查找使用阿拉丁产品的科研文献

Application of N-Doped MoS2 Nanocrystals for Removal of Azo Dyes in Wastewater

Haijiao Lu,Jingkang Wang,Beiqian Tian,Xin Huang,Jingtao Bi,Ting Wang,Hongxun Hao

As persistent and detrimental contaminants, azo dyes are difficult to be removed from wastewater. It is a worldwide challenge to develop efficient technologies for their removal. Adsorption is widely recognized to be a practical, efficient, and low-cost technology for removal of contaminants. Compared with various conventional adsorbents, MoS 2 nanocrystals possess larger specific surface area, higher surface energy, and better adsorptive properties. Since nitrogen-doping is a common approach for modification of materials, N-doped MoS 2 nanocrystals (NDMN) were first used as adsorbents for removal of the azo dye methyl orange. Compared with bulk MoS 2 and MoS 2 nanocrystals, NDMN showed much higher efficiency and reusability. This study provides inspiration for exploring and expanding the applications of NDMN.

Electrochemical conversion of palmitic acid via Kolbe electrolysis for synthesis of n-triacontane

Yimeng Zhang,Guangrui Liu,Jinhu Wu

Fatty acids in vegetable oils and animal fats are a potential feedstock for the production of synthetic waxes, and this kind of waxes can be a substitute for petroleum waxes in the future because the feedstock is renewable. This paper described an optimization study on the production of n-triacontane (NTA) from palmitic acid via Kolbe electrolysis using a biphasic solvent system (H 2 O/MeOH as aqueous phase, petroleum ether as organic phase). Response surface methodology (RSM) and Taguchi methodology (TM) were employed to research the production of NTA affected by amounts of KOH, reaction temperature, cell voltage and reaction time. On the basis of analysis of variance and range analysis of the two methods above, the maximum NTA yield was achieved at amounts of KOH of 1.3 equiv., reaction temperature of 57 °C, cell voltage of 20.0 V and reaction time of 20 h for RSM; while the amounts of KOH of 1.3 equiv., reaction temperature of 55 °C, cell voltage of 20.0 V and reaction time of 20 h for TM. Under these optimal conditions, the experimental yields of NTA were 69.5% and 64.7% for RSM and TM, respectively. The final product met the relevant standards of the needle penetration, lead, water soluble acids and alkalis, odor and polycyclic aromatic hydrocarbons by referring to Chinese waxes product standards. The results showed strong potential market applications of Kolbe electrolysis waxes.

N-Halamine polymer from bipolymer to amphiphilic terpolymer with enhancement in antibacterial activity

Dan Chang,Zhiying li,Xiao Wang,Chongyi Zhu,Alideertu Dong,Ge Gao

A novel N -halamine terpolymer, i.e. , P(ADMH-MMA-HEMA)-Cl, with high antibacterial efficacies were fabricated via a free-radical copolymerization of 3-allyl-5,5-dimethylhydantoin(ADMH), methyl methacrylate(MMA), and hydroxyethyl methacrylate (HEMA), followed by a chlorination treatment using sodium hypochlorite as chlorinating agent. A controllable synthesis of P(ADMH-MMA-HEMA)-Cl was achieved by tuning chlorination conditions, such as chlorination temperature, reactant concentration, chlorination time, etc . A series of antibacterial assays were conducted, and the as-prepared products P(ADMH-MMA-HEMA)-Cl showed good killing capabilities against both Gram-positive and Gram negative bacteria. Remarkably, compared to N -halamine biopolymer counterparts, e.g. , P(ADMH-HEMA)-Cl and P(ADMH-MMA)-Cl, and the as-prepared N -halamine terpolymer P(ADMH-MMA-HEMA)-Cl presented the enhancement in antibacterial efficiency toward pathogens. It is believed that this approach offers great potential to be utilized in various fields where antibacterial properties are highly required.

ZIF-8 nanocrystals derived N-doped carbon decorated graphene sheets for symmetric supercapacitors

Liang Wang,Chengxin Wang,Haifei Wang,Xinyan Jiao,Yu Ouyang,Xifeng Xia,Wu Lei,Qingli Hao

Sandwich-like ZIF-8 nanocrystal derived N-doped carbon decorated graphene sheets are developed through in-situ growth and followed by a thermal annealing treatment. The sandwich-like N-doped carbon decorated graphene sheets (NCGs) contain graphene substrate and the carbon nanoparticles with 30–50 nm in size. The sandwich-like NCGs generate a large specific surface area of 816.4 m 2  g −1 . With the high surface area and nitrogen doping, the as-fabricated NCGs as electrode materials for supercapacitor exhibit high specific capacitance of 225.0 F g −1  at 0.5 A g −1 , an enhanced rate capability and excellent electrochemical stability with 96.8% retention after 10000 cycles even at 10 A g −1 . The symmetry supercapacitor based on NCGs delivers an energy density of 12.7 Wh kg −1  at a specific power of 447 W kg −1 . When the power density increases to 15126 W kg −1 , the energy density can still keep 6.5 W h kg −1 . Furthermore, the symmetry supercapacitor shows an excellent cycle stability with 96.6% capacitance retention at 2 A g −1 after 10000 cycles.

Highly selective N-glucuronidation of four piperazine-containing drugs by UDP-glucuronosyltransferase 2B10

Danyi Lu,Dong Dong,Baojian Wu

N-methyl-2-pyrrolidone exfoliated graphene as highly sensitive analytical platform for carbendazim

Piaopiao Wei,Tian Gan,Kangbing Wu

Graphene nanosheets (GS) with approximately 10–15 layers was prepared via ultrasonic exfoliation of graphite powder in N -methyl-2-pyrrolidone (NMP), and confirmed using transmission electron microscopy (TEM) and atomic force microscopy (AFM). X–ray photoelectron spectra (XPS) and Raman spectra were employed to get further insights into the structural characteristics of exfoliated GS. On the surface of the GS modified glassy carbon electrode (GS/GCE), oxidation signals corresponding to carbendazim, a widely used pesticide, were greatly improved due to the higher accumulation ability, as determined by chronocoulometry. The oxidation mechanism of carbendazim was studied using a rotating disk electrode, and two electrons were transferred. Depending on the signal amplification of GS, a highly sensitive analytical platform for carbendazim was constructed. The linear range was from 1.0 to 300.0 μg L −1 (0.005–1.57 μM), and the detection limit was 0.15 μg L −1 (0.78 nM). Finally, this newly developed sensor was used to detect carbendazim in ground water, soil, and cucumber samples with satisfactory accuracy.

Influence of Water on Passivation of Zr in n-butanol Solution Containing Bun4NBr

Xiyun YANG,Jianfeng ZHANG,Shenghai YANG,Niuchang OUYANG

To understand the role of water on zirconium passivation in n-butanol solutions containing Bun4NBr, composition and corrosion properties of the passive film were studied using cyclic voltammetry, X-ray photoelectron and electrochemical impedance spectroscopy. Zirconium undergoes spontaneous passivation followed by pitting corrosion as a result of passivity breakdown by the aggressive attack of bromide anions. The passive film consists mainly of ZrO2, ZrO2·2H2O and a small amount of zirconium butoxide. The pitting potential shifts positively and pitting corrosion is seriously inhibited with the addition of a small amount of water. Water improves the pitting corrosion resistance of the passive film by changing the thickness and the relative ratio of OH−/O2−. The result is helpful to electrosynthesize zirconium butoxide with high energy efficiency.

Factors affecting N-nitrosodimethylamine formation from poly(diallyldimethyl-ammonium chloride) degradation during chloramination

Siying Tan,Shaojie Jiang,Xiaoyu Li,Qiuhong Yuan

Poly(diallyldimethylammonium chloride) (polyDADMAC) has been shown to be an important precursor of the probable human carcinogen N-nitrosodimethylamine (NDMA) when in contact with chloramine. In this study, we conducted an orthogonal experiment design to evaluate the effects of pH values, ammonia, bromide, natural organic matter (NOM) and monochloramine dosages on the formation of NDMA from polyDADMAC during chloramination. Meanwhile, single-factor experiments of pH, bromide and NOM prove the results of orthogonal experiment. The results supported that pH was the most critical factor affecting NDMA formation from polyDADMAC during chloramination, and the highest NDMA formation from polyDADMAC occurred at pH near 7 due to released DMA from polyDADMAC degradation and the critical importance of low concentrations of dichloramine in water. In the presence of excess bromide, the NDMA formation was enhanced significantly at all different pH values owing to bromochloramine, which has higher electronegativity of the brominated nitrogen atom than monochloramine or dichloramine. The NDMA formation from polyDADMAC in the presence of NOM was 41.7% lower than NDMA formation in the absence of NOM. The overwhelming majority of NDMA formation from polyDADMAC under simulated conditions was lower than the current advisory levels (i.e. 9 ng l−1 in Ontario, 10 ng l−1 in California).

Thermal conductivity modification of n-octanoic acid-myristic acid composite phase change material

Yinghui Wang,Xuelai Zhang,Jun Ji,Yuyang Li,Jotham Muthoka Munyalo,Biao Liu,Xiaofeng Xu,Sheng Liu

Considering the low thermal conductivity of organic phase change materials (PCMs), a modification of Octanoic acid (OA) and Myristic acid (MA) binary mixture with a mass ratio of 87:13 was studied. The influence of expanded graphite (EG) and Hydroxylated multi-walled carbon nanotubes (MWCNTs) on the thermal conductivity of OA-MA were compared and analyzed. The morphology of these two nanoparticals and OA-MA/EG PCM were measured by scanning electronic microscope (SEM). 7 wt% EG was finally selected as the additive to modify the thermal conductivity of OA-MA. By differential scanning calorimeter (DSC), the phase transition temperature was measured to be 6.8 °C and the enthalpy of fusion was 136.3 J/g. The thermal conductivity of OA-MA/EG was 0.9975 W/(m·K) tested by Hot Disk, which remarkably increased by 235.75% compared with the thermal conductivity of OA-MA. Undergoing 100 freeze-thaw cycles, the properties of the OA-MA/EG did not change significantly, which shows the composite PCM is especially suitable for its application in pharmaceutical refrigerated transport system.

N-type Bi-doped SnSe Thermoelectric Nanomaterials Synthesized by a Facile Solution Method

Xiaofang Li,Chen Chen,Wenhua Xue,Shan Li,Feng Cao,Yuexing Chen,Jiaqing He,Jiehe Sui,Xingjun Liu,Yumei Wang,Qian Zhang

An n-type Bi-doped SnSe was synthesized by a facile solution method followed by spark plasma sintering. We used bismuth(III) 2-ethyhexanoate as a cationic dopant precursor, which can absorb on the powder surface and then diffuse into the lattice to realize the substitution of Sn by Bi. A strip structure with low-angle boundary was constructed for effective phonon scattering. With increasing content of Bi, the carrier concentration decreased from 1.35 × 1019 cm–3 (p-type) in undoped SnSe to 4.7 × 1014 cm–3 (n-type) in Sn0.99Bi0.01Se and then increased to 1.3 × 1015 cm–3 (n-type) in Sn0.97Bi0.03Se. The Seebeck coefficient changed from positive to negative and presented n-type conducting behavior in the whole measured temperature range from 300 to 773 K, reaching a maximum absolute value of ∼900 μV K–1 at room temperature and ∼300 μV K–1 at 773 K. Considering the rich variety of metal 2-ethylhexanoates, higher thermoelectric performance is expected by different cationic doping in solution-synthesized nanomaterials.

Poly(N-isopropylacrylamide)/mesoporous silica thermosensitive composite hydrogels for drug loading and release

Zhaofu Zhang,Shuo Wang,Geoffrey I. N. Waterhouse,Qihai Zhang,Lifang Li

Temperature-sensitive hydrogels are attracting increasing attention for controlled drug delivery. However, achieving high drug loadings and sustained drug release remains challenging. Herein, we describe the successful synthesis of a series of novel temperature-sensitive poly( N -isopropylacrylamide) (PNIPA)/mesoporous silica nanoparticles (MSN) hydrogels by physical crosslinking of NIPA with MSN. The external and internal structures, temperature sensitivity, drug-loading capacity, and blood compatibility of the PNIPA/MSN composite hydrogels are studied. Results show that MSN addition improved the network structure and adjusted the size of the hole, MSN could also act as drug carrier, thereby enhancing the drug loading capacity. The composite hydrogels underwent a phase transition at 33.7 °C (at the lower critical solution temperature). The hemolysis rate of the composite hydrogels was less than 1%, thus they can be classified as a nonhemolytic materials with good biocompatibility. The composite hydrogels reported here thus have great potential in drug transport and temperature-activated drug release. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48391.

Fe-N-doped carbon nanofiber and graphene modified separator for lithium-sulfur batteries

Xiong Song,Suqing Wang,Guoping Chen,Tuo Gao,Yue Bao,Liang-Xin Ding,Haihui Wang

A novel lightweight, multi-functional layer comprised of 1D porous Fe-embedded nitrogen-doped carbon nanofibers (Fe-N-C) and 2D graphene sheets is introduced to modify a commercial polypropylene (PP) separator for use in lithium-sulfur batteries. Benefiting from the high electrical conductivity and strong lithium polysulfide (LiPS) chemical adsorption ability of Fe-N-C, the porous intercalation-structured modified layer exhibits excellent ability to suppress LiPS shuttling while maintaining high lithium-ion transport, and the modified layer functions as a highly conductive upper current collector to reutilize active sulfur species. The cell assembled with the modified multifunctional separator shows a high rate capability and excellent cycling stability, exhibiting a capacity of 847.9 mAh g −1 at 2 C and a low degradation rate of 0.053% per cycle over 500 cycles at 0.5 C.