Perfluorooctanoic acid (C(7)F(15)COOH, PFOA) has increasingly attracted worldwide concerns due to its global occurrence and resistance to most conventional treatment processes. Though TiO(2)-based photocatalysis is strong enough to decompose most organics, it is not effective for PFOA decomposition. We first find that indium oxide (In(2)O(3)) possesses significant activity for PFOA decomposition under UV irradiation, with the rate constant about 8.4 times higher than that by TiO(2). The major intermediates of PFOA were C(2)-C(7) shorter-chain perfluorocarboxylic acids, implying that the reaction proceeded in a stepwise manner. By using diffuse reflectance infrared Fourier transform spectroscopy, (19)F magic angle spinning nuclear magnetic resonance, and electron spin resonance, we demonstrate that the terminal carboxylate group of PFOA molecule tightly coordinates to the In(2)O(3) surface in a bidentate or bridging configuration, which is beneficial for PFOA to be directly decomposed by photogenerated holes of In(2)O(3) under UV irradiation, while PFOA coordinates to TiO(2) in a monodentate mode, and photogenerated holes of TiO(2) preferentially transform to hydroxyl radicals, which are inert to react with PFOA. PFOA decomposition in wastewater was inhibited by bicarbonate and other organic matters; however, their adverse impacts can be mostly avoided via pH adjustment and ozone addition.
Airborne particulate matter (APM) has an important role in inhalation exposure, especially in China. The environmental occurrence of conventional and unknown per- and polyfluoroalkyl substances (PFASs) in APM remains unclear. Therefore, in this study, a two-stage experiment was designed to identify potential PFASs and to investigate their distribution in APM. Indoor and outdoor APM samples were collected from five selected cities in China. Through PFAS homologue analysis and suspect screening, 50 peaks were identified with different confidence levels (levels 1-3). Among the identified PFASs, 34 emerging PFASs including p-perfluorous nonenoxybenzenesulfonate, 6:2 polyfluoroalkyl phosphate diester, n:2 fluorotelomer sulfonates, n:2 fluorinated telomer acids, n:2 chlorinated polyfluoroalkyl ether sulfonic acids, 1:n polyfluoroalkyl ether carboxylic acids (1:n PFECAs), perfluoroalkyl dioic acids (PFdiOAs), hydro-substituted perfluoroalkyl dioic acids (H-PFdiOAs), and unsaturated perfluorinated alcohols (UPFAs) were identified in APM. In particular, 1:n PFECAs, PFdiOAs, H-PFdiOAs, and UPFAs were first detected in APM. Although human exposure to perfluorooctanoic acid via inhaled APM was noted to not be a risk (hazard quotient <0.1) in this study, the expansion of the PFASs screened in APM implies that human exposure to PFASs might be much more serious and should be considered in future risk assessments in China.
batteries, sodium-selenium (Na-Se) batteries, Li-tellurium (Li-Te) batteries, and Na-S batteries) have their own distinctive applications due to their various characteristics. To explore new materials with high performance, large studies have been devoted to the development of nextgeneration batteries.Porous carbon (PC) materials possess many unique properties due to their large surface areas, high conductivity, large pore volumes, high thermal stability, and surface functionalities, [22][23][24] leading to their wide use in energy storage and conversion. Traditionally, PC can be obtained via various methods, such as the direct heat treatment of organic precursors, hard template or nanocast methods, and soft template methods. However, the production of PC from these methods cannot be scaled-up because of certain barriers (disordered structure with wide size distributions, complicated processes, etc.). [23,25,26] Metal-organic frameworks (MOFs) have drawn wide research interest as a novel class of porous materials that are crystalline materials consisting of metal ions and organic ligands. [4,21,[27][28][29][30][31] Since the report on the MOF-templated synthesis of PC in 2008, [32] a large number of studies have been reported on the use of MOFs as suitable precursors/templates for carbon synthesis. [22,26,[33][34][35] At present, a large number of studies indicate that zeolitic imidazolate framework-8 (ZIF-8), MOF-5, MIL-125 (Ti) (MIL = Materials of Institute Lavoisier), and ZIF-67 with excellent thermal stability and unique porous structures are the more commonly used MOF precursors (Scheme 1). [3,36,37] All of them, ZIF-8, possessing nitrogen-containing ligands, has high porosity and thermal stability. [38][39][40] MOF-5 possesses excellent thermal stability, high porosity, and so on. [41] MIL-125, an active photocatalyst, includes cyclic octamers of TiO 2 octahedra. [42,43] ZIF-67 has a tunable pore aperture, highly stable structure, and catalytic activity. [37,44,45] The above-mentioned MOFs have been widely used for gas adsorption, molecular separation, catalysis, batteries, supercapacitors, and so on. [13,14,33] Moreover, carbon hybrids containing nanostructured metal species (e.g., metal oxides (MOs)) are likely to form under in situ carbonization conditions. [46] Compared with the carbonaceous materials from conventional precursors, MOF-derived carbon materials have significant advantages with high specific surface areas, tailorable porosities, unique morphologies, and easy functionalization with other heteroatoms. [14,23,31] For example, Xu and co-workers [47] obtained 1D carbon nanorods via the pyrolysis The applications of carbon and carbon-based materials with high porosity, high surface area, and functionalities based on metal-organic framework precursors and/or templates have attracted significant research interest in recent years, particularly in the field of batteries. The chemical and physical properties of carbon and carbon-based materials obtained by the heat treatment of various metal-organic ...
Perfluorooctanoic acid (PFOA), a perfluoroalkyl acid, can result in hepatotoxicity and neurobehavioral effects in animals. The metabolome, which serves as a connection among transcriptome, proteome and toxic effects, provides pathway-based insights into effects of PFOA. Since understanding of changes in the metabolic profile during hepatotoxicity and neurotoxicity were still incomplete, a high-throughput targeted metabolomics approach (278 metabolites) was used to investigate effects of exposure to PFOA for 28 d on brain and liver of male Balb/c mice. Results of multivariate statistical analysis indicated that PFOA caused alterations in metabolic pathways in exposed individuals. Pathway analysis suggested that PFOA affected metabolism of amino acids, lipids, carbohydrates and energetics. Ten and 18 metabolites were identified as potential unique biomarkers of exposure to PFOA in brain and liver, respectively. In brain, PFOA affected concentrations of neurotransmitters, including serotonin, dopamine, norepinephrine, and glutamate in brain, which provides novel insights into mechanisms of PFOA-induced neurobehavioral effects. In liver, profiles of lipids revealed involvement of β-oxidation and biosynthesis of saturated and unsaturated fatty acids in PFOA-induced hepatotoxicity, while alterations in metabolism of arachidonic acid suggesting potential of PFOA to cause inflammation response in liver. These results provide insight into the mechanism and biomarkers for PFOA-induced effects.
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