title: Decomposition pathways of polytetrafluoroethylene by co-grinding with strontium/calcium oxides.
abstract: Waste polytetrafluoroethylene (PTFE) could be easily decomposed by co-grinding with inorganic additive such as strontium oxide (SrO), strontium peroxide (SrO2) and calcium oxide (CaO) by using a planetary ball mill, in which the fluorine was transformed into nontoxic inorganic fluoride salts such as strontium fluoride (SrF2) or calcium fluoride (CaF2). Depending on the kind of additive as well as the added molar ratio, however, the reaction mechanism of the decomposition was found to change, with different compositions of carbon compounds formed. CO gas, the mixture of strontium carbonate (SrCO3) and carbon, only SrCO3were obtained as reaction products respectively with equimolar SrO, excess SrO and excess SrO2to the monomer unit CF2of PTFE were used. Excess amount of CaO was needed to effectively decompose PTFE because of its lower reactivity compared with strontium oxide, but it promised practical applications due to its low cost.
authors.affiliation: a School of Resources and Environment Engineering , Wuhan University of Technology , Wuhan , People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qu
authors.affiliation: a School of Resources and Environment Engineering , Wuhan University of Technology , Wuhan , People's Republic of China.
authors.forename: Xiaoman
authors.initials: X
authors.lastname: He
authors.affiliation: a School of Resources and Environment Engineering , Wuhan University of Technology , Wuhan , People's Republic of China.
authors.forename: Qiwu
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: b College of Ecological Environment and Urban Construction , Fujian University of Technology , Fuzhou , People's Republic of China.
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Liu
authors.affiliation: c Institute of Multidisciplinary Research for Advanced Materials , Tohoku University , Sendai , Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Saito
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011138:Polytetrafluoroethylene / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*; D018505:Waste Management / Q000379:methods
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D011138:Polytetrafluoroethylene; C016538:lime; D013324:Strontium
keywords: Mechanochemistry; defluorination; polytetrafluoroethylene; reaction pathway; strontium oxides