The formation condition, morphology evolution, reaction mechanism and adsorption properties of hydrochars prepared from corn stalk were explored using a hydrothermal method at low temperatures for a ...continuous period of reaction time. The experimental results showed that by prolonging the reaction time up to 26 h, corn stalk could be converted into hydrochar via HTC at a low temperature of 200 °C. It was found that hemicellulose was completely dissolved and more amorphous phases of cellulose and soluble lignin were fragmented and dissolved with increase of the reaction time. The ester, furfural and phenolic derivatives underwent a series of reactions in an aqueous solution to form polymerized hydrochar microspheres, whereas the non-dissolved cellulose and lignin went through a heterogeneous pyrolysis-like process to form polyaromatic char with an interconnected porous network structure. The as-prepared hydrochars with oxygen-containing functional groups and unique porous network structures could adsorb a larger amount of Cr( vi ) than commercial activated carbon and were an effective and green sustainable adsorbent for the removal of Cr( vi ) from an aqueous solution.
•Comparison of enzyme-linked immunosorbent assays for lupine allergen detection.•Determination of detection capability for three different lupine species.•Investigation of lupine cross-reactivity to ...related legumes.
Lupine belongs to the genus Lupinus and includes three species commonly consumed by humans. The Lupinus genus is closely related to other legumes, such as peanuts, soya, chickpeas, peas, lentils and beans. However, the consumption of lupine (and related legumes) can cause severe allergenic reactions. Therefore, reliable analytical detection methods are required for the analysis of food samples. In this study three commercially available ELISA test kits were analyzed for the detection capability of three common lupine species, as well as cross-reactivity to related legumes. All three ELISA test kits could detect the lupine species, though with different sensitivities. Cross-reactivity varied for the ELISA test kits and all showed some cross-reactivity to related legume samples analyzed.
A flame retardant with enhanced phosphorus–nitrogen content, 5,5-dimethyl-2-(phenyl(phenylamino)methyl)-1,3,2-dioxaphosphinane 2-oxide (DPPO), was synthesized by the reaction of ...5,5-dimethyl-1,3,2-dioxaphosphinane 2-oxide (DDPO) with N-benzylideneaniline. The structure of DPPO was characterized by nuclear magnetic resonance (1H NMR and 31P NMR) and Fourier transform infrared (FT-IR) spectroscopy. The thermal stability of DPPO was characterized by thermogravimetric analysis (TGA). The solubilities of DPPO were measured in different solvents including ethyl acetate, methanol, chloroform, acetonitrile, acetone, 1,2-dichloroethane, 1,4-dioxane, dichloromethane, tetrachloromethane, benzene, tetrahydrofuran, and isopropanol at temperature ranging from 278.15 to 347.15 K by the gravimetrical method. The mole fraction solubilities of DPPO in the above-mentioned organic solvents were correlated as the Apelblat equation, and the calculated values with equations shows good consistency with the experimental values. The root-mean-square deviation was less than 0.1%, and the average relative error was less than 0.04 in all of the experiments.
The formation condition, morphology evolution, reaction mechanism and adsorption properties of hydrochars prepared from corn stalk were explored using a hydrothermal method at low temperatures for a ...continuous period of reaction time. The experimental results showed that by prolonging the reaction time up to 26 h, corn stalk could be converted into hydrochar
via
HTC at a low temperature of 200 °C. It was found that hemicellulose was completely dissolved and more amorphous phases of cellulose and soluble lignin were fragmented and dissolved with increase of the reaction time. The ester, furfural and phenolic derivatives underwent a series of reactions in an aqueous solution to form polymerized hydrochar microspheres, whereas the non-dissolved cellulose and lignin went through a heterogeneous pyrolysis-like process to form polyaromatic char with an interconnected porous network structure. The as-prepared hydrochars with oxygen-containing functional groups and unique porous network structures could adsorb a larger amount of Cr(
vi
) than commercial activated carbon and were an effective and green sustainable adsorbent for the removal of Cr(
vi
) from an aqueous solution.
Hydrochar spheres were formed by the condensation, polymerization and pyrolysis behavior of hemicellulose, amorphous cellulose and soluble lignin.
Halogen-free flame retardant is receiving an increased attention recently due to its hypotoxicity and high efficiency. Intumescent flame retardant is a hot spot in research of the halogen-free flame ...retardant. In this work, a P-N containing intumescent flame retardant named hydrolyzed starch phosphamide from melamine was synthesized via hydrolysis of starch, phosphorylation of the starch with phosphorus oxychloride, and the reaction between the phosphorylated starch and melamine. PU/hydrolyzed starch phosphamide from melamine composites was prepared using different additive amounts of hydrolyzed starch phosphamide from melamine. Fourier transform infrared, scanning electron microscopy, and thermogravimetric analysis were used to characterize the structures and thermal stabilities of related compounds. Flame retardation performance of hydrolyzed starch phosphamide from melamine was investigated by UL94, limit oxygen index test, and cone calorimetry. Result shows that the PU/hydrolyzed starch phosphamide from melamine composites with 30.0 php of hydrolyzed starch phosphamide from melamine got a limit oxygen index of 29.0 and UL94-V0 ranking. Heat release rate, rate of smoke release, and total smoke release were decreased distinctly.
•The MIP Co/Fe@CNF can effectively detect and degrade wastewater containing PFOA.•Imprinted cavities can shorten the transfer distance between free radicals and target contaminants.•Compared to HPLC, ...MIP Co/Fe@CNF is effective in the detection process.•The catalytic mechanism of MIP Co/Fe@CNF in the detection and degradation process was revealed.
The polyfuoroalkyl substances, especially perfluorooctanoic acid (PFOA), are emerging as harmful environmental micropollutants that are known to globally contaminate water, air, and soil resources. Herein considering the urgent demand for the sensitive detection and effective degradation of PFOA present in water environment, a novel molecular imprinting polymer (MIP) MOFs (Co/Fe)-driven carbon nanofiber (Co/Fe@CNF) electrode has been developed for electrochemical detection and electro-Fenton (EF) degradation of PFOA. MIP was formed by one-pot step by electro-polymerization of the pyrrole in the presence of PFOA template on the Co/Fe@CNF. The MIP has a strong adsorption force on PFOA for the special O–H-π hydrogen bond between PFOA and the imprinting site, helped PFOA to access the surface of electrode. Therefore, the resulting MIP Co/Fe@CNF was able to detect PFOA with a good linear response in the range of 1 × 10-8–9 × 10-5 M, and the limit of detection (LOD) was reached 1.073 × 10-9 M. Moreover, the imprinted cavity on MIP can precisely adsorb PFOA and its intermediates to shorten the transmission distance between free radicals and targets, which enhanced the degradation ability in the EF process, and the targeted degradation efficiency reached 93% with 180 min.
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•Pre-oxidation of K2S2O8 with CuO/FeSO4 catalytic is effective in removing humic acid.•Pre-oxidation is effective on ceramic membrane fouling control.•CuO enhances the generation of ...active free radicals facilitated by FeSO4.
Recently, persulfate oxidation technology has been widely utilized for the degradation of natural organic matter (NOM) in water treatment. This study proposed novel enhanced ceramic membrane filtration system by persulfate (PS) pre-oxidation with CuO and FeSO4 catalytic, which can achieve the high NOM remove performance and low membrane fouling. Firstly, the removal efficiency and mechanism of humic acid (HA) using the CuO/FeSO4/K2S2O8 advanced oxidation system under various operating conditions were investigated. The results indicate that optimal conditions (FeSO4 at 0.016 g/L, CuO at 0.048 g/L, and K2S2O8 at 0.6 g/L) result in substantial removal effects of total organic carbon (TOC, approximately 80 %) and excitation-emission matrix (EEM) spectra by CuO/FeSO4/K2S2O8. Subsequently, with the cycling operation conditions, enhanced ceramic membrane filtration with CuO/FeSO4/K2S2O8 pre-oxidation demonstrates effective removal of HA (approximately 85 %) and significant reduction of membrane fouling (around 60 %), as confirmed by EEM and TOC analysis. Furthermore, during continuous operation, CuO/FeSO4/K2S2O8 pre-oxidation proves to be effective in removing surface water contaminants (approximately 65 %) and mitigating membrane fouling (around 50 %). Finally, through the measurement of Fe2+, Cu2+, and Cu+ concentrations, as well as Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) characterization of CuO, it becomes evident that CuO exhibits synergistic effects with FeSO4 by adsorbing Fe2+ from the solution and reducing Cu2+ to Cu+. This process generates SO4•−, ·OH, and ·O2−radicals within the CuO/FeSO4/K2S2O8 oxidation system. The proposed ceramic membrane filtration system in this study shows great potential in the drinking water treatment for NOM removal.
The residual stress introduced by laser shock peening (LSP) is one of the most important factors in improving metallic fatigue life. The shock wave pressure has considerable influence on residual ...stress distribution, which is affected by the distribution of laser energy. In this work, a titanium alloy is treated by LSP with flat-top and Gaussian laser beams, and the effects of spatial energy distribution on residual stress are investigated. Firstly, a 3D finite element model (FEM) is developed to predict residual stress with different spatial energy distribution, and the predicted residual stress is validated by experimental data. Secondly, three kinds of pulse energies, 3 J, 4 J and 5 J, are chosen to study the difference of residual stress introduced by flat-top and Gaussian laser beams. Lastly, the effect mechanism of spatial energy distribution on residual stress is revealed.
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•The prepared functional 3D CuO/CuS-NS skeleton realizes the high stability Li metal anode.•The DFT results prove that the functional skeleton has high lithiophility and can induce ...homogeneous Li deposition.•Li-plated 3D CuO/CuS-NS skeleton exhibits enhanced cycle stability over 1000 h at 2 mA cm−2.
The intrinsic high activity and skeletonless development of lithium (Li) metal have resulted in gruesome security issues, limiting the widespread use of Li metal anodes. Herein, a three-dimensional (3D) nanosheet skeleton with CuO/CuS (3D CuO/CuS-NS skeleton) is designed as the functional Li metal anode current collector. The functional skeleton’s 3D structure features a large specific surface area to reduce the local current density and inhibit dendrite growth. CuO/CuS loaded by the skeleton can be employed as lithiophilic sites to direct the uniform deposition of Li metal, according to density functional theory (DFT). Furthermore, during the first deposition, CuO/CuS can interact with Li metal to produce Li2O/Li2S, in which Li2S can act as an artificial protective layer to effectively improve the cycle stability of the cells. The dendrite-free deposition in the depositional process demonstrates that the 3D CuO/CuS-NS skeleton can achieve excellent Li metal anode stability. The Li metal anodes with 3D CuO/CuS-NS skeletons also exhibit outstanding electrochemical stability over 1000 h of long-term cycling. In full cells assembled with commercial LiCoO2 cathodes, the 3D CuO/CuS-NS skeletons exhibit good rate performance and capacity retention performance.
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