NANOTECHNOLOGY
·
2019
·Vol. 30
·期 31
·315601
·
IF 3.399
Shiping Sun,Erchuang Fan,Hongliang Xu,Wenbo Cao,Gang Shao,Bingbing Fan,Hailong Wang,Rui Zhang
Modified g-C3N4 samples (g-X, where X corresponds to the number of hours of acid treatment of the melamine) with outstanding photocatalytic performance were prepared by using hydrochloric acid-treated melamine as a precursor and calcining at 550 °C for 2 h. An x-ray diffractometer, field-emission scanning electron microscope, infrared spectrometer, N2 adsorption–desorption test, x-ray photoelectron spectroscopy, and ultraviolet–visible diffuse–reflectance spectroscopy analysis were carried out to characterize the phase composition, microstructure, chemical structure, specific surface area (SSA), chemical states, elemental composition and optical properties of the samples, respectively. The photocatalytic performance of the samples was evaluated by degrading the Rhodamine B (RhB) aqueous solution. The results showed that the crystal structure and vibration bands of melamine changed due to the reaction with hydrochloric acid. The crystallinity and grain size of g-C3N4 in g-X (X = 1, 2, 4, 6, 8, 10) reduced, and the SSA values of g-X increased compared to that of the g-0 sample, which was synthesized from pristine melamine. The g-X samples exhibited excellent photocatalytic activity towards degradation of RhB compared to g-0. The photocatalytic activity of the g-X samples increased gradually as the acid treatment time of the melamine increased from 1 h to 2 h, and then decreased gradually with the extension of the acid treatment time. The rate constant (k) values of g-X are higher than that of g-0. g-2 presented the highest rate constant (k = 0.052 min−1), which was 5.5 times higher than that of g-0. The improved photocatalytic activity of the g-X samples was attributed to the higher SSA value, the appearance of surface defects, the outstanding photo-carrier separation efficiency and stronger light harvesting ability of g-X, with the last two factors being more significant. Acid treatment of melamine is helpful in the preparation of high performance g-C3N4 photocatalyst, and the microstructure and photocatalytic performance of g-C3N4 were affected significantly by the acid treatment time.
研究领域:
材料科学
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化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 45
·26029-26038
·
IF 10.733
Xiaojian Shan,Zhang Cao,Guobin Zhu,Yan Wang,Qunting Qu,Gao Liu,Honghe Zheng
Silicon materials are the most viable candidates to overcome the limitations of the capacity and energy density of conventional graphite. Nevertheless, this technology is still at an early stage and needs competitive strategies for the electrode fabrication. Herein, a functionalized 3-dimensional (3-D) polyvinyl alcohol (PVA) network is prepared via in situ cross-linking with a trimethylol melamine (TMM) bridge, which enables an electrode with much improved mechanics and ionic conductivity. Under optimized conditions, the nano-Si anode using the obtained 3-D PVA binder exhibits superior electrochemical properties with the first coulomb efficiency of 90.81% and a reversible capacity of more than 3000 mA h g−1. At 20 C (84 A g−1) current density, the Si anode is able to deliver a capacity of 2338 mA h g−1. After 500 electrochemical cycles, it can still retain more than 85% of the initial capacity. The underlying mechanisms for the electrochemical enhancement are discussed in terms of the electrode laminate mechanics and the improved ionic transportation due to the TMM incorporation. The simple and facile method by adopting a functional cross-linker shows great promise for use with Si anodes in lithium ion batteries.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Jing Li,Qian Li,Lu-shuang Li,Li Xu
Perfluoroalkyl and polyfluoroalkyl substances are priority contaminants of global concern. It is urgent to remove them from the environment. Adsorption is an efficient approach, but the adsorption capacity and regeneration of adsorbent were not satisfactory. In the present study, mesoporous melamine-formaldehyde resin microsphere (MMFRS) was fabricated through suspension polymerization. Owing to its mesoporous property and large anion-exchange capacity of 0.3 mmol/g, MMFRS was applied to the adsorption of perfluorooctanoic acid, a model target. The sorption kinetics obeyed pseudo-second-order equation and the sorption isotherms fitted both Freundlich and Langmuir models well. MMFRS exhibited a superiority over commercial powdered activated carbon on the adsorption amount. The sorption could reach equilibrium within 24 h. In addition, the material could be easily and economically regenerated by dilute NH 3 ·H 2 O (7.5 mM); a regeneration percentage (>85%) after 20 recycles was obtained. This study provides a facile, environmentally-friendly and low energy-consumption strategy for removal of perfluorooctanoic acid from aqueous solution in waste-water treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Spectroscopy
·
2016
·
IF 0.814
Tong Wu,Hui Chen,Zan Lin,Chao Tan
Melamine is a nitrogen-rich substance and has been illegally used to increase the apparent protein content in food products such as milk. Therefore, it is imperative to develop sensitive and reliable analytical methods to determine melamine in human foods. Current analytical methods for melamine are mainly chromatography-based methods, which are time-consuming and expensive and require complex pretreatment and well-trained technicians. The present paper investigated the feasibility of using near-infrared (NIR) spectroscopy and chemometrics for identifying and quantifying melamine in liquor milk. A total of 75 samples were prepared. Uninformative variable elimination-partial least square (UVE-PLS) and partial least squares-discriminant analysis (PLS-DA) were used to construct quantitative and qualitative models, respectively. Based on the ratio of performance to standard deviate (RPD), UVE-PLS model with 3 components resulted in a better solution. The PLS-DA model achieved an accuracy of 100% and outperformed the optimal reference model of soft independent modeling of class analogy (SIMCA). Such a method can serve as a potential tool for rapid screening of melamine in milk products.
研究领域:
食品科学
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分析化学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Jianlong Ge,Fei Wang,Xia Yin,Jianyong Yu,Bin Ding
Severe environmental and ecological issues arising from frequent oil spill accidents have been great worldwide concerns. Considering the abruptness, complex condition, and long-term perniciousness of the spilled oil, the development of economic and versatile materials to quickly remove oil contaminants, especially for oil with high viscosity from a large water body, is of significant importance but remains a big challenge. Herein, we demonstrated a facile strategy to fabricate a versatile hierarchical structured sponge with superhydrophobicity and powerful oil capillarity via the in situ polymerization of a novel phenolic resin (polybenzoxazine) composite open-cell sponges. The tunable hierarchical structures of the as-prepared sponge significantly improved its water repellence and oil capillarity; meanwhile, a plausible mechanism is also proposed. With the merits of high porosity, excellent water repellence, enhanced oil capillarity, and robust mechanical stability, the obtained sponge exhibited an intriguing oil spill cleanup performance with fast oil absorption speed, good recyclability, and high absorption capacity. Besides that, the modified sponge could also be utilized for the separation of oil/water mixture with individual phase and the surfactant-stabilized emulsion solely under the drive of gravity. The robust oil/water separation performance, low cost, and facile synthesis strategy make the resultant sponges a competitive material for the large-scale oil spill emergency remediation.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
IF 3.652
Chengle Wang,Juan Li,Peng Ding
In this paper, supermolecular structure of melamine phosphomolybdate (MAPMo) was tailored by changing the ratio of MA/PMo. Effects of MAPMo on flame retardant efficiency of polypropylene/intumescent flame retardant (PP/IFR) system were investigated by using limiting oxygen index (LOI), UL-94 testing, microscale combustion calorimetry (MCC) etc. The thermal degradation behaviors of PP composites were tested by thermal gravimetric analysis (TGA). The results showed that the formation of supermolecular increases the thermal stability of MA and the ratio of MA/PMo has great effect on flame retardancy of PP/IFR. With the addition of 15.5 wt% IFR and 0.5 wt% MAPMo (MA/PMo ≤ 3), the PP composites can pass the UL-94 V-0 test without melt-dripping. In addition, more or less MAPMo are not suitable for improving flame retardancy of PP, the best content of MAPMo (3:1) is 0.3–0.8 wt%. The morphology of char residue reveals that the MAPMo promotes the reaction between APP and PER, accelerates the formation of perfect charring layer. Moreover, the MAPMo modifies the degradation of MA and tailors the surface morphology of the char residue. MAPMo doesn’t modify the bonds of the char compared to neat PP/IFR but improve the quality of char. It is the good char layers that protects the inside matrix from the erosion of heat and gas, resulting in good flame retardant properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Wenkai Cao,Shan Shan,Keyu Xing,Xudong Jing,Juan Peng,Xiaoyue Xiao,Daofeng Liu,Jun Xia,Weihua Lai
A simple and rapid colorimetric method for the detection of melamine in milk samples is described. Polythymidine oligonucleotide was adsorbed on to the surface of gold nanoparticles (AuNPs), protecting it from aggregation. In the presence of melamine, polythymidine oligonucleotide combined with melamine formed a double-strand DNA-like structure, allowing AuNPs aggregation. In the presence of positively charged SYBR Green I (SG I), AuNPs were further aggregated. In the presence of melamine and SG I, aggregation of AuNPs was synergistic. Thus, in this principle, melamine can be detected visually. Plasmon resonance peak changes enabled detection of melamine quantitatively using UV–vis spectroscopy. The limit of detection for this colorimetric method was 16 μg L –1 with a good linear range from 19.5 μg L –1 to 1.25 × 10 3 μg L –1 , and detection took only 1 min. The method was successfully applied for detection of melamine in milk samples.
研究领域:
分析化学
·
食品科学
·
纳米生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers of Chemical Science and Engineering
·
2022
·Vol. 16
·期 8
·1247-1258
·
IF 4.803
Li Meng,Fang Yuanfeng,Liu Chun,Zhou Mengmeng,Miao Xiaomei,Pei Yongbing,Yan Yue,Xiao Wenjun,Qiu Huayu,Wu Lianbin
In this study, a durable superhydrophobic/superoleophilic melamine foam was fabricated by a facile and rapid one-step thiol-ene click chemistry and Michael addition reaction, which demonstrated excellent robustness in oil/water separation. First, 1H, 1H, 2H-perfluoro-1-hexene reacted with thiol-functionalized polyhedral oligomeric silsesquioxane via the thiol-ene click chemistry to obtain a fluorinated thiol-functionalized polyhedral oligomeric silsesquioxane solution. Subsequently, the melamine foam was immersed to the solution system to form nanoaggregates on the melamine foam surface by the Michael addition reaction in the presence of ultraviolet light. The micro/nano rough structure and low surface energy of the nanoaggregates layer endowed the pristine melamine foam with superhydrophobicity; the water contact angle was greater than 150°. More importantly, the as-prepared melamine foam could withstand harsh conditions, such as a corrosive solution environment, strong ultraviolet light, mechanical compression, high and low temperature exposure, and ultrasonic washing. Driven by gravity, the as-prepared melamine foam could efficiently separate the oil/water mixtures and maintain 98% separation efficiency at high and low temperatures. In addition, it maintained the desirable absorption capability in different oil/organic solvents even after 15 absorption cycles. Accordingly, this facile, low-cost, and robust one-step method provides important support for the superhydrophobic oil/water separation field.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
FOOD CONTROL
·
2014
·
IF 2.819
Juan Song,Fangying Wu,Yiqun Wan,Lihua Ma
Multiple methods have been published to detect melamine, only a few offer sensitivities below 50 nM with complicated procedures and sophisticated equipments. We demonstrate here a simple, rapid and lower-cost assay with high sensitivity for the melamine detection in milk samples using sulfanilic acid-modified silver nanoparticles (SAA-AgNPs). Due to the special chemical structures, SAA shows similar response to its analogues, which reveals that the selectivity and sensitivity of SAA itself is poor. However, the formation of SAA-AgNPs dramatically improves the selectivity of SAA and only melamine reacts with SAA-AgNPs. The possible mechanism is discussed. The interaction between exocyclic amine of melamine and SAA induces rapid aggregation of SAA-AgNPs accompanied by a naked-eye visible color change, resulting in precise quantification of melamine that can be monitored by a simple UV-visible spectrometer. Metal ions, amino acids and sugars that are common in milk have negligible interference influences. The extinction ratio (A 620nm /A 390nm ) is correlated with the melamine concentration over the range of 0.1–3.1 μM. The detection limit is 10.6 nM, which is much lower than the safety limits (8 μM for infant formula in China, 20 μM in both the USA and EU and 1.2 μM in the CAC review for melamine in liquid infant formula). The method is applied successfully to determine melamine in pretreated milk products, indicating the potential practical use for the products suspected of melamine exposure.
研究领域:
分析化学
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食品安全
·
纳米技术
✓ 已验证
DOI
高影响因子
TALANTA
·
2018
·
IF 4.244
Xiaojuan Liu,Ningning Xu,Panpan Gai,Feng Li
Since melamine is a strong hazard to human health, the development of new methods for highly sensitive detection of melamine is highly desirable. Herein, a novel fluorescent biosensing strategy was designed for sensitive and selective melamine assay based on the recognition ability of abasic (AP) site in triplex towards melamine and signal amplification by Mg 2+ -dependent DNAzyme. In this strategy, the melamine-induced formation of triplex DNA was employed to trigger the strand displacement reaction (SDR). The SDR process converted the specific target recognition into the release and activation of Mg 2+ -dependent DNAzyme, which could catalyze the cleavage of fluorophore/quencher labeled DNA substrate (FQ), resulting in a significantly increased fluorescent signal. Under the optimal conditions, the fluorescent signal has a linear relationship with the logarithm of the melamine concentration in a wide range of 0.005–50 μM. The detection limit was estimated to be 0.9 nM (0.1ppb), which is sufficiently sensitive for practical application. Furthermore, this strategy exhibits high selectivity against other potential interfering substances, and the practical application of this strategy for milk samples reveals that the proposed strategy works well for melamine assay in real samples. Therefore, this strategy presents a new method for the sensitive melamine assay and holds great promise for sensing applications in the environment and the food safety field.
研究领域:
生物化学
·
食品安全
·
分析化学
✓ 已验证
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2021
·
IF 10.618
Bin Qiao,Jiakun Xu,Wenhao Yin,Wanmeng Xin,Lixin Ma,Jie Qiao,Yi Liu
Herein, we report a method that combined “aptamer-locker” DNA with CRISPR/Cas12a-based biosensing for sensitive and rapid melamine analysis. Three strategies were harnessed for designing the DNA sensors that were well characterized by circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC) in the absence and presence of melamine. The detection parameters were optimized to achieve good analytic performance. As a result, a limit of detection (LOD) as low as 38 nM was achieved, which is below the threshold (1.0 mg/kg) of allowable melamine in infant milk products. In addition, the sensors show high selectivity for melamine against other analogues such as cyanuric acid , ammeline and ammelide . Moreover, our method was effective for rapid melamine analysis in whole milk samples, with or without sample pretreatment , in less than 20 min. Adopting a commercially available portable fluorimeter, on-site analysis of melamine in milk was accomplished. The strategies demonstrated here can expand to detect other non-nucleic-acid targets by simply replacing the aptamers.
研究领域:
分析化学
·
分子生物学
·
生物技术
·
食品安全
✓ 已验证
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 16
·7924-7931
·
IF 3.269
Aiping Gao,Yiran Li,Haiting Lv,Dan Liu,Na Zhao,Qianqian Ding,Xinhua Cao
In this study, a new gelator containing lenalidomide and cholesterol groups was synthesized, which could form stable gels in 1,4-dioxane and mixed solvents of DMF/H2O (v/v, 1/1). The self-assembly process was studied and certified by field emission scanning electron microscopy, UV-vis, IR, XRD, and CA. Based on the results obtained from the abovementioned analyses, the self-assembly structure, aggregation pattern, and surface wettability could be tuned via the addition of melamine due to intermolecular hydrogen bonding between compound 1 and melamine (MA). The irregular lumpy and the closely packed fiber structures could be turned into microbelt and sparse fiber structures after the addition of MA, respectively. Moreover, the hydrophobicity of the xerogel film of 1-MA was obviously increased. The mechanical strength of gel 1-MA was obvisously enhanced due to the addition of MA. The UV-vis, IR, and XRD experiment results showed that the self-assembly process and mode of 1 was changed due to the addition of MA through intermolecular hydrogen bonding between 1 and MA. Therefore, these results provide a method for the regulation of the self-assembly process via intermolecular noncovalent interaction.
研究领域:
化学
·
材料科学
·
生物医学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）