Extraction of Polychlorinated Biphenyls (PCBs) and Dibenzyl Disulfide from Transformer Oils using Polar Aprotic Solvents andReductive Dehalogenation of Extracted PCBs

0429476 - ÚCHP 2015 RIV GR eng C - Konferenční příspěvek (zahraniční konf.)
Kaštánek, Petr - Kaštánek, František - Maléterová, Ywetta - Matějková, Martina - Spáčilová, Lucie - Šolcová, Olga
Extraction of Polychlorinated Biphenyls (PCBs) and Dibenzyl Disulfide from Transformer Oils using Polar Aprotic Solvents andReductive Dehalogenation of Extracted PCBs.
Proceedings of the International Conference Protection and Restoration of the Environment XII. Thessaloniki: Grafima Publ, 2014 - (Liakopoulos, A.; Kungolos, A.; Christodoulatos, C.; Koutsospyros, A.), s. 604-609. ISBN 978-960-88490-5-1.
[International Conference on Protection and Restoration of the Environment /12./. Skiathos island (GR), 29.06.2014-03.07.2014]
Institucionální podpora: RVO:67985858
Klíčová slova: extraction * polychlorinated biphenyls * polar aprotic solvent
Kód oboru RIV: CI - Průmyslová chemie a chemické inženýrství

Extractions of PCBs from mineral oils with polar aprotic solvents (PAS) acrylonitrile AC, dimethyl sulfoxide DMSO, dimethyl formamide DMF, N-methyl pyrrolidone NMP and propylene carbonate PC were performed in order to compare the extraction efficiencies. In a single-stage extraction performed at room temperature, the efficiencies ranged from the highest to the lowest as follows: NMP → DMF → DMSO → PC → AC. NMP exhibited the highest efficiency, around 70%. . Pyridine N-oxide was also used as a catalyst for interfacial mass transfer in an attempt to increase the efficiency of the extraction. NMP was evaluated as having the best chance to be used in industry. Vacuum distillation and reductive dechlorination catalyzed by microparticles of bimetallic catalyst (Pd/Fe, 0.3%wt Pd on grey cast iron) were the two methods used to isolate the extracted PCBs from the solvent. When borohydride was added to the reaction mixture (< 0.1M), the reaction rates were almost one order of magnitude higher. The influence of microwave irradiation on the rate of extraction and reductive dehalogenation was evaluated. The extraction efficiency of DBDS from contaminated transformer oil with the help of NMP is sufficiently high (over 99 %) and feasible within reasonabletime. The remaining concentration of DBDS after a single-step extraction from transformer oil containing corrosive sulphur was low enough (approx. 0.1 ppm), and it is possible to consider the transformer oil after the extraction procedure as free from corrosive sulphur.
Trvalý link: http://hdl.handle.net/11104/0234586