Low-molecular-weight carboxylic acids produced from hydrothermal treatment of organic wastes

Quitain, Armando T.; Faisal, Muhammad; Kang, Kilyoon; Daimon, Hiroyuki; Fujie, Koichi

doi:10.1016/s0304-3894(02)00024-9

Cited by 137 publications

(56 citation statements)

References 20 publications

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“…The MW pretreatment facilitates the hydrolysis of polymer and compounds with poor biodegradability [45] to produce simpler compounds that can be more readily biodegradable [46]. In the present study, the final pH of pretreated sludge was found to be notably lower than the initial pH (Table 2), possibly owing to dissolution of carboxylic acids and volatile fatty acids generated by complex organic matter in association with cell lysis [47,48] in the initial high-pH group. Thus, the final pH of slurry may remain within the natural range, which will be beneficial for subsequent treatment of sludge.…”

Section: Optimization Of the Mw-h 2 O 2 Process For Organic Matter Rementioning

confidence: 51%

Multivariate analysis of sludge disintegration by microwave–hydrogen peroxide pretreatment process

Wang

Gui

et al. 2015

Journal of Hazardous Materials

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h i g h l i g h t s• Investigation of TSS, H 2 O 2 dosage, pH and interactions on MW sludge pretreatment.• Quadratic models were drawn for 16 response variables with good predictive ability.• Models could optimize the treatment process for multiple disintegration objectives. a r t i c l e i n f o ) has been shown to offer considerable advantages owing to its flexible control, low overall cost, and resulting higher soluble chemical oxygen demand (SCOD); accordingly, the method has been proposed recently as a means of improving sludge disintegration. However, the key factor controlling this sludge pretreatment process, pH, has received insufficient attention to date. To address this, the response surface approach (central composite design) was applied to evaluate the effects of total suspended solids (TSS, 2-20 g/L), pH (4-10), and H 2 O 2 dosage (0-2 w/w) and their interactions on 16 response variables (e.g., SCOD released , pH, H 2 O 2 remaining ). The results demonstrated that all three factors affect sludge disintegration significantly, and no pronounced interactions between response variables were observed during disintegration, except for three variables (TCOD, TSS remaining , and H 2 O 2 remaining ). Quadratic predictive models were constructed for all 16 response variables (R 2 : 0.871-0.991). Taking soluble chemical oxygen demand (SCOD) as an example, the model and coefficients derived above were able to predict the performance of microwave pretreatment (enhanced by H 2 O 2 and pH adjustment) from previously published studies. The predictive models developed were able to optimize the treatment process for multiple disintegration objectives.

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Section: Optimization Of the Mw-h 2 O 2 Process For Organic Matter Rementioning

confidence: 51%

Multivariate analysis of sludge disintegration by microwave–hydrogen peroxide pretreatment process

Wang

Gui

et al. 2015

Journal of Hazardous Materials

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“…All sugars were higher at milder conditions but decreased gradually as temperature and pressure increased. Quitain et al (2002) stated that the reducing sugar content was dropped as the temperature and reaction time increases and this is perhaps due to the degradation into other products such as ketones/aldehydes, and it could lead to produce the organic acids. Therefore, PHWH treatment without acid or base catalyst is a promising step towards bioethanol production.…”

Section: Hydrolysis Efficiencymentioning

confidence: 99%

Physical and functional properties of tunicate (Styela clava) hydrolysate obtained from pressurized hydrothermal process

et al. 2017

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In this study, marine tunicate Styela clava hydrolysate was produced by an environment friendly and green technology, pressurized hot water hydrolysis (PHWH) at different temperatures (125-275°C) and pressure 50 bar. A wide range of physico-chemical and bio-functional properties such as color, pH, protein content, total carbohydrate content, reducing sugar content, and radical scavenging activities of the produced hydrolysates were evaluated. The appearance (color) of hydrolysates varied depending on the temperature; hydrolysates obtained at 125-150°C were lighter, whereas at 175°C gave reddish-yellow, and 225°C gave dark brown hydrolysates. The L* (lightness), a* (red-green), and b* (yellow-blue) values of the hydrolysates varied between 35.20 and 50.21, −0.28 and 9.59, and 6.45 and 28.82, respectively. The pH values of S. clava hydrolysates varied from 6.45 (125°C) to 8.96 (275°C) and the values were found to be increased as the temperature was increased. The hydrolysis efficiency of S. clava hydrolysate was ranged from 46.05 to 88.67% and the highest value was found at 250°C. The highest protein, total carbohydrate content, and reducing sugar content of the hydrolysates were found 4.52 mg/g bovine, 11.48 mg/g and 2.77 mg/g at 175, and 200 and 200°C, respectively. Hydrolysates obtained at lower temperature showed poor radical scavenging activity and the highest DPPH, ABTS, and FRAP activities were obtained 10.25, 14.06, and 10.91 mg trolox equivalent/g hydrolysate (dry matter basis), respectively. Therefore, S. clava hydrolysate obtained by PHWH at 225-250°C and 50 bar is recommended for bio-functional food supplement preparation.

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“…The aqueous phase solutions produced from corn stalks, peanut shells, and de-oiled peanut meal were acidic. Organic acids may have been released by the thermal reaction; during the hydrothermal process, cellulose, glucose, soluble protein, and amino acids are degraded to low molecular weight carboxylic acids (Quitain et al 2002). Those acids include acetic acid, formic acid, propionic acid, succinic acid, lactic acid, etc., and their dissociation constants (pKa) are between 2.0 and 5.0.…”

Section: Nutrient Extraction From Biomassmentioning

confidence: 99%

Subcritical Water Hydrolysis Treatment of Waste Biomass for Nutrient Extraction

Tu¹,

Huang²,

Xu³

et al. 2016

BioResources

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Nutrients were extracted from corn stalks, peanut shells, de-oiled peanut meal, chicken manure, and sewage sludge by a subcritical water (SCW) hydrolysis reaction. Compared with the other feedstock, the aqueous phases extracted from de-oiled peanut meal showed the highest watersoluble organic carbon, amino acid, total nitrogen, and phosphorus contents. The effects of solution pH, final hydrothermal temperature, and reaction time on nutrient extraction from de-oiled peanut meal were investigated. The analysis showed that alkaline reagents promoted liquefaction. The highest yield of the total primary nutrients (82.6%) was obtained with extraction reaction at 180 °C for 1.5 h using 0.1 mol/L KOH. The liquid fraction from this reaction was investigated for its potential use as a fertilizer with germination experiments. A higher germination index and root activity were obtained using the liquid extract with the appropriate dilution. These results indicated that subcritical water hydrothermal treatment is a viable way to recover nutrients from biomass wastes. In addition, de-oiled peanut meal is a suitable feedstock for the production of nutrient-rich liquid extract.

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Low-molecular-weight carboxylic acids produced from hydrothermal treatment of organic wastes

Cited by 137 publications

References 20 publications

Multivariate analysis of sludge disintegration by microwave–hydrogen peroxide pretreatment process

Multivariate analysis of sludge disintegration by microwave–hydrogen peroxide pretreatment process

Physical and functional properties of tunicate (Styela clava) hydrolysate obtained from pressurized hydrothermal process

Subcritical Water Hydrolysis Treatment of Waste Biomass for Nutrient Extraction

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