ENERGY & FUELS
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2019
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IF 3.021
Hao Ling,Sen Liu,Tianyu Wang,Hongxia Gao,Zhiwu Liang
To get a more accurate mass transfer coefficient model of CO2 into aqueous monoethanolamine (MEA)/N,N-dimethylethanolamine (DMEA) solution in a packed column, the Henry’s law constant, equilibrium CO2 solubility, volumetric overall mass transfer coefficient (KGav), overall gas-phase mass transfer coefficient (KG), and effective gas–liquid interfacial area (av) were comprehensively studied. The Henry’s law constant was obtained using a jacketed stirred glass reactor, and the equilibrium CO2 solubility was investigated using a bubbling absorption reactor. Additionally, the mass transfer performance was measured and evaluated experimentally in a packed column with DX-Type structured packing in terms of KGav, KG, and av. These experiments were conducted under the MEA/DMEA concentration of 6 kmol·m–3 with ratio of 5:1. The dynamic changes of solubility, species concentration, and absorption heat of solution were analyzed under different CO2 loadings. The experimental results showed that the relationship of successive absorption without synergistic effect from the perspective of equilibrium state for the MEA/DMEA solution and the blended MEA/DMEA solution can reduce the CO2 absorption heat compared to that of MEA solution. Furthermore, a predicted model of KGav, which should be suitable for different solution systems with DX-Type structured packings in a packed column, was also proposed and developed based on the KG model and av model in this work.
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BIOSENSORS & BIOELECTRONICS
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2017
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IF 7.78
Yan Li,Junlin He,Jun Chen,Yazhen Niu,Yilin Zhao,Yuchan Zhang,Chao Yu
In this study, a dual-type responsive electrochemical immunosensor was developed for the quantitative detection of proprotein convertase subtilisin/kexin type 9 (PCSK9), a potential biomarker of cardiovascular disease in serum. N-doped graphene nanoribbons (N-GNRs) with good conductivity were used as the sensing matrix modifying the glassy carbon electrode. Palladium platinum alloy (PdPt) nanoparticles with high catalytic performance toward the reduction of hydrogen peroxide (H 2 O 2 ) were reduced onto amino-functionalized fullerene (n-C 60 -PdPt) and significantly amplified the electrochemical signal recorded by the amperometric i-t curve. Furthermore, staphylococcus protein A (SPA) with antibody orientation function was introduced to improve the immunoreaction efficiency. Accordingly, a label-free immunosensor was fabricated based on n-C 60 -PdPt/N-GNRs for the quick detection of PCSK9. Meanwhile, to realize ultrasensitive detection of PCSK9, Pt-poly (methylene blue) (Pt-PMB) nanocomposites synthesized by a one-pot method for the first time were used as a novel signal label, which exhibited uniform morphology as well as good conductivity and produced an electrochemical signal recorded by differential pulse voltammetry (DPV). Herein, a novel sandwich-type immunosensor was designed using n-C 60 -PdPt/N-GNRs as the sensing matrix and Pt-PMB as the signal label for sensitive detection of PCSK9. Under optimal conditions, the label-free immunosensor showed a linear range of 10 pg mL −1 to 100 ng mL −1 with a detection limit of 3.33 pg mL −1 (S/N=3), and the sandwich-type immunosensor exhibited a linear range of 100 fg mL −1 to 100 ng mL −1 with a detection limit of 0.033 pg mL −1 (S/N=3) for PCSK9 detection, indicating its potential application in clinical bioassay analysis.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2017
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IF 3.154
Lili Zhang,Hailong Lu,Juan Yu,Zhiguo Wang,Yimin Fan,Xiaofan Zhou
Lignocelluloses (LCs) with various amounts of lignin (even as high as 18.4%) were successfully dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO/H2O) solution with stirring at 85 °C within 5 h. For the developmental dissolution methods of LCs with a high lignin content in NMMO/H2O solution, the following two pretreatment steps of LCs were necessary: (1) glycerol swelling and (2) mechanical extrusion. The mechanical extrusion pretreatment under glycerol swelling dissociated the fiber bundles of LCs to thinner fibers and, thus, enhanced the accessibility and solubility of the LCs in NMMO/H2O. The crystal structure of the pretreated LCs had no significant transformation during pretreatment, while the diameters of the fiber bundles were reduced from 50–60 to 10–12 μm, as investigated by X-ray diffraction and scanning electron microscopy. After the dissolution–regeneration process of LCs, the fiber bundles of the LCs disappeared and the crystal type of cellulose in the LCs was transformed from cellulose I to cellulose II, which indicated the complete dissolution of LCs.
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LANGMUIR
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2016
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IF 3.993
Ge Wang,Peiyi Wu
In this paper, one LCST-type thermoresponsive poly(ionic liquid) (PIL), poly(tetrabutylphosphonium styrenesulfonate) (P[P4,4,4,4][SS]), was introduced to poly(N-isopropylacrylamide) (PNIPAM) by two different ways, mixing and copolymerization. Interestingly, they show distinct thermoresponsive phase transition behaviors, evidenced by temperature-variable 1H nuclear magnetic resonance and Fourier transform infrared in combination with the perturbation correlation moving window (PCMW) technique. The PNIPAM/P[P4,4,4,4][SS] mixture exhibits a sharp and drastic phase transition, similar to that of pure PNIPAM. In the statistical copolymer, PNIPAM-co-P[P4,4,4,4][SS], the thermosensitivity of P[P4,4,4,4][SS] is largely suppressed, resulting in a linear, mild, and incomplete phase transition, which has never been reported before. This abnormal phenomenon is shown to arise from the outstanding hydration ability of P[P4,4,4,4][SS]. Our findings should be conducive to improving our understanding of the interaction between LCST-type polymers with distinct structures and provide a new perspective for preparing thermoresponsive materials with linear phase transition behavior.
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POLYMER DEGRADATION AND STABILITY
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2014
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IF 2.633
Si Chen,Xiaopeng Xu,Jiahuan Zhang,Wei Tang,Yingjun Qu,Xu Wang
A series of novel ureido organic stabilizers for poly(vinyl chloride) (PVC) with different length of alkyl chains, including N,N' -bis(phenylcarbamoyl)ethylenediamine (NA2), N,N' -bis(phenylcarbamoyl)butylenediamine (NA4) and N,N' -bis(phenylcar- bamoyl)hexamethylenediamine (NA6) were designed and synthesized, which have greater stabilizing efficiency compared with Ca/Zn stabilizers and phenylurea at the same concentration in PVC mixtures. The results of Congo red test, discoloration test, thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectra showed that the ureido moieties of NAn ( n = 2, 4, 6) have stronger ability to replace the labile chlorine atoms in PVC chains, but weaker ability to absorb hydrogen chloride (HCl) than those in phenylurea . On the other hand, longer alkyl chains in the synthesized organic stabilizers had positive effect in stabilizing efficiency for PVC, which was proved by the results that NA6 was the most efficient stabilizer among the present study, followed by NA4 and NA2. Furthermore, mixing the model compound NA6 with zinc stearate in different mass ratios led to a true synergistic effect, the “zinc burning” of PVC products was remarkably postponed.
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ENVIRONMENTAL RESEARCH
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2024
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IF 7.7
Yang Wang,Xiaoqing He,Peng Gao,Li Feng,Liqiu Zhang
Limited utilization of photogenerated charge carriers in titanium dioxide under visible light have hinder its application development. To address this challenge, a novel N-doped carbon quantum dots (N-CQDs) and oxygen vacancies (OVs) synergistically decorated on TiO 2 (P25) was synthesized through a facile one-step hydrothermal method. Under visible light irradiation, the first order reaction rate constants of formaldehyde (HCHO) photocatalytic oxidation by OVs-TiO 2 and N-CQDs/OVs-TiO 2 was significantly higher than that of pristine P25, with 10.1 and 16.7 folds increase, respectively. Characterization results confirmed the generation of OVs on the surface of N-CQDs/TiO 2 composite. The optical and electrochemical experiments suggested the electron capture center effect of OVs and the properties of N-CQDs in unique up-converted photoluminescence , efficient charge separation, as well as significant adsorption in visible light region. In addition, the work function also clarified that photoelectrons could transfer from N-CQDs to OVs-TiO 2 . Furthermore, different relative humidity and electron paramagnetic resonance (EPR) experiments demonstrated that the hydroxyl radical (•OH) was the dominant reactive radical in HCHO photodegradation . The •O 2 − could also enhance the photodegradation efficiency of HCHO. This work provides an in-depth understanding on the complementary roles of N-CQDs and OVs and is helpful for designing metallic oxide photocatalysts for volatile organic compounds removal.
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JOURNAL OF MOLECULAR LIQUIDS
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2024
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IF 5.3
Fan Yang,Tianzhao Wu,Tinghe Song,Qinqin Zhang,Zhigang Zhang
During the preparation of n-propyl acetate (NPAC), an azeotropic mixture of NPAC and n-propanol (NPA) will form inevitably, which is difficult to separate by ordinary distillation. In this work, COSMO-RS model was applied to screen appropriate ionic liquids (ILs) to separate the binary azeotrope of NPAC - NPA. 1-decyl-3-methylimidazolium acetate ([DMIM][Ac]), 1-octyl-3-methylimidazolium acetate ([OMIM][Ac]), and 1-hexyl-3-methylimidazolium acetate ([HMIM][Ac]) were selected as entrainers based on solvent capacity and selectivity. The vapor–liquid equilibrium (VLE) data of the binary system (NPA - NPAC) and the ternary system (NPA - NPAC - IL) were measured at atmospheric pressure. The thermodynamic consistency of VLE data was verified by van Ness test and Wisniak's L-W test. The NRTL (non-random two liquids) model was used to correlate the VLE experimental data and obtained good applicability. The experimental results demonstrated that all three ionic liquids can improve the relative volatility of NPAC to NPA, and the separation effect is more obvious with the increase of ionic liquid content. The separation performance order of three ionic liquids follows: [HMIM][Ac] > [OMIM][Ac] > [DMIM][Ac]. Finally, ESP analysis, mutual penetration analysis, and IGMH analysis plus QTAIM topological analysis were used to explore the mechanism of separation. The analysis results indicate that the interaction between ionic liquids and NPA is stronger than that between ionic liquids and NPAC. In addition, the stronger interaction between [DMIM][Ac] and NPA is due to their strong hydrogen bond (HB) interactions.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2024
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IF 2
Feihu Li,Yidong Gu,Yanli Sun,Dahaun Liu,Qunsheng Li
In the esterification reaction of n-propanol and acetic acid to produce n-propyl acetate, the presence of a mixture of n-propanol and n-propyl acetate is inevitable. However, the system of n-propanol and n-propyl acetate has an azeotropic point, which makes it impossible for conventional distillation to separate the two substances completely. Therefore, 1-ethyl-3-methylimidazolium acetate ([EMIM][OAC]) and 1-hexyl-3-methylimidazolium acetate ([HMIM][OAC]) were selected as entrainers to conduct the vapor–liquid equilibrium experiment of n-propanol + n-propyl acetate + [EMIM][OAC] and n-propanol + n-propyl acetate + [HMIM][OAC] at atmospheric pressure in this study. The experimental data were regressed by the NRTL model and UNIFAC-Lei model. NRTL model was in better agreement with the experimental data. The results showed that both [EMIM][OAC] and [HMIM][OAC] could separate the n-propanol + n-propyl acetate system, and [EMIM][OAC] showed the enormous separation potential of ionic liquids based on [OAC]− as anions for the azeotropic system.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2025
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IF 3.8
Xie Baogang,Zhan Dujuan,Wu Le,Wang Lele,Lei Yongrong,Liu Meng,Liu Xiaodan,Li Suping
Congenital heart disease (CHD) poses significant clinical challenges due to limitations in early prenatal diagnosis. This study aimed to identify serum metabolic biomarkers for CHD using a combined metabolomics approach. Serum samples from 55 pregnant women carrying fetuses with confirmed CHD (CHDP group) and 49 healthy controls (ZCP group) were analyzed via non-targeted 1 HNMR metabolomics, revealing distinct metabolic profiles. Six choline pathway metabolites were further quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Among these, N,N-dimethylglycine (DMG) exhibited the most significant reduction in the CHDP group (1.07 ± 0.03 vs. 1.55 ± 0.04 µg/mL, p < 0.001), with an area under the ROC curve (AUROC) of 0.883 in the discovery cohort. Validation in an independent cohort (58 CHDP vs. 62 ZCP) confirmed DMG’s diagnostic potential (AUROC = 0.818). While betaine-homocysteine methyltransferase 2 (BHMT2) activity showed no intergroup differences, DMG’s consistent performance highlights its utility as a non-invasive biomarker. This study underscores the clinical value of metabonomics in prenatal CHD screening and establishes DMG as a promising diagnostic marker, potentially improving early detection and perinatal management. Graphical abstract
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ANALYTICA CHIMICA ACTA
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2012
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IF 4.555
Tao Li,Haoyue Xie,Zhifeng Fu
A facile, sensitive and universal method was established for analysis of biogenic amines using micellar electrokinetic chromatography coupled with chemiluminescent (CL) detection. It was found that diperiodatocuprate (III) (K 5 [Cu(HIO 6 ) 2 ], DPC), a transition metal chelate at unstable high oxidation state, could effectively enhance the reaction between luminol-type compound and hydrogen peroxide, to produce very strong CL signal. In addition, triethylamine was found to be able to effectively improve the yield of the derivatization reaction between biogenic amines and a luminol-type derivatization reagent, N -(4-aminobutyl)- N -ethylisoluminol (ABEI). Based on these facts, three biogenic amines were pre-column derivatized with ABEI, and post-column detected using high sensitive luminol-hydrogen peroxide-DPC CL system. Since the background was quite low, and the signal was quite strong, a considerable improved sensitivity was obtained. The presented method had been successfully applied to simultaneously analyze glycine, proline and phenylalanine with the detection limits (S/N = 3) of 0.030 μmol L −1 , 0.23 μmol L −1 and 0.21 μmol L −1 , respectively. To evaluate its potential application value, glycine in saliva and urine samples was detected using this method, and satisfied results were obtained. This approach can be further extended to detection of many other compounds such as peptides and drugs by using luminol-type derivatization reagent.
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JOURNAL OF ORGANIC CHEMISTRY
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2017
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IF 4.849
Xiaoxia Wang,Na Li,Zhongfeng Li,Honghua Rao
A dehydrogenative C(sp2)–N bond-forming strategy via copper-catalyzed intramolecular C–H/N–H coupling has been developed, which systematically unraveled the feasibility and practicality for benzoimdazo[1,2-a]indole formations through oxidative anilidic N–H activation. The merit of this strategy is illustrated by the broad tolerance of functionalities, as well as the utilization of extremely cheap copper catalysis to realize potentially useful indole-fused tetracycles in a step- and atom-economical manner.
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ACS Applied Polymer Materials
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2022
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IF 4.855
Yun Huang,Weida Zeng,Peirong Li,Qiang Liao,Ao Xia,Xianqing Zhu,Xun Zhu
Microalgal biofilm is one of the most promising candidates for renewable feedstock accumulation and carbon neutralization. To synergistically enhance cell adhesion during the microalgal biofilm formation stage and detachment during the harvesting stage, a surface possessing controllable properties is expected. However, the enhancement of the adhesion capacity of a conventional N-isopropylacrylamide (NIPAM) coating to microalgal cells only happens when the temperature reaches its lower critical solution temperature (LCST) of 33 °C, but at the optimum growth temperature of microalgae (25 °C) its adhesion capacity is dramatically weakened. In this study, a nondependent and environment-friendly thermoresponsive coating with a flexible LCST (22.3–25.0 °C) was prepared by cross-linking poly(NIPAM-co-N-tert-butylacrylamide) onto polydopamine to accelerate the adhesion of microalgal cells onto the coating at the optimum growth temperature of microalgae (25 °C). The coatings exhibited outstanding temperature-switchable performance due to competition between hydrophobic groups and hydrophilic groups in polymer molecules. Based on the temperature-switchable characteristic, the adhesion density of Chlorella sorokiniana MB-1 (C. sorokiniana) on the coating was increased by 49.4% compared to the conventional coating at 25 °C. Meanwhile, at 15 °C, the detachment efficiency of these cells on the coating reached 96.5%. The energy barrier between the C. sorokiniana and the coating was reduced by 54.8% compared to that of these cells on conventional coating, resulting in excellent cell adhesion and release. This report not only designs smart polymers for adjusting the adhesion of microalgal cells but also provides a sustainable strategy for microalgal biofilm cultivation.
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