POLYMER DEGRADATION AND STABILITY
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2021
·
IF 5.03
Dongyue Liu,Yihua Cui,Tianlong Zhang,Wenhua Zhao,Pengfei Ji
The introduction of traditional flame retardants into epoxy resins (EP) usually generated a number of harmful smoke during burning. A novel flame retardant ( d ZIF-8) was synthesized via functionalization of zeolitic imidazolate frameworks-8 by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives (DMZ). The flame retardancy and smoke suppression of the d ZIF-8 modified EP were studied. The combustion results showed that d ZIF-8 can effectively reduce the fire risk of EP. Compared with the neat EP, the value of peak heat release rate (PHRR), the total smoke release rate (TSRR) and the maximum smoke density of the EP containing 2% d ZIF-8 were decreased by 51%, 47% and 36%, respectively. The TG-FTIR results showed that the production of the pyrolysis gaseous products was inhibited by d ZIF-8 during the decomposition of EP. In addition, the synergistic effect between the DMZ and the zeolitic imidazolate frameworks-8 improved the flame retardancy of the EP. Meanwhile, the increase in the flame-retardant performance of the d ZIF-8 modified EP was caused by the quenching effect of the free radical containing phosphorus in gas phase and the charring effect of pyrophosphoric acid and zinc oxide in condensed phase. The morphology of d ZIF-8 crystal changed from granular to laminar, indicating that the introduction of DMZ affected the crystal growth of d ZIF-8. The laminar structure of the d ZIF-8 provided a layered barrier effect during the burning process of EP.
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NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 41
·19416-19424
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IF 3.591
Xuefeng Tong,Jingjing Zhang,Qibin Chen,Honglai Liu
The removal of Congo red (CR) from aqueous solution was reported in this work using a zeolitic imidazolate framework-8/graphene oxide/magnetic chitosan (ZIF-8-GMCS) composite as a novel bio-adsorbent. Such a ZIF-8-GMCS composite consisted of magnetic Fe3O4 and ZIF-8 nanoparticles, single-layer graphene oxide (GO) and chitosan (CS), where ZIF-8 nanoparticles with a relatively regular geometry were in situ grown on the surface of the composites. The surface morphology and chemical composition of ZIF-8-GMCS were characterized using various techniques. Herein, the impact of adsorbent dosage, interference of other anionic dyes, initial pH of CR, ionic strength, initial concentration of CR solution, contact time and adsorption temperature on the adsorption performance was systematically explored. The results showed that the adsorption processes follow the Langmuir isotherm model and pseudo-second-order model and the maximum adsorption capacity derived from the Langmuir model is 476.19 mg g−1 at 303.15 K, which is higher than that of most magnetic adsorbents toward CR. Moreover, the adsorption of ZIF-8-GMCS toward CR could be ascribed to the cooperative effect of electrostatic, hydrogen-bonding, coordination and π–π stacking interactions. Our finding demonstrates that ZIF-8-GMCS derived from biomass resources shows potential application prospects in the decontamination of dye wastewater.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 95
·期 3
·730-738
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IF 2.659
Yating Wang,Xu Li,Xiu Dai,Yixing Zhan,Xiaoqing Ding,Ming Wang,Xinglong Wang
BACKGROUND With the rapid industrial and urbanization development, a large amount of oily wastewater is generated from various sources. It is mutagenic and carcinogenic to human health and seriously affects the ecosystem. In this study PLA/ZIF-8@C600 nanofibers were prepared for oil adsorption. RESULTS Hybrid nanoparticles (ZIF-8@C600) of carbon black C600 and zeolitic imidazolate framework-8 (ZIF-8) with high specific surface area and porous structure were prepared by co-deposition and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FITR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and contact angle measurement. Biodegradable composite nanofiber membranes of poly(lactic acid) (PLA) and ZIF-8@C600 were manufactured by electrospinning. The SEM and contact angle results showed that the addition of ZIF-8@C600 could adjust the diameter, porosity, pore size and hydrophobicity of the composite electrospun nanofibers. The PLA/ZIF-8@C600 porous membranes had good oil sorption properties in oil–water mixture and emulsion. The oil adsorption capacity of the sample with 1 wt% ZIF-8@C600 was improved by ∼72.59% compared with that of pure PLA (13.5 g g −1 ), which demonstrated that the PLA/ZIF-8@C600 fibers were good candidates as oil sorbents. The adsorption kinetics of the membranes on paraffin liquid was in accordance with pseudo-second-order kinetics. CONCLUSION The addition of hybrid ZIF-8@C600 improved the hydrophobic properties and oil adsorption capacity of PLA/ZIF-8@C600 porous membranes. Because PLA is an environmentally friendly polymer, composite membranes based on it can avoid secondary pollution. Overall, these findings have good prospects for future treatment of oily wastewater. © 2019 Society of Chemical Industry
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BIOTECHNOLOGY LETTERS
·
2019
·Vol. 42
·期 2
·269-276
·
IF 2.154
Cai Xinyong,Zhang Mengjie,Wei Wei,Zhang Yinjun,Wang Zhao,Zheng Jianyong
A novel enzyme immobilization method employing metal–organic framework (MOF) encapsulation and macroporous resin adsorption was developed in this study. Candida antarctica lipase B (CALB) was firstly encapsulated onto metal–organic frame structures (Zeolitic imidazole framework-8, ZIF-8) and further bonded to macroporous resin by physical adsorption. Under optimized immobilization conditions, the activity of the prepared immobilized lipase (CALB-ZIF-8@D101) determined via the methyl esterification of oleic acid was 38.4 U/mg. Compared with free lipase, the immobilized lipase exhibited improved thermal and operational stability and organic solvent tolerance. These results demonstrate that the immobilization method of ZIF-8 encapsulation and macroporous resin adsorption enhanced enzyme properties at a superior level.
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高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2019
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IF 3.218
Yaru Chu,Feng Gao,Fei Gao,Qingxiang Wang
The zeolitic imidazolate framework ZIF-8 was synthesized and mixed with chitosan (CS) solution to obtain a homogeneous dispersion. Then the dispersion of ZIF-8 and CS (ZIF-8-CS) modified glassy carbon electrode is fabricated and utilized for stripping voltammetric analysis of Hg 2+ , Cu 2+ , Pb 2+ and Cd 2+ for the first time. The large surface area effect and strong enriching effect of the nanosized ZIF-8 to the four heavy metal ions contribute to significantly enhance analytical signals. Under the optimum conditions, the stripping peak current densities linearly increased with Hg 2+ concentration in the range from 1.0 μM to 80.0 μM, and with Cu 2+ , Pb 2+ and Cd 2+ concentrations in the range from 1.0 μM to 100.0 μM. The analytical sensitivity for the four ions are estimated to be 14.20 μA·μM −1 ·cm −2 (Hg 2+ ), 2.797 μA·μM −1 ·cm −2 (Cu 2+ ), 5.203 μA·μM −1 ·cm −2 (Pb 2+ ) and 1.390 μA·μM −1 ·cm −2 (Cd 2+ ), respectively. The limits of detection for the four ions were estimated to be 0.0293 μM (Hg 2+ ), 0.108 μM (Cu 2+ ), 0.0619 μM (Pb 2+ ) and 0.135 μM (Cd 2+ ), respectively. The ZIF-8 based modified electrode also presented excellent anti-interference ability, and good reliability for monitoring the four ions in real water samples.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2019
·
IF 5.107
Tie Gao,Zhenzhen Liu,Haibo Li
Heteroatom doped carbonaceous material has attracted enormous attentions in electrochemical research community due to the replacement of some carbon atoms in the carbon skeleton result in charge redistribution and thus the modification of physiochemical properties. In this work, we proposed a facial approach to synthesize nitrogen and titanium co-doped hierarchical mesoporous carbon ((N, Ti)-HMCs) by employing ZIF-8 as procures for capacitive deionization (CDI) with enhanced performance. The as-prepared (N, Ti)-HMCs exhibits novel cubic structure, high doping content and high specific surface area of 1025.93 m 2 /g. The Raman spectra revealed the presence of abundant structural defects in (N, Ti)-HMCs rather than HMCs which is beneficial to promote the electrosorption. Besides, the electrochemical analysis demonstrated that (N, Ti)-HMCs owns improved specific capacitance and lower resistivity as compared to that of HMCs. Moreover, by examining the CDI performance of (N, Ti)-HMCs in a batch mode experiment, it illustrated high salt removal capacity of 13.89 mg/g at 1.2 V in a 500 mg/L NaCl solutions and outstanding adsorption rate of 3.53 mg/(g·min). Thus, (N, Ti)-HMCs should be proposed as superior electrode materials for enhanced CDI. Our work also strengthens the emphasis on heteroatom doped carbonaceous materials in CDI.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Jialin Shi,Lina Zhang,Nannan Sun,Deng Hu,Qun Shen,Fang Mao,Qiang Gao,Wei Wei
Metal–organic frameworks (MOFs) are promising hosts for catalytic active sites due to their adjustable porosity and framework chemistry. Strategies to improve synergistic effects between the installed sites and the parent MOF are highly desired. Herein, a facile and rapid method for the preparation of xAg@ZIF-8 materials was reported. The materials were systematically characterized and used as catalysts for carboxylation of terminal alkynes via direct insertion of CO2 to the C(sp)–H bond (CTACO2). It was found that the integrity of the ZIF-8 structure could be retained upon Ag loading, but short-range crystalline ordering was modified. Two types Ag species could be installed, namely, highly dispersed Ag(I) in the backbone (AgHD) and aggregated Ag(0) nanoparticles on the outer surface (AgNP). The AgNP sites are highly effective for the activation of terminal alkynes due to its high accessibility, while the AgHD-modified ZIF-8 framework worked as a CO2 reservoir with enhanced affinity. Combination of these factors translated to high activity in the CTACO2 process, the measured turnover frequency and time yield are among the highest among most heterogeneous catalysts.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Feng Chen,Songlin Dong,Zhi Wang,Jiayou Xu,Rui Xu,Jixiao Wang
The incompatibility between nanofillers and polymer, caused by the agglomeration of nanoparticles and their weak interaction with each other, is still a challenge to develop mixed matrix composite membrane . Herein, we introduced the ZIF-8-TA nanoparticles synthesized by in situ hydrophilic modification into the hydrophilic poly(vinylamine) (PVAm) matrix to prepare composite membranes for H 2 purification. The dispersion of ZIF-8 in water was improved by tannic acid modification, and the compatibility between ZIF-8 particles and PVAm matrix was enhanced by chemical crosslinking between the quinone groups in oxidized tannic acid (TA) and the amino groups in PVAm. Moreover, the compatibility between hydrophobic polydimethylsiloxane (PDMS) gutter layer and hydrophilic separation layer was achieved by the adhesion of TA-Fe 3+ complex to the surface of PDMS layer during membrane preparation. The interlayer hydrophilic modification and the formation of separation layer were accomplished in one step, which simplified the preparation process. The experimental results indicated that when the TA addition used for modification was 0.5 g and the ZIF-8-TA 0.5 content in membrane was 12 wt%, the prepared membrane showed the best separation performance with the CO 2 permeance of 987 GPU and the CO 2 /H 2 selectivity of 31, under the feed gas pressure of 0.12 MPa.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Yongcun Song,Nan Wang,Li-ye Yang,Yang−guang Wang,Di Yu,Xiao-kun Ouyang
Metal–organic frameworks (MOFs) have received special attention from scientists owing to their excellent adsorption performance. However, the difficulty in separating MOFs from adsorbed metals following use has limited their application. A zeolitic imidazole-based MOF with broad applicability for sorption of Pb(II) is examined. In this work, a novel adsorbent employing ZIF-8/calcium alginate microparticles was prepared using sodium alginate and ZIF-8. This adsorbent was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The performance of the ZIF-8@CA microparticles in adsorbing Pb(II) from a Pb(II) solution was investigated, and the impacts of the initial Pb(II) concentration, reaction time, pH, and reaction temperature on the reaction process were investigated. The results showed that ZIF-8@CA microparticles exhibited a maximum adsorption capacity of 1321.21 mg/g at pH 5 after 120 min, and the adsorption process was found to fit the Langmuir isotherm model (R2 = 0.9856) and the pseudo-second-order kinetic model (R2 = 0.9999). These results showed that the adsorption of Pb(II) was an endothermic process. The regeneration experiment with ZIF-8@CA revealed that the removal efficiency of Pb(II) was greater than 80% even after five cycles.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Meixia Wang,Jing Zhang,Xibin Yi,Xinfu Zhao,Benxue Liu,Xiaochan Liu
In this study, chitosan was used to prepare nitrogen-doped carbon aerogels (CAs) anchored by ZIF-8 derived porous carbon (ZIF-8-C) using a facile in-situ deposition method combined with subsequent carbonization. CAs possessing a 3D mesoporous structure with interlaced nanosheets can be used as the skeleton for growth of ZIF-8 derived microporous carbon. The coexistence of mesopores and micropores can not only create more channels for electrolyte ions accessing, but also can provide electrical-double-layer capacitance. The results of electrochemical performance revealed that the ZCCA composite electrode shows the large specific capacitance of 241.6 F/g at a current density of 0.5 A/g in 2.0 M KOH electrolyte and superior cycle performance (capacity retention of 90% after 5000 cycles). The improvement in the electrochemical properties is owed to its hierarchically porous structure, ultrahigh specific surface area and moderate nitrogen contents. The preparation method offers the smart design of CAs-supported MOF-derived material for high-performance energy storage applications.
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TALANTA
·
2019
·
IF 4.916
Yan-Qiu Zhang,Xiao-Han Wu,Shun Mao,Wen-Quan Tao,Zhuo Li
Antibiotics are one of the emerging contaminants in water, which have a great impact on ecosystems and human health. It has been challenging to simultaneously realize low-cost, rapid, highly sensitive and selective detection of antibiotics with conventional methods. Here, we report luminescent chemosensors for detecting antibiotics in water, based on metal-organic framework (MOF), i.e., zeolitic imidazolate framework-8 (ZIF-8), loaded with rhodamine B (RhB) and fluorescein disodium salt (FSS) dyes. Compared with ZIF-8, the fluorescence signals of RhB@ZIF-8 and FSS@ZIF-8 were significantly improved and presented ultrahigh sensitivity to nitrofurans (NFAs) and tetracyclines (TCs) with fluorescence quenching and fluorescence enhancement in water, respectively. The unique structures and properties of RhB@ZIF-8 and FSS@ZIF-8 lead to outstanding sensitivities in antibiotic detection. For instance, the RhB@ZIF-8 sensor shows the lower limit of detection (LOD) of 0.26 μM to nitrofurantoin (NFT), 0.47 μM to nitrofurazone (NFZ), 0.11 μM to tetracycline (TC), and 0.14 μM to oxytetracycline (OTC); while the FSS@ZIF-8 sensor shows the LOD of 0.31 μM to NFT, 0.35 μM to NFZ, 0.17 μM to TC, and 0.16 μM to OTC. In addition, NFT and TC were also successfully detected by FSS@ZIF-8 in water from real water environment. The results indicate that dye@MOF-based luminescent composites are favorable for antibiotic detection, presenting great potentials in water quality monitoring.
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高影响因子
DYES AND PIGMENTS
·
2018
·
IF 3.767
Xiran Yang,Simin Liu
The host−guest interactions between Auramine O ( AuO ) dye and cucurbit[ n ]uril (CB[ n ], n = 7, 8) were investigated in aqueous solution by 1 H NMR, UV/Vis, fluorescence spectroscopic techniques and single crystal diffraction. The results indicate the simultaneous formation of 1:1 and 2:1 inclusion complexes between CB[7] and AuO with two binding constants as 1.17 × 10 5 M −1 and 3.99 × 10 2 M −1 by UV/Vis spectroscopy titration (1.20 × 10 5 M −1 and 5.26 × 10 3 M −1 by fluorescence spectroscopy) in phosphate buffer (pH 7.4). And a 1:2 homoternary inclusion complex CB[8]· AuO 2 with binding constant as 2.95 × 10 9 M −2 (by fluorescence spectroscopy titration) is detected. Interestingly, the appearance of intense new broad emission band with big red-shift (100 nm) with respect to that of AuO proves the formation of excimer upon encapsulation of AuO molecules in CB[8]. Determination of single crystal structure of CB[8]· AuO 2 further discloses the existence of J-type dimer with intermolecular CH···π interactions between two included phenyl groups on AuO molecules. Upon host−guest complexation of AuO with CB[7] or CB[8], the p K a shifts of AuO were measured.
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