PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2024
·
IF 5.3
Yuwen Deng,Zaili Xiong,Jijun Guo,Bingzhi Liu,Meirong Zeng,Zhandong Wang,Zhongyue Zhou,Wenhao Yuan,Fei Qi
Elucidating the oxidation chemistry of polycyclic aromatic hydrocarbons (PAHs) aids in understanding the degradation reaction processes of PAHs, as well as their competitive roles in PAH growth. In this work, ozone-assisted oxidation of indene , the smallest prototype PAH molecule, was investigated in an atmospheric jet stirred reactor at 400–550 K. Ab initio quantum chemistry calculations were conducted to characterize the oxidation kinetics of indene and interpret the experimental observations. Fingerprint oxidation products including 2-(2-oxoethyl) benzoic acid, 2-(formylmethyl) benzaldehyde , 1,2-indanedione and 1-indanone were identified by synchrotron vacuum ultraviolet photoionization mass spectrometry . The initial C 9 H 8 O 3 adduct resulting from O 3 -addition to indene exhibits high instability and is primarily detected as 2-(2-oxoethyl)benzoic acid following ozonolysis reactions. Minor amounts of vinylhydroperoxide were also observed as isomeric products of the C 9 H 8 O 3 adduct. Theoretical calculations indicate that indene ozonolysis is highly structure-dependent, where the conformation of the C 9 H 8 O 3 adduct determines the configuration of the resulting Criegee intermediates (CI). The distinctive reaction pathways introduced by the bifunctionalized characteristics of indene-derived large CIs are emphasized in this study. syn -Configuration CI features more conversion pathways compared to anti -CI due to the interaction between CI functionality and the neighboring aldehyde group, among which the bicyclic ring-closure reaction yielding secondary ozonide is most favored. The dioxirane intermediates generated from anti -CIs can undergo the Crossed Acid-forming channel to yield the target acid products, which provides an alternative way for dioxirane conversion. Further theoretical analyses demonstrate that ozonolysis is not the exclusive mechanism for indene oxidation under O 3 -assisted conditions. Instead, it is accompanied by low-temperature reactions initiated by OH/O 2 , leading to key products such as 2-(formylmethyl) benzaldehyde and 1-indanone. The present work aims to unravel the elusive chemistry involved in the O 3 -initiated oxidation of indene, providing new insights into the distinctive kinetics introduced by large bifunctionalized CIs in the ozonolysis of structurally similar PAHs.
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ACS Nano
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2018
·
IF 13.709
Xiaodong Qi,Dan Zhang,Zhongbao Ma,Wenxin Cao,Ying Hou,Jiaqi Zhu,Yang Gan,Ming Yang
We overcome the fundamental dilemma in achieving hard materials with self-healing capability by integrating an epidermis-like hierarchical stratified structure with attractive mechanical and barrier properties of graphene oxide and show that such biomimetic design enables a smart hierarchical coating system with a synergetic healing effect and a record-high stiffness (31.4 ± 1.8 GPa)/hardness (2.27 ± 0.09 GPa) among all self-healable polymeric films even comparable to that of tooth enamel. A quasi-linear layer-by-layer (LBL) film with constituent graphene oxide is deposited on top of an exponential LBL counterpart as a protective hard layer, forming a hierarchical stratified assembly mimicking the structure of epidermis. The hybrid multilayers can achieve a complete restoration after scratching thanks to the mutual benefit: The soft underneath cushion can provide additional polymers to assist the recovery of the outer hard layer, which in turn can be a sealing barrier promoting the self-healing of the soft layer during stimulated polymer diffusion. The presenting hybridization mode of LBL assembly represents a promising tool for integrating seemingly contradictory properties in artificial materials with potential performances surpassing those in nature.
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Soft Matter
·
2018
·Vol. 14
·期 9
·1552-1558
·
IF 3.709
Qingming Ma,Hao Yuan,Yang Song,Youchuang Chao,Sze Yi Mak,Ho Cheung Shum
Partitioning refers to the distribution of solute molecules in the two immiscible phases of a mixture of two solutions, such as an aqueous two-phase system (ATPS). The partitioning of RNA and peptide has been adjusted in situ to facilitate their assembly into intracellular membraneless organelles. Despite the immense potential of this approach in artificial systems, a partitioning-dependent assembly of macromolecules has been limited, due to the sophisticated processing associated with their in situ modification. Here we demonstrate an approach to direct the assembly of polyelectrolytes in an ATPS through varying their partitioning via pH changes. Microcapsules can be converted to microgel particles as the polyelectrolytes selectively partition to different emulsion phases when changing pH. Such partitioning-dependence can also be equally applied for complexing hydrophilic nanoparticles with polyelectrolytes in an ATPS. By enabling access of hydrophilic materials across the aqueous interface freely, the ATPS allows modification of their intrinsic properties in situ; this advantage will inspire more versatile control over the partitioning of hydrophilic materials and will create new multi-functional biomaterials.
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高影响因子
MICROCHIMICA ACTA
·
2017
·Vol. 185
·期 1
·1-8
·
IF 4.58
Song Yuhong,Ma Ruiyang,Jiao Caina,Hao Lin,Wang Chun,Wu Qiuhua,Wang Zhi
A magnetic mesoporous poly(melamine-formaldehyde) composite (Fe 3 O 4 -mPMF) was prepared via grafting poly(melamine-formaldehyde) onto the surface of amino-functionalized magnetite (Fe 3 O 4 ) nanoparticles. The material was characterized by scanning electron micrography, transmission electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. It has a large surface area, a typical mesoporous structure, and a high thermal stability. It was employed as a magnetic sorbent for the solid phase extraction of the following endocrine disrupting chemicals (EDCs): Bisphenol A, 4-tert-butylphenol, 4-tert-octylphenol and nonylphenol. The EDCs were then quantified by HPLC. Under the optimized conditions, the response to the EDCs is linear in the range of 0.5–100 ng·mL −1 , and the limits of detection are 0.02–0.1 ng·mL −1 . The high adsorption capability of the Fe 3 O 4 -mPMF is mainly attributed to multiple interactions including π-stacking, hydrogen bonding, and hydrophobic interactions. The method was applied to the extraction of EDCs from spiked river water and bottled juice samples. The results demonstrated that the Fe 3 O 4 -mPMF is an efficient adsorbent for the extraction of organic compounds with large conjugated π-system, plenty of hydrogen-bonding sites, and strong hydrophobicity.
A magnetic mesoporous polymelamine-formaldehyde composite (Fe 3 O 4 -mPMF) was prepared and employed as a magnetic sorbent for the solid phase extraction of endocrine disrupting chemicals from river water and bottled juice samples prior to high-performance liquid chromatographic analysis.
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CHEMOSPHERE
·
2017
·
IF 4.208
Xufang Li,Weiyu Chen,Luming Ma,Hongwu Wang,Jinhong Fan
An Fe-based catalyst was used as a heterogeneous catalyst for the ozonation of industrial wastewater , and key operational parameters (pH and catalyst dosage) were studied. The results indicated that the Fe-based catalyst significantly improved the mineralization of organic pollutants in wastewater. TOC (total organic carbon) removal was high, at 78.7%, with a catalyst concentration of 200 g/L, but only 31.6% with ozonation alone. The Fe-based catalyst significantly promoted ozone decomposition by 70% in aqueous solution. Hydroxyl radicals (·OH) were confirmed to be existed directly via EPR (electron paramagnetic resonance) experiments, and ·OH were verified to account for about 34.4% of TOC removal with NaHCO 3 as a radical scavenger. Through characterization by SEM-EDS (field emission scanning electron microscope with energy-dispersive spectrometer), XRD (X-ray powder diffraction) and XPS (X-ray photoelectron spectroscopy), it was deduced that FeOOH on the surface of the catalyst was the dominant contributor to the catalytic efficiency. The catalyst was certified as having good stability and excellent reusability based on 50 successive operations and could be used as a filler simultaneously. Thereby, it is a promising catalyst for practical industrial wastewater advanced treatment.
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CHEMICAL ENGINEERING SCIENCE
·
2018
·
IF 3.306
Jiamin Hou,Yanying Wei,Sheng Zhou,Yanjie Wang,Haihui Wang
We propose a strategy for rapid in situ fabrication of zeolitic imidazolate framework-8 (ZIF-8) hybrid membrane with assistance of the two dimensional (2D) graphitic carbon nitride (g-C 3 N 4 ) nanosheets at room temperature. The negatively charged g-C 3 N 4 nanosheets with abundant nitrogen coordinating sites are capable to capture and anchor Zn 2+ and thus provide a large number of heterogeneous nucleation sites for the formation of initial ZIF-8 crystals. During the cyclical spin coating of the Zn 2+ /g-C 3 N 4 nanosheets and the ligand (2-methylimidazole), the in situ formed ZIF-8 crystal nucleus on g-C 3 N 4 nanosheets promote the further growth of continues defect-free membranes. The ZIF-8/g-C 3 N 4 membrane with thickness of ∼240 nm can be obtained using this strategy within 30 min at room temperature, which is attractive for fast and facile preparation of molecular sieving membranes. Moreover, it exhibits promising H 2 /CO 2 separation performance with the selectivity up to 42, which is superior to many other ZIF-8 membranes.
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CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Zhanying Li,Lin Shao,Wenbin Hu,Tingting Zheng,Lingbin Lu,Yang Cao,Yongjun Chen
Absorption is one of the most important methods for oil spill cleanup. An ideal absorbent is expected to possess advantages of low cost, green, high absorption capacity and excellent reusability. In this paper, a new kind of cellulose aerogel was successfully fabricated via cellulose oxidation, crosslinking, freeze drying and cold plasma modification. The obtained aerogel (water contact angle up to 152.8°) exhibited outstanding oil/water selectivity and high absorption capacity (13.77–28.20 g/g) for various oils and organic solvents. What's more, this kind of aerogel could be reused by simple compression. The absorption-desorption process could be repeated for at least 50 cycles. Through the kinetic analysis, it was found that the pseudo-second order model was more appropriate for the aerogel’s oil absorption process. Owing to its low cost, hydrophobicity, high absorption capacity and excellent reusability, this kind of aerogel is expected to be used in oils and organic solvents spill cleanup and oil/water separation field.
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MATERIALS & DESIGN
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2018
·
IF 4.525
Sen-Qiang Wu,Jing-Wen Wang,Jing Shao,Lei Wei,Ren-Kui Ge,Hua Ren
High dielectric constant (high- k ) polymeric materials suitable for electromechanical transducers should meet the requirements of low dielectric loss. This work introduced a ternary nanocomposite with acrylate elastomer (AE) as matrix, and chemically reduced graphene oxides (G) and poly(ionic liquid)s (PILs) as co-filler, of which AE was synthesized by solution polymerization . A unique hybrid (H) was fabricated by the ionic liquid monomers polymerized on the surface of graphene. Afterwards, hybrid of different filler contents was added into AE to prepare nanocomposites with solution casting method. The favorable π-π interaction between PILs and graphene made the co-filler a better dispersion in the matrix, which contributed to the enhanced dielectric property of the resultant nanocomposites. Dielectric constant of H/AE nanocomposite at 10 2 Hz was as high as 680 and the dielectric loss was only 0.34 when the filler content (1.69 vol%) approached to the percolation threshold ( f c ), which was attributed to PILs anchored on the surface of graphene acting as spacers and PILs cut the leakage currents induced by the direct connection of graphene. Moreover, the composite was still flexible that could engender larger strain in area.
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RSC Advances
·
2018
·Vol. 8
·期 3
·1361-1370
·
IF 2.936
Song Li,Wenzhi Li,Qi Zhang,Riyang Shu,Huizhen Wang,Haosheng Xin,Longlong Ma
The lignin-first biorefinery method appears to be an attractive approach to produce phenolic chemicals. Herein, corn stover was employed for the production of phenolic monomers using an unsupported non-noble MoS2 catalyst. The yield of phenolic monomers was enhanced from 6.65% to 18.47% with MoS2 at 250 °C and about 75% lignin was degraded with more than 90% glucan reserved in the solid residues. The Fourier-Transform Infrared (FT-IR) and heteronuclear single quantum coherence-nuclear magnetic resonance (1H–13C HSQC-NMR) characterization suggested that the cleavage of the β-O-4, γ-ester and benzyl ether linkages were enhanced, promoting the delignification and the depolymerization of lignin. The catalyst performance was relatively effective with 14.30% phenolic monomer yield after the fifth run. The effects of the reaction temperature, the initial hydrogen pressure, the dosage of catalyst, and the reaction time were investigated. The model reactions were also proposed for the potential mechanism study. This work provides some basic information for the improvement of the graminaceous plant lignin-first process with a non-noble metal catalyst.
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PROCESS BIOCHEMISTRY
·
2024
·
IF 3.7
Puhong Yi,Yue Xu,Hanlin Liu,Yuhua Hao,Mengdan Liu,Zhiqiang Liu,Yaping Xue,Liqun Jin,Yuguo Zheng
2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid (PPO) is a valuable prochiral keto acid for the asymmetric synthesis of the important herbicide L-phosphinothricin (L-PPT). Developing an efficient biocatalytic pathway to meet the increasing demand for PPO is highly attractive. In this study, a robust D-amino acid aminotransferase from Cytobacillus firmus ( Cf DAAT) was screened, which exhibited excellent tolerability to D,L-PPT and showed remarkable specific activity and affinity toward pyruvate (61.9 U/mg, Km = 7.4 mM). A designed co-substrate regeneration system was then introduced to shift the reaction equilibrium forward by coupling with D-amino acid oxidase (DAAO) and catalase (CAT). An efficient whole-cell biocatalyst was obtained by fine-tuning RBS intensity to coordinate the co-expression of the three enzymes. Moreover, the optimum conditions to promote overall conversion efficiency were identified by response surface methodology. Consequently, with only a catalytic amount of pyruvate (3.33 mol%) added in a 1 L reaction system, 200 mM D-PPT (400 mM D,L-PPT) was completely converted in 10 h, resulting in a PPO productivity of 3.33 g⋅L −1 ⋅h −1 , and a notable conversion rate of >99% at 300 mM D-PPT in 16 h. It demonstrated a considerable catalytic level and provided a competitive route for industrial PPO production from D,L-PPT.
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Communications Materials
·
2025
·Vol. 6
·期 1
·1-8
·
IF 9.6
Lin Cunjian,Yang Rujun,Wu Zishuang,Wang Yajing,Zhan Chenhan,Miyata Hirohisa,Zeng Xiankan,Zheng Yuantian,You Shihai,Lv Ying,Zhuang Yixi,Xie Rong-Jun,Ueda Jumpei
Persistent luminescence (PersL) in inorganic materials, lasting from seconds to even days, has attracted considerable attention. Despite the promise of electric power-driven PersL for lighting and display device applications due to its convenience and manageability, studies on electrically driven inorganic PersL are lacking. Here, we report an inorganic PersL in electroluminescent devices, which shows an energy storage effect that persists beyond 24 h after charging with an alternating current electric field at 250 K. The spin-coating method-prepared emission layer composites consist of a small bandgap copper-doped zinc sulfide core, a high dielectric constant alumina shell and a chemically passivated dielectric polydimethylsiloxane medium (ZnS:Cu@AlO x @PDMS), and these composites exhibit well-distributed electric fields and excellent operational stability. Thermoluminescence characterization reveal that PersL with an ~ 0.3 eV trap depth in electroluminescent devices mainly arises from the charge separation via hot-electron impact excitation and charge trapping within trap states in the emission layer. This study on electrically chargeable PersL in alternating current-driven electroluminescent devices can enhance our understanding of luminescence mechanisms in inorganic semiconductors.
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BIOORGANIC CHEMISTRY
·
2024
·
IF 4.5
He Liu,Shixi Wang,Meng Xu,Kaiyue Zhang,Qian Gao,Hualei Wang,Dongzhi Wei
( R )-selective transaminases show promise as catalysts for the asymmetric synthesis of chiral amines, which are building blocks of various small molecule drugs. However, their application is limited by poor substrate acceptance and low catalytic efficiency. Here, a potential ( R )-selective transaminase from Fodinicurvata sediminis (FsTA) was identified through a substrate truncating strategy, and used as starting point for enzyme engineering toward catalysis of 4-hydroxy-2-butanone, a substrate that poses challenges in catalysis. Molecular docking and dynamics simulations revealed Y90 as the key residue responsible for poor substrate binding. Starting from the variant (Y90F, mut1) with initial activity, FsTA was systematically modified to improve substrate-binding through active site reshaping and consensus sequence strategy, yielding three variants (H30R, V152K, and Y156F) with improved activity. A quadruple mutation variant H30R/Y90F/V152K/Y156F (mut4) was also found to show a 7.95-fold greater catalytic efficiency ( k cat / K M ) than the initial variant mut1. Furthermore, mut4 also enhanced the thermostability of enzyme significantly, with the T m value increasing by 10 °C. This variant also exhibited significantly improved activity toward a series of ketones that are either not accepted or poorly accepted by the wild-type. This study provides a basis for the rational design of an active to creating variants that can accommodate novel substrates.
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