| Abstract | The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite (KBi) in degrading pentachlorophenol (PCP) through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi-PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner-sphere complex between the phenolic group of the organic molecules and the structural Mn(IV). This is indicated by the changes induced in birnessite MnO6 layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn(IV) reduction, the consequent formation of Mn(III) and new vacancies, and free Mn2+ ions release. The PCP degradation extent is limited by the presence of chloro-substituents on the aromatic ring. |
| Text | 201263 2013 birnessite pentachlorophenol mechanochemistry Mechanochemical degradation of pentachlorophenol onto birnessite Di Leo P., Pizzigallo Maria Donata R., Ancona V., Di Benedetto F., Mesto E., Schingaro E., Ventruti G. Consiglio Nazionale delle Ricerche Istituto di Metodologie per l Analisi Ambientale, C. da S. Loja, Zona Industriale, 85050 Tito Scalo PZ , Italy Dipartimento di Biologia e Chimica Agroforestale e Ambientale, Universita di Bari Aldo Moro, Via Amendola 165/a, 70126 Bari, Italy; Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle Acque, Via F. De Blasio 5, 70132 Bari, Italy; Dipartimento di Chimica, Universita di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy; Dipartimento di Scienze della Terra e Geoambientali, Universita degli Studi di Bari Aldo Moro , Via E. Orabona 4, 70123 Bari, Italy The existence of a lot of worldwide pentachlorophenol contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite KBi in degrading pentachlorophenol PCP through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner sphere complex between the phenolic group of the organic molecules and the structural Mn IV . This is indicated by the changes induced in birnessite MnO6 layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn IV reduction, the consequent formation of Mn III and new vacancies, and free Mn2 ions release. The PCP degradation extent is limited by the presence of chloro substituents on the aromatic ring. 303 310 Published version Articolo in rivista Elsevier 0304 3894 Journal of hazardous materials Print Journal of hazardous materials Print J. hazard. mater. Print Journal of hazardous materials. Print valeria.ancona ANCONA VALERIA TA.P02.031.001 Impatto dei cambiamenti climatici sulla gestione delle risorse idriche |
