Distribution characteristics of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in rivers around fluorine industrial parks

全（多）氟化合物（Perfluoroalkyl and Polyfluoroalkyl substances, PFASs）凭借其独特的理化性质在生产与生活中应用广泛，同时也导致其在环境中普遍存在。目前，PFASs在全球大气、水体、沉积物、生物体等各种环境介质中被广泛检出，并且部分单体能够通过食物链富集放大，对生态系统和人类健康造成极大威胁，引起国际关注。随着PFOS和PFOA相继被列入《斯德哥尔摩公约》，短链PFASs及新型PFASs的生产和使用逐步扩大，且在环境中不断检出，成为新的研究热点。 本研究采取固相萃取（SPE）富集结合超高效液相色谱/质谱联用（UPLC-MS/MS）检测的手段，对河流-近海环境中21种PFASs的污染特征进行分析。本研究的工作分为两部分开展：1. 以不同氟工业园区周边河流为研究对象，对比分析辽宁细河、山东小清河、长江江苏段表层沉积物中PFASs污染特征。2. 以三个区域中污染最严重的小清河为研究对象，分析整个流域PFASs污染特征及悬浮颗粒物（SPM）-水之间分配规律。具体结论如下： 1. 三个氟工业园附近河流表层沉积物中，PFASs污染水平和组成特征均有显著差异。小清河表层沉积物PFASs是三个区域中含量最高的，其次为细河，最后为长江。小清河表层沉积物中全氟辛酸(PFOA)和六氟环氧丙烷二聚酸(HFPO-DA)为优势污染物；细河表层沉积物中主要污染物是全氟丁烷磺酸(PFBS)和HFPO-DA；长江表层沉积物中全氟十四酸(PFTeDA)和6:2氟调磺酸(6:2 FTS)为主要污染物。不同区域河流河流沉积物中PFASs的浓度水平与组成特征的差异与不同工业园区规模、生产工艺、产能和生产模式有关。三个区域表层沉积物中PFASs含量与沉积物理化性质相关性不明显，说明PFASs在沉积物中的转移和富集过程受多种因素共同作用。 2. 小清河表层水体和SPM中均存在PFASs污染。小清河表层水体PFASs浓度范围为94.0 ~ 444000 ng/L，主要污染物为PFOA、PFHpA和HFPO-TA。SPM中，PFASs浓度范围为34.6 ~ 94900 ng/g dw，HFPO-TA和PFOA是主要的污染物。PFASs污染水平在氟化物工业园下游的东竹龙支流X10站位急剧上升，说明点源排放是造成PFASs污染的主要原因，且对小清河干流PFASs污染造成影响。PFASs在SPM水两相的分配与碳链长度及污染物性质有关。研究结果发现，长链PFCAs和PFSAs更容易分配在SPM中。此外，水体中SPM的浓度升高会对PFASs的分配行为产生影响。 通过对比不同工业园区周边河流表层沉积物中PFASs的污染水平及组成的不同，发现不同工业园的规模、产能和生产模式都有可能对其周边环境介质产生不同的影响，化合物性质、沉积物理化性质在不同区域对PFASs影响也存在差异。其中沉积物中PFASs污染最为严重的小清河，其水体中PFASs污染直接受点源排放的影响，且PFASs在SPM-水两相之间的分配行为受化合物性质、水体中SPM浓度影响。因此，在后续研究PFASs在水环境中的分布、分配以及迁移转化要综合考虑点源特点、化合物性质、环境介质理化性质等因素，以期对环境中PFASs做出更加全面详细的分析

典型氟工业园周边河流沉积物中全(多)氟化合物的分布特征

采用超高效液相色谱/质谱联用(UPLC/MS-MS)分析了我国重要的氟化物工业园区周边河流———辽宁细河(阜新段)、山东小清河(淄博段)和长江(江苏常熟段)表层沉积物中全(多)氟烷基化合物(PFASs)的污染状况.细河表层沉积物中,PFASs含量范围(以干重计,下同)为15.8~ 2770ng·g~(-1),全氟丁烷磺酸(PFBS)和六氟环氧丙烷二聚酸(HFPO-DA)是主要污染物;小清河表层沉积物中,PFASs含量为12.2~ 7853ng·g~(-1),全氟烷基辛酸(PFOA)和HFPO-DA为主要污染物;长江表层沉积物中,PFASs含量为9.20~ 35.9ng·g~(-1),全氟十四酸(PFTeDA)和6∶ 2氟调磺酸(6∶ 2FTS)为主要污染物.工业园区废水排放(点源污染)是本研究中3个区域PFASs的主要来源.3个区域PFASs含量及组成差异明显,与工业园区生产规模和产业类型有关.PFASs含量及各组分含量与TOC、沉积物粒径没有显著相关性,PFASs各组分间相关性也有差异,说明PFASs在沉积物中的富集过程与多种因素有关

Distribution Characteristics of Per-/polyflouralkyl Substances in River Sediments Around Typical Fluorine Industrial Parks

Perfluoroalkyl and polyfluoroalkyl substances(PFASs)are a group of manmade chemicals and are ubiquitously detected in aquatic environments.China is a major producer and consumer of PFASs.In this study,we investigated the occurrence and characteristics of PFASs in the surface sediments from three fluorine industrial parks in North China,the Xihe River in Liaoning Province(Fuxin Section),the Xiaoqing River in Shandong Province(Zibo Section),and the Yangtze River in Jiangsu Province(Changshu Section),using the UPLC/MS-MS method.The total concentration of PFASs(Sigma PFASs)in surface sediments of the Xihe River ranged from 15.8 to 2 770 ng·g~(-1),and PFTeDA and HFPO-DA were the dominant pollutants.In the surface sediments of the Xiaoqing River,Sigma PFASs ranged from 12.2 to 7 853 ng·g~(-1),and PFOA and HFPO-DA were the dominant pollutants.In the surface sediments of the Yangtze river,Sigma PFASs ranged from 9.20 to 35.9 ng·g~(-1),and PFTeDA and 6∶ 2 FTS were the main pollutants.Sewage discharge from the industrial parks(point source pollution)was the main source of PFASs in three regions in this study.The PFAS content and composition in three regions varied significantly depending on the production capacity and industry type.There was no significant correlation between the content of PFASs and its components and the particle size and TOC of the sediments.The correlations between the components of PFASs indicated that the enrichment process of PFASs in sediments was impacted by various factors

Impact of Water Content on the Performance of LiFePO4 Based Lithium-Ion Battery

通过库仑法水分测试仪标定不同水分含量（0.3‰ ~ 0.7‰）的磷酸铁锂正极片，将其制备成软包型锂离子电池，对其电化学循环性能、倍率性能、交流阻抗进行了测试. 结果表明，不同水分含量极片制备的电池循环性能及倍率性能与电极水分含量有密切关系，水分含量在0.4‰ ~ 0.5‰之间时循环性能最优，水分含量超过0.6‰时电化学性能衰减严重，电池的内阻和电化学反应阻抗明显增加. 将循环200周后的软包电池进行拆解，分别使用激光粒度仪、XRD、SEM对循环后磷酸铁锂正极片进行微观形貌分析，发现水分含量超过0.6‰时极片表面发生颗粒破裂现象. XRD晶相分析表明，随着水分含量的升高，衍射峰晶面的位置有所偏移，但主要衍射峰的位置基本相同，晶型并未发生改变.Through different dry conditions and measuring by moisture test instrument, cathode pole pieces with different water contents of 0.3‰ ~ 0.7‰ were obtained to prepare lithium-ion batteries. Cycling performance and high rate performance at 1C ~ 5C discharge rates were tested. Moreover, ASR performances of LiFePO4 base lithium-ion batteries after 200 cycles with different water contents were investigated by EIS. The results showed that the cycle performance and rate performance were closely related to the water content of the electrode. When the water content went up to 0.6‰ the cycle stability and rate performance fell. Meanwhile, the internal resistance and the electrochemical reaction impedance increased after 200 cycles. The cells after running 200 cycles were dismantled to obtain the powder material which was studied by laser particle size analyzer, XRD and SEM to research the microstructure. The results revealed that when the water content exceeded 0.6‰ the obvious particle fracture phenomenon appeared. The XRD data indicated that the position of the main diffraction peak kept nearly the same and the crystal phase of the cathode material remained unchanged.国家自然科学基金项目（No. 21336003）及上海市浦江人才计划（No. 13PJ1433500）作者联系地址：1. 上海交通大学化学工程系，上海电化学能源器件工程技术研究中心，上海 200240；2. 中聚电池研究院，上海 200241Author's Address: 1. Shanghai Electrochemical Energy Devices Research Center, Department of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; 2. Sinopoly Battery Research Center, Shanghai 200241, China通讯作者E-mail：[email protected]