Perfluoroalkyl Functionalized Superhydrophobic Covalent Organic Frameworks for Excellent Oil-Water Membrane Separation and Anhydrous Proton Conduction.

Rapid economic development has led to oil pollution and energy shortage. Membrane separation has attracted much attention due to its simplicity and efficiency in oil-water-separation. The development of membrane materials with enhanced separation properties is essential to improve the separation-efficiency. Proton exchange membrane fuel cells (PEMFCs) are expected to replace conventional engines due to their high-power-conversion rates and other favorable properties. Anhydrous-proton-conducting materials are vital components of PEMFCs. However, developing stable proton-conducting materials that exhibit high conductivity at varying temperatures remains challenging. Herein, two covalent organic frameworks (COFs) with long-side-chains are synthesized, and their corresponding COF@SSN membranes. Both membranes can effectively separate oil-water mixtures and water-in-oil emulsions. The TFPT-AF membrane achieves a maximum oil-flux of 6.05 × 105 g h-1 m-2 with an oil-water separation efficiency of above 99%, which is almost unchanged after 20 consecutive uses. COF@H3PO4 doped with different ratios of H3PO4 is prepared, the results show that the perfluorocarbon-chain system has  excellent anhydrous proton conductivity , achieving an ultra-high proton-conductivity of 3.98 × 10-1 S cm-1 at 125 °C. This study lays the foundation for tailor-made-functionalization of COF through pre-engineering and surface-modification, highlighting the great potential of COFs for oil-water separation and anhydrous-proton-conductivity.

Comprehensive assembly and comparative examination of the full mitochondrial genome in Castanea mollissima Blume.

The Chinese chestnut, Castanea mollissima Blume, a nut-bearing tree native to China and North Korea, belongs to the Fagaceae family. As an important genetic resource, C. mollissima is vital in enhancing edible chestnut varieties and offers significant insights into the origin and evolution of chestnut species. While the chloroplast genome of C. mollissima has been sequenced, its mitochondrial genome (mitogenome) remains largely uncharted. In this study, we have characterized the C. mollissima mitogenome, assembling it utilizing reads from both BGI and Nanopore sequencing platforms, and conducted a comparative analysis with the mitochondrial genomes of closely related species. The mitogenome of C. mollissima manifests a polycyclic structure consisting of two circular molecules measuring 363,232 bp and 24,806 bp, respectively. This genome encompasses 35 unique protein-coding genes, 19 tRNA genes, and three rRNA genes. A total of 139 SSRs were identified throughout the entire C. mollissima mitogenome. Furthermore, the combined length of homologous fragments between the chloroplast and mitochondrial genomes was 5766 bp, constituting 1.49% of the mitogenome. We also predicted 484 RNA editing sites in C. mollissima, demonstrating C-to-U RNA editing. Phylogenetic analysis of related species' mitogenomes showed that C. mollissima was closely related to Lithocarpus litseifolius (Hance) Chun and Quercus acutissima Carruth. Interestingly, the mitogenome sequences of C. mollissima, L. litseifolius, Q. acutissima, Fagus sylvatica L., and Juglans mandshurica Maxim did not show conservation in their alignments, indicating frequent genome reorganization. This report marks the inaugural study of the C. mollissima mitogenome, serving as a benchmark genome for economically significant plants within the Castanea genus. Moreover, it supplies invaluable information that can guide future molecular breeding efforts and contribute to the broader understanding of chestnut genomics.

Highly efficient and continuous activation of O2 by a novel FexP-FeCu composite for water purification and insights into the activation mechanisms through DFT calculation.

Degradation of organic pollutants through O2 activation catalyzed by transitional metals is challenging without addition of external chemicals and input of energy. We prepare a novel Fe based catalyst by compositing carbon, iron phosphide (FexP), iron carbide (FexC), Fe0 and Cu NPs, which can continuously activate O2 to produce high amount of 1O2,·O2- and·OH radicals in a wide pH range. DFT calculation discloses that O2 molecules are dissociated into *O or exist as O-O in various configurations. The Fe-O2, Cu-O2 and FeP-O2 surfaces can react with H2O molecules to generate *OOH, *OH and/or OH-. The sorbed-O2 intermediates on FexC surface might be released as 1O2 or·O2-. The oxidative O2-sorbed surfaces and in-situ produced oxygen reactive species contribute to the efficient and pH-indenpendent degradation of organic pollutants. Cu NPs accelerate Fe2+/Fe3+ cycles and offer impetus to initiate O2 activation due to the potential difference between Fe and Cu. The recycling test and XPS results confirm that the mutual electron transferring among carbon, FexC, FexP, Fe and Cu maintains reactivity and stability of the catalysts.

Novel ternary Cu0-coupled core-shell Fe0/C nanoparticles micro-electrolysis system toward degradation of organic pollutants: Synergistic effects and removal mechanism.

A ternary micro-electrolysis system consisting of carbon-coated metallic iron with Cu nanoparticles (Fe0/C@Cu0) was synthesized for the degradation of sulfathiazole (STZ). Fe0/C@Cu0 catalysts exhibited excellent reusability and stability owing to the inner tailored Fe0 with persistent activity. The connection between Fe and Cu elements in the Fe0/C-3@Cu0 catalyst prepared with iron citrate as iron source exhibited a tighter contact than the catalysts prepared with FeSO4·7H2O and iron(II) oxalate as iron sources. Especially, unique core-shell structure of Fe0/C-3@Cu0 catalyst is more conducive to promoting the degradation of STZ. A two-stage reaction with rapidly degradation followed by gradual degradation was revealed. The mechanism of STZ degradation could be explained by the synergistic effects of Fe0/C@Cu0. Carbon layer with remarkable conductivity allowed electrons from Fe0 transferred freely to the Cu0. The electron-rich Cu0 releases electrons, facilitating the degradation of STZ. Furthermore, the high potential difference between cathode (C and Cu0) and anode (Fe0) accelerate the corrosion of Fe0. Importantly, Fe0/C@Cu0 catalysts exhibited excellent catalytic performance for sulfathiazole degradation in landfill leachate effluent. Results presented provide a new strategy for treatment of chemical wastes.

Sulfurized nano zero-valent iron prepared via different methods: Effect of stability and types of surface corrosion products on removal of 2,4,6-trichlorophenol.

Sulfurization improves the stability and activity of nano zero-valent iron (nZVI). The sulfurized nZVI (S-nZVI) were prepared with ball milling, vacuum chemical vapor deposition (CVD) and liquid-phase reduction techniques and the corresponding products were the mixture of FeS2 and nZVI (nZVI/FeS2), well-defined core-shell structure (FeSx@Fe) or seriously oxidized (S-nZVI(aq)), respectively. All these materials were applied to eliminate 2,4,6-trichlorophenol (TCP) from water. The removal of TCP was irrelevant with the structure of S-nZVI. Both nZVI/FeS2 and FeSx@Fe showed remarkable performance for the degradation of TCP. S-nZVI(aq) possessed poor mineralization efficiency to TCP due to its bad crystallinity degree and severe leaching of Fe ions, which retarded the affinity of TCP. Desorption and quenching experiments suggested that TCP removal by nZVI and S-nZVI was based on surface adsorption and subsequent direct reduction by Fe0, oxidation by in-situ produced ROS and polymerization on the surface of these materials. In the reaction process, the corrosion products of these materials transformed into crystalline Fe3O4 and α/ß-FeOOH, which enhanced the stability of nZVI and S-nZVI materials and was conductive to the electron transferring from Fe0 to TCP and strong affinity of TCP onto Fe or FeSx phases. All these were contributed to high performance of nZVI and sulfurized nZVI in removal and minerazilation of TCP in continuous recycle test.

Tuning the lattice parameters and porosity of 2D imine covalent organic frameworks by chemically integrating 4-aminobenzaldehyde as a bifunctional linker.

As the available building blocks are limited, improving the structural complexity of covalent organic frameworks (COFs) is still challenging. In this work, a new three-component COF synthesis strategy is established by using 4-aminobenzaldehyde as the bifunctional linker. The lattice parameters, crystallinity, and porosity of these COFs can be efficiently tuned by varying the amount of this linker. This work provides a new way to expand the structural diversity and complexity of imine-linked COFs.

The extraction of polycyclic aromatic hydrocarbons from water samples with aromatic-dithiocarbamate modified magnetic nanoparticles.

Considering the urgent need for the analysis of trace-level pollutants in water samples, the pre-concentration of micropollutants in water samples has been the focus of extensive research. Among current pretreatment methods, the solid phase extraction (SPE) technique has received enormous attention because of its low cost, ease of operation and high efficiency. In this work, a new adsorbent (Fe3O4@Au@DTC NPs) was acquired through modification of Fe3O4 nanoparticles (NPs) with gold (Au) and dithiocarbamate (DTC). To investigate their application ability, the adsorbent were utilized as an SPE adsorbent to enrich polycyclic aromatic hydrocarbons in water (PAHs, fluoranthene, pyrene, benzo anthracene, benzo fluoranthene, benzo pyrene). The obtained Fe3O4@Au@DTC NPs were confirmed by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and UV-Vis spectrum. Under optimal conditions, the calibration curves were obtained in the range of 10-500 ng L-1, while the limit of detection (LOD) ranged in 1.17-2.31 ng L-1. Furthermore, 50 mg of Fe3O4@Au@DTC NPs could extract trace PAHs from 500 mL real water samples into 1 mL eluent, and the spiked recoveries of five PAHs in river water and tap water reached 72-106% with relative standard deviations varying between 3.3-5.18%. Through the conversion of amines into DTC, we acquire desiring group modified Fe3O4 NPs, which showed great prospects in magnetic solid-phase extraction sphere and environmental field.

Constructing chemical stable 4-carboxyl-quinoline linked covalent organic frameworks via Doebner reaction for nanofiltration.

Covalent linkages are the key component of covalent organic frameworks (COFs). The development of stable and functional linkages is essential to expand the COFs family and broaden their application prospects. In this work, we report the synthesis of crystalline and chemical stable 4-carboxyl-quinoline linked COFs (QL-COFs) via Doebner reactions in both one-pot (OP) and post-synthetic modification (PSM) methods. Both methods can be universally applied to most of the reported imine COFs family via bottom-up construction or linkage conversion. Owing to the contractive pore size, more hydrophilic structure and better chemical stability than the conventional imine COFs endowed by 4-carboxyl-quinoline linkage, QL-COFs are supposed to possess a wider application range. We further demonstrate the nanofiltration membrane (NFM) based on QL-COF exhibited a desirable separation capacity with high rejection for small dye molecules (> 90%), high water permeance (850 L m-2 h-1 MPa-1) and tolerance of extreme conditions (1 M HCl/NaOH), which were benefitted from the enhanced properties of QL-COFs. Additionally, efficient ion sieving properties were also achieved by QL-COF membrane. We anticipate that this work opens up a way for the construction of robust and functional COFs materials for practical applications.

One-pot molten salt method for constructing CdS/C3N4 nanojunctions with highly enhanced photocatalytic performance for hydrogen evolution reaction.

The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution. In this study, we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of CdS and C3N4 nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature, a little higher than the melting point of thiourea. The as-prepared CdS/C3N4 materials exhibit high efficiency for photocatalytic hydrogen evolution reaction (HER) with the HER rate as high as 15,866 µmol/(g∙hr) under visible light irradiation (λ > 420 nm), which is 89 and 9 times those of pristine C3N4 and CdS, respectively. Also, the apparent quantum efficiency (AQE) of CdS/C3N4-1:2-200-2 (CdS/C3N4-1:2-200-2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200°C for two hours) reaches 3.25% at λ = 420 ± 15 nm. After irradiated for more than 24 hr, the HER efficiencies of CdS/C3N4 do not exhibit any attenuation. The DFT calculation suggests that the charge difference causes an internal electric field from C3N4 pointing to CdS, which can more effectively promote the transfer of photogenerated electrons from CdS to C3N4. Therefore, most HER should occur on C3N4 surface where photogenerated electrons accumulate, which largely protects CdS from photo-corrosion.

Mechanochemical Construction 2D/2D Covalent Organic Nanosheets Heterojunctions Based on Substoichiometric Covalent Organic Frameworks.

Combining different semiconductor materials to construct heterojunctions is a promising method to achieve efficient photocatalysis; however, it is still a challenge to accurately construct heterojunctions through molecular regulation. In this work, we take advantage of the remaining aldehyde groups in a substoichiometric covalent organic framework (denoted as PTO-COF) to achieve precise construction of covalently linked 2D/2D covalent organic nanosheets (CONs) heterojunctions through mechanochemical methods. The ultrathin structure of CONs endowed them with superior photoinduced charge generation and separation. Additionally, the energy bands of two CONs materials in heterojunctions were precisely coupled in a Z-scheme by the well-designed covalent linkages, which lead to a 190% enhancement of photocatalytic degradation efficiency for PTO/TpMa CONs heterojunctions as compared with pure COFs. This work provides new insights for design and synthesis of innovative 2D organic heterojunction photocatalysts.

Single-crystalline Fe7S8/Fe3O4 coated zero-valent iron synthesized with vacuum chemical vapor deposition technique: Enhanced reductive, oxidative and photocatalytic activity for water purification.

Well-defined core/shell type single crystalline Fe7S8/Fe3O4 coated α-Fe hybrids (Fe7S8/Fe3O4@Fe) are synthesized with vacuum chemical vapor deposition (CVD) technique. The CVD process triggers conversion of naturally formed Fe3O4 layer on the surface of commercial Fe nanoparticles from amorphous into single crystalline phase. The Fe7S8/Fe3O4 coat promotes the surface affinity of dissolved oxygen and targets and rapidly transfers electrons from the Fe core to targets, which decreases water splitting on Fe7S8/Fe3O4@Fe surface and endows Fe7S8/Fe3O4@Fe with ultra-strong reducibility and improved oxidative ability under different conditions. Different with the sulfurized ZVI prepared with hydrothermal or solvothermal method, the increase of reaction solution pH is retarded due to the relieved water splitting instead of releasing H+ via oxidation of S2-/S22- on the Fe7S8 coat. The cooperation of Fe7S8 with Fe3O4 and α-Fe not only improves the anti-oxidation ability of Fe7S8 coating but also broadens its band gap. By using Fe7S8/Fe3O4@Fe nanohybrids as photocatalysts, light irradiation accelerates the degradation of organic pollutants combined with enhanced mineralization efficiency. The Fe7S8/Fe3O4@Fe exhibits good performance when it is utilized to treat the influent from a municipal sewage treatment plant upon air aeration or under visible light and solar light irradiation.

A feasible strategy to improve confident elemental composition determination of compounds in complex organic mixture such as natural organic matter by FTICR-MS without internal calibration.

Confident elemental composition determination of compounds in complex samples such as natural organic matter (NOM) by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is challenging due to the interference between multiple components in these samples during detection. Here the performance of Solarix 15T-FTICR-MS in terms of accurate relative natural isotope abundance (RIA) and mass measurements for elemental composition determination of compounds in complex samples such as NOM was systematically evaluated. The optimal sweep excitation power values ranging from 20% to 22% was found to significantly diminish the underestimation of RIA measurement for 13C1 peaks of NOM components by FTICR-MS. Random error was found to be one of the main sources for the RIA errors of 13C1 peaks with S/N ratios <25. The mean averaged RIA errors of less than 10% could be obtained by averaging the measured RIAs of each 13C1 peaks in five replicated runs. By adjusting the total ion abundance of NOM complex sample between 3.8-E7 and 1.4-E8 which was simultaneously similar to that of external calibrant during detection, mass errors of lower than 1 ppm for NOM components with m/z lower than 700 Da could be obtained without internal calibration. Meanwhile, a linear correlation between mass errors of ions in NOM complex sample and their m/z values could be obtained. The mass error deviation derived from the linearity was firstly used as new criterion to reduce the number of false formula candidates. A novel strategy of combination of high mass accuracy, high spectral accuracy, and mass error deviation for elemental composition determination of unknown compounds in complex sample such as NOM by FTICR-MS was proposed and applied for different complex samples. Compared to the traditional method, about one fold increasement in the number of the unique formula assignments for measured ions was obtained by using our strategy.

Advanced molecular-fingerprinting analysis of dissolved organic sulfur by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry using optimal spray solvent.

Molecular level characterization of dissolved organic sulfur (DOS) by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) is necessary for further understanding of the role of DOS in the environment. Here, ESI spray solvent, a key parameter for ion production during ESI process, was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS. 100% MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM, which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected. The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50% MeOH aqueous solution (731) or 50% ACN aqueous solution (653). Moreover, due to the enhancement of ionization efficiency of DOS during ESI processes, the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100% MeOH as spray solvent, which were hardly obtained using 50% MeOH aqueous solution as spray solvent. The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample. A simple method based on 100% MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied, and the results revealed more molecular information of DOS in sea DOM samples.

Ultrafine Pd nanoparticles loaded benzothiazole-linked covalent organic framework for efficient photocatalytic C-C cross-coupling reactions.

We proposed a strategy that a benzothiazole-linked covalent organic framework (TTT-COF) was used as a substrate to prepare metal composite photocatalyst Pd NPs@TTT-COF. Firstly, benzothiazole linked TTT-COF exhibited superior chemical stability and photoresponse. Moreover, a finer particle size (2.01 nm) and more uniform distribution of Pd NPs were observed in Pd NPs@TTT-COF owing to the binding interaction between Pd NPs and S in benzothiazole groups. Pd NPs@TTT-COF exhibited superior efficiency and reusability in photocatalytic C-C cross-coupling reactions. Mechanism study suggested that photogenerated electrons and holes on TTT-COF played important roles in these reactions.

Strengthened Fenton degradation of phenol catalyzed by core/shell Fe-Pd@C nanocomposites derived from mechanochemically synthesized Fe-Metal organic frameworks.

We have prepared core/shell structured hollow Fe-Pd@C nanomaterials derived from Fe-metal organic frameworks which were synthesized via cheap, fast and simple mechanochemical technique. The obtained Fe-Pd@C can steadily and continuously release Fe2+ from the galvanic corrosion of Fe0 anode to trigger H2O2 decomposition into hydroxyl radicals and cause fast (10 min) and efficient (mineralization rate 95%) degradation of phenol. The presence of low level of Pd NPs in Fe-Pd@C (mass ratio of the raw material: Fe/Pd = 100:1) facilitated fast Fe3+/Fe2+ redox cycle and thus improved the catalytic performance and pH endurance of the Fe-Pd@C. After recycled four times, Fe-Pd@C remained high catalytic performance and released low level of iron ions (2.5 mg L-1), which reduced the production of iron sludge after usage. In contrast to zero-valent iron (ZVI) and commercial physically mixed Fe/C materials, the core/shell structure of Fe-Pd@C ensured efficient electron transferring from Fe0 to carbon cathode and targets, and prevented the precipitation of iron ions on Fe0 surface, avoiding the deactivation of Fe0 and termination of Fe-C internal micro-electrolysis (IME) and extending their service life. The reactive species quenching experiments and ESR characterization proved the synergistic effect of electrons and hydroxyl free radicals on degradation of phenol. The carbon-centered DMPO radical detected in reaction solution can be regarded as a proof for the strengthened oxidation ability of the combined IME and Fenton reaction.

Ball milling synthesis of covalent organic framework as a highly active photocatalyst for degradation of organic contaminants.

Facile, environmentally-friendly fabrication of high-yield and stable covalent organic framework (COF) materials has been a limitation to their large-scale production and application. In this work, ball milling was used to synthesize COF by mechanochemical reaction between 1,3,5-triformylphloroglucinol (Tp) and melamine (MA) at ambient temperature. Different routes (liquid-free, solvent-assisted and catalyst-assisted) and proportions of liquids (solvents or catalyst) were investigated. Two morphologies were obtained when various amounts of liquid were added during grinding. The two forms were interwoven thread-shaped and exfoliative thin ribbon-like structures. Further, visible-light photocatalytic (λ > 400 nm) performance and mechanism of the two structures of COFs were investigated. The exfoliative ribbon-like structures exhibited greater rates of photodegradation of phenol and retained 87.6% of initial photodegradation after being used four times. Addition of liquid catalyst not only improved crystallinity of the COF materials, but also enhanced rates of photocatalytic reactions. Photocatalytic activity of the exfoliative structure of TpMA synthesized by ball milling was comparable with that of the photocatalyst prepared by use of the solvothermal method, while time to prepare the catalyst was shortened by 36-fold and the amount of solvent used was reduced by 8-fold at room temperature. Mechanochemical synthesis is a promising potential tool for large-scale production of COFs, which will make greater use of COFs for degradation of pollutants.

Covalent-organic frameworks as adsorbent and matrix of SALDI-TOF MS for the enrichment and rapid determination of fluorochemicals.

An imine-linked two-dimensional covalent organic framework, via the condensation of 1, 3, 5-triformylbenzene and p-phenylenediamine (COF-LZU1) is used as both adsorbent and matrix of SALDI-TOF MS for the rapid analysis of fluorochemicals. COF-LZU1 can efficiently assist the laser desorption/ionization of fluorochemicals and function well in negative ion modes without background interference. COF-LZU1 with large surface area, high porosity and suitable hydrophobicity, also can enrich trace amounts of fluorochemicals from solution effectively and quickly through hydrophobic interaction. Therefore, COF-LZU1-solid-phase extraction (SPE) enrichment is combined with SALDI-TOF MS measurement to provide the rapid and high sensitive analysis of fluorochemicals in water samples. The LODs of fluorochemicals can reach ppt or subppt levels. Besides, this method shows robust anti-interference ability. With the assistance of COF-LZU1, trace levels of fluorochemicals could be quantitatively and sensitively analyzed from environmental water samples in a rapid, sensitive and convenient way.

Preliminary investigation on cytotoxicity of fluorinated polymer nanoparticles.

As well-known persistent organic pollutants (POPs), organofluorine pollutants such as perfluorooctane sulfonate (PFOS) have been proven to be bioaccumulated and harmful to health. However, toxicological assessment of organofluorinated nanoparticles, which have emerged as a novel tool for biomedical and industrial applications, is lacking, to the best of our knowledge. To assess the biological effects and health risk of fluorinated nanoparticles, trifluoroethyl aryl ether-based fluorinated poly(methyl methacrylate) nanoparticles (PTFE-PMMA NPs) were synthesized with various fluorine contents (PTFE-PMMA-1 NPs 12.0wt.%, PTFE-PMMA-2 NPs 6.1wt.% and PTFE-PMMA-3 NPs 5.0wt.%), and their cytotoxicity was investigated in this study. The in vitro experimental results indicated that the cytotoxicity of PTFE-PMMA NPs was mild, and was closely related to their fluorine (F) contents and F-containing side chains. Specifically, the cytotoxicity of PTFE-PMMA NPs decreased with increasing F content and F-containing side chains. After exposure to PTFE-PMMA NPs at a sublethal dose (50µg/mL) for 24hr, the phospholipid bilayer was damaged, accompanied by increasing permeability of the cell membrane. Meanwhile, the intracellular accumulation of reactive oxygen species (ROS) occurred, resulting in the increase of DNA damage, cell cycle arrest and cell death. Overall, the PTFE-PMMA NPs were found to be relatively safe compared with typical engineered nanomaterials (ENMs), such as silver nanoparticles and graphene oxide, for biomedical and industrial applications.

Multifunctional Au NPs-polydopamine-polyvinylidene fluoride membrane chips as probe for enrichment and rapid detection of organic contaminants.

High-throughput and rapid detection of hazardous compounds in complicated samples is essential for the solution of environmental problems. We have prepared a "pH-paper-like" chip which can rapidly "indicate" the occurrence of organic contaminants just through dipping the chip in water samples for short time followed by fast analysis with surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The chips are composed of polyvinylidene fluoride membrane (PVDFM), polydopamine (PDA) film and Au nanoparticles (Au NPs), which are layer-by-layer assembled according to the adhesion, self-polymerization and reduction property of dopamine. In the Au NPs loaded polydopamine-polyvinylidene fluoride membrane (Au NPs-PDA-PVDFM) chips, PVDFM combined with PDA film are responsible for the enrichment of organic analyte through hydrophobic interactions and π-π stacking; Au NPs serve as effective SALDI matrix for the rapid detection of target analyte. After dipping into water solution for minutes, the Au-PDA-PVDFM chips with enriched organic analytes can be detected directly with SALDI-TOF MS. The good solid-phase extraction performance of the PDA-PVDFM components, remarkable matrix effect of the loaded AuNPs, and sensitivity of the SALDI-TOF MS technique ensure excellent sensitivity and reproducibility for the quantification of trace levels of organic contaminants in environmental water samples.

Continuous generation of hydroxyl radicals for highly efficient elimination of chlorophenols and phenols catalyzed by heterogeneous Fenton-like catalysts yolk/shell Pd@Fe3O4@metal organic frameworks.

Core/shell Fe3O4-decorated Pd nanoparticles (NPs) hybrids (Pd@Fe3O4) are prepared through a "green", and one-pot chemical process. The Pd@Fe3O4 hybrids consisted of faceted quasi-spherical Pd nanoparticles (NPs) cores (∼20 nm) surrounded by close-packed Fe3O4 NPs (∼7 nm). To improve the stability and avoid aggregation of Pd@Fe3O4 hybrids in water, hollow Fe-metal organic frameworks (Fe-MOFs) were applied to enwrap Pd@Fe3O4 to obtain yolk/shell structured composites. Sub-10 nm Fe3O4 and Pd NPs close to each other were distributed evenly in the MOFs shell of Pd@Fe3O4@MOFs. The yolk/shell Pd@Fe3O4@MOFs can catalyze the oxidative degradation of chlorophenols and phenols by hydroxyl radicals (OH) decomposed from H2O2. With low molar ratio of H2O2/pollutants, the pollutants are degraded and mineralized efficiently and rapidly. The outstanding catalytic efficiency of Pd@Fe3O4@MOFs is contributed by the fast and continuous generation of OH radicals in Pd@Fe3O4@MOFs suspension which is detected with the electron spin resonance spin-trap technique and a continuous-flow chemiluminescence system. Lack of consumption of hydroperoxyl radicals/superoxide radicals (HO2/O2-) in the Pd@Fe3O4@MOFs-H2O2 system might suggest that the production of OH radicals results from the electron transferring from Pd to Fe3O4 component both in the inner Pd@Fe3O4 and MOF shell, which facilitates fast Fe(III)/Fe(II) redox cycle.