 3 /H 2 O 2 /BC processes. With the use of the Arrhenius equation, the activation energy (E a ) was calculated to be 10 kJ mol -1 . The results also showed that under the different temperatures, the reaction of the catalytic ozonation of HS was defined as diffusion controlled in accordance with the activation energy. These findings suggest that the HCOBC can be applied as an efficient and feasible method for the removal of HS from water.

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Section: Resultssupporting

confidence: 71%

Degradation of humic acids through heterogeneous catalytic ozonation with bone charcoal

Mortazavi

Asgari

Hashemian

et al. 2010

Reac Kinet Mech Cat

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“…4 shows that at low O 3 dose (1 mg/L), the THM4 formation was reduced from 288.5 to 216.8 μg/L under the subsequent chlorination; thereafter a gradual increase in THM4 was observed as the ozone dose further increased to 3 and 5 mg/L. Previous studies showed that ozonation with a low dose could break the aromatic rings and double bonds of DOM (Chang et al, 2002;Imai et al, 2009), thus reducing the THM4 formation to some extent. However, ozonation with a high dose may give rise to new organic precursors (e.g., methyl-ketone-like structures) from DOM to produce more THM4 during the subsequent disinfection process (Richardson et al, 1999;von Gunten, 2003).…”

Section: Formation Of I-thms and Hacamsmentioning

confidence: 95%

Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater

Zhang

Dong

Adams

et al. 2015

Journal of Environmental Sciences

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“…Thus, it can be assumed that the HA was degraded to lower molecular weight components throughout the reaction. Imai et al (2009) demonstrated that the ozonation process that was applied to marine HA was not able to transform organic carbon into carbon dioxide completely. Furthermore, in another report (Yu et al 2005), 31 % abatement of DOC could be determined in the course of the application of a higher ozone dose to natural humic water.…”

Section: Investigation Of Natural Humic Water Degradation By Catalytimentioning

confidence: 98%

Experimental study of humic acid degradation and theoretical modelling of catalytic ozonation

Türkay

İnan

Димогло

2014

Environ Sci Pollut Res

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The efficiency of TiO2 as a catalyst in the ozonation of humic acid (HA) was evaluated in a comprehensive manner. Ozonation, catalytic ozonation and adsorption experiments were conducted using both synthetic HA solution and natural water. HA degradation was evaluated in terms of DOC, VIS400 and UV254. It was shown that the addition of catalyst positively affects the mechanism of ozonation. An increase in HA degradation was observed for all these parameters. The impact of catalyst dose and initial pH value of HA on the efficacy of catalytic ozonation was investigated. The highest removal efficiencies were achieved with the dose of 1 g l(-1) of TiO2 (Degussa P-25) and in the acidic pH region. The catalytic ozonation process was efficient also on natural water component although not at the same level as it was on synthetic water. The adsorptive feature of P-25 was considered to have a clear evidence of the catalytic ozonation mechanism. The mechanism of catalysis on the surface of metal oxides was elucidated with the help of quantum-chemical calculations. In the framework of Density Function Theory (DFT), the O3 decomposition was calculated in the catalytic and non-catalytic processes. Donor-acceptor properties of the frontier (highest occupied and lowest unoccupied molecular orbitals, HOMO/LUMO) orbitals are discussed. Electron density distribution and reaction mechanism of superoxide particles formation, which participate in the process of HA ozonation are analyzed.

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Degradation of marine humic acids by ozone-initiated radical reactions

Cited by 37 publications

References 27 publications

Degradation of humic acids through heterogeneous catalytic ozonation with bone charcoal

Degradation of humic acids through heterogeneous catalytic ozonation with bone charcoal

Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater

Experimental study of humic acid degradation and theoretical modelling of catalytic ozonation

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