MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Song He,Qilin Chen,Guanyu Chen,Guibin Shi,Chichi Ruan,Mengmeng Feng,Yuansheng Ma,Xin Jin,Xinyu Liu,Chunhua Du,Chunxiang He,Huaming Dai,Chengyang Cao
Preparation of high specific surface area activated carbon from rice husk for the removal of ofloxacin from medical wastewater. The optimum conditions for the preparation of activated carbon were a nitrogen doping ratio of 1:1:4 and an activation temperature of 800 °C (AC). The samples were characterised by N 2 adsorption isotherms , BET, FT-IR, TGA , XPS and SEM. The data showed that the specific surface area of AC was up to 1818.20 m 2 g −1 with a total pore volume of 1.12 cm 3 g −1 . AC formed N-containing functional groups on the surface and had good thermal stability. Scientific batch experiment studies were conducted to investigate the effect of pH, initial concentration, temperature and coexisting ions on the ofloxacin adsorption. The q e reached a maximum value of 780 ± 20 mg g −1 and maintained a removal efficiency of 51.1% after four regeneration cycles. The adsorption equilibrium data and the adsorption process were well represented by Langmuir model and general-order kinetic model, respectively. Thermodynamic studies of adsorption had shown that the adsorption process was autogenous and endothermic. Possible adsorption mechanisms for this material were also analysed. Finally, treatment of synthetic medical wastewater with AC resulted in a high removal rate of 98.3%. The superior adsorption properties combined with ease of preparation, ease of separation and excellent regeneration properties, make this material potentially effective for the removal ofloxacin from real medical wastewater.
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Frontiers in Microbiology
·
2021
·
IF 5.64
Liu Xinning,Liu Yuanchang,Zhao Guangjian,Zhang Yidan,Liu Lu,Wang Juan,Wang Yifan,Zhang Siyu,Li Xin,Guo Dongliang,Wang Peng,Xu Ximing
Vibrio vulnificus is a zoonotic bacterium that is capable of causing highly lethal diseases in humans; this pathogen is responsible for 95% of all seafood-related deaths in the United States. Arylamine N-acetyltransferases (NAT, E.C. 2.3.1.5) is a major family of xenobiotic-metabolizing enzymes that can biotransform aromatic amine chemicals. In this research, to evaluate the effect of NAT on acetyl group transformation in arylamine antibiotics, we first used sequence alignment to study the structure of V. vulnificus NAT [(VIBVN)NAT]. The nat gene encodes a protein of 260 amino acids, which has an approximate molecular mass of 30 kDa. Then we purified recombinant (VIBVN)NAT and determined the enzyme activity by PNPA and DTNB methods. The DTNB method indicates that this prokaryotic NAT has a particular substrate specificity towards aromatic substrates. However, (VIBVN)NAT lost most of its activity after treatment with high concentrations of urea and H2O2. In addition, we also explored the stability of the enzyme at different temperatures and pH values. In analyzing the influence of metal ions, the enzyme activity was significantly inhibited by Zn2+ and Cu2+. The kinetic parameters Km and Vmax were determined using hydralazine, isoniazid, 4-amino salicylic acid, and 4-chloro-3-methylaniline as substrates, and the Tm, Tagg and size distribution of (VIBVN)NAT were observed. In particular, a molecular docking study on the structure of (VIBVN)NAT was conducted to understand its biochemical traits. These results showed that (VIBVN)NAT could acetylate various aromatic amine substrates and contribute to arylamine antibiotic resistance in V. vulnificus.
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PubMed
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JOURNAL OF MOLECULAR LIQUIDS
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2023
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IF 6
Wenshuai Qi,Quanhua Deng,Na Du,Wanguo Hou
Surfactant-free microemulsions (SFMEs) refer to the microemulsions formed with two immiscible fluids (generally called the oil and water phases) in the presence of an amphi -solvent rather than the traditional surfactants. The understanding of SFMEs is still limited now. In the current work, the phase behavior of the ternary mixture of n -butanol (oil phase), ethanol ( amphi -solvent), and water was investigated. The ternary phase diagram shows a single-phase homogeneous region and a multiphase region. The mesoscale structuring was observed within the macroscopically homogeneous single-phase zone near the phase boundary using dynamic light scattering (DLS) and small-wide angle X-ray scattering (SWAXS) techniques. That is, microemulsions are formed in the ternary mixture without the traditional surfactants. In addition, the electrical conductivity and micropolarity of the single-phase mixtures were determined, suggesting the existence of three types of microstructures, i.e. , oil-in-water (O/W), bicontinuous (BC), and water-in-oil (W/O), for the SFMEs. The subregions corresponding to the three microstructures were roughly identified in the ternary phase diagram. n -Butanol is one of the extremely weak hydrophobic substances, and the detection of microemulsions in the mixture indicates that the formation of SFMEs is a universal phenomenon. This study provides a better understanding of the phase behavior of ternary liquid mixtures.
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ACS Nano
·
2019
·
IF 13.903
Xifan Chen,Yuanzhi Zhu,Miao Zhang,Jinyi Sui,Wenchao Peng,Yang Li,GuoLiang Zhang,Fengbao Zhang,Xiaobin Fan
MXenes, a family of two-dimensional (2D) transition-metal carbide and nitride materials, are supposed to be promising pseudocapacitive materials because of their high electronic conductivity and hydrophilic surfaces. MXenes, prepared by removing the “A” elements of their corresponding MAX phases by hydrofluoric acid (HF) or LiF–HCl etching, possess abundant terminal groups like −F, −OH, and −O groups. It has been proven that the MXenes with fewer −F terminal groups and more −O groups showed a higher pseudocapacitor performance. In organic reactions, −OH and −X (X = halogen) groups could turn to ether groups in strong nucleophilic reagent. Inspired by that, herein, we report an n-butyllithium-treated method to turn the −F and −OH terminal groups to −O groups on the Ti3C2Tx MXenes. Two types of Ti3C2Tx MXenes prepared by either HF or LiF–HCl etching were systematically investigated, and a comparison with the traditional KOH/NaOH/LiOH-treated method was also carried out. It is found that most of the −F terminal groups on the Ti3C2Tx MXenes can be successfully removed by n-butyllithium, and abundant −O terminal groups were formed. The n-butyllithium-treated Ti3C2Tx MXenes show promising applications in high-performance pseudocapacitors. A record high capacitance of 523 F g–1 at 2 mV s–1 was obtained for the n-butyllithium-treated Ti3C2Tx MXenes, and 96% capacity can remain even after 10 000 cycles.
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ACS Synthetic Biology
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2019
·
IF 5.571
Yu Ping,Xiaodong Li,Baofu Xu,Wei Wei,Wenping Wei,Guoyin Kai,Zhihua Zhou,Youli Xiao
N-Methylpyrrolinium-derived alkaloids like tropane alkaloids, nicotine, and calystegines are valuable plant source specialized metabolites bearing pharmaceutical or biological activity. Microbial synthesis of the critical common intermediate N-methylpyrrolinium would allow for sustainable production of N-methylpyrrolinium-derived alkaloids. Here, we achieve the production of N-methylpyrrolinium both in Escherichia coli and in Saccharomyces cerevisiae by employing the biosynthetic genes derived from three different plants. Specifically, the diamine oxidases (DAOs) from Anisodus acutangulus were first characterized. Then, we produced N-methylpyrrolinium in vitro from l-ornithine via a combination of the three cascade enzymes, ornithine decarboxylase from Erythroxylum coca, putrescine N-methyltransferase from Anisodus tanguticus, and DAOs from A. acutangulus. Construction of the plant biosynthetic pathway in E. coli and S. cerevisiae resulted in de novo bioproduction of N-methylpyrrolinium with titers of 3.02 and 2.07 mg/L, respectively. Metabolic engineering of the yeast strain to produce N-methylpyrrolinium via decreasing the flux to the product catabolism pathway and improving the cofactor supply resulted in a final titer of 17.82 mg/L. This study not only presents the first microbial synthesis of N-methylpyrrolinium but also lays the foundation for heterologous biosynthesis of N-methylpyrrolinium-derived alkaloids. More importantly, the strains constructed herein can serve as important alternative tools for identifying undiscovered pathway enzymes with a synthetic biology strategy.
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JOURNAL OF CHEMICAL RESEARCH
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2018
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IF 0.668
Can Jin,Feng Wang,Bin Sun,Xiaohui Zhuang
A novel method for the preparation of N-chloroaldimines from commonly available aromatic aldehydes has been developed. The reaction proceeded effectively by two steps: aldehydes were initially transformed into imines and then chloro-substitution with NaClO2 gave the N-chloroaldimines. This simple protocol allows for the preparation of a variety of aromatic N-chloroaldimines in moderate to excellent yields without the isolation of the imine intermediate. We also found that 3-nitrobenzaldehyde and 4-cyanobenzaldehyde were converted into the related benzonitrile directly under the standard conditions.
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Journal of CO2 Utilization
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2019
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IF 5.189
Weiqi Liu,Zhichao Miao,Zhenbin Li,Xiaozhong Wu,Pengfei Zhou,Jinping Zhao,Huahua Zhao,Weijiang Si,Jin Zhou,Shuping Zhuo
A series of Co@N-C materials are synthesized from pyrolysis of ZIF-67 at different temperatures and employed as catalyst for electrochemical reduction of CO 2 (CO 2 RR) to syngas. Through a systematical investigation of the relationship between structure of Co@N-C catalysts and their catalytic activity, it could be found that the Co species exposed on the material surface mainly promote the hydrogen evolution reaction (HER) process to produce H 2 , while the Co particles packaged by N-C skeleton provide electrons and transfer them to CO 2 molecule through the Co -N- C skeleton, promoting the CO 2 reduction reaction. Following this thinking, the pristine Co@N-C materials are treated by aqua regia to remove the surface exposed Co species. After acid treatment, the affinity of H species sharply decreases, and adsorption of CO 2 and transfer of electron to CO 2 are successfully improved. The acid-treated Co@N-C catalysts exhibit improved catalytic activity, faradic efficiency of CO, and stability in CO 2 RR process. Among all these catalysts, the obtained Co@N-C-700-A shows highest CO 2 reduction activity and stability, achieving a specific current of 25 A∙g (cat) −1 and a productivity of 0.266 mol (CO) h −1 ∙ g(cat) −1 at a mild potential of -0.57 V vs. RHE. The ratio of CO/H 2 in products could be adjusted in the range of 1/4 to 1.5/1.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2016
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IF 3.138
Hongli Liu,Xiaoli Liu,Lin Yue,Qixing Jiang,Wenshui Xia
N , O -Carbonylated chitosan derivative (NTCS) was synthesized via oxidation and substitution reaction, respectively. The carboxyethylation of the polysaccharide was identified by Fourier transform infrared (FTIR), 1 H nuclear magnetic resonance (NMR), X-ray diffraction analysis (XRD), Zeta potential measurement and Thermogravimetric analysis (TGA). It is revealed that compared with chitosan (CS), NTCS exhibited an excellent solubility in distilled water, high in vitro bile acid binding capacity, as well as a low viscosity. The in vitro bile acid binding capacity reached 17.21 mg/g, which was 4.5-fold higher than that of CS. The results suggest that NTCS may be useful as a potential functional food supplement in food industry or a key ingredient in the pharmaceutical industry. These findings provide important supports for developing new food additive, and expand the scope of application of CS in the food industry.
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POLYMERS FOR ADVANCED TECHNOLOGIES
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2017
·Vol. 28
·期 9
·1107-1114
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IF 1.907
Yuchen Huang,Longbao Feng,Yi Zhang,Liumin He,Changyong Wang,Jiake Xu,Jianping Wu,Thomas Brett Kirk,Rui Guo,Wei Xue
Chitosan (CHI) is a versatile biological material that is well known for its hemostatic properties. This preliminary study evaluated several self-assembling hydrophobically modified chitosan (HM–CHI) sponges to determine their efficacy on hemostasis . Fourier transform infrared (FT-IR) spectroscopy was used to determine the successful graft of dodecyl groups onto the nitrogen atoms of CHI molecules. A platelet aggregation assay revealed that HM–CHI accelerated the platelet aggregation rate. Fluorescence spectroscopy showed that the HM–CHI changed the structure of fibrinogen in blood. Activated partial thromboplastin time, prothrombin time, fibrinogen time, and thromboelastographic assays were used to explore the effect of HM–CHI on the autologous blood coagulation pathway. Finally, a hemostatic sponge was made with HM–CHI and freeze-dried zeolite composite film and was applied to the rat femoral artery hemostasis model. A hemostasis time of 86 ± 5 sec was achieved, which was significantly better than the one composed with pure CHI. The experimental results of the HM–CHI hemostatic materials are inspiring and will encourage the research and development of such materials. HM–CHI may be a strong candidate as a safe and effective hemostatic material. Copyright © 2017 John Wiley & Sons, Ltd.
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FUEL
·
2016
·
IF 3.611
Erjiang Hu,Hongzhen Tian,Xinyi Zhang,Xiaotian Li,Zuohua Huang
N -butanol is a promising alternative fuel for automobile whose explosion characteristics should be a major focus before widely used. Unfortunately, limit researches focusing on its explosion characteristics have been launched until now. In this study, the effects of n -butanol addition on the explosive characteristics of iso-octane-air mixtures with various concentrations and initial pressures and temperatures were experimentally investigated and analysed on the basis of combustion pressure history. The explosion pressure p exp and the maximum explosion pressure p max , the maximum rate of pressure rise ( d p / d t ) max , the deflagration index K G , and combustion duration t c as well as flame development period t d , were examined. Results show that with the increase of n -butanol blending ratio, explosion pressure does not change, while explosion duration is decreased, so the maximum rate of pressure rise is increased. It was found that pressure curves of rich mixtures oscillate in the vicinity of pressure peak at elevated pressures, and the pressure oscillation greatly shortens the explosion duration and increases the maximum rate of pressure rise. In addition, with the increase of n -butanol blending ratio, the pressure oscillation intensity is decreased.
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REACTIVE & FUNCTIONAL POLYMERS
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2015
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IF 2.515
Shulan Yan,Xiufang Yan,Xuexiang Shao,Jie Liang
An effective and easily recovered porous divinylbenzene (DVB) cross-linked antimicrobial polymeric resin containing N-halamine functional groups, poly (styrene-co-N-(t-Bu)-N-chloro-acryl amide) (PSA-N-Cl) resin, has been synthesized by a suspension copolymerization of styrene and acrylic acid and DVB, an amination with tert-butylamine and triethylenediamine (TEDA), and then a facile chlorination in diluted NaOCl solution. The as-prepared porous DVB cross-linked PSA-N-Cl resin was characterized by Brunauer–Emmett–Teller (BET) analysis, field emission scanning electron microscopy (FE-SEM), Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). BET analysis indicated that PSA-N-Cl resin has a very large surface area (124.9 m 2 /g) which is favorable for the quick water disinfection . Antibacterial tests showed that the as-prepared PSA-N-Cl resin possesses powerful antibacterial efficacies against both Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). The as-prepared PSA-N-Cl resin was capable of about 7.95-log and 7.81-log reductions of E. coli and S. aureus within 1 and 3 min of contact times, respectively. Also, the regenerability and preliminary storage stability of the as-prepared PSA-N-Cl resin were investigated.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Jun Xiu Chen,Agul Bao,Dalai Siqin
In this study, we prepared N/S-codoped porous carbon materials via a one-step doping method using lignin as the carbon source, thiourea as the N and S source, and KOH as the activator. The synthesized material exhibited a rich N content and a certain S content. The important reason the CO2 adsorption characteristic of the carbon materials were investigated by modulating the thiourea proportion and doping temperature. Results indicate that at a thiourea ratio of 1:4 and a doping temperature of 700 °C, the material exhibited an outstanding CO2 adsorption capacity of 3.49 mmol/g. Various characterizations revealed that such a high adsorption capacity is attributed to the combination of a microporous structure and excellent surface chemical properties. The doping of S atoms resulted in the formation of effective active sites, increased the defect density of the material, and promoted the generation of N functional groups, thereby enhancing the efficiency of CO2 adsorption. In addition, the material exhibits high CO2/N2 selectivity and cycling stability. The overall results indicate that lignin-derived N/S-codoped porous carbon can serve as a potential adsorbent for CO2 capture.
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