RENEWABLE ENERGY
·
2023
·
IF 8.7
Qiaofei Zhang,Wenlei Xie,Jiangbo Li,Lihong Guo
For the purpose of fabricating an efficient solid acid catalyst for biodiesel production from low-grade acidic oils, bimetallic silica mesoporous composites with different Zr/Al molar ratios were initially synthesized via a facile one-step hydrothermal method , and then sulfated with sulfuric acid at different concentrations to get a series of sulfated Zr x -Al y -KIT-6 catalysts (denoted as SZA-K, where x/y represents the molar ratio of Zr to Al). The sulfated bimetallic solid catalysts were fully characterized by using XRD , FT-IR, TEM, SEM, EDS, NH 3 -TPD, and nitrogen porosimetry measurements. Results showed that the remarkable amount of acidic sites in the catalysts was derived from the Zr and Al incorporation and further sulfation, and specifically, the Zr 4+ and Al 3+ could afford abundant weak acid sites while the inductive effect of SO 4 2− species greatly influences the acidic strength of this solid catalyst. In combination with the enhancement in mass transfer resulting from the inherent interconnected mesoporous structure, the SZA-K catalyst could facilitate the transesterification reaction to take place efficiently. The sulfated Zr 5 –Al 1 -KIT-6 catalyst (Zr/Al molar ratio of 5/1, treated using 0.75 mol/L sulfuric acid for 12 h) exhibited enhanced acid strength with larger number of acidic sites (7.81 mmol/g), resulting in a high catalytic performance to the oil transesterification reaction. An oil conversion of 96.3% was attained for the transesterification reaction performed at 120 °C for 7 h by using a methanol/oil molar ratio of 20:1 and a catalyst dosage of 6 wt%. Further, this solid catalyst exhibited better acid and water-resistance capacity with above 80% of oil conversion even with 10% of free fatty acid (FFA) and 2% of moisture present in the low-grade acidic oils. Meanwhile, the good reusability was shown for this catalyst with 80.1% conversion even after reusing for three cycles. The good stability of the solid catalyst was resulted from the strong interactions between the acidic species and the bimetallic composite support.
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MICROCHIMICA ACTA
·
2023
·Vol. 190
·期 8
·1-8
·
IF 5.7
Li Dawei,Ren Yaofei,Chen Ruoyang,Wu Haoyu,Zhuang Shaoyong,Zhang Ming
A spiral interdigitated MXene–assisted field effect transistor (SiMFETs) was proposed for determination of IL-6 in patients with kidney transplantation infection. Our SiMFETs demonstrated enhanced IL-6 detection range of 10 fg/mL–100 ng/mL due to the combination of optimized transistor’s structure and semiconducting nanocomposites. Specifically, on one hand, MXene-based field effect transistor drastically amplified the amperometric signal for determination of IL-6; on the other hand, the multiple spiral structure of interdigitated drain-source architecture improved the transconductance of FET biosensor. The developed SiMFETs biosensor demonstrated satisfactory stability for 2 months, and favorable reproducibility and selectivity against other biochemical interferences. The SiMFETs biosensor exhibited acceptable correlation coefficient ( R 2 =0.955) in quantification of clinical biosamples. The sensor successfully distinguished the infected patients from the health control with enhanced AUC of 0.939 (sensitivity of 91.7%, specificity of 86.7%). Those merits introduced here may pave an alternative strategy for transistor-based biosensor in point-of-care clinic applications. Graphical Abstract
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POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Yanlu Sun,Zhengqi Wang,Dequn Wu,Xueli Wang,Jianyong Yu,Ruchao Yuan,Faxue Li
The absence of inherently flame-retardant polyamide 6 (FR-PA6) with enhanced anti-dripping and melt spinnability has significantly limited its further application in textiles. In this work, a binary reactive flame retardant composed of commercial 9,10-dihydro-10-[2,3- di ( hydroxycarbonyl ) propyl ]-10-phosphaphenanthrene-10-oxide (DDP) and synthesized polydiphenylsiloxane (PDPS) was employed to fabricate FR-PA6 through a facile synthetic route. The prepared FR-PA6 containing 5 wt% DDP and 5 wt% PDPS (FR-PA6-5-5) exhibited a UL94 V-0 rating with no melt-droplets during combustion, a 31.0% reduction in heat release rate and a 18.8% decrease in total heat release compared to pure PA6 in cone calorimetric tests. The improved fire safety of FR-PA6-5-5 was contributed to the gas-phase quenching and dilution effect and the condensed-phase barrier effect, which was enhanced by the synergistic charring effect achieved through the formation of P(= O )-O-Si. Additionally, FR-PA6-5-5 exhibited excellent melt spinnability as demonstrated by the successful preparation of filaments with a tensile strength of approximately 2.27 cN/dtex.
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Polymers
·
2023
·Vol. 15
·期 8
·1887
·
IF 5
Hui Fang,Guifeng Li,Kai Wang,Fangjuan Wu
This study investigates the effect of adding stearic acid (SA) on the thermal conductivity of polyamide 6 (PA6)/boron nitride (BN) composites. The composites were prepared by melt blending, and the mass ratio of PA6 to BN was fixed at 50:50. The results show that when the SA content is less than 5 phr, some SA is distributed at the interface between BN sheets and PA6, which improves the interface adhesion of the two phases. This improves the force transfer from the matrix to BN sheets, promoting the exfoliation and dispersion of BN sheets. However, when the SA content was greater than 5 phr, SA tends to aggregate and form separate domains rather than being dispersed at the interface between PA6 and BN. Additionally, the well-dispersed BN sheets act as a heterogeneous nucleation agent, significantly improving the crystallinity of the PA6 matrix. The combination of good interface adhesion, excellent orientation, and high crystallinity of the matrix leads to efficient phonon propagation, resulting in a significant improvement in the thermal conductivity of the composite. The highest thermal conductivity of the composite is achieved when the SA content is 5 phr, which is 3.59 W m−1K−1. The utilization of a composite material consisting of 5phr SA as the thermal interface material displays the highest thermal conductivity, and the composite also demonstrates satisfactory mechanical properties. This study proposes a promising strategy for the preparation of composites with high thermal conductivity.Keywords:thermal conductivity;polyamide;boron nitride;stearic acid
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TALANTA
·
2019
·
IF 4.916
Yujuan Cao,Song Wang,Wei Wu,Hong Peng,Ying Yu,Debin Zhu
An efficient fluorescent probe based on cucurbit[6]uril modified CdTe quantum dots (CB[6]@QDs) was prepared. This novel probe showed significant and selective fluorescence quenching and complexation capacity to p-nitroaniline, its interaction mechanism was studied by both experimental and theoretical methods. Furthermore, a fluorescent method was developed for the determination of p-nitroaniline in different environmental samples. The fluorescence intensity of CB[6]@QDs showed a good linearity response to p-nitroaniline in the concentration range of 2.5 × 10 −7 -3.0 × 10 −6 mol/L with a correlation coefficient (R 2 ) of 0.9976, the limit of detection (LOD) was 6 × 10 −8 mol/L and the limit of quantification (LOQ) was 2 × 10 −7 mol/L. Moreover, about 0–1.5 × 10 −6 mol/L p-nitroaniline were determined in environmental samples, the recoveries were in the range of 88–109% with the relative standard deviations (n = 3) of 1.2–4.5%. Compared with previous fluorescent methods, the present method shortened and simplified the sample pretreatment as well as enhanced the sensitivity and selectivity of analytical method. No further sample pretreatment procedure is needed and the LOD of present method was one order of magnitude less than previous fluorescent methods, showed it is a simple, selective and sensitive method.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2019
·Vol. 2019
·期 9
·1212-1219
·
IF 2.578
Xin Yu Deng,Kai Chen,Ming-Dong Chen,Li Bin Lü,Zhu Tao
Graphical The probe responds to Cs + cations in alkali metal systems, Ba 2+ and Sr 2+ cations in alkaline earth metal systems; Eu 3+ , Tm 3+ , and Yb 3+ cations in lanthanide systems, and Cr 3+ , Fe 3+ , and Hg 2+ cations in systems containing transition and other metal cations, by obvious fluorescence quenching. Based on the study of a known host–guest inclusion complex comprising cucurbit[6]uril (Q[6]) and a hemicyanine dye, trans -4-[4-(dimethylamino)styryl]-1-pyridinium iodide ( t -DSMI), a water-soluble symmetric tetramethylcucurbit[6]uril (TMeQ[6]), was selected to construct a t -DSMI-based probe to test the response to various metal cations in neutral water. The experimental results revealed that the probe responded to Cs + cations in alkali metal systems, Ba 2+ and Sr 2+ cations in alkaline earth metal systems, Eu 3+ , Tm 3+ and Yb 3+ cations in lanthanide systems, and Cr 3+ , Fe 3+ and Hg 2+ cations in systems containing transition and other metal cations, via obvious fluorescence quenching.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 44
·6644-6650
·
IF 3.474
Ying-Jie Jia,Yi-Gang Chen,Xiao-Ni Yao,Xian-Ming Zhang
A series of alkali earth cadmium selenites including MgCd3(SeO3)4 (1), Ca0.7Cd2.3(SeO3)3 (2), SrCd(SeO3)2 (3) and BaCd(SeO3)2 (4) are synthesized by hydrothermal reaction and studied in detail by single crystal and powdered X-ray diffractions, thermal analyses, IR and UV spectral measurements and dipole moment calculation. 1 features a 3D anionic [Cd3(SeO3)4]2− framework constructed from isolated SeO3 trigonal pyramids and 2D [Cd3O12]n layers, in which the [Cd3O12]n layer is composed of edge-shared [Cd2O10]16− dimers and butterfly-like [Cd4O20]32− tetramers. 2 shows a smooth 2D [Cd2(SeO3)3]n layer composed of unique [Cd(SeO3)]n double chains. 3 exhibits a wavelike 2D [Cd(SeO3)2]n layer constructed from corner-shared CdO6 octahedra and isolated SeO3 trigonal pyramids. 4 displays a windmill-like 1D [Cd(SeO3)2]n chain built from zigzag [CdO4]n chain motifs and isolated SeO3 trigonal pyramids. The alkali earth oxide motifs demonstrate interesting and regular changes from isolated MgO6 octahedra, CaO7 polyhedra, and SrO9 tri-capped trigonal prisms based on a ribbon chain to BaO12 icosahedra based on a brucite-like layer, and meanwhile the SeO3 groups are observed from variable tetradentate to hexadentate coordination modes. These flexible motifs reveal that cadmium selenites are strongly affected by the size of the alkali earth cations, providing a feasible approach to modulating their space structure via selection of template cation.
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TEXTILE RESEARCH JOURNAL
·
2017
·
IF 1.443
Liu Liu,Yeping Xiang,Ruiyun Zhang,Bei Li,Jianyong Yu
In this study, different dosages of NaClO were used in the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-laccase degumming system to remove non-cellulosic materials, and their effects on the structure of hemp fibers were analyzed and discussed. A scanning electron microscope was used to depict the surface morphology of fibers after oxidative degumming under various dosages of NaClO in the TEMPO-laccase degumming system. Chemical composition analysis was used to determine the content changes of the different components. Meanwhile, the content of functional groups was also discussed. Fourier transfer infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X-ray diffraction were employed to evaluate the microstructural changes of degummed hemp fibers obtained from the degumming processes with different dosages of NaClO. The results showed that after the TEMPO-laccase system degumming process with a NaClO dosage of 16%, the cleanest and smoothest surface of degummed fibers could be observed and the non-cellulosic materials were significantly removed without any crystalline transformation or damage in the cellulose. This research could shed light on determining favorable operation parameters for hemp oxidation degumming and increasing the degumming efficiency, as well as in the oxidation control and quality assurance of hemp fibers for textile downstream end uses.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2012
·Vol. 26
·期 9
·478-482
·
IF 2.061
Wenyi Chu,Xinmin Li,Yanjun Hou,Hua Wang,Hongyu Li,Xiaobin Yuan,Zhizhong Sun
Pd/C-catalyzed Suzuki–Miyaura cross-coupling between aryl bromides and arylboronic acids in 50% methanol aqueous solution proceeded smoothly in the presence of 18-crown-6. Various aryl bromides bearing electron-withdrawing groups and electron-donating groups coupled with arylboronic acid in high yields. In addition, the catalyst could be recycled five times without loss of activity. Copyright © 2012 John Wiley & Sons, Ltd.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2012
·
IF 3.456
Xuzhu Zhang,Fang Du,Jin Huang,Wei Lu,Shiyuan Liu,Jiahui Yu
This research is aimed to develop a biodegradable micelle delivery system with sheddable poly (ethylene glycol) shell to achieve the reduction-triggered intracellular sustained release of 6-mercaptopurine (6-MP) and decreased toxicity. Firstly, the amino-disulfide linked poly (ethylene glycol) monomethyl ether (mPEG-SS-NH 2 ) was synthesized by the amidation reaction between cystamine and active ester of mPEG and p-nitrophenyl chloroformate (p-NPC) (mPEG–NPC). And then, the five-member rings in poly ( l -succinimide) (PSI) were successively opened by mPEG-SS-NH 2 and 2-(pyridyldithio)-ethylamine (PDA) to produce the graft copolymer of mPEG-SS-NH- graft -PAsp-PDA. To avoid the drug initial burst, 6-MP was covalently conjugated with mPEG-SS-NH- graft -PAsp-PDA by thoil–disulfide exchange reaction to give the resultant product mPEG-SS-NH- graft -PAsp-MP. The product was found to form spherical micelles in aqueous media because of its amphiphilic nature with average particle size of 160 nm measured by dynamic light scattering (DLS). It was found that the mPEG-SS-NH- graft -PAsp-MP micelles, though stable in phosphate buffer solution (PBS), were prone to aggregation in the presence of dithiothreitol (DTT). The in vitro drug release studies revealed the release of 6-MP were distinct from the conventional micelles whose drugs loaded by physical encapsulation. Sustained release profile of 6-MP over 85 h was found in the presence of DTT (40 mM) simulating the intracellular condition while minimal drug release was observed within 24 h at the level of DTT corresponding to extracellular environment. Remarkably, the cell viability results showed there was essential decrease of cytotoxicity to HL-60 cell line compared to free 6-MP.
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ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Jinxia Zhang,Dan Liu,Binghui Liu,Juan Xiang
The assessment of major depressive disorder (MDD) treatment efficacy typically relies on clinician-rated scales of depressive symptoms with a notable absence of predictive biomarkers. In this study, a concentration ratio of serum brain-derived neurotrophic factor (BDNF) to interleukin-6 (IL-6) was identified as a promising predictive biomarker. To overcome the significant disparity in blood levels between BDNF (ng·mL–1 range) and IL-6 (pg·mL–1 range), a dual-pathway signal amplification method involving small carbon dots (Fe-CDs and Pb-CDs) was employed. Fe-CDs exhibited a nanozyme-like behavior, effectively enhancing the signal through solution reactions, rendering it ideal for IL-6 detection at low concentrations. Meanwhile, Pb-CDs, laden with numerous signal molecules, amplified signals via the surface pathway and were suitable for BDNF detection. This dual signal output approach met the distinct sensitivity needs for quantifying IL-6 and BDNF, achieving detection limits of 0.1 pg·mL–1 and 0.02 ng·mL–1, respectively. Analysis of clinical samples showed that the concentration ratio of BDNF to IL-6 not only effectively differentiates MDD patients from healthy controls but also strongly correlates with individual treatment responses, affirming its value as a biomarker for MDD diagnosis and treatment efficacy evaluation.
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COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Yanlu Sun,Xilin Pei,Zhengqi Wang,Dequn Wu,Xueli Wang,Jianyong Yu,Ruchao Yuan,Faxue Li
In the pursuit of enhancing the fire safety of polyamide 6 (PA6), the addition of flame retardants generally leads to hydrogen bond dissociation, which results in detrimental effects on the mechanical properties of PA6 composites and impedes processing and application in the textile field. In this study, a macromolecular flame retardant, PPB, designed with hydrogen bond donor-acceptor spacing aligned with PA6, was synthesized to increase the number of hydrogen bonds. The addition of 10 wt% PPB to the PA6 matrix (PA6/PPB10) endowed the composite with the limiting oxygen index (LOI) increased to 31.6 % and V-0 rating in the vertical burning (UL-94) test. PA6/PPB10 also exhibited significant enhancement in tensile strength by 12.6 % compared to pure PA6 and demonstrated a superior ultraviolet protection factor (UPF) value of 573, greatly exceeding the value of 3 for PA6. The quenching effect, diluting effect in the gas phase, and hydrogen bond interactions between PPB and PA6 backbones imparted PA6/PPB composites with satisfactory flame retardancy and mechanical properties. As a representative example, PA6/PPB10 was melt-spun into filaments with a pleasing tenacity of 3.6 cN/dtex and self-extinguishing capability within 5 s after ignition, confirming the sustained comprehensive properties after spinning and drawing into filaments.
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