Thermal defluorination behaviors of PFOS,PFOA and PFBS during regeneration of activated carbon by molten salt  

作　　者：Zhichao Shen Lu Zhan Zhenming Xu 

机构地区：[1]School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]School of Ecological and Environmental Sciences,East China Normal University,Shanghai 200241,China

出　　处：《Frontiers of Environmental Science & Engineering》2022年第8期183-192,共10页环境科学与工程前沿（英文）

基　　金：This work was financially supported by the National Key R&D Program of China(No.2019YFC1904400)。

摘　　要：Current study proposes a green regeneration method of activated carbon(AC)laden with Perfluorochemicals(PFCs)from the perspective of environmental safety and resource regeneration.The defluorination efficiencies of AC adsorbed perfluorooctanesulfonate(PFOS),perfluorooctanoic acid(PFOA)and perfluorobutanesulfonate(PFBS)using three molten sodium salts and one molten alkali were compared.Results showed that defluorination efficiencies of molten NaOH for the three PFCs were higher than the other three molten sodium salts at lower temperature.At 700°C,the defluorination efficiencies of PFOS and PFBS using molten NaOH reached to 84.2%and 79.2%,respectively,while the defluorination efficiency of PFOA was 35.3%.In addition,the temperature of molten salt,the holding time and the ratio of salt to carbon were directly proportional to the defluorination efficiency.The low defluorination efficiency of PFOA was due to the low thermal stability of PFOA,which made it difficult to be captured by molten salt.The weight loss range of PFOA was 75°C–125°C,which was much lower than PFOS and PFBS(400°C–500°C).From the perspective of gas production,fluorine-containing gases produced from molten NaOH-treated AC were significantly reduced,which means that environmental risks were significantly reduced.After molten NaOH treatment,the regenerated AC had higher adsorption capacity than that of pre-treated AC.

关 键 词：PFCS Molten sodium hydroxide Thermal degradation Activated carbon regeneration 

分 类 号：X17[环境科学与工程—环境科学]