INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2013
·
IF 3.548
Wenyu Liu,Haokun Cai,Ping Lu,Qiumei Xu,Yafeng Zhongfu,Jian Dong
Catalyzed sodium borohydride hydrolysis is a highly valuable method to produce clean hydrogen energy for portable applications. This study provides a new and fast route to preparation of reusable hybrid materials composed of nickel-boron based nanoclusters dispersed in nanoporous poly(acrylamide) hydrogels for catalyzed hydrogen production . Palladium was added to the Ni–B catalysts during chemical reduction under the protection of poly(N-vinylpyrrolidone). The resulting nanoclusters immobilized in the hydrogels were essentially alloy particles with uni-modal size distributions and average diameters ranging from ca . 4–8 nm. Pd exerted significant promoting effects on the activities of the Ni–B catalysts. The highest activity was achieved for Pd–Ni–B nanoclusters with a charge ratio of Pd/Ni = 1/20 in moles, which exhibited activity nearly twice that of a Ni–B catalyst and good recyclability for consecutive uses. The hydrogen production rates also increased with the decreasing particle sizes. The activation energy , enthalpy and entropy for the reaction were determined to be 31.10 kJ mol −1 , 28.39 kJ mol −1 and -45.22 J mol −1 K −1 , respectively. The activation energy is lower than that of previously reported polymer-stabilized Co(0), Fe(0), or Ni(0) nanoparticle catalysts.
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Analytical Methods
·
2015
·Vol. 8
·期 5
·1044-1051
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IF 1.821
Xianfu Meng,Yanxia Xu,Jinliang Liu,Lining Sun,Liyi Shi
A novel fluorescent chemosensor containing two rhodamine B moieties per molecule was synthesized and characterized as an “off–on” fluorescent probe for the detection of copper ions (Cu2+). The crystal structure of the chemosensor was confirmed by X-ray analysis and the recognition mechanism of detecting Cu2+ was proposed with absorption and fluorescence characterization. The chemosensor showed high selectivity and sensitivity and good repetition in sensing Cu2+, and the detection limit is as low as 38.00 nM. In addition, the chemosensor displayed low cytotoxicity as revealed by methyl thiazolyl tetrazolium (MTT) assays and was successfully applied to fluorescence test paper and living cell imaging for detecting Cu2+. Therefore, based on its environmental friendliness and good biocompatibility, the results offered the advantages including the detection of Cu2+ in the environment and bioimaging of intracellular Cu2+.
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ANALYST
·
2017
·Vol. 142
·期 16
·2936-2944
·
IF 3.885
Jiamin Gao,Cheng Zhao,Zhuomin Zhang,Gongke Li
Reliable quantification by surface enhanced Raman scattering (SERS) highly depends on the development of a reproducible substrate with excellent anti-interference capability. In this work, an intrinsic internal standard (IS) SERS substrate based on a diblock copolymer, polystyrene-block-poly-4-vinylpyridine (PS-b-P4VP), as a template was developed by a modified block copolymer lithography (BCL) technique of reserving the diblock copolymer template. This substrate generated a stable vibration peak at 1066 cm−1 attributed to poly(4-vinylpyridine) (P4VP) which could be used as an intrinsic IS for precise SERS quantification. A series of characterization results showed that the diblock copolymer template endowed this substrate with homogeneous distribution of Au nanoparticles, excellent stability and reproducibility. A minor relative standard deviation (RSDs) of SERS responses at 1066 cm−1 was measured and calculated to be 4.3% from ten different substrates in the same batch, which suggested good substrate-to-substrate reproducibility of this substrate. Finally, this intrinsic IS substrate was successfully applied for the rapid quantification of a trace banned dye, chrysoidine, in food samples with complicated matrices by SERS. It was proved that chrysoidine could be found and quantified to be 0.50 and 0.41 mg L−1 in a positive dried bean curd stick and chilli powder sample respectively with good recoveries by this substrate coupled with SERS. The development of intrinsic IS substrates would benefit rapid and accurate quantification of trace targets in complex samples coupled with SERS analysis.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2016
·
IF 4.179
Yuan Wang,Yan-Ling Luo,Feng Xu,Ya-Shao Chen,Wei Tang
Ferrocene-containing amphiphilic block copolymers , poly(2-acryloyloxyethyl ferrocenecarboxylate)- block -poly(2-(dimethylamino) ethyl methacrylate) (PAEFc- b -PDMAEMA), were synthesized via sequential ATRP , and self-assembled into globular nanoscaled micelle aggregates. The copolymer micelles exhibited reversible redox on-off switch feature, which was mediated by using H 2 O 2 , KMnO 4 , NaClO and FeCl 3 as a model of oxidants and ascorbic acid as a model of reductants. The micelle nanoparticles were used to load and deliver anticancer drug, 10-hydroxycamptothecine, finding that the encapsulated drug was rapidly delivered by selectively responding to redox environments in cancer cells. MTT assays were performed to uncover cytotoxicity of the developed copolymer micelles and potentiality used for cancer therapy.
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DRUG DELIVERY
·
2016
·
IF 4.843
Chang Li,Yan Shen,Chunmeng Sun,Nihad Cheraga,Jiasheng Tu
To investigate the physicochemical properties, immunosafety and chronic toxicity of monomethoxypoly(ethylene glycol)-b-poly(lactic acid) (mPEG-PLA), a copolymer used as a carrier for paclitaxel (PTX) delivery. The H-Nuclear Magnetic Resonance (H-NMR), dynamic light scattering and fluorescence probe technique were conducted to determine the physicochemical properties of mPEG-PLA copolymer. PTX-loaded polymeric micelles were characterized regarding their particle size, entrapment efficiency (EE), drug loading (DL), in vitro drug release and hemolysis rate. The complement activation in human serum and mast cells degranulation were performed by ELISA and RBL-2H3 cell line in vitro, respectively. The chronic toxicity study was carried out on beagle dogs. The optimized PTX-loaded mPEG-PLA (40/60) micelles showed a particle size of 37 nm and EE of 98.0% with a DL of 17.0% w/w. Transmission electron microscopy (TEM) analyses showed that mPEG-PLA (40/60) micelles have spherical shape with dense core. In vitro release study showed a sustained release for 24 h, and the hemolysis study revealed that mPEG-PLA (40/60) was a safe nanocarrier for intravenous administration. mPEG-PLA (40/60) showed a lower complement activation ability compared to mPEG-PLA (50/50) and Cremophor® EL (Cr EL). Furthermore, the chronic toxicity of PTX-loaded mPEG-PLA (40/60) micelles was significantly lower than those of mPEG-PLA (50/50) and Cr EL.
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PROGRESS IN ORGANIC COATINGS
·
2016
·
IF 2.632
Jiahui Su,Xiaoxuan Liu,Chengjing Xiong,Hong Huang,Yanyan Cui
In this study, we prepared a novel triblock copolymer, PDMS- b -(PMAEBB- co -PDMAEMA) 2 ( tri -PI) bearing side-chain benzophenone (BP) and coinitiator amine, as a macro-photoinitiator via reversible addition-fragmentation chain transfer (RAFT) copolymerization of the polymerizable photoinitiator 2-(methacryloyloxy)ethyl-2-benzoylbenzoate (MAEBB) and the unsaturated coinitiator amine 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a bifunctional polydimethylsiloxane (PDMS) macro-chain transfer agent (macro-CTA). The structure of synthesized copolymer was confirmed by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance ( 1 H NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The effects of the photoinitiator/coinitiator ratio, concentration, and photoinitiator systems on the photopolymerization kinetics of tri(propylene glycol) diacrylate (TPGDA) were investigated by real-time FT-IR. The mobility of the tri -PI chain segments was proven by X-ray photoelectron spectroscopy (XPS), and the surface morphology of TPGDA curing coatings was studied by scanning electron microscopy (SEM). Results showed that tri-PI strongly suppressed the effect of oxygen inhibition on the photopolymerization system. Tri-PI was also used in the curing of UV-curable waterborne polyurethane acrylate (UV-WPUA) resin to determine its versatility.
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RSC Advances
·
2017
·Vol. 7
·期 29
·17873-17881
·
IF 3.108
Piyong Zhang,Ting Song,Tingting Wang,Heping Zeng
A broad spectrum absorption photocatalytic system has been expected for a long time, especially for catalysts where the absorption mainly concentrates on the ultraviolet region, like TiO2. Here, dye sensitization was used to realize this expectation for TiO2. Anatase TiO2 was prepared by a hydrothermal method and then modified with Cu nanoparticles (NPs) by chemical reduction reaction. The highest H2 production rate was 3.33 mmol g−1 h−1 for Cu(3%)–TiO2 (content of Cu NPs was 3 wt%) and for pure TiO2 was only 0.356 mmol g−1 h−1. Next, the Cu(3%)–TiO2 photocatalyst was sensitized with various amounts of Erythrosin B (ErB) and the highest H2 production rate was 13.4 mmol g−1 h−1 with 3 mg of ErB in the photoreaction system. Under monochromatic light irradiation (500, 550, 600 and 650 nm), no photocatalytic activity was detected for Cu(3%)–TiO2 and some photocatalytic activities were obtained for sensitized Cu(3%)–TiO2, indicating that ErB sensitization can extend the visible light harvesting ability efficiently. Through photoelectrochemical analysis, electron–hole separation and transfer processes were promoted significantly by modification with Cu NPs and then sensitization by ErB. A possible ErB sensitization mechanism is proposed between ErB and Cu–TiO2 for the improvement of the photocatalytic activity.
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Analytical Methods
·
2016
·Vol. 8
·期 45
·8042-8048
·
IF 1.915
Zhen Cheng,Fang Zhang,Xianping Chen,Lingling Du,Chutong Gao,Kejun Tan
A simple, highly sensitive and selective assay method has been developed for the determination of perfluorooctane sulfonate (PFOS), a kind of emerging persistent organic pollutant, which is bio-accumulative, resistant to degradation and toxic. It was found that PFOS can form complexes with protonated Janus Green B (JGB) through electrostatic interaction in pH 5.8 citric acid–sodium citrate (CA–NaCA) buffer medium resulting in a remarkable enhancement of the resonance light scattering (RLS) intensity of the system. The study shows that the maximum scattering wavelength is located at 319.0 nm and the enhanced RLS intensities are in proportion to the concentration of PFOS in the range of 0.05–9.0 μmol L−1 (R2 = 0.9958), with a detection limit of 5.6 nmol L−1 (3σ). Under the same experimental conditions, various perfluorinated compounds (PFPrA, PFBA, PFPeA, PFHeA, PFHpA, PFOA, PFNA, and PFBS) and JGB interactions were studied and the scattering signal changes very little. Based on the above discussion, a simple, highly sensitive and selective resonance light scattering analysis method was established for the detection of PFOS. In this work, the optimum reaction conditions were investigated. The reaction mechanism between JGB and PFOS was also studied by the absorption spectrum, scanning electron microscopy (SEM), the combination ratio and so on. This method is successfully applied to the selective detection of PFOS in environmental water samples with RSD ≤2.7%.
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CHINESE JOURNAL OF POLYMER SCIENCE
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2016
·Vol. 34
·期 9
·1079-1090
·
IF 1.811
Liu Wei,Zhang Hai-shan,Ji Xiang-ling
The hybrid structures of polystyrene- b -poly(ethylene oxide) (PS- b -PEO) block copolymer and inorganic nanoparticles with good stability and biocompatibility have potential applications in drug delivery and bioimaging. Spherical co-assemblies of PS 120 - b -PEO 318 and oleylamine-capped CdS quantum dots (QDs) are produced successfully in this work by adding water to a mixed common solvent, such as N , N -dimethylmethanamide (DMF)/chloroform, DMF/tetrahydrofuran (THF), or DMF/toluene. The energy dispersive X-ray (EDX) spectrum indicates that QDs are located at the interface between the core and shell of the spherical co-assemblies. The co-assembly process during water addition is traced by transmission electron microscopy (TEM) and turbidity measurement. Spherical co-assemblies are formed through budding from bilayers of the block copolymer and QDs. The morphology of the co-assemblies is related to the miscibility of the QD-dispersing solvents with water and the morphology changes from a spherical to a vesicle-like structure with DMF/toluene. Increasing THF content in the mixed solvent causes morphological transitions from spherical co-assemblies to multi-branched cylinders and micelles where QDs are located in the central core. Increasing chloroform content yields vesicle-like structures with protruding rods on the surface. The mechanism of the morphological transitions is also discussed in detail.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Liang Zhang,Rouying Cai,Yao Wang,Chenfang Miao,Menghan Zhang,Chen Zheng,Jianzhong Zhang,Zhengjun Huang,Shaohuang Weng
Low molecular weight heparin (LMWH) plays an important role in the prevention and treatment of venous thromboembolism. Sensitive and facile monitoring of LMWH is of great significance for clinical special populations. Herein, using enoxaparin (Enox) as the typical representative of LMWH, a convenient and accurate fluorescence method was developed for Enox detection using carbon dots with antioxidant activity (A-CDs) as probe and polymyxin B (PMB) as medium agent. Compared with the simple Enox or PMB, the formed complex of PMB and Enox (PMB-Enox) based on the electrostatic interaction exhibited a new absorbance peak at 340 nm. Correspondingly, the absorbance of PMB-Enox overlapped with the exciting wavelength of A-CDs at 350 nm and effectively quenched the fluorescence of A-CDs through inner filter effect (IFE). The decreased fluorescence intensities of A-CDs were controlled by the increased Enox with constant PMB. A linear fitting equation was obtained between the quenching efficiency (QE) of A-CDs and variable contents of Enox in the range of 0.8–25.0 μg/mL. And the limit of detection (LOD) was 0.64 μg/mL. The recovery of the injection of Enox in human plasma was acceptable with rational relative standard deviations. Moreover, this fluorescence sensing strategy possesses the prospect of developing reliable pharmaceutical analysis method based on the consideration of drug’s property and pharmacological action and the controllable design of fluorescence probes.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Haoning Yang,Yu Mu,Dan Zheng,Tess Puopolo,Lejie Zhang,Zhuo Zhang,Sai Gao,Navindra P. Seeram,Hang Ma,Xueshi Huang,Liya Li
Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity ; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein , a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB- Z -N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction , hydrogen bond , and hydrophobic forces. The GUB- Z -N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.
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JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Zezhuang Cao,Jinlan Xu,Wanchun Tan,Huan Tang,Huan Li,Yikai Li
Sulfate radical advanced technologies (SR-AOPs) has been increasingly applied for chemical oxidation of toxic wastewater treatment, while the sluggish kinetics of Fe(III)/Fe(II) cycling remains a serious problem in its application. In this study, a novel co-catalyst of humic acid-Fe incorporated biochar (HA-Fe@BC) was successfully synthesized that can greatly accelerate the Fe(II) regeneration. More than 95 % organic pollutants could be degraded in HA-Fe@BC/peroxydisulfate (PDS) system, especially for the model pollutant Rhodamine B (an almost 8.0-fold kinetic increase). More excitingly, the superior catalytic activity of HA-Fe@BC for PDS activation may be attributed to the ample surface C-OH and C=O groups, accelerated electron transfer and formed surface HA-Fe@BC-PDS* complex with efficient oxidation activity. Radical capture, quenching experiments and electrochemical analysis confirmed that the HA-Fe@BC/PDS was caused by radicals (SO 4 •- + O 2 •- +•OH = 68.13 %) and non-radical (surface-mediated electron transfer and 1 O 2 = 26.33 %) pathways. Besides, it also exhibited anti-interference performance against anions and organic matter (eg. Cl - , Br - , NO 3 – , and PO 4 3- ). Furthermore, the degradation pathways were proposed by LC-MS assisted with density functional theory (DFT) calculations, and the mechanism was proposed comprehensively. This work demonstrates the PDS activation by HA-Fe@BC through free radical and non-free radical pathways, which provides insight into application of biochar-based materials for wastewater treatment.
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