FOOD CHEMISTRY
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2021
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IF 7.514
Yingying Hu,Rentian Guan,Shuai Zhang,Xiaoyu Fan,Wenjing Liu,Keying Zhang,Xiaodong Shao,Xia Li,Qiaoli Yue
A convenient fluorescence sensor of tetracycline (TC) was constructed based on carbon dots (CDs) and polyvinyl alcohol (PVA) hydrogel film. The immobilization of CDs in PVA carrier can stabilize the fluorescence of CDs by inhibiting the fluorescence quench due to the aggregation of CDs with time. CDs were prepared by a hydrothermal method. CDs showed bright blue fluorescence with the quantum yield of 0.35. The fluorescence of CDs was quenched by TC owing to the inner filter effect. The linear range for TC detection was 0–350 µM and the limit of detection was 0.17 µM. To test conveniently, PVA film was employed to upload CDs. Therefore, a novel sensor for TC was constructed in a visual mode. By comparison with the most of previous works, the present method displayed higher sensitivity and better selectivity. The results suggest that the present sensor has potential applications in the real-time detection of TC in food analysis.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Chengyuan Duan,Meili Ding,Yi Feng,Mengjue Cao,Jianfeng Yao
Integration of Lewis acid and base sites and oxygen surface groups in one catalyst is favorable to promote CO 2 cycloaddition reaction. Here, Zn-ZIF-L was used as starting material to design one kind of catalyst with multiple active sites via pyrolysis and oxidization treatment. The well-dispersed ZnO nanoparticles and pyridinic nitrogen in nitrogen-doped carbon serve as Lewis acid and base sites to activate epoxide and CO 2 while oxygen surface groups help promote the ring-opening reaction of epoxides. Results show that Zn-ZIF-L derived catalyst displays high catalytic activities for CO 2 cycloaddition (6 h, 83% of yield) under mild conditions (70 °C and 0.1 MPa CO 2 ) and outperforms ZIF-8 derived catalyst. Moreover, the obtained catalyst also achieves a satisfactory photothermal catalysis of cycloaddition reaction under light irradiation (120 mW/cm 2 ), which makes our sample a promising catalyst for CO 2 conversion.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Huiwang Dai,Wenjun Zhou,Wei Wang,Zhiqi Liu
In this study, three Co/N-C catalysts were prepared by pyrolysis of bimetallic zeolitic imidazole frameworks with different Co/Zn ratio, and the critical active Co species in peroxymonosulfate (PMS) activation was investigated. The three catalysts had distinct cobalt species but similar N configuration and graphitization degree. The Co species were distributed as single atoms (Co SAs) at a Co/Zn molar ratio of 1:8, while Co nanoclusters (Co NCs) and Co nanoparticles (NPs) would be formed with further increase in Co content. The degradation efficiency of BPA did not show correlation with the increasing of Co content in catalyst. Based on the catalytic performance comparison and reactive species detection, Co SAs was identified as active sites, which could interact with PMS to generate 1 O 2 via path of PMS→HOO*→O*→ 1 O 2 . However, the role of NCs and NPs in directly activating PMS was negligible. In addition, the increase of Co content in Co/N-C catalyst would result in mass cobalt leaching, which enhanced the BPA degradation via homogeneous catalytic reactions with Co IV as reactive species. It is an effective way to design the Co/N-C catalyst with high catalytic activity and stability via regulating the formation of Co SAs.
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RSC Advances
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2021
·Vol. 11
·期 56
·35268-35273
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IF 3.361
Bin Li,Jizhen Liu,Dandan Fu,Yongjing Li,Xiaojia Xu,Ming Cheng
In this study, a simple and eco-friendly method was proposed to efficiently prepare nanocomposite hydrogels with excellent mechanical properties and satisfactory pH response behaviour by frontal polymerization (FP) of DEM in close to 4 minutes. Acrylamide (AM) and choline chloride (ChCl) were used as raw materials to synthesize deep eutectic monomers (DEMs). Nitrogen-doped carbon nanotubes were dispersed in DEMs as fillers, and poly(acrylamide)/nitrogen-doped carbon nanotube (PAM/N-CNT) nanocomposite hydrogels were prepared by FP. The non-covalent interactions between PAM hydrogels and N-CNTs was verified by Fourier infrared spectroscopy. The mechanical properties of PAM/N-CNT nanocomposite hydrogels were investigated, as well as the swelling and pH response properties. The results showed that the compressive strength of PAM hydrogels was significantly enhanced by the addition of N-CNTs due to the hydrophobic interaction of N-CNTs, which also causes sensitive response properties of the PAM hydrogels in acid solution.
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POLYMER DEGRADATION AND STABILITY
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2021
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IF 5.03
Chao Wan,Huajun Duan,Chenhao Zhang,Jianfan Cao,Jiahao Zou,Junjun Zhang,Huiru Ma
In order to obtain an efficient flame retardant without sacrificing mechanical properties and transparency of epoxy resin (EP), a P/N/S-containing flame retardant (STP) by combining 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with Schiff base intermediate synthesized by the reaction of sulfathiazole and 2-thenaldehyde was successfully synthesized. The synthesis of STP was verified and the properties of modified EP were studied. The test results indicated that STP slowed down the degradation rate of EP. The glass transition temperature (T g ) of the flame-retardant epoxy resin (FREP) samples were well maintained and even improved after introducing a certain amount of STP. Furthermore, FREP with low phosphorus content exerted excellent flame retardant ability, EP/5%STP (phosphorus content: 0.27 wt%) obtained the V-0 rating of UL-94 test with the value of limiting oxygen index (LOI) 33.5%. In contrast with EP, the peak heat release rate (PHRR), total heat release (THR) and total smoke production (TSP) of EP/7.5%STP were respectively decreased by 33.31%, 26.04% and 28.75%. Mechanical performance tests show that STP improved the tensile and flexural strength of EP. It is worth mentioning that the EP modified with STP still maintains good transparency.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Shizong Wang,Jianlong Wang
In this study, cobalt embedded into oxygen and nitrogen co-doped CNTs (Co@N-O-CNTs) was prepared by pyrolysis and used to activate peroxymonosulfate (PMS) for degradation of sulfamethoxazole. The experimental results showed that the content of oxygen precursor had important influence on the catalytic activity of Co@N-O-CNTs. When the content of oxygen precursor was 2 g, Co@N-O-CNTs exhibited better catalytic activity than previously reported Co@N-CNTs. Bulk and surface-bound radicals resulted in sulfamethoxazole (SMX) degradation, in which SMX degradation rate reached 0.247 min −1 with the mineralization of 35.6%. The possible pathway of SMX degradation was proposed based on the identified degradation products. Characterization results indicated that nitrogen, oxygen and cobalt in the structure of Co@N-O-CNTs-2 were active sites for PMS activation. Theoretical calculation suggested that nitrogen and oxygen co-doping created more active sites to activate PMS compared with single nitrogen doping. During the six cycling experiments, Co@N-O-CNTs-2 exhibited good catalytic and structural stability. The influencing factors, including temperature, pH, PMS concentration, chloridion, bicarbonate and humic acids were investigated. This study could provide a way to boost active sites of nitrogen doped carbonaceous materials to effectively activate PMS for degradation of emerging organic pollutants.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
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IF 8.128
Huaying Hou,Zhongxu Wang,Yajie Ma,Kai Yu,Jingxiang Zhao,Huiming Lin,Fengyu Qu
The intracellular O 2 -supply not only can relieve tumor hypoxia but also enhance the effects of photodynamic therapy (PDT). In this work, metallic Mo 2 [email protected] N [email protected] nanoparticles were constructed to reveal the near infrared (NIR)-photocatalytic O 2 generation and promote photodynamic therapy (PDT). Here, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O nanorods and urea were adopted as resources that were calcined to obtain Mo 2 [email protected] N -carbon nanoparticles (20 nm). All samples displayed high NIR absorption as well as photothermal conversion efficiency of up to 52.7 % (Mo 2 [email protected] N [email protected] ). The density functional theory calculations demonstrated the metallic characteristic of Mo 2 C and that the consecutive interband/intraband charge-transition was responsible for the high NIR harvest and redox ability of electron-hole pairs, making the NIR-photocatalytic O 2 and reactive oxygen species (ROS) generation. In comparison with the pure Mo 2 C, the heterostructure displayed twice the performance due to the enhanced charge-segregation between Mo 2 C and N -carbon. Given the high X-ray absorption coefficient and photothermal ability, the nanocomposite could be used in novel computer tomography and photothermal imaging contrast. Furthermore, the novel biodegradation and metabolism behaviors of nanocomposites were investigated, which were reflected as elimination from the body (mouse) via feces and urine within 14 days. The as-synthesized Mo 2 [email protected] N [email protected] nanocomposites integrated the dual-model imaging, intracellular O 2 -supply, and phototherapy into one nanoplatform, revealing its potential for anti-cancer therapy.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
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IF 8.128
Mingliang Ma,Zijian Liao,Xuewei Su,Qixi Zheng,Yanyan Liu,Yan Wang,Yong Ma,Fei Wan
Increasing electromagnetic (EM) radiation has driven the rapid development of carbon-based EM wave absorption materials, but the design of light-weight and efficient carbon-based materials remains a huge challenge. Herein, N -doped carbon fibers embedded with CoNi alloy particles (CoNi/C fibers) were synthesized via electrospinning technology and carbonization . Then, conductive polypyrrole-coated CoNi/C fibers (CoNi/C@PPy composites) were synthesized by chemical polymerization. As-synthesized CoNi/C@PPy composites showed outstanding EM wave absorption property due to the synergistic effect between CoNi, N -doped carbon fibers and PPy. The optimal reflection loss (RL) is -68.78 dB (12.90 GHz) with the thickness of 2.43 mm and the low filler loading of 15 wt%. The widest effective absorption bandwidth (EAB) is 5.62 GHz with the thickness of 2.10 mm and the low filler loading of 20 wt%. The outstanding EM wave absorption property is mainly attributed to 3D network structure, great impedance matching and strong dielectric loss. The results showed that embedding magnetic alloy particles in carbon fibers coated with conductive polymers is an effective strategy for constructing efficient lightweight EM wave absorption materials.
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MINERALS ENGINEERING
·
2021
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IF 4.765
Huifang Yang,Kaihua Huang,Xiaoyu Cao,Xiaoping Huang,Zhanfang Cao,Hong Zhong,Hu Zhou,Jianxian Zeng,Jianrong Xue,Rui Zhang
The flotation performance and hydrophobic mechanism of O-ethyl-N-benzoyl thionocarbamate (EBZTC) on chalcopyrite were first estimated by single flotation experiments, batch adsorption experiments, contact angle measurements, DFT calculation and FTIR analysis. Single flotation experiments illustrated that a flotation recovery of 96.7% was achieved to chalcopyrite when EBZTC was used compared to 90% with SIBX at pH 6.5. Adsorption experiments indicated that the adsorption process of EBZTC on chalcopyrite surface was an exothermic monolayer chemisorption process. Hydrophobic mechanism demonstrated that EBZTC chemisorbed onto the chalcopyrite surface through the chemical reactions of C O and C S groups to the copper species with the formation of C O Cu and C S Cu bonds, which resulted in the coverage of the hydrophobic groups of EBZTC onto the chalcopyrite surface to enhance its hydrophobicity.
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International Journal of Polymeric Materials and Polymeric Biomaterials
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2021
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IF 2.604
Changgui Li,Yuheng Qiu,Rongguo Li,Mengting Li,Ziyu Qin,Xueqiong Yin
A thermo-sensitive film composed of polycaprolactone and poly(N-isopropylacrylamide) was fabricated via electrospinning, with ketoconazole as the model drug. The morphology, elemental composition, and surface hydrophilicity of the nanofibres were characterized, and the results showed that nanofibres switched from a hydrophilic to a hydrophobic state as the temperature increased from 25 °C to 37 °C. The drug release profiles of the films suggested that sustained drug release behavior was achieved, and a lower temperature induced a faster delivery. Therefore, the prepared nanofibres could be highly applicable as wound dressings for on-demand and sustained drug release systems based on their temperature-responsive properties.
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Nanomaterials
·
2021
·Vol. 11
·期 11
·2776
·
IF 5.076
Yuan Huang,Haoting Yan,Chenyang Zhang,Yize Wang,Qinhong Wei,Renkun Zhang
Metal-supported catalyst with high activity and relatively simple preparation method is given priority to industrial production. In this work, this study reported an easily accessible synthesis strategy to prepare Mott-Schottky-type N-doped carbon encapsulated metallic Co (Co@Np+gC) catalyst by high-temperature pyrolysis method in which carbon nitride (g-C3N4) and dopamine were used as support and nitrogen source. The prepared Co@Np+gC presented a Mott-Schottky effect; that is, a strong electronic interaction of metallic Co and N-doped carbon shell was constructed to lead to the generation of Mott-Schottky contact. The metallic Co, due to high work function as compared to that of N-doped carbon, transferred electrons to the N-doped outer shell, forming a new contact interface. In this interface area, the positive and negative charges were redistributed, and the catalytic hydrogenation mainly occurred in the area of active charges. The Co@Np+gC catalyst showed excellent catalytic activity in the hydrogenation of phenylacetylene to styrene, and the selectivity of styrene reached 82.4%, much higher than those of reference catalysts. The reason for the promoted semi-hydrogenation of phenylacetylene was attributed to the electron transfer of metallic Co, as it was caused by N doping on carbon.Keywords:cobalt catalyst;N-doped carbon;Mott-Schottky effect;catalytic hydrogenation;phenylacetylene
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CHEMICAL ENGINEERING JOURNAL
·
2021
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IF 13.273
Chenglin Liu,Zhijie Liang,Chun Yang,Fuyi Cui,Zhiwei Zhao
N-nitrosamines (NAs), a class of emerging nitrogenous disinfection byproducts , have been detected remarkably in drinking/reclaimed water. There is a significant risk of excessive levels of NAs in the chlorination of the polluted source water, especially in the direct chlorination of nitrite-enriched groundwater. Considering the co-pollution of nitrite and micro-organic pollutants on groundwater, experiments were conducted on chlorination of nitrite-enriched water with precursor of antibiotics, and it was confirmed that the Cl 2 : N (molar ratio of chlorine to nitrite), contacting time, pH, and DO appreciably influenced the NAs formation potential. The molecular electric potential revealed that different dissociation status of precursors has a specific correlation with NAs formation potential (FP). The nitrite significantly increased the NAs FP because the reactive nitrogen species (RNS) formed in the oxidation process from nitrite to nitrate. Sequences of transformation products are determined to support the RNS promoted hypothesis of N-nitrosodimethylamine (NDMA) formation mechanism; furthermore, theoretical investigation in the reaction of dimethylamine (DMA) with different RNS verified the above hypothesis.
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