JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 16
·6848-6860
·
IF 3.553
Wu Xuewen,Jiao Tiantian,Xu Changli,Li Wei,Xiong Yan
In this paper, we reported a rapid and simple approach to synthesize molecularly imprinted polymers (MIPs) materials for sensing of 2,4-dichlorophenoxyacetic acid (2,4-D) residues in environmental water and mixed juice. Initially, MIPs materials were prepared via visible light-initiated reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization at ambient temperature using 2,4-D and its analogs as template molecules, in which 4-vinyl pyridine (4-VP), ethylene glycol dimethacrylate (EGDMA), (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO), 2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoic acid (DDMAT) were functional monomer, cross-linker, visible light initiator and RAFT agent, respectively. Then, the morphologies of the MIPs materials were characterized by FT-IR, SEM and DLS. The results showed that the MIPs materials were well-distributed spherical particles with sizes ranging from 1 to 2 μm. Furthermore, a four-channel MIPs sensor array included four polymer microspheres with a fluorescent dye displacement procedure was developed to distinguish the templates and their chemical analogs at the ppm concentration level. With the support of principal component analysis and hierarchical cluster analysis, the four-channel MIPs sensor array proves to be a simple and effective method to recognize and distinguish the templates and nontemplates in aqueous solution with 100% accuracy. Finally, the four-channel MIPs sensor array was also found to have satisfactory accuracy in monitoring 2,4-D contaminated environmental water and mixed juice.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 26
·11970-11983
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IF 3.553
Niu Yingchun,Li Xueai,Dong Wenqi,Zhang Can,Zhao Kuihu,Wang Fengyan,Wang Haiyan
Carbon and iron composites have drawn much attention for their unique electromagnetic properties. In addition, nitrogen doping of carbon can effectively modulate the dielectric properties of carbon. Therefore, synthesis of N-doped carbon and iron composites is an alternative method for obtaining high-efficiency microwave absorption materials. In previous studies, the synthesis process was very complicated including multistep routes. In this work, N-doped carbon with embedded Fe/Fe 3 C was synthesized in-situ via pyrolysis of amino phenol formaldehyde resin (APF) scattered with Fe 2 O 3 nanoparticles (APF/Fe 2 O 3 ), which was obtained through a simple hydrothermal process. During the heat-treatment process, the APF resin was converted into N-doped carbon, and simultaneously, the Fe 2 O 3 was reduced to iron nanoparticles. Then, inevitably, the iron nanoparticles reacted with carbon to form Fe 3 C at the interface between the iron particles and carbon. Taking advantage of multiple heterogenous interface, the interfacial polarization relaxation could be enhanced. Therefore, the N-doped carbon with embedded Fe/Fe 3 C particles displays microwave absorption with a maximum reflection loss of − 70 dB. Moreover, the effective absorption bandwidth (reflection loss of less than − 10 dB) reaches 6.02 GHz at a thickness of 2.13 mm. This study not only provides composites of N-doped carbon with embedded Fe/Fe 3 C particles with excellent stable microwave absorption but also offers a simple method for synthesizing N-doped carbon with embedded Fe/Fe 3 C particles.
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高影响因子
Silicon
·
2020
·Vol. 13
·期 2
·531-541
·
IF 1.499
Li Feifei,Jiang Xuesong,Zuo Qiuxia,Li Jingwei,Ban Boyuan,Chen Jian
Iron is a major impurity in quartz sand and must be strictly removed in many applications. However, the iron removal rate in most of the conventional purification process is not high enough. In this study, a fast, low-energy consuming, environment-friendly and simple process for purifying quartz is demonstrated by a combination of microwave heating and ultrasound-assisted acid leaching treatment. Using the characteristics of selective heating of microwave, the micro-inclusions burst and generate cracks in the surrounding quartz matrix far below the α/β phase transition temperature, which enables removal of the impurities in the subsequent processing steps and reduces iron diffusion into the quartz matrix. Microwave process sequence, time, and temperature are all important factors, and appropriate parameters need to be explored. Ultrasound can assist acid leaching removal of Fe impurities through the cracks. Under optimized conditions, the iron content can be reduced to below 0.167 ppmw with one single purification pass.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2020
·Vol. 144
·期 3
·721-728
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IF 2.731
Li Heping,Liang Daolun,Liu Jianzhong
Nano-materials are potential substitutes for micro-sized solid propellant ingredients for improving energy density and reaction activity. So far, several nano-carbides act as accelerants for boron (B) oxidation reaction but their promotive effects and corresponding action mechanisms have rarely been reported. In this work, four nano-carbides [nano-boron carbide (nB 4 C), nano-titanium carbide (nTiC), nano-zirconium carbide (nZrC), and nano-silicon carbide (nSiC)] were evaluated by thermogravimetric differential scanning calorimetry-combined thermal analysis system and thermodynamic software FactSage 6.2. Among the four nano-carbides, nTiC ranked as the best accelerant by reducing the initial oxidation temperature of B by 10.7% and increasing heat release by 16.0%. By comparison, nB 4 C and nZrC were ranked as second and third best accelerants with abilities of decreasing the initial oxidation temperature (by 5.4% and 3.3%, respectively) and raising heat release (both by 6.2%). On the other hand, though nSiC slightly decreases the initial oxidation temperature of B, heat release of B + nSiC was lower than that of original B. The action mechanisms of nano-carbides were found complex, and one nano-carbide can accelerate B oxidation following one or several approaches. First, the nano-carbide can be oxidized before B to offer extra heat and induce the oxidation of B. The produced gaseous oxidation product CO 2 by nano-carbide may then help break down the liquid oxide film deposited on B particle surface. Third, the reaction between nano-carbide and B would generate borides, which may diminish accumulated liquid oxide film at low temperatures. Finally, the corresponding oxide will be produced to catalyze the oxidation of B. Overall, these findings look promising for future performance improvement of B-based solid propellants.
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2020
·Vol. 412
·期 13
·3063-3071
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IF 3.637
Li Hongmei,Yue Xiaxia,Gao Ningning,Tang Jun,Lv Xiaoyi,Hou Junwei
Clopidol is one of the most widely used anti-coccidiosis drugs. Its residues in poultry products and the environment pose a serious threat to human health. In this work, microwave-assisted synthesis of magnetic ionic liquid/gold nanoparticles (MIL-Au NPs) as the SERS substrates were first designed for sensitive and reliable determination of clopidol residue in egg samples. The experiment shows that MIL(1-methyl-3-hexyl imidazole ferric tetrachloride ([C 6 mim]FeCl 4 )) and microwave play a key role in the dispersion and morphology of Au NPs. Under the optimal conditions, the as-prepared MIL-Au NPs were applied to the SERS detection of clopidol in methanol and egg solution and its detection limits can be as low as to 0.5 μg/kg (equal to 0.5 ppb) in both solutions. The standard curves with regression coefficients of 0.9298 and 0.93496 were constructed in the linear range of 100–1000 ppb and 0.5–50 ppb for clopidol in egg solutions. Moreover, satisfactory recoveries (97.5–103.2%) were obtained for egg samples. The developed SERS method provides a way for quantitation of clopidol and can be applied for the convenient, reliable, and highly sensitive detection of antibiotic residues in food and environment, which has great potential in food safety and biological monitoring.
Graphical abstract
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PubMed
高影响因子
Journal of Food Measurement and Characterization
·
2020
·Vol. 14
·期 4
·2021-2029
·
IF 1.648
Hussain Abid,Pu Hongbin,Sun Da-Wen
Surface-enhanced Raman spectroscopy (SERS) with cysteamine modified silver-coated gold nanoparticles (Au@Ag-CysNPs) was presented for fast screening of oxamyl and thiacloprid in liquid samples of milk. Concentrations at different levels were detected ranging from 0.5 to 10 ppm by choosing 500–1600 cm −1 spectral range. A strongest Raman peak at 679 cm −1 was ascribed to oxamyl, whereas a band at 1095 cm −1 was associated with thiacloprid in milk samples. The morphology and average size of core-shell nanoparticles (Au@AgNPs) and Au@Ag-CysNPs were acquired by High-resolution transition electron microscopy images and dynamic light scattering. Images showed that Au@AgNPs which had a core size of 28 nm and a shell of 6 nm thickness was modified with 6 nm cysteamine hydrochloride successfully. High coefficient of determination (R 2 ) values of 0.9968 and 0.9875 was calculated for oxamyl and thiacloprid with the limits of detection of 0.031 ppm and 0.023 ppm, respectively. The current novel nanoparticle was easy to prepare and was suitable to serve as a sensitive substrate for SERS detection applications, which could be employed for assessing other accidental contaminants in other food matrices in future studies.
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高影响因子
COLLOID AND POLYMER SCIENCE
·
2020
·Vol. 298
·期 4
·495-504
·
IF 1.536
Zhang Xuechun,Cao Yongbin,Jiang Qin,Zhang Yuanying,Yang Wuli
Cross-linked poly(methyl methacrylate) (PMMA) microspheres have been successfully prepared by using the asymmetric cross-linker allyl methacrylate (AMA) via dispersion polymerization. The influence of the AMA amount and polymerization process on the PMMA particle size and morphology has been studied thoroughly. It was found that micron-sized, cross-linked PMMA particles with narrow size distributions could be obtained by a semi-continuous process with the asymmetric cross-linker AMA. The obtained micron-sized, cross-linked PMMA particles could be further used as a light diffusion agent in a polycarbonate matrix, and their light diffusion properties were significantly enhanced by increasing the gel content in the cross-linked particles. Moreover, the influence of the polymerization process, cross-linker content in PMMA and PMMA content in the polycarbonate matrix on light diffusion was carefully investigated. The results showed that the PMMA particles containing 5.0 wt% AMA, obtained by semi-continuous polymerization, had a higher haze and gel content and exhibited a better light diffusion effect than did the other particles.
We prepared cross-linked PMMA microspheres by dispersion polymerization with asymmetric cross-linker AMA and obtained light diffusers by blending cross-linked PMMA microspheres with matrix PC.
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高影响因子
JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
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2020
·Vol. 58
·期 2
·520-531
·
IF 1.946
Lan Qiuyu,Lin Zhaohui,Dong Hongmin,Wu Dingtao,Lin Derong,Qin Wen,Liu Jiang,Yang Wenyu,Zhang Qing
Influence of lyophilized okara with varying particle sizes (250–380, 150–180, 120–150, and < 75 μm) on the quality of glucono-δ-lactone-induced tofu was investigated. Adding okara significantly ( p < 0.05) improved the yield, water-holding capacity, cooking loss, and nutritional value of the conventional tofu. The gel strength and sensory score of the okara-added tofu (OAT) increased with the decreasing of the particle size of okara, and these quality attributes of the OAT were better than those of the conventional tofu, except for the OAT with 250–380 μm okara. The microstructural profile of the OAT with reduced okara particle size was similar to that of the conventional tofu. Theoretically, the addition of okara mainly impacted the interactions among denatured proteins via disulfide bonding and hydrophobic interactions and the sizes of insoluble solid and oil droplet in soymilk, thereby affecting the formation of the gel network and finally the edible quality of tofu. In conclusion, the addition of okara with appropriate particle sizes can remarkably improve the processing quality and nutritional value of tofu, which is beneficial to the reasonable exploration of okara for the producers of soybean products.
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PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2020
·Vol. 36
·期 6
·1284-1291
·
IF 1.063
Yu Xinyue,Zhong Yao,Sun Yu,Chen Yanwei
Gold nanostars(Au NSs) are asymmetric anisotropic nanomaterials with sharp edge structure. As a promising branched nanomaterial, Au NS has excellent plasmonic absorption and scattering properties. In order to tune the plasmonic photothermal and surface-enhanced Raman scattering(SERS) activity of Au NSs to obtain the desired characteristics, the effects of reagents on the local surface plasmon resonance(LSPR) bands of Au NSs were studied and the morphology and size were regulated. Nanoparticles with different sharp edges were synthesized to make their local plasmon resonance mode tunable in the visible and near-infrared region. The effects of the number and sharpness of different tips under the control of AgNO 3 on the photothermal response of Au NSs and the SERS activity and their mechanism were discussed in detail. The results show that as the length of the branch tip becomes longer and the sharpness increases, the plasmonic photothermal effect of Au NSs is strengthened, and the photothermal conversion efficiency is the highest up to 40% when the length of Au NSs is the longest. Au NSs with high SERS activity are used for the Raman detection substrate. Based on this property, the quantitative detection of the pesticide thiram is achieved.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 25
·11609-11621
·
IF 3.553
Wang Wei,Peng Rui,Liu Jiali,Wang Zhenzhen,Guo Tao,Liang Qisheng,Carrier Andrew J.,Wang Li,Zhang Xu
Herein, we constructed a nano-CuO film on copper foil for the in situ generation of reactive chlorine species (RCS) for the contact killing of bacteria and biofilm suppression and dispersal. Both Staphylococcus aureus and Escherichia coli were susceptible to this treatment . Additionally, we demonstrate the solid nano-CuO interface-based heterogeneous Fenton chemistry rather than leached copper-ion-based homogeneous Fenton chemistry is responsible for RCS generation and bacterial cytotoxicity. This process is modulated by the H 2 O 2 and Cl − concentrations in bacterial growth environment. The potential applications for in situ generation of RCS might be the incorporation of CuO nanoparticles into functional food contact surfaces as well as coating materials for marine biofouling control.
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高影响因子
Chemistry Africa-A Journal of the Tunisian Chemical Society
·
2020
·Vol. 3
·期 3
·727-734
·
IF 0
Wang Yanfang,Guo Ying,Pan Kunming,Lin Xiaoyun,Ni Yongnian
In this paper, an electrochemical sensor based on depositing acid chrome blue K on the surface of glassy carbon electrode was developed for detection of nitrofurazone. The obtained poly-ACBK film was characterised by atomic force microscope. The experimental results indicated that the Poly-ACBK/GCE showed good electrocatalytic activity to the redox reactions of nitrofurazone by differential pulse voltammetry and cyclic voltammetry in Britton-Robinson buffer solution, and the different redox peak currents were observed in different pH ranges (2.0–6.0, 7.0–12.0). Base on these, electrochemical reaction mechanism of nitrofurazone was presented in different pH ranges. Under the optimal conditions, a linear relationship between the reduction peak currents and concentrations for nitrofurazone is figured out in the range of 0.75‒192 μM, with detection limits of 0.25 µM (S/N = 3). This sensor produced satisfactory reproducibility and stability and was successfully applied to monitor of nitrofurazone in real samples (nasal drops).
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CELLULOSE
·
2020
·Vol. 27
·期 12
·6861-6870
·
IF 4.21
Zeng Tong,Ke Xun,Li Lijuan,Cheng Xinlei,Ni Yonghao,Ouyang Xinhua,Zhang Xingye,Chen Lihui,Huang Liulian,Hu Hui-Chao
Abstract This work developed a novel method for the determination of N-methyl morpholine N-oxide (NMMO) in the solution of biorefining, such as lyocell or biomass pretreatment. Copper hydride in situ (CuH) was generated in alkaline solution from sodium borohydride and cupric ion to completely reduce NMMO to N-methyl morpholine (NMM). Finally, the generated volatile NMM was analyzed by headspace gas chromatography. The generation of in situ CuH, complete reduction of NMMO, and the gas–liquid equilibration of NMM can be synchronously completed at 80 °C in 30 min, with a cupric ion concentration of 20 μmol, sodium hydroxide (0.8 mmol), sodium borohydride (3.0 mg), and 1.0 mL 30% ammonium hydroxide in 5.0 mL aqueous solution. The lowest limit of NMMO quantification was 42 mg/L in the present method, with good precision (standard deviation = 5.62%) and accuracy (recoveries from 95.9 to 106%). The present method has high accuracy, sensitivity, and throughput. It should be a useful tool to determine the content of NMMO and allow optimize the cost efficiency. Graphic abstract
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高影响因子
危险品化学品经营许可证（带存储）