Ozonolysis Of Humic Acid And Its Effect On Decoloration And Biodegradability

Takahashi, Nobuyuki; Nakai, Toshihiro; Satoh, Y.; Katoh, Yoshishige

doi:10.1080/01919512.1995.10555764

Cited by 31 publications

(15 citation statements)

References 8 publications

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“…∑ OH "scavenging" by DOM has been studied for a variety of natural waters and DOM isolates (Hoigné and Bader, 1978;Hoigné and Bader, 1979;Haag and Hoigné, 1985;Hoigné et al, 1989;Mopper and Zhou, 1990;Zepp et al, 1992;Haag and Yao, 1992;Brezonik and Fulkerson-Brekken, 1998;Westerhoff et al, 1999;Goldstone et al, 2002;Southworth and Voelker, 2003). In addition, it is assumed that ∑ OH is the reactive species responsible for the formation of low molecular weight fragments and discoloration during the treatment of wastewater by ozonolysis or irradiation with H 2 O 2 (Takahashi et al, 1995). ∑ OH is also thought to be important in certain processes used for degradation of humic acids in the treatment of drinking water (Staehelin and Hoigné, 1985;Gjessing, 1991;Cooper et al, 1996;Wang et al, 2001).…”

Section: Cdom + Hv Ae Ae Ohmentioning

confidence: 99%

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

White

Vaughan

Zepp

2003

Aquatic Sciences - Research Across Boundaries

150

149

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Photochemical reactions involving colored dissolved organic matter (CDOM) in natural waters are important determinants of nutrient cycling, trace gas production and control of light penetration into the water column. In this study the role of the hydroxyl radical ( ∑ OH) in CDOM photodegradation was explored as well as the contribution of photo-Fenton chemistry to ∑ OH formation. Photochemically produced ∑ OH was observed under aerobic and dioxygen-depleted conditions in highly colored, acidic natural water samples obtained from a freshwater reach of the Satilla River, a river in the southeastern United States. Net aerobic ∑ OH formation along with the production of hydrogen peroxide and Fe(II) provided evidence of photo-Fenton produced ∑ OH. A reduction in ∑ OH production in the presence of iron chelators further suggests the Aquat. Sci. 65 (2003) 402-414 Aquatic Sciences importance of iron and the photo-Fenton reaction in this water. Apparent quantum yield values for the photochemical production of ∑ OH were determined from 300-320 nm. In addition, the relationship between ∑ OH photoproduction and effects of irradiation on the optical properties of CDOM was examined. Changes in the light absorption and fluorescence properties of water samples from the Satilla River and other natural waters were compared to ∑ OH production rates. The ability of constituents of Satilla River water, principally the dissolved organic matter, to scavenge ∑ OH was also considered. Results indicate that the photoFenton reaction accounts for more than 70% of total photochemical ∑ OH production in Satilla River water. Given the significant levels of ∑ OH produced in this water, it is possible that ∑ OH influences CDOM photobleaching.

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Section: Cdom + Hv Ae Ae Ohmentioning

confidence: 99%

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

White

Vaughan

Zepp

2003

Aquatic Sciences - Research Across Boundaries

150

149

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“…The change in UV 254 is a function of O 3 and • OH exposure. True color can also be used to evaluate the oxidation of chromophoric EfOM during ozonation (14). The use of color as a surrogate would allow wastewater utilities to accomplish two treatment objectives by directly measuring color removal and indirectly measuring pharmaceutical oxidation.…”

Section: Introductionmentioning

confidence: 99%

Using Ultraviolet Absorbance and Color To Assess Pharmaceutical Oxidation during Ozonation of Wastewater

Wert

Rosario‐Ortiz

Snyder

2009

Environ. Sci. Technol.

118

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The reduction of ultraviolet (UV) absorbance at 254 nm (UV 254 ) and true color were identified as appropriate surrogates to assess the oxidation of six pharmaceuticals (i.e., carbamazepine, meprobamate, dilantin, primidone, atenolol, and iopromide) during ozonation of wastewater. Three tertiary-treated wastewaters were evaluated during oxidation with ozone (O 3 ) and O 3 coupled with hydrogen peroxide (O 3 /H 2 O 2 ). The correlation between pharmaceutical oxidation and removal of UV 254 was dependent upon the reactivity of each specific compound toward ozone, as measured by the second-order rate constant (k′′ O 3 ). Oxidation of compounds with k′′ O 3 > 10 3 M -1 s -1 correlated well (R 2 > 0.73) with UV 254 reduction between 0-50%. Oxidation of compounds with apparent k′′ O 3 < 10 M -1 s -1 resulted primarily from hydroxyl radicals and correlated well (R 2 > 0.80) with the UV 254 reduction of 15-65%. The removal of true color also correlated well (R 2 > 0.85) with the oxidation of pharmaceuticals during the ozonation of two wastewaters. These correlations demonstrate that UV 254 reduction and true color removal may be used as surrogates to evaluate pharmaceutical oxidation in the presence or absence of dissolved ozone residual during advanced wastewater treatment with O 3 or O 3 /H 2 O 2 . The use of online UV 254 measurements would allow wastewater utilities to optimize the ozone dose required to meet their specific treatment objectives.

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“…However, the increases in TOC and COD Mn removal leveled off at ozone doses of 1.8 and 1.2 mg/L, respectively, giving maximum removal rates of TOC and COD Mn at approximately 55 and 63%, respectively. NOM could be decomposed by ozone to low‐molecular‐weight compounds, which are easily biodegraded by BAC (Takahashi et al, 1995). However, with the increase in ozone dose, ozone consumption through the oxidation of biodegradable dissolved organic carbon produced in the early stage of ozonation (Fahmi et al, 2003) also increased, which stopped the increase of organics removal at certain ozone doses.…”

Section: Resultsmentioning

confidence: 99%

Removal of organics and control of bromate for a southern china water supply

Guo¹,

Pei²,

Yang³

et al. 2007

Journal AWWA

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A pilot plant with successive preozonation, coagulation-sedimentation, sand filtration, postozonation, and biological activated carbon was operated for more than six months to treat reservoir water containing 15-38 µg/L of bromide in southern China. Preozonation enhanced the removal of chemical oxygen demand using potassium permanganate as the oxidant (COD Mn ) and ultraviolet light absorbance at 254 nm (UV 254 ) using coagulationsedimentation but did not improve total organic carbon (TOC)-removal effectively. However, preozonation markedly enhanced the removal of trihalomethane formation potential (THMFP) by the conventional process, and THMFP removal by the combination of preozonation and conventional treatment was 57% using an ozone dose of 0.8 mg/L. Almost no bromate formed during preozonation. An ozone dose of 2.0 mg/L (0.5 mg/L and 1.5 mg/L for pre-and postozonation, respectively) was found to be the optimal dosage for the maximum removal of organics (65% of THMFP, 52% of TOC, 63% of COD Mn , and 84% of UV 254 ) while keeping bromate under 5 µg/L. A combination of conventional treatment with preozonation should be a suitable alternative if the primary goal is to remove THMFP.

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Ozonolysis Of Humic Acid And Its Effect On Decoloration And Biodegradability

Cited by 31 publications

References 8 publications

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

Using Ultraviolet Absorbance and Color To Assess Pharmaceutical Oxidation during Ozonation of Wastewater

Removal of organics and control of bromate for a southern china water supply

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