ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2017
·Vol. 409
·期 30
·7063-7075
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IF 3.431
Wang Meng,Jiao Yang,Cheng Chunsheng,Hua Jianhao,Yang Yaling
A novel and sensitive method based on nitrogen-doped carbon quantum dots as a fluorescence probe coupled with magnetic solid-phase extraction (MSPE) purification for analysis of folic acid (FA) in human serum samples has been established for the first time. In the developed system, magnetic nanoparticles coated with hexanoic acid (Fe 3 O 4 @C 6 ) were synthesized by a one-step chemical co-precipitation method with good magnetic properties and dispersibility for sample purification, and it is better to be separated from the sample. High fluorescence nitrogen-doped carbon quantum dots (N-CQDs), simply prepared using a one-step hydrothermal method with nitrilotriacetic acid, could be selectively quenched by FA. Based on this phenomenon, a fluorescence assay was proposed for specific determination of FA. Various operational experiment parameters have been studied and optimized in detail. Under the optimum experimental conditions, the detection limit of the proposed method for FA was evaluated to be 0.5 nM (S/ N = 3), while the relative standard deviation (RSD) was 1.2% ( n = 6). Finally, the proposed method was applied for determination of trace levels of FA from human serum samples and quantitative recoveries were achieved within the range of 95.7–103.5%. All of the results showed that the proposed method had significant application in further research.
Schematic of synthesis of N-CQDs and schematic of suggested mode for analysis of folic acid (FA).
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2017
·Vol. 55
·期 13
·2211-2220
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IF 2.952
Yuchen Feng,Suyun Jie,Bo-Geng Li
Fatty acid-derived cyclooctenes, including n -hexanoic acid ( M1 ), n -octanoic acid ( M2 ), lauric acid ( M3 ), and palmitic acid ( M4 ), were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst ( G2 ). In all the cases, the regio-irregular unsaturated polymers with pendent linear branches were obtained, which could be saturated by chemical hydrogenation with TSH/TPA in high conversion, yielding ethylene/vinyl ester copolymers with pendent linear branches on precisely every eighth backbone carbon. Both unsaturated and saturated polymers were amorphous, and their structures were characterized by FTIR, 1 H and 13 C NMR spectra, and elemental analysis. Differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) were used to study their thermal properties. The chain length of branches greatly affected the thermal properties of polymers. After hydrogenation, the thermal degradation stability of polymers was relatively improved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2211–2220
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Journal of Coatings Technology and Research
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2017
·Vol. 14
·期 3
·505-516
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IF 1.557
Huang Shan,Xiao Juan,Zhu Yan’an,Qu Jinqing
A series of multiarm star hydroxyl-terminated polyesters (MHPs) were synthesized through a “one-pot” method with di-trimethylolpropane as the core molecule, 2,2-dimethylolpropionic acid as the AB 2 -type monomer, ε-caprolactone, and monocarboxylic acids as modifiers. The influence of different monocarboxylic acids on the viscosities of polyesters and their 2K-PU films hardness was studied and it was found that MHPs prepared from lauric acid displayed the higher films hardness and lower viscosities. IR spectra of MHPs disclosed the ring-opening reaction between ε-caprolactone and hydroxyl groups occurred. 1 H NMR spectra demonstrated that the molecular structures of MHPs were irregular due to the multiplicity of reaction processes. The measured number-average molecular weights ( M
n ) of MHPs were around 715–1854 g/mol with the PDI of 1.45–2.05. MHPs exhibited lower viscosities in the range of 3304–9060 mPa s at 100% solid contents and possessed lower intrinsic viscosities compared with linear polymers of similar molecular weight. The cured films of MHPs exhibited excellent impact resistance, adhesion, flexibility, and high hardness and displayed good thermal stability with 5% weight loss at 280°C. The solution viscosities of MHPs were less than 450 mPa s at 80% solid contents, and the VOC contents of 2K-PU coatings obtained from MHPs were low to 300 g/L.
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INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2017
·Vol. 41
·期 15
·2555-2564
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IF 2.598
Zhao Wang,Shang Liu,Guixiang Ma,Shaolei Xie,Guangwei Du,Jinhe Sun,Yongzhong Jia
Summary To satisfy the application demands for latent heat storage in the temperature range from 5°C to 15°C, an original composite phase change material (PCM), CA-NA/EG (caprylic-nonanoic acid/expanded graphite), was prepared and characterized. For CA-NA/EG, the mass ratio of CA and NA was 8:2, and the mass percentage of the CA-NA in CA-NA/EG composite PCM was determined as 90% by leakage test. The melting and freezing points of the CA-NA/EG were 6.84°C and 9.34°C, and corresponding latent heats were 108.75 kJ/kg and 107.67 kJ/kg. In addition, its thermal conductivity, thermal stability and reliability were investigated by thermal conductivity apparatus (TCA), thermal gravimetric analyzer (TGA), and accelerated thermal cycle test for 100 melt/freeze cycles, respectively. The results showed that the CA-NA/EG had a good thermal stability and an excellent thermal reliability. Moreover, the thermal conductivity of CA-NA/EG had an improvement of 25% than that of the CA-NA. On the other hand, the accelerated thermal cycle test also indicated that the CA-NA/EG had no supercooling during all melt/freeze cycles. Therefore, the prepared composite PCM, CA-NA/EG, can be applied for low-temperature thermal energy storage owing to its proper melting temperature, acceptable latent heat and thermal conductivity, excellent thermal stability and reliability.
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CHEMISTRY OF MATERIALS
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2017
·
IF 9.466
Aifei Wang,Yanyan Guo,Faheem Muhammad,Zhengtao Deng
Hollow nanocrystals have attracted considerable attention in many areas of materials science because of their unique geometry, large surface area, high loading capacity and low density, and potential applications in catalysis, energy storage, drug delivery, and molecular separation. So far, numerous hollow nanostructured materials, such as noble metals, metallic oxides, hydroxides, and chalcogenides, have been reported. However, there is no report about the hollow metal halide perovskite nanocrystals yet. Herein, for the first time, we report the controlled synthesis of metal halide perovskite hollow nanocrystals, i.e., CsSnBr3 cubic nanocages, through a facile hot-injection colloidal approach. The formation of nanocages was controlled by rationally choosing the precursors and reaction temperature and was achieved through the self-assembly driven process. The as-synthesized CsSnBr3 nanocages exhibit excellent oxygen resistibility under desiccation conditions. Furthermore, treatment of CsSnBr3 nanocages with perfluorooctanoic acid results in an improved stability against moisture, oxygen, and light. This work represents a step toward hollow nanocrystals of metal halide perovskites for optical, electronic, and optoelectronic applications.
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Journal of the Taiwan Institute of Chemical Engineers
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2016
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IF 2.848
Ling Qin,Zhiping Zhou,Jiangdong Dai,Ping Ma,Haibin Zhao,Jinsong He,Atian Xie,Chunxiang Li,Yongshen Yan
In this research, shrimp shell, as an abundant, environmental-friendly and renewable biomass source, was successfully converted into novel N-doped hierarchically porous carbons (N-HPCs) via a simple self-template carbonization and KOH activation. The physical–chemical properties of N-HPCs were characterized by FT-IR, SEM, TEM, Raman, BET and elemental analysis. The optimum N-HPCs (named N-HPC-850-2) exhibited the highest specific surface area (3171 m 2 /g) and total pore volume (1.934 cm 3 /g), and was used to effectively eliminate sulfamethazine (SMZ) and chloramphenicol (CAP) from water. Batch adsorption results showed increasing temperature was in favor of adsorption and the N-HPC-850-2 had a high adsorption affinity toward two antibiotics over a broad pH range. Adsorption isotherm data were fitted with Langmuir model very well, with the maximum monolayer adsorption capacity of 699.3 and 742.4 mg/g for SMZ and CAP at 318 K, respectively. The pseudo-second-order rate model described adsorption kinetics data well and adsorption processes were governed predominately by intra-particle diffusion and film diffusion. The thermodynamic parameters indicated the spontaneous and endothermic adsorption. Importantly, the N-HPC-850-2 adsorbent also exhibited a good regeneration capacity. Here, we provided a promising approach to prepare low-cost and high-performance biomass-based N-HPCs for fast and highly efficient removal of antibiotics from aquatic system.
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Nanoscale
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2017
·Vol. 9
·期 44
·17248-17253
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IF 7.367
Yibing Xu,Qiang Zhang,Longfei Lv,Wenqian Han,Guanhong Wu,Dong Yang,Angang Dong
Discretely sized semiconductor clusters have attracted considerable attention due to their intriguing optical properties and self-assembly behaviors. While lead halide perovskite nanostructures have been recently intensively explored, few studies have addressed perovskite clusters and their self-assembled superstructures. Here, we report the room-temperature synthesis of sub-2 nm CsPbBr3 clusters and present strong evidence that these ultrasmall perovskite species, obtained under a wide range of reaction conditions, possess a specific size, with optical properties and self-assembly characteristics resembling those of well-known II–VI semiconductor magic-sized clusters. Unlike conventional CsPbBr3 nanocrystals, the as-synthesized CsPbBr3 nanoclusters spontaneously self-assemble into a hexagonally packed columnar mesophase in solution, which can be further converted to single-crystalline CsPbBr3 quantum nanoribbons with bright deep-blue emission at room temperature. Such a conversion of CsPbBr3 nanoclusters to nanoribbons is found to be driven by a ligand-destabilization-induced crystallization and mesophase transition process. Our study will facilitate the investigation of perovskite nanoclusters and offer new possibilities in the low-temperature synthesis of anisotropic perovskite nanostructures.
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ENERGY AND BUILDINGS
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2017
·
IF 4.067
Zhao Wang,Guixiang Ma,Shang Liu,Yan Jing,Jinhe Sun,Yongzhong Jia
The thermal properties of caprylic acid, nonanoic acid and their binary system were investigated by differential scanning calorimetry (DSC). The phase diagram for the binary system was constructed, and the experiment results showed that the eutectic temperature and the molar fraction of caprylic acid for the eutectic mixture are 1.83 °C and 0.483, respectively. To satisfy the application demands of the temperature scope from 5 °C to 15 °C, another binary mixture for the binary system with a molar fraction of 0.814 for caprylic acid component is found successfully, and it has good thermal properties that the melting temperature and the latent heat are 7.6 °C and 123 J g −1 , respectively. What is more, the latent heat and melting temperature for the binary mixture do not change at all nearly after being cycled 100 times during the whole melting process. As a novel phase change material (PCM) for application in the field of air conditioning and cooling, the binary mixture has own unique thermal advantages.
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JOURNAL OF CHROMATOGRAPHY A
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2024
·
IF 3.8
Yanhui Zhang,Hongbo Li,Xiaoqin Hai,Xiaoli Guo,Xin Di
A green and recyclable switchable supramolecular deep eutectic solvent (SS-DES) was designed and prepared for effective extraction of flavonoids from Scutellariae Radix . The novel SS-DES has both excellent extraction performance of DES and the host guest inclusion of cyclodextrin, thereby showing superior extraction efficiency and selectivity. The characteristic of polarity switching can endow the SS-DES with achieving homogeneous extraction and rapid two-phase separation, shorting per-treatment time largely. Parameters affecting the extraction performance were investigated by the response surface methodology. The results indicated that the SS-DES showed better extraction yield of total flavonoids (157.95 mg/g) compared with pure DES (135 mg/g) and traditional organic solvent (60 % ethanol, 104.87 mg/g). Moreover, the switching mechanism of SS-DES was characterized by FT-IR and 1 H NMR, and the extraction mechanism was studied by density functional theory and molecular docking analysis. After evaluating the ecological impact of the method, the cytotoxicity of SS-DES was investigated and the result displayed that its toxicity was very low or even negligible with the EC 50 >2000 mg/L. After being adsorbed by macroporous AB-8 resin, the regenerated SS-DES was recycled 5 times and the extraction efficiency still remained above 90 %, indicating the desirable reusability. Therefore, the proposed method was efficient and sustainable, and revealed favorable application prospect for the extraction of bio-active compounds from plant materials.
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FOOD CHEMISTRY
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2024
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IF 8.5
Xiaojiao Zheng,Xingle Guo,Yawen Zhang,Jiajun Han,Xu Jing,Junxue Wu
A novel, environmentally friendly, and efficient method for determining triazine herbicides in water, tea, and juice was developed by combining magnetic dispersive micro-solid phase extraction (MD-μSPE) with magnetic dispersive liquid-liquid microextraction (MDLLME), followed by high-performance liquid chromatography (HPLC). The pretreatment process, utilized magnetic biochar (MBC) and magnetic deep eutectic solvent (MDES) as the adsorbent and extractant, respectively. Fe(NO 3 ) 3 was loaded onto waste mushroom sticks to prepare MBC via impregnation-pyrolysis, while tri- n -butylphosphine oxide, nonanoic acid, and FeCl 3 were combined through hydrogen bonds to form MDES. This approach significantly reduced environmental impact using waste materials and shortened separation times. The method demonstrated excellent linearity (1–100 μg L −1 ), low detection limits (0.3 μg L −1 ), and good precision (RSDs <6.5 %). Recoveries in water, tea, and juice ranged from 80.1 % to 90.6 %. This combined MD-μSPE-MDLLME approach offers a greener and more efficient extraction process for separating and concentrating pesticides from complex food samples.
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BIORESOURCE TECHNOLOGY
·
2024
·
IF 9.7
Bo Zhou,Dianzhan Wang,Guangliang Zhao,Mingjiang Zhang,Xuan Liu,Dejin Zhang,Jianru Liang,Lixiang Zhou
The activated sludge process is the most widely used technology for treating municipal wastewater. However, thick foam often occurs in activated sludge process. Here, we reported for the first time the effect of food waste hydrolysate (FWH) as an external carbon source on defoaming in activated sludge process. The study found that FWH was effective in defoaming at a wide dose range of 50–1600 mg/L total solids, as exhibiting that the foaming tendency of FWH-added foam mixed liquor was reduced to 0 mL-foam/mL-air·min from initial 0.171 mL-foam/mL-air·min in the control without adding FWH with 100 % of defoaming efficiency. Fatty acids, oils, and solid particles in FWH jointly contributed to the deformation. Among these factors, the concentration of long-chain unsaturated fatty acids was mainly responsible for the defoaming. This work provides a cost-effective strategy to solve the foaming problem in activated sludge process as well as providing external carbon sources.
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BIORESOURCE TECHNOLOGY
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2024
·
IF 9.7
Shuo Zou,Jiena Chen,Yee-Ying Lee,Yong Wang,Zhen Zhang
Partial acylglycerols are valued for their emulsifying and stabilizing properties, yet precise green synthesis remains challenging due to low yield and selectivity. This study aimed to elucidate the “lipase selectivity-substrate structure-product composition” relationship to enhance the yield of targeted partial acylglycerol. The results showed that lipase exhibited a greater selectivity towards fatty acids with shorter chain lengths and higher unsaturation. Hydroxyl donors also affected the esterification process, with the enzyme-acyl complex exhibiting selectivity towards hydroxyl donors as follows: glycerol > monoacylglycerol > diacylglycerol. Substrate ratio significantly influenced enzymatic reactions; a 10:1 ratio favored triacylglycerol formation (>80 %), while a 1:1 ratio produced > 90 % partial acylglycerols. Molecular docking simulations revealed that substrates primarily interacted with lipase through hydrogen bonding and hydrophobic interactions. A comprehensive understanding of lipase selectivity patterns could facilitate the design of more efficient reaction systems, enabling the conversion of basic lipid resources into desired high value-added products.
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