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Start Over Topic carbon dioxide Journal chemosphere
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1. Removing perfluorooctane sulfonate and perfluorooctanoic acid from solid matrices, paper, fabrics, and sand by mineral acid suppression and supercritical carbon dioxide extraction.

Author

Chen HY, Liao W, Wu BZ, Nian H, Chiu K, and Yak HK

Subjects
Alkanesulfonic Acids chemistry, Caprylates chemistry, Environmental Pollutants chemistry, Fluorocarbons chemistry, Methanol chemistry, Nitric Acid chemistry, Pressure, Solubility, Temperature, Time Factors, Alkanesulfonic Acids isolation & purification, Caprylates isolation & purification, Carbon Dioxide chemistry, Chemical Fractionation methods, Environmental Pollutants isolation & purification, Fluorocarbons isolation & purification, Paper, Silicon Dioxide chemistry
Abstract

The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from solid matrices has received considerable attention because of the environmental persistence, bioaccumulation, and potential toxicity of these compounds. This study presents a simple method using concentrated HNO(3) as a suppression agent, and methanol-modified supercritical carbon dioxide (Sc-CO(2)) extraction for removing PFOS and PFOA from solid matrices. The optimal conditions were 16 M HNO(3) and 20% (v/v) methanol containing Sc-CO(2), under a pressure of 20.3 MPa and a temperature of 50 °C. Extraction time was set at 70 min (40 min for static and 30 min for dynamic extraction). PFOA and PFOS were identified and quantitated by liquid chromatography/mass spectrometry. The extraction efficiencies (with double extractions) were close to 100% for PFOA and 80% for PFOS for both paper and fabric matrices. The extraction efficiencies for sand were approximately 77% for PFOA and 59% for PFOS. The results show that this method is accurate, and effective, and that it provides a promising and convenient approach to remediate the environment of hazardous PFOA and PFOS contamination., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Published
2012
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2. Determination of the aerobic biodegradability of polymeric material in a laboratory controlled composting test

Author

U. Pagga, D.B. Beimborn, J. Boelens, and B. De Wilde

Subjects
Paper, Environmental Engineering, Polyesters, Health, Toxicology and Mutagenesis, chemistry.chemical_element, engineering.material, Valerate, chemistry.chemical_compound, Waste Management, Environmental Chemistry, Cellulose, Soil Microbiology, chemistry.chemical_classification, Waste management, Compost, fungi, Public Health, Environmental and Occupational Health, Reproducibility of Results, General Medicine, General Chemistry, Test method, Carbon Dioxide, Biodegradation, Pollution, Test (assessment), Bacteria, Aerobic, Waste treatment, Biodegradation, Environmental, chemistry, engineering, Environmental science, Carbon
Abstract

A laboratory method is presented for investigating the biodegradation of an organic test material in an aerobic composting system based on the evolution of carbon dioxide. In addition to carbon conversion, biodegradation can also be monitored through weight loss and physical disintegration. The test method is different from other biodegradation tests, especially aquatic tests, because of the elevated temperature representative for real composting conditions and also because of enhanced fungal degradation activities. A ring test was run using paper and poly-beta-hydroxybutyrate/valerate as test materials and cellulose powder as a reference material. The test results and the experience gained by the participants showed that the method is suitable and practicable. Experience with real technical-scale composting facilities confirms that the method provides test results of high predictive value. The test is designed to become a European Standard in connection with determining the compostability of packagings and packaging materials.

Published
1995

3. Removing perfluorooctane sulfonate and perfluorooctanoic acid from solid matrices, paper, fabrics, and sand by mineral acid suppression and supercritical carbon dioxide extraction

Author

Hungchi Nian, Hsiang-Yu Chen, Weisheng Liao, Ben-Zen Wu, Kong-Hwa Chiu, and Hwa-Kwang Yak

Subjects
Paper, Environmental Engineering, Time Factors, Health, Toxicology and Mutagenesis, Chemical Fractionation, Nitric Acid, chemistry.chemical_compound, Pressure, Environmental Chemistry, Solubility, chemistry.chemical_classification, Fluorocarbons, Supercritical carbon dioxide, Methanol, Extraction (chemistry), Public Health, Environmental and Occupational Health, Supercritical fluid extraction, Temperature, Mineral acid, General Medicine, General Chemistry, Carbon Dioxide, Silicon Dioxide, Pollution, Sulfonate, chemistry, Alkanesulfonic Acids, Environmental chemistry, Perfluorooctanoic acid, Environmental Pollutants, Caprylates
Abstract

The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from solid matrices has received considerable attention because of the environmental persistence, bioaccumulation, and potential toxicity of these compounds. This study presents a simple method using concentrated HNO(3) as a suppression agent, and methanol-modified supercritical carbon dioxide (Sc-CO(2)) extraction for removing PFOS and PFOA from solid matrices. The optimal conditions were 16 M HNO(3) and 20% (v/v) methanol containing Sc-CO(2), under a pressure of 20.3 MPa and a temperature of 50 °C. Extraction time was set at 70 min (40 min for static and 30 min for dynamic extraction). PFOA and PFOS were identified and quantitated by liquid chromatography/mass spectrometry. The extraction efficiencies (with double extractions) were close to 100% for PFOA and 80% for PFOS for both paper and fabric matrices. The extraction efficiencies for sand were approximately 77% for PFOA and 59% for PFOS. The results show that this method is accurate, and effective, and that it provides a promising and convenient approach to remediate the environment of hazardous PFOA and PFOS contamination.

Published
2012