Change of monochloroacetic acid to biodegradable organic acids by hydrothermal reaction

Kim, Kyoungrean; Fujita, Masafumi; Daimon, Hiroyuki; Fujie, Koichi

doi:10.1016/j.jhazmat.2003.12.010

Cited by 5 publications

(9 citation statements)

References 18 publications

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“…The decomposition rates of CAAs under hydrothermal conditions are discussed. Figure 3 shows reaction rate constants of CAAs by hydrothermal reaction at 250 o C and previous results of MCAA [11]. Reaction rate constants increased by about 2.3 times with an increase in the number of attached chlorine atoms.…”

Section: Reaction Mechanism Of Caas Under Hydrothermal Conditionsmentioning

confidence: 67%

“…Reaction was conducted at 250 o C and 4 MPa. From our previous research [11], mineralization was less than 3 % followed by structural conversion from MCAA to biodegradable organic acid under the reaction conditions. The heat-up state of reactor from room temperature to 90 % of each reaction temperature was defined as transition state.…”

Section: Product Evaluationmentioning

confidence: 85%

“…The reaction pathway of CAAs under hydrothermal conditions is represented in Figure 2. In our previous research, partial destruction of MCAA by hydrolysis, production of biodegradable glycolic acid and decomposition of glycolic acid to other organic acids were reported [11]. Based on the results of ion chromatography, attached recalcitrant chlorine atoms of DCAA and TCAA were removed less than 7 min at the tested conditions.…”

Section: Reaction Mechanism Of Caas Under Hydrothermal Conditionsmentioning

confidence: 85%

“…While, reactor 2 requires 1.5 min to reach the same temperature. The heat-up time depends on the desired reaction temperatures [11,12]. Reactor 2 was only used to investigate reaction rates within 9 min, because of its short heat-up time.…”

Section: Batch Reactor Apparatusmentioning

confidence: 99%

“…Hydrothermal reaction has been attracting many researchers, because of the fascinating characteristics of water as reaction medium at elevated temperatures and pressures [8,9]. In our previous research, we reported the possibility of biodegradability improvement of poly vinyl alcohol (PVA) in 10 min by hydrothermal reaction [10], structural conversion and reaction mechanism of monochloroacetic acid (MCAA) under hydrothermal conditions [11]. However, more extended investigation is required to clarify the reaction mechanism of various refractory pollutants, including other kinds of CAAs, under hydrothermal conditions and to apply this technology to real wastewater.…”

Section: Introductionmentioning

confidence: 99%

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Application of Hydrothermal Reaction to Biodegradability Improvement of Refractory Pollutants: Structural Conversion of Di- and Trichloroacetic Acid to Biodegradable Products

Kim

Fujita

Daimon

et al. 2003

J. of Wat. & Envir. Tech.

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Biodegradability improvement of refractory pollutants by hydrothermal reaction was investigated based on their structural conversion. Di-and Trichloroacetic acid were used as test sample, representing linear hydrocarbon structured refractory pollutants. At 250 o C and 4 MPa, attached recalcitrant chlorine atoms were eliminated by hydrolysis at the beginning of hydrothermal reaction. Biodegradable organic acids were yielded from hydrolyzed intermediates by dehydration and thermal decomposition. The decomposition rates of chloroacetic acids increased with increasing the number of attached chlorine atoms. During the initial structural conversion by hydrothermal reaction, the reduction of carbon contents of dichloroacetic acid did not exceed 6 % under the tested conditions. The similar results, however, were not observed in case of trichloroacetic acid. Biodegradable products were reduced by thermal decomposition as reaction time increased. The biodegradability of reaction products was not fatally retarded despite the presence of chlorine ions under the tested conditions. Hydrothermal reaction was proved as suitable pretreatment method to obtain biodegradable products from the structural conversion of refractory pollutants such as chloroacetic acids for the following biological treatment methods.

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Section: Reaction Mechanism Of Caas Under Hydrothermal Conditionsmentioning

confidence: 67%

Section: Product Evaluationmentioning

confidence: 85%

Section: Reaction Mechanism Of Caas Under Hydrothermal Conditionsmentioning

confidence: 85%

Section: Batch Reactor Apparatusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Application of Hydrothermal Reaction to Biodegradability Improvement of Refractory Pollutants: Structural Conversion of Di- and Trichloroacetic Acid to Biodegradable Products

Kim

Fujita

Daimon

et al. 2003

J. of Wat. & Envir. Tech.

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Analysis of anthocyanins in red onion using capillary electrophoresis‐time of flight‐mass spectrometry

et al. 2008

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For the first time, a capillary electrophoresis-time of flight-mass spectrometry analysis method for detecting anthocyanins in red onion was developed. The analysis method included the use of silica capillaries coated with poly-LA 313 (polycationic amine-containing polymer) and an MS-compatible volatile background electrolyte (BGE). The method was environmentally friendly and sensitive; and its rapidness combined with an acidic BGE helped in preventing anthocyanin degradation. By using high-resolution TOF-MS with pre-run tuning of masses, low mass errors were achieved in the determination of conjugated anthocyanins in red onion, and a simultaneous up-front fragmentation provided confirmation of the aglycon backbone for their secure identification. Most anthocyanins (at least seven out of ten) known in red onion from the literature were found, as well as one new for this matrix.

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Effect of pressure on organic acid production from Japanese beech treated in supercritical water

2009

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The effect of pressure as described by density was studied on organic acid production from Japanese beech (Fagus crenata) treated in supercritical water. At a reaction temperature of 380°C, the maximum yield of organic acids was 35% at a pressure of 30 MPa (density of water: 0.53 g/ ml) for 1 min in a batch-type system. Furthermore, the yield of organic acids decreased with increasing reaction pressure. It was also found that fragmented products from sugars such as methylglyoxal and glycolaldehyde could be more easily converted to organic acids than dehydrated products such as furfural and 5-hydroxymethyl furfural. This result suggests that organic acids can be mainly derived from fragmented products.

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Change of monochloroacetic acid to biodegradable organic acids by hydrothermal reaction

Cited by 5 publications

References 18 publications

Application of Hydrothermal Reaction to Biodegradability Improvement of Refractory Pollutants: Structural Conversion of Di- and Trichloroacetic Acid to Biodegradable Products

Application of Hydrothermal Reaction to Biodegradability Improvement of Refractory Pollutants: Structural Conversion of Di- and Trichloroacetic Acid to Biodegradable Products

Analysis of anthocyanins in red onion using capillary electrophoresis‐time of flight‐mass spectrometry

Effect of pressure on organic acid production from Japanese beech treated in supercritical water

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