Dataset Information

Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates.

ABSTRACT: Removal of nonylphenol ethoxylates (NPEOs) in aqueous solution by Fenton oxidation process was studied in a laboratory-scale batch reactor. Operating parameters, including initial pH temperature, hydrogen peroxide, and ferrous ion dosage, were thoroughly investigated. Maximum NPEOs reduction of 84% was achieved within 6?min, under an initial pH of 3.0, 25°C, an H2O2 dosage of 9.74×10(-3) M, and a molar ratio of [H2O2]/[Fe(2+)] of 3. A modified pseudo-first-order kinetic model was found to well represent experimental results. Correlations of reaction rate constants and operational parameters were established based on experimental data. Results indicated that the Fenton oxidation rate and removal efficiency were more dependent on the dosage of H2O2 than Fe(2+), and the apparent activation energy (?E) was 17.5?kJ/mol. High-performance liquid chromatography and gas chromatograph mass spectrometer analytical results indicated degradation of NPEOs obtained within the first 2?min stepwise occurred by ethoxyl (EO) unit shortening. Long-chain NPEOs mixture demonstrated a higher degradation rate than shorter-chain ones. Nonylphenol (NP), short-chain NPEOs, and NP carboxyethoxylates were identified as the primary intermediates, which were mostly further degraded.

SUBMITTER: Cui K

PROVIDER: S-EPMC4027986 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates.

Cui Kai K Yi Hao H Zhou Zi-Jian ZJ Zhuo Qiong-Fang QF Bing Yong-Xin YX Guo Qing-Wei QW Xu Zhen-Cheng ZC

Environmental engineering science 20140501 5

Removal of nonylphenol ethoxylates (NPEOs) in aqueous solution by Fenton oxidation process was studied in a laboratory-scale batch reactor. Operating parameters, including initial pH temperature, hydrogen peroxide, and ferrous ion dosage, were thoroughly investigated. Maximum NPEOs reduction of 84% was achieved within 6 min, under an initial pH of 3.0, 25°C, an H2O2 dosage of 9.74×10-3 M, and a molar ratio of [H2O2]/[Fe2+] of 3. A ...[more]

PMID: 24868141

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Project description:Purpose:The present study aimed to determine whether whole-body fat oxidation and muscle deoxygenation kinetics parameters during exercise were related in individuals with different aerobic fitness levels. Methods:Eleven cyclists [peak oxygen uptake ( V.O2?p?e?a?k ): 64.9 ± 3.9 mL?kg-1?min-1] and 11 active individuals ( V.O2?p?e?a?k : 49.1 ± 7.4 mL?kg-1?min-1) performed a maximal incremental cycling test to determine V.O2?p?e?a?k and a submaximal incremental cycling test to assess whole-body fat oxidation using indirect calorimetry and muscle deoxygenation kinetics of the vastus lateralis (VL) using near-infrared spectroscopy (NIRS). A sinusoidal (SIN) model was used to characterize fat oxidation kinetics and to determine the intensity (Fatmax) eliciting maximal fat oxidation (MFO). The muscle deoxygenation response was fitted with a double linear model. The slope of the first parts of the kinetics (a 1) and the breakpoint ([HHb]BP) were determined. Results:MFO (p = 0.01) and absolute fat oxidation rates between 20 and 65% V.O2?p?e?a?k were higher in cyclists than in active participants (p < 0.05), while Fatmax occurred at a higher absolute exercise intensity (p = 0.01). a 1 was lower in cyclists (p = 0.02) and [HHb]BP occurred at a higher absolute intensity (p < 0.001) than in active individuals. V.O2?p?e?a?k was strongly correlated with MFO, Fatmax, and [HHb]BP (r = 0.65-0.88, p ? 0.001). MFO and Fatmax were both correlated with [HHb]BP (r = 0.66, p = 0.01 and r = 0.68, p < 0.001, respectively) and tended to be negatively correlated with a 1 (r = -0.41, p = 0.06 for both). Conclusion:This study showed that whole-body fat oxidation and muscle deoxygenation kinetics were both related to aerobic fitness and that a relationship between the two kinetics exists. Individuals with greater aerobic fitness may have a delayed reliance on glycolytic metabolism at higher exercise intensities because of a longer maintained balance between O2 delivery and consumption supporting higher fat oxidation rates.

Dataset Information

Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates.

Publications

Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates.

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