查找使用阿拉丁产品的科研文献

Oxidative degradation of tetracycline using persulfate activated by N and Cu codoped biochar

Quanfa Zhong,Qintie Lin,Runlin Huang,Hengyi Fu,Xiaofeng Zhang,Haoyu Luo,Rongbo Xiao

A nitrogen and copper codoped biochar (N-Cu/biochar) material was prepared and used to activate persulfate (PS) for tetracycline (TC) degradation. The material was characterized by SEM, FT-IR, XRD and XPS. The results showed that the N-Cu/biochar had a flaky carbon structure with urchin-like copper growing on the carbon surface, a large specific surface area of 352.43 m 2 /g that provided sufficient active sites for catalytic reaction, and abundant functional groups. Quenching experiments and electron paramagnetic resonance (EPR) experiments verified the reaction pathway mechanisms. The main free radical in the system was HO ; another possible mechanism is the nonradical pathway of electron transfer between TC and PS on the surface of the catalyst, and this electron transfer could lead to TC degradation. All the TC was removed within 120 min at a catalyst dosage of 200 mg/L, PS dosage of 0.5 mM, and pH of 7.0. Chloride and bicarbonate ions had little effect on the degradation of TC. HPLC-MS was used to investigate the main degradation intermediates and the possible transformation pathways were proposed. The toxicity of TC and its intermediates were evaluated by bioluminescence inhibition method. The high catalytic efficiency and low consumables of the N-Cu/biochar/PS system could provide a new strategy for the remediation of wastewater.

N-doped reduced graphene oxide supported mixed Ni2PCoP realize efficient overall water electrolysis

Xiao Zhang,Jiangwei Li,Yanfang Sun,Zijian Li,Pei Liu,Qingyun Liu,Lin Tang,Jinxue Guo

Searching active and cost-effective bifunctional electrocatalysts for overall water splitting is a vital but challenging task towards clean and sustainable energy sources. Here, mixed metal phosphides of Ni 2 P CoP anchored on N-doped reduced graphene oxide (NiCoP/N-rGO) as efficient and earth-abundant electrocatalysts for water splitting are reported. The large active sites, synergism, and hybridization with N-doped rGO endow NiCoP/N-rGO electrocatalyst with outstanding oxygen evolution reaction activity that is better than benchmark RuO 2 in alkaline electrolyte , as well as active hydrogen evolution reaction in acidic, neutral, and alkaline solution. NiCoP/N-rGO has further been employed as both anode and cathode in a two-electrode alkaline water electrolyzer towards overall water splitting, exhibiting advanced electrochemical performances with a low cell voltage of 1.57 V at a current density of 20 mA cm −2 . Moreover, the overall water splitting in this two-electrode electrolyzer can be driven by a single-cell AA battery (nominal voltage of 1.5 V), making NiCoP/N-rGO as the promising efficient cost-effective catalysts for water electrolysis.

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.

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).

Temperature-Responsive Electrocatalysis Based on Poly(N-Isopropylacrylamide)-Modified Graphene Oxide (PNIPAm-GO)

Hairan Zhang,Qiuyue Zhang,Ling Zhang,Tingting Pei,Erni Li,Huiting Wang,Qian Zhang,Lixin Xia

Graphical Making the switch : A thermally responsive poly( N -isopropylacrylamide)-modified graphene oxide (PNIPAm-GO) nanocomposite was synthesized by using a covalent “grafting-from” strategy. It was further applied as an intelligent PNIPAm-GO/GC electrode to display switchable electrocatalysis toward 1,4-dihydro-β-nicotinamide adenine dinucleotide and dopamine (see scheme). Poly( N -isopropylacrylamide)-modified graphene oxide (PNIPAm-GO), which is a type of thermally responsive GO, was designed and synthesized through a covalent “grafting-from” strategy. The as-prepared modified nanosheets integrated the individual advantages of two components, such as the thermal sensitivity of the PNIPAm terminal as well as the conductivity and the open 2D structure of the GO substrate. PNIPAm-GO was able to perform the reversible regulation of hydrophilicity/hydrophobicity in aqueous solution upon variations in the temperature. Such a unique property might also lead to the utilization of PNIPAm-GO as an intelligent electrode material to achieve a switchable electrochemical response toward a [Fe(CN) 6 ] 3−/4− probe. The PNIPAm-GO modified glassy carbon electrode (PNIPAm-GO/GC electrode) was able to exhibit better electrochemical performance in an ON/OFF switching effect than the PNIPAm-modified glassy carbon electrode (PNIPAm/GC electrode) without GO owing to the intrinsic properties and large surface area of the introduced GO. Moreover, it was found that the PNIPAm-GO/GC electrode also displayed excellent thermally responsive electrocatalysis toward the detection of 1,4-dihydro-β-nicotinamide adenine dinucleotide (NADH) and dopamine (DA), which resulted in two different catalytic statuses on the same electrode. This kind of switchable catalytic performance of the PNIPAm-GO/GC electrode might greatly enhance the flexibility of its application, and thus it is expected to have wide potential for applications in the fields of biosensors and biocatalysis.

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.

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.

Comparison of the methods for profiling N-glycans—hepatocellular carcinoma serum glycomics study

Ran Wang,Yufei Liu,Chang Wang,Henghui Li,Xin Liu,Liming Cheng,Yanhong Zhou

Monitoring serum glycomics is one of the most important emerging approaches for diagnosis of various cancers, and the majority of previous studies were based on MALDI-MS or HPLC analysis. Considering the difference of these analytical methods employed for serum glycomics, it is necessary to compare the effectiveness of different analytical methods for monitoring the aberrant changes in serum glycomics. In this study, a strategy based on machine learning was firstly applied for comparing the analysis results of MALDI-MS and HPLC on the same serum glycomics of hepatocellular carcinoma (HCC) samples. The capability of these two analytical methods for identifying HCC is demonstrated by the classification results obtained from MALDI-MS and HPLC data. In addition, by comparing glycomics which were significantly correlated with HCC based on MALDI-MS and HPLC, some N-glycans which may be the potential biomarkers for HCC were identified, validating the capability of these two analytical methods for the differentiated identification in the analysis of glycomics. Meanwhile, it is noteworthy that various physiological and environmental factors may cause the aberrant changes in glycosylation, and all these interference factors may be minimized by analyzing the same sample sets of HCC. Overall, these results showed that MALDI-MS and HPLC are complementary in qualitative and quantitative analysis of serum glycomics.

Facile Fabrication of N-Doped Magnetic Porous Carbon for Highly Efficient Mercury Removal

Lijin Huang,Man He,Beibei Chen,Bin Hu

N-doped magnetic porous carbon (N-MPC) is an emerging adsorbent for water pollution control. However, high cost and multisteps procedure make the direct fabrication of N-MPCs difficult until now. Herein, highly dispersed N-MPCs were synthesized by a facial one-pot solid-state pyrolysis strategy. Heating the mixture of ZnO, Co(OH)2, and 2-methylimidazole (HmIm), Zn/Co bimetallic ZIFs formed at the initial stages, being the primary self-template to produce N-MPCs during subsequent high-temperature treatment. By altering the pyrolysis temperature and the molar ratio of ZnO/Co(OH)2 in the precursor, the magnetism, nitrogen content, and surface areas of N-MPCs can be easily controlled. Due to its high special surface areas and the decoration of abundant nitrogen functional groups (pyrrole-N and pyridinic-N), the optimized N-MPC-700-7/3 exhibited a superior adsorption performance for Hg2+ uptake (489 mg g–1). Moreover, the N-MPCs exhibited fast dynamics in adsorption (K2 = 0.47 g mg–1 min–1) and good chemical stability. The simple, sustainable, and impressive method provides an attractive way to manufacture efficiency MPC sorbents, and the prepared N-MPCs merit good application potential in environmental remediation.

Highly Photoluminescent and Stable N-Doped Carbon Dots as Nanoprobes for Hg2+ Detection

Longshi Rao,Yong Tang,Hanguang Lu,Shudong Yu,Xinrui Ding,Ke Xu,Zongtao Li,Jin Z. Zhang

We developed a microreactor with porous copper fibers for synthesizing nitrogen-doped carbon dots (N-CDs) with a high stability and photoluminescence (PL) quantum yield (QY). By optimizing synthesis conditions, including the reaction temperature, flow rate, ethylenediamine dosage, and porosity of copper fibers, the N-CDs with a high PL QY of 73% were achieved. The PL QY of N-CDs was two times higher with copper fibers than without. The interrelations between the copper fibers with different porosities and the N-CDs were investigated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR). The results demonstrate that the elemental contents and surface functional groups of N-CDs are significantly influenced by the porosity of copper fibers. The N-CDs can be used to effectively and selectively detect Hg2+ions with a good linear response in the 0~50 μM Hg2+ions concentration range, and the lowest limit of detection (LOD) is 2.54 nM, suggesting that the N-CDs have great potential for applications in the fields of environmental and hazard detection. Further studies reveal that the differentdorbital energy levels of Hg2+compared to those of other metal ions can affect the efficiency of electron transfer and thereby result in their different response in fluorescence quenching towards N-CDs.Keywords:microreactor;carbon dots;porous copper fibers;Hg2+detection