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  • Solid-state NMR for metal-containing zeolites: From active sites to reaction mechanism
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-22
    Xingling Zhao, Jun Xu, Feng Deng

    Abstract Metal-containing zeolite catalysts have found a wide range of applications in heterogeneous catalysis. To understand the nature of metal active sites and the reaction mechanism over such catalysts is of great importance for the establishment of structure-activity relationship. The advanced solid-state NMR (SSNMR) spectroscopy is robust in the study of zeolites and zeolite-catalyzed reactions. In this review, we summarize recent developments and applications of SSNMR for exploring the structure and property of active sites in metal-containing zeolites. Moreover, detailed information on host-guest interactions in the relevant zeolite catalysis obtained by SSNMR is also discussed. Finally, we highlight the mechanistic understanding of catalytic reactions on metal-containing zeolites based on the observation of key surface species and active intermediates.

  • Optimization of electrochemically synthesized Cu 3 (BTC) 2 by Taguchi method for CO 2 /N 2 separation and data validation through artificial neural network modeling
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-16
    Kasra Pirzadeh, Ali Asghar Ghoreyshi, Mostafa Rahimnejad, Maedeh Mohammadi

    Abstract Cu3(BTC)2, a common type of metal organic framework (MOF), was synthesized through electrochemical route for CO2 capture and its separation from N2. Taguchi method was employed for optimization of key parameters affecting the synthesis of Cu3(BTC)2. The results indicated that the optimum synthesis conditions with the highest CO2 selectivity can be obtained using 1 g of ligand, applied voltage of 25 V, synthesis time of 2 h, and electrode length of 3 cm. The single gas sorption capacity of the synthetized microstructure Cu3(BTC)2 for CO2 (at 298 K and 1 bar) was a considerable value of 4.40 mmol · g−1. The isosteric heat of adsorption of both gases was calculated by inserting temperature-dependent form of Langmuir isotherm model in the Clausius-Clapeyron equation. The adsorption of CO2/N2 binary mixture with a concentration ratio of 15/85 vol-% was also studied experimentally and the result was in a good agreement with the predicted value of IAST method. Moreover, Cu3(BTC)2 showed no considerable loss in CO2 adsorption after six sequential cycles. In addition, artificial neural networks (ANNs) were also applied to predict the separation behavior of CO2/N2 mixture by MOFs and the results revealed that ANNs could serve as an appropriate tool to predict the adsorptive selectivity of the binary gas mixture in the absence of experimental data.

  • Perspective of mixed matrix membranes for carbon capture
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-16
    Shinji Kanehashi, Colin A. Scholes

    Polymeric membrane-based gas separation has found wide applications in industry, such as carbon capture, hydrogen recovery, natural gas sweetening, as well as oxygen enrichment. Commercial gas separation membranes are required to have high gas permeability and selectivity, while being cost-effective to process. Mixed matrix membranes (MMMs) have a composite structure that consists of polymers and fillers, therefore featuring the advantages of both materials. Much effort has been made to improve the gas separation performance of MMMs as well as general membrane properties, such as mechanical strength and thermal stability. This perspective describes potential use of MMMs for carbon capture applications, explores their limitations in fabrication and methods to overcome them, and addresses their performance under industry gas conditions.

  • Coextraction of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation process
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-15
    Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

    Abstract High-manganese containing vanadium wastewater (HMVW) is commonly produced during the vanadium extraction process from vanadium titano-magnetite. HMVW cannot be reused and discharged directly, and is harmful to the environment and affect product quality due to heavy metals in the wastewater. The wastewater is usually treated by lime neutralization, but valuable metals (especially V and Mn) cannot be recovered. In this study, an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process. In the solvent extraction process, 98.15% of vanadium was recovered, and the V2O5 product, with a purity of 98.60%, was obtained under optimal conditions. For the precipitation process, 91.05% of manganese was recovered as MnCO3 which meets the III grade standard of HG/T 2836-2011. Thermodynamic simulation analysis indicated that MnCO3 was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated. The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V2O5 and MnCO3 displayed a good degree of crystallinity. The treated wastewater can be returned for leaching, and resources (V and Mn) in the wastewater were utilized efficiently in an environmentally friendly way. Therefore, this study provides a novel method for the coextraction of V and Mn from HMVW.

  • Postsynthesis of hierarchical core/shell ZSM-5 as an efficient catalyst in ketalation and acetalization reactions
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-15
    Peng Luo, Yejun Guan, Hao Xu, Mingyuan He, Peng Wu


  • Synthesis of micro/meso porous carbon for ultrahigh hydrogen adsorption using cross-linked polyaspartic acid
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-15
    Jun Wei, Jianbo Zhao, Di Cai, Wenqiang Ren, Hui Cao, Tianwei Tan


  • Layer-like FAU-type zeolites: A comparative view on different preparation routes
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-10
    Bastian Reiprich, Tobias Weissenberger, Wilhelm Schwieger, Alexandra Inayat

    The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance. After a short general survey into routes for the preparation of hierarchical pore systems in FAU, we will review the currently existing strategies for the synthesis of FAU with layer-like morphology. Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture. However, a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives, just by finely adjusting the crystallization temperature. This additive-free preparation route for layer-like FAU, which appears very attractive from an ecological as well as economic point of view, is highlighted in this review. Concluding, a comparison, including powder X-ray diffraction, scanning and transmission electron microscopy, nitrogen physisorption and elemental analysis, between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural, morphological and textural differences and similarities of these materials.

  • Reduced texaphyrin: A ratiometric optical sensor for heavy metals in aqueous solution
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-08
    Harrison D. Root, Gregory Thiabaud, Jonathan L. Sessler

    We report here a water-soluble metal cation sensor system based on the as-prepared or reduced form of an expanded porphyrin, texaphyrin. Upon metal complexation, a change in the redox state of the ligand occurs that is accompanied by a color change from red to green. Although long employed for synthesis in organic media, we have now found that this complexation-driven redox behavior may be used to achieve the naked eye detectable colorimetric sensing of several number of less-common metal ions in aqueous media. Exposure to In(III), Hg(II), Cd(II), Mn(II), Bi(III), Co(II), and Pb(II) cations leads to a colorimetric response within 10 min. This process is selective for Hg(II) under conditions of competitive analysis. Furthermore, among the subset of response-producing cations, In(III) proved unique in giving rise to a ratiometric change in the ligand-based fluorescence features, including an overall increase in intensity. The cation selectivity observed in aqueous media stands in contrast to what is seen in organic solvents, where a wide range of texaphyrin metal complexes may be prepared. The formation of metal cation complexes under the present aqueous conditions was confirmed by reversed phase high-performance liquid chromatography, ultra-violet-visible absorption and fluorescence spectroscopies, and high-resolution mass spectrometry.

  • Sponge-based materials for oil spill cleanups: A review
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-08
    Edward Mohamed Hadji, Bo Fu, Ayob Abebe, Hafiz Muhammad Bilal, Jingtao Wang

    Elimination of leaked oil from aquatic environs has recently gained importance owing to the disasters associated with leakages into marine environments. The need for an environmentally friendly and viable line of action concerning the environs has brought forward numerous affordable, non-toxic, and decomposable materials; further, diverse biomasses for fabricating nano- to micro-scale materials, membranes, and sponges/aerogels have also been incorporated for the elimination and retrieval of oils from water. Moreover, selectivity, sorption capacity, and reusability of these materials after the retrieval of oils are also desired from the viewpoint of sustainability. This review encompasses the recent progress in the field of elimination and retrieval of oil spills using various sponge-based materials.

  • Diporphyrin tweezer for multichannel spectroscopic analysis of enantiomeric excess
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-08
    Daniel T. Payne, Mandeep K. Chahal, Václav Březina, Whitney A. Webre, Katsuhiko Ariga, Francis D’Souza, Jan Labuta, Jonathan P. Hill

    Abstract Chiral 1,1’-binaphthyl-linked diporphyrin ‘tweezers’ (R)-1/(S)-1 and the corresponding zinc(II) complexes (R)-2/(S)-2 were prepared as chiral host molecules, and their utility for chiral analyses (especially enantiomeric excess (ee) determinations) were evaluated. Tris(1-n-dodecyl)porphyrins were used for the first time as the interacting units. Host capabilities of the diporphyrin tweezers were investigated by titrations with (R,R)- and (S,S)-cyclohexane-1,2-diamine (CHDA). The host molecules could be used as multichannel probes of ee by using UV-vis, circular dichroism (CD), fluorescence emission and 1H nuclear magnetic resonance (1H-NMR) methods. Chiral configurations could also be differentiated using CD or 1H-NMR spectroscopy. All three optical techniques give good resolution of ee with reasonable sensitivity considering the low concentrations used (ca. 10−6 mol·L−1). The ee determination of CHDA enantiomers using NMR spectroscopy is also possible because of the reasonably well separated resonances in the case of (R,R)- and (S,S)-CHDA. Non-metallated (R)-1/(S)-1 hosts could not be used to detect chiral information in a strongly acidic chiral guest. This work demonstrates the utility of 1,1’-binapthyl-linked chiral hosts for chiral analysis of ditopically interacting enantiomers.

  • Fabrication of titanosilicate pillared MFI zeolites with tailored catalytic activity
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-04
    Baoyu Liu, Qiaowen Mu, Jiajin Huang, Wei Tan, Jing Xiao

    Abstract Titanosilicate pillared MFI zeolite nanosheets were successfully synthesized by infiltrating the mixed tetraethyl orthosilicate (TEOS)/tetrabutyl orthotitanate (TBOT) solvent into the gallery space between adjacent MFI zeolite layers. The obtained zeolite catalysts were characterized using powder X-ray diffraction, N2 adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy techniques. The H2O2 oxidation of dibenzothiophene (DBT) was used to evaluate the catalytic performance of the obtained titanosilicate pillared MFI zeolites. The conversion of DBT and selectivity of dibenzothiophene sulfone (DBTS) were most affected by the textural properties of the zeolites. This was attributed to the DBT and DBTS molecules being larger than micropores of the MFI zeolites. The conversion of DBT and yield of DBTS could be systematically tailored by tuning the molar ratio of the TEOS/TBOT solvent. These results implied that a balance between the meso- and microporosity of zeolites and tetrahedrally coordinated Ti (IV) active sites of titanosilicate pillars can be achieved for the preparation of desired catalysts during the oxidation of bulk S compounds.

  • Improved CO 2 capture performances of ZIF-90 through sequential reduction and lithiation reactions to form a hard/hard structure
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-04
    Mahboube Ghahramaninezhad, Fatemeh Mohajer, Mahdi Niknam Shahrak

    Abstract Post-synthetic functionalization or modification has been regarded as a promising strategy to treat surfaces of adsorbents for their applications in targeted adsorption and separation processes. In this work, a novel microporous adsorbent for carbon capturing was developed via functionalization of zeolitic imidazolate frame-work-91 (ZIF-91) to generate a hard/hard (metal-oxygen) structure named as lithium-modified ZIF-91 (ZIF-91-OLi compound). To this purpose, the ZIF-91 compound as an intermediate product was achieved by reduction of ZIF-90 in the presence of NaBH4 as a good reducing agent. Afterwards, acidic hydrogen atoms in the hydroxyl groups of ZIF-91 were exchanged with lithium cations via reaction of n-BuLi compound as an organo lithium agent through an appropriate procedure. In particular, the as-synthesized ZIF-91-OLi operated as an excellent electron-rich center for CO2 adsorption through trapping the positive carbon centers in the CO2 molecule. DFT calculations revealed that the presence of lithium over the surface of ZIF-91-OLi adsorbent plays an effective role in double enhancement of CO2 storage via creating a strong negative charge center at the oxygen atoms of the imidazolate linker as a result of the lithium/hydrogen exchange system. Finally, the selectivity of CO2/N2 was investigated at different temperatures, revealing the ZIF-91-OLi as a selective adsorbent for industrial application.

  • 更新日期:2020-01-04
  • Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-03
    Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

    The Fischer-Tropsch synthesis (FTS) continues to be an attractive alternative for producing a broad range of fuels and chemicals through the conversion of syngas (H2 and CO), which can be derived from various sources, such as coal, natural gas, and biomass. Among iron carbides, Fe2C, as an active phase, has barely been studied due to its thermodynamic instability. Here, we fabricated a series of Fe2C embedded in hollow carbon sphere (HCS) catalysts. By varying the crystallization time, the shell thickness of the HCS was manipulated, which significantly influenced the catalytic performance in the FTS. To investigate the relationship between the geometric structure of the HCS and the physic-chemical properties of Fe species, transmission electron microscopy, X-ray diffraction, N2 physical adsorption, X-ray photo-electron spectroscopy, hydrogen temperature-programmed reduction, Raman spectroscopy, and Mössbauer spectroscopy techniques were employed to characterize the catalysts before and after the reaction. Evidently, a suitable thickness of the carbon layer was beneficial for enhancing the catalytic activity in the FTS due to its high porosity, appropriate electronic environment, and relatively high Fe2C content.

  • Facile synthesis of hierarchical flower-like Ag/Cu 2 O and Au/Cu 2 O nanostructures and enhanced catalytic performance in electrochemical reduction of CO 2
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-03
    Mengyun Wang, Shengbo Zhang, Mei Li, Aiguo Han, Xinli Zhu, Qingfeng Ge, Jinyu Han, Hua Wang

    Novel, hierarchical, flower-like Ag/Cu2O and Au/Cu2O nanostructures were successfully fabricated and applied as efficient electrocatalysts for the electrochemical reduction of CO2. Cu2O nanospheres with a uniform size of ∼180 nm were initially synthesized. Thereafter, Cu2O was used as a sacrificial template to prepare a series of Ag/Cu2O composites through galvanic replacement. By varying the Ag/Cu atomic ratio, Ag0.125/Cu2O, having a hierarchical, flower-like nanostructure with intersecting Ag nanoflakes encompassing an inner Cu2O sphere, was prepared. The as-prepared Agx/Cu2O samples presented higher Faradaic efficiencies (FE) for CO and relatively suppressed H2 evolution than the parent Cu2O nanospheres due to the combination of Ag with Cu2O in the former. Notably, the highest CO evolution rate was achieved with Ag0.125/Cu2O due to the larger electroactive surface area furnished by the hierarchical structure. The same hierarchical flower-like structure was also obtained for the Au0.6/Cu2O composite, where the FECO (10%) was even higher than that of Ag0.125/Cu2O. Importantly, the results reveal that Ag0.125/Cu2O and Au0.6/Cu2O both exhibit remarkably improved stability relative to Cu2O. This study presents a facile method of developing hierarchical metal-oxide composites as efficient and stable electrocatalysts for the electrochemical reduction of CO2.

  • Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic method
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-02
    Zhaoyou Zhu, Guoxuan Li, Yao Dai, Peizhe Cui, Dongmei Xu, Yinglong Wang

    The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.

  • Co-conversion of methanol and n -hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2020-01-02
    Shumei Wei, Yarong Xu, Zhaoyang Jin, Xuedong Zhu

    The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization. In this study, intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-11 zeolites. The physicochemical properties of ZSM-5/ZSM-11 intergrown zeolite were analyzed using X-ray diffraction, N2 isothermal adsorption-desorption, the temperature-programmed desorption of ammonium, scanning electron microscopy, Fourier transform infrared spectra of adsorbed pyridine, and nuclear magnetic resonance of 27Al, and compared with those of the ZSM-5 and ZSM-11 zeolites. The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400°C, 0.5 MPa (N2), methanol:n-hexane = 7:3 (mass ratio), and weight hourly space velocity = 1 h−1 (methanol). Compared to the ZSM-5 and ZSM-11 zeolites, the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area, a unique crystal structure, moderate acidity, and suitable Brønsted/Lewis acid ratio. The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate, n-hexane conversion rate, and aromatic selectivity. The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal structure. The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.

  • Thermodynamic analysis of ethanol synthesis from hydration of ethylene coupled with a sequential reaction
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-20
    Jie Gao, Zhikai Li, Mei Dong, Weibin Fan, Jianguo Wang

    Abstract Coal-based ethanol production by hydration of ethylene is limited by the low equilibrium ethylene conversion at elevated temperature. To improve ethylene conversion, coupling hydration of ethylene with a potential ethanol consumption reaction was analyzed thermodynamically. Five reactions have been attempted and compared: (1) dehydration of ethanol to ethyl ether (2C2H5OH ⇔ C2H5OC2H5 + H2O), (2) dehydrogenation of ethanol to acetaldehyde (C2H5OH ⇔ CH3CHO + H2), (3) esterification of acetic acid with ethanol (C2H5OH + CH3COOH ⇔ CH3COOC2H5 + H2O), (4) dehydrogenation of ethanol to ethyl acetate (2C2H5OH ⇔ CH3COOC2H5 + 2H2), and (5) oxidative dehydrogenation of ethanol to ethyl acetate (2C2H5OH + O2 ⇔ CH3COOC2H5 + 2H2O). The equilibrium constants and equilibrium distributions of the coupled reactions were calculated and the effects of feed composition, temperature and pressure upon the ethylene equilibrium conversion were examined. The results show that dehydrogenation of ethanol to acetaldehyde has little effect on ethylene conversion, whereas for dehydrogenation of ethanol to acetaldehyde and ethyl acetate, ethylene conversion can be improved from 8% to 12.8% and 18.5%, respectively, under conditions of H2O/C2H4 = 2, 10 atm and 300°C. The esterification of acetic acid with ethanol can greatly enhance the ethylene conversion to 22.5%;in particular, ethylene can be actually completely converted to ethyl acetate by coupling oxidative dehydrogenation of ethanol.

  • Hypoxia-induced activity loss of a photo-responsive microtubule inhibitor azobenzene combretastatin A4
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-19
    Yang An, Chao Chen, Jundong Zhu, Pankaj Dwivedi, Yanjun Zhao, Zheng Wang

    Abstract The conformation-dependent activity of azobenzene combretastatin A4 (Azo-CA4) provides a unique approach to reduce the side-effects of chemotherapy, due to the light-triggered conformation transition of its azobenzene moiety. Under hypoxic tumor microenvironment, however, the high expression of azoreductase can reduce azobenzene to aniline. It was postulated that the Azo-CA4 might be degraded under hypoxia, resulting in the decrease of its anti-tumor activity. The aim of this study was to verify such hypothesis in HeLa cells in vitro. The quantitative drug concentration analysis shows the ratio-metric formation of degradation end-products, confirming the bioreduction of Azo-CA4. The tubulin staining study indicates that Azo-CA4 loses the potency of switching off microtubule dynamics under hypoxia. Furthermore, the cell cycle analysis shows that the ability of Azo-CA4 to induce mitotic arrest is lost at low oxygen content. Therefore, the cytotoxicity of Azo-CA4 is compromised under hypoxia. In contrast, combretastatin A4 as a positive control maintains the potency to inhibit tubulin polymerization and break down the nuclei irrespective of light irradiation and oxygen level. This work highlights the influence of hypoxic tumor microenvironment on the anti-tumor potency of Azo-CA4, which should be considered during the early stage of designing translational Azo-CA4 delivery systems.

  • Easy access to pharmaceutically relevant heterocycles by catalytic reactions involving α-imino gold carbene intermediates
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-19
    Ximei Zhao, Matthias Rudolph, Abdullah M. Asiri, A. Stephen K. Hashmi

    This review summarizes recent advances in the field of gold-catalyzed synthesis of pharmaceutically relevant aza-heterocycles via in situ generated α-imino gold carbene complexes as intermediates.

  • Linking renewables and fossil fuels with carbon capture via energy storage for a sustainable energy future
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-19
    Dawid P. Hanak, Vasilije Manovic

    Renewable energy sources and low-carbon power generation systems with carbon capture and storage (CCS) are expected to be key contributors towards the decarbonisation of the energy sector and to ensure sustainable energy supply in the future. However, the variable nature of wind and solar power generation systems may affect the operation of the electricity system grid. Deployment of energy storage is expected to increase grid stability and renewable energy utilisation. The power sector of the future, therefore, needs to seek a synergy between renewable energy sources and low-carbon fossil fuel power generation. This can be achieved via wide deployment of CCS linked with energy storage. Interestingly, recent progress in both the CCS and energy storage fields reveals that technologies such as calcium looping are technically viable and promising options in both cases. Novel integrated systems can be achieved by integrating these applications into CCS with inherent energy storage capacity, as well as linking other CCS technologies with renewable energy sources via energy storage technologies, which will maximise the profit from electricity production, mitigate efficiency and economic penalties related to CCS, and improve renewable energy utilisation.

  • A novel method for generating distillation configurations
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-16
    Hongzhe Hou, Yiqing Luo

    An improved matrix method for generating distillation configurations with (N−1) and less than (N−1) columns was proposed for the separation of an N-component mixture into essentially pure product streams based on the concepts of streams matrix and 0–1 matrixes proposed by Agrawal. In contrast with the matrix method developed by Agrawal, the present method removes the intermediate process centered on the splits, and complex column configurations, allowing the direct generation of multi-feeds and multi-product streams. Furthermore, certain configurations that cannot be generated directly and that are missing in the matrix method are obtained. Through rigorous simulations and optimization, we have demonstrated that these configurations have the potential to outperform certain existing configurations.

  • Electrochemical sensor investigation of carbon-supported PdCoAg multimetal catalysts using sugar-containing beverages
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-16
    Firat Salman, Hilal C. Kazici, Hilal Kivrak

    Novel PdCoAg/C nanostructures were successfully synthesized by the polyol method in order to develop electrocatalysts, related to the glucose sensor performance of the high glycemic index in beverages. The characterization of this novel PdCoAg/C electrocatalyst was performed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy equipped with energy dispersive X-ray. The characterization results revealed that electronic state of the PdCoAg/C electro-catalyst was modified by the addition of the third metal. The electrochemical performances of the sensor were investigated by cyclic voltammetry and differential pulse voltammetry. The prepared enzyme-free sensor exhibited excellent catalytic activity against glucose with a wide detection range (0.005 to 0.35 mmol · L−1), low limit of detection (0.003 mmol · L−1), high sensitivity (4156.34 µA · mmol−1 · L · cm−2), and long-term stability (10 days) because of the synergistic effect between the ternary metals. The glucose contents of several energy drinks, fruit juices, and carbonated beverages were analyzed using the novel PdCoAg/NGCE/C sensor system. These results indicate the feasibility for applications in the foods industry.

  • 4-Amino-1,8-naphthalimide based fluorescent photoinduced electron transfer (PET) pH sensors as liposomal cellular imaging agents: The effect of substituent patterns on PET directional quenching
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-10
    Miguel Martínez-Calvo, Sandra A. Bright, Emma B. Veale, Adam F. Henwood, D. Clive Williams, Thorfinnur Gunnlaugsson

    Four new fluorescent sensors (1–4) based on the 4-amino-1,8-naphthalimide fluorophores (Naps) have been synthesized based on the classical fluorophorespacer-receptor model. These four compounds all gave rise to emission bands centred at ca. 535 nm, which were found to be highly pH dependent, the emission being ‘switched on’ in acidic media, while being quenched due to PET from the amino moieties to the excited state of the Nap at more alkaline pH. The luminescent pH dependence for these probes was found to be highly dependent on the substitution on the imide site, as well as the polyamine chain attached to the position 4-amino moiety. In the case of sensor 2 the presence of the 4-amino-aniline dominated the pH dependent quenching. Nevertheless, at higher pH, PET quenching was also found to occur from the polyamine site. Hence, 2 is better described as a receptor1-spacer1-fluorophore-spacer2-receptor2 system, where the dominant PET process is due to (normally less favourable) ‘directional’ PET quenching from the 4-amino-aniline unit to the Nap site. Similar trends and pH fluorescence dependences were also seen for 3 and 4. These compounds were also tested for their imaging potential and toxicity against HeLa cells (using DRAQ5 as nuclear stain which does now show pH dependent changes in acidic and neutral pH) and the results demonstrated that these compounds have reduced cellular viability at moderately high concentrations (with IC50 values between ca. 8–30 µmol·L−1), but were found to be suitable for intracellular pH determination at 1 µmol ·L−1concentrations, where no real toxicity was observed. This allowed us to employ these as lysosomal probes at sub-toxic concentrations, where the Nap based emission was found to be pH depended, mirroring that seen in aqueous solution for 1–4, with the main fluorescence changes occurring within acidic to neutral pH.

  • Hierarchical ZSM-5 zeolite with radial mesopores: Preparation, formation mechanism and application for benzene alkylation
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-10
    Darui Wang, Hongmin Sun, Wei Liu, Zhenhao Shen, Weimin Yang

    Hierarchical ZSM-5 zeolite with radial mesopores is controllably synthesized using piperidine in a NaOH solution. The piperidine molecules enter the zeolite micropores and protect the zeolite framework from extensive desilication. The areas containing fewer aluminum atoms contain fewer piperidine protectant molecules and so they dissolve first. Small amounts of mesopores are then gradually generated in areas with more aluminum atoms and more piperidine protectant. In this manner, radial mesopores are formed in the ZSM-5 zeolite with a maximal preservation of the micropores and active sites. The optimal hierarchical ZSM-5 zeolite, prepared with a molar ratio of piperidine to zeolite of 0.03, had a mesopore surface area of 136 m2·g−1 and a solid yield of 80%. The incorporation of the radial mesopores results in micropores that are interconnected which shortened the average diffusion path length. Compared to the parent zeolite, the hierarchical ZSM-5 zeolite possesses more accessible acid sites and has a higher catalytic activity and a longer lifetime for the alkylation of benzene.

  • Thermal and catalytic pyrolysis of a synthetic mixture representative of packaging plastics residue
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-07
    Simona Colantonio, Lorenzo Cafiero, Doina De Angelis, Nicolò M. Ippolito, Riccardo Tuffi, Stefano Vecchio Ciprioti

    A synthetic mixture of real waste packaging plastics representative of the residue from a material recovery facility (plasmix) was submitted to thermal and catalytic pyrolysis. Preliminary thermogravimetry experiments coupled with Fourier transform infrared spectroscopy were performed to evaluate the effects of the catalysts on the polymers’ degradation temperatures and to determine the main compounds produced during pyrolysis. The thermal and catalytic experiments were conducted at 370°C, 450°C and 650°C using a bench scale reactor. The oil, gas, and char yields were analyzed and the compositions of the reaction products were compared. The primary aim of this study was to understand the effects of zeolitic hydrogen ultra stable zeolite Y (HUSY) and hydrogen zeolite socony mobil-5 (HZSM5) catalysts with high silica content on the pyrolysis process and the products’ quality. Thermogravimetry showed that HUSY significantly reduces the degradation temperature of all the polymers—particularly the polyolefines. HZSM5 had a significant effect on the degradation of polyethylene due to its smaller pore size. Mass balance showed that oil is always the main product of pyrolysis, regardless of the process conditions. However, all pyrolysis runs performed at 370°C were incomplete. The use of either zeolites resulted in a decrease in the heavy oil fraction and the prevention of wax formation. HUSY has the best performance in terms of the total monoaromatic yield (29 wt-% at 450°C), while HZSM5 promoted the production of gases (41 wt-% at 650°C). Plasmix is a potential input material for pyrolysis that is positively affected by the presence of the two tested zeolites. A more effective separation of polyethylene terephthalate during the selection process could lead to higher quality pyrolysis products.

  • An efficient technique for improving methanol yield using dual CO 2 feeds and dry methane reforming
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-12-05
    Yang Su, Liping Lü, Weifeng Shen, Shun’an Wei

    Steam methane reforming (SMR)-based methanol synthesis plants utilizing a single CO2 feed represent one of the predominant technologies for improving methanol yield and CO2 utilization. However, SMR alone cannot achieve full CO2 utilization, and a high water content accumulates if CO2 is only fed into the methanol reactor. In this study, a process integrating SMR with dry methane reforming to improve the conversion of both methane and CO2 is proposed. We also propose an innovative methanol production approach in which captured CO2 is introduced into both the SMR process and the recycle gas of the methanol synthesis loop. This dual CO2 feed approach aims to optimize the stoichiometric ratio of the reactants. Comparative evaluations are carried out from a techno-economic point of view, and the proposed process is demonstrated to be more efficient in terms of both methanol productivity and CO2 utilization than the existing stand-alone natural gas-based methanol process.

  • Erratum to: Polypyrrole@NiCo hybrid nanotube arrays as high performance electrocatalyst for hydrogen evolution reaction in alkaline solution
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-08-22
    Shenghua Ye, Gaoren Li

    Figure 2(b) on Page 476: It has come to our attention that the data of (i) Co NTAs in Fig. 2(b) is not correct, because we imported the same group of data of PPy@NiCo HNTAs accidentally while plotting with Origin. The corrected Fig. 2(b) is shown below. The data analysis and conclusions are not affected by this unintentional error.

  • Improved film evaporator for mechanistic understanding of microwave-induced separation process
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-05-29
    Xin Gao, Dandan Shu, Xingang Li, Hong Li

    Microwave-induced film evaporation separation process has been reported recently to separate the polar/nonpolar mixture. However, the efficiency of the separation is still too low for practical applications, which requires further enhancement via different strategies such as optimization design of evaporator structure. In addition the depth understanding of the separation mechanisms is great importance for better utilization of the microwave-induced separation process. To carry out these investigations, a novel microwave-induced falling film evaporation instrument was developed in this paper. The improvement of the enhancement effect of microwave-induced separation was observed based on the improved film evaporator. The systematic experiments on microwave-induced separation with different binary azeotropic mixtures (ethanol-ethyl acetate system and dimethyl carbonate (DMC)-H2O system) were conducted based on the new evaporator. For the ethanol-ethyl acetate system, microwave irradiation shifted the direction of evaporation separation at higher ethanol content in the starting liquid mixture. Moreover, for DMC-H2O system microwave-induced separation process broke through the limitations of the traditional distillation process. The results clearly demonstrated the microwave-induced evaporation separation process could be commendably applied to the separation of binary azeotrope with different dielectric properties. Effects of operating parameters are also investigated to trigger further mechanism understanding on the microwave-induced separation process.

  • Microwave-assisted catalyst-free hydrolysis of fibrous cellulose for deriving sugars and biochemicals
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-04-05
    Songshan Jiang, Helen Daly, Huan Xiang, Ying Yan, Huiping Zhang, Christopher Hardacre, Xiaolei Fan

    Microwave (MW) assisted catalyst-free hydrolysis of fibrous cellulose (FC, cellulolysis) at 200°C promoted a cellulose conversion of ca. 37.2% and quantitative production of valuable C5/C6 sugars (e.g., glucose) and the according platform biochemicals (e.g., 5-hydroxymethylfurfural), corresponding to an overall selectivity of 96.5%. Conversely, conventional hydrothermal cellulolysis under similar conditions was not effective, even after 24 h, carbonising the FC. Based on the systematic study of MW-assisted cellulolysis, the specific interaction between water molecules and macroscopic FC under the MW irradiation was proposed, accounting for the interpretation of the experimental observation. The kinetic energy of water molecules under the MW irradiation facilitated the C–C (in the non-hindered surface–CH2OH groups) and C–O–C bond breaking (inside the cellulose cavities) in FC, producing primary cellulolysis products of xylose, glucose and cellobiose.

  • Fabrication of form stable NaCl-Al 2 O 3 composite for thermal energy storage by cold sintering process
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-07-24
    Bilyaminu Suleiman, Qinghua Yu, Yulong Ding, Yongliang Li

    A form stable NaCl-Al2O3 (50–50 wt-%) composite material for high temperature thermal energy storage was fabricated by cold sintering process, a process recently applied to the densification of ceramics at low temperature 300°C under uniaxial pressure in the presence of small amount of transient liquid. The fabricated composite achieved as high as 98.65% of the theoretical density. The NaCl-Al2O3 composite also retained the chloride salt without leakage after 30 heating-cooling cycles between 750°C–850°C together with a holding period of 24 h at 850°C. X-ray diffraction measurements indicated congruent solubility of the alumina in chloride salt, excellent compatibility of NaCl with Al2O3, and chemical stability at high temperature. Structural analysis by scanning electron microscope also showed limited grain growth, high density, uniform NaCl distribution and clear faceted composite structure without inter-diffusion. The latent heat storage density of 252.5 J/g was obtained from simultaneous thermal analysis. Fracture strength test showed high sintered strength around 5 GPa after 50 min. The composite was found to have fair mass losses due to volatilization. Overall, cold sintering process has the potential to be an efficient, safe and cost-effective strategy for the fabrication of high temperature thermal energy storage materials.

  • A combination process of mineral carbonation with SO 2 disposal for simulated flue gas by magnesia-added seawater
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-11-08
    Yingying Zhao, Mengfan Wu, Zhiyong Ji, Yuanyuan Wang, Jiale Li, Jianlu Liu, Junsheng Yuan

    The desulfurization by seawater and mineral carbonation have been paid more and more attention. In this study, the feasibility of magnesia and seawater for the integrated disposal of SO2 and CO2 in the simulated flue gas was investigated. The process was conducted by adding MgO in seawater to reinforce the absorption of SO2 and facilitate the mineralization of CO2 by calcium ions. The influences of various factors, including digestion time of magnesia, reaction temperature, and salinity were also investigated. The results show that the reaction temperature can effectively improve the carbonation reaction. After combing SO2 removal process with mineral carbonation, Ca2+ removal rate has a certain degree of decrease. The best carbonation condition is to use 1.5 times artificial seawater (the concentrations of reagents are 1.5 times of seawater) at 80°C and without digestion of magnesia. The desulfurization rate is close to 100% under any condition investigated, indicating that the seawater has a sufficient desulfurization capacity with adding magnesia. This work has demonstrated that a combination of the absorption of SO2 with the absorption and mineralization of CO2 is feasible.

  • Pore-scale simulation of water/oil displacement in a water-wet channel
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-10-01
    Jin Zhao, Guice Yao, Dongsheng Wen

    Water/oil flow characteristics in a water-wet capillary were simulated at the pore scale to increase our understanding on immiscible flow and enhanced oil recovery. Volume of fluid method was used to capture the interface between oil and water and a pore-throat connecting structure was established to investigate the effects of viscosity, interfacial tension (IFT) and capillary number (Ca). The results show that during a water displacement process, an initial continuous oil phase can be snapped off in the water-wet pore due to the capillary effect. By altering the viscosity of the displacing fluid and the IFT between the wetting and non-wetting phases, the snapped-off phenomenon can be eliminated or reduced during the displacement. A stable displacement can be obtained under high Ca number conditions. Different displacement effects can be obtained at the same Ca number due to its significant influence on the flow state, i.e., snapped-off flow, transient flow and stable flow, and ultralow IFT alone would not ensure a very high recovery rate due to the fingering flow occurrence. A flow chart relating flow states and the corresponding oil recovery factor is established.

  • Experimental and theoretical study of microwave enhanced catalytic hydrodesulfurization of thiophene in a continuous-flow reactor
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-10-24
    Hui Shang, Pengfei Ye, Yude Yue, Tianye Wang, Wenhui Zhang, Sainab Omar, Jiawei Wang

    Hydrodesulfurization (HDS) of thiophene, as a gasoline model oil, over an industrial Ni-Mo/Al2O3 catalyst was investigated in a continuous system under microwave irradiation. The HDS efficiency was much higher (5%–14%) under microwave irradiation than conventional heating. It was proved that the reaction was enhanced by both microwave thermal and non-thermal effects. Microwave selective heating caused hot spots inside the catalyst, thus improved the reaction rate. From the analysis of the non-thermal effect, the molecular collisions were significantly increased under microwave irradiation. However, instead of being reduced, the apparent activation energy increased. This may be due to the microwave treatment hindering the adsorption though upright S-bind (η1) and enhancing the parallel adsorption (η5), both adsorptions were considered to favor to the direct desulfurization route and the hydrogenation route respectively. Therefore, the HDS process was considered to proceed along the hydrogenation route under microwave irradiation.

  • A new approach for scheduling of multipurpose batch processes with unlimited intermediate storage policy
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-11-07
    Nikolaos Rakovitis, Nan Zhang, Jie Li, Liping Zhang

    The increasing demand of goods, the high competitiveness in the global marketplace as well as the need to minimize the ecological footprint lead multipurpose batch process industries to seek ways to maximize their productivity with a simultaneous reduction of raw materials and utility consumption and efficient use of processing units. Optimal scheduling of their processes can lead facilities towards this direction. Although a great number of mathematical models have been developed for such scheduling, they may still lead to large model sizes and computational time. In this work, we develop two novel mathematical models using the unit-specific event-based modelling approach in which consumption and production tasks related to the same states are allowed to take place at the same event points. The computational results demonstrate that both proposed mathematical models reduce the number of event points required. The proposed unit-specific event-based model is the most efficient since it both requires a smaller number of event points and significantly less computational time in most cases especially for those examples which are computationally expensive from existing models.

  • Signal promoting role of a p -type transition metal dichalcogenide used for the detection of ultra-trace amounts of diclofenac via a labeled aptasensor
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-04-23
    Abdolhamid Hatefi-Mehrjardi, Amirkhosro Beheshti-Marnani, Zarrin Es′haghi

    A p-type transition metal dichalcogenide (WS2) was synthesized and hybridized with graphene oxide via a simple hydrothermal method. The as-prepared material was used to modify a glassy carbon electrode for the fabrication of a simple, stable, and repeatable methylene blue-labeled “signal-off” aptasensor used for the sensitive determination of very low amounts of sodium diclofenac (DCF). The synthetic material, modification process, and role of WS2 in the current response enhancement were studied by X-ray diffraction, energydispersive X-ray spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, Hall effect, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Subsequently, a wide linear range of DCF concentration (0.5–300 nmol/L), very low limit of detection (0.23 nmol/L), and good selectivity were obtained using the differential pulse voltammetry method with the assembled aptasensor. Finally, the fabricated aptasensor was successfully developed for physiological real samples with significant recoveries.

  • Molecular tailoring to improve polypyrrole hydrogels’ stiffness and electrochemical energy storage capacity
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-06-22
    Evelyn Chalmers, Yi Li, Xuqing Liu

    This research looks at ways of tailoring and improving the stiffness of polypyrrole hydrogels for use as flexible supercapacitor electrodes. Molecules providing additional cross-linking between polypyrrole chains are added post-polymerisation but before gelation, and are found to increase gel stiffness by up to 600%, with the degree of change dependent on reactant type and proportion. It was also found that addition of phytic acid led to an increase in pseudocapacitive behaviour of the hydrogel, and thus a maximum specific capacitance of 217.07 F·g−1 could be achieved. This is an increase of 140% compared to pristine polypyrrole hydrogels produced by this method.

  • Photothermal materials for efficient solar powered steam generation
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-10-24
    Fenghua Liu, Yijian Lai, Binyuan Zhao, Robert Bradley, Weiping Wu

    Solar powered steam generation is an emerging area in the field of energy harvest and sustainable technologies. The nano-structured photothermal materials are able to harvest energy from the full solar spectrum and convert it to heat with high efficiency. Moreover, the materials and structures for heat management as well as the mass transportation are also brought to the forefront. Several groups have reported their materials and structures as solutions for high performance devices, a few creatively coupled other physical fields with solar energy to achieve even better results. This paper provides a systematic review on the recent developments in photothermal nanomaterial discovery, material selection, structural design and mass/heat management, as well as their applications in seawater desalination and fresh water production from waste water with free solar energy. It also discusses current technical challenges and likely future developments. This article will help to stimulate novel ideas and new designs for the photothermal materials, towards efficient, low cost practical solar-driven clean water production.

  • Kinetic Monte Carlo simulations of plasma-surface reactions on heterogeneous surfaces
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-08-22
    Daniil Marinov

    Reactions of atoms and molecules on chamber walls in contact with low temperature plasmas are important in various technological applications. Plasma-surface interactions are complex and relatively poorly understood. Experiments performed over the last decade by several groups prove that interactions of reactive species with relevant plasma-facing materials are characterized by distributions of adsorption energy and reactivity. In this paper, we develop a kinetic Monte Carlo (KMC) model that can effectively handle chemical kinetics on such heterogenous surfaces. Using this model, we analyse published adsorption-desorption kinetics of chlorine molecules and recombination of oxygen atoms on rotating substrates as a test case for the KMC model.

  • GO-modified flexible polymer nanocomposites fabricated via 3D stereolithography
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-09-23
    Chi Him Alpha Tsang, Adilet Zhakeyev, Dennis Y. C. Leung, Jin Xuan

    Graphene oxide (GO) induced enhancement of elastomer properties showed a great deal of potential in recent years, but it is still limited by the barrier of the complicated synthesis processes. Stereolithography (SLA), used in fabrication of thermosets and very recently in “flexible” polymers with elastomeric properties, presents itself as simple and user-friendly method for integration of GO into elastomers. In this work, it was first time demonstrated that GO loadings can be incorporated into commercial flexible photopolymer resins to successfully fabricate GO/elastomer nanocomposites via readily accessible, consumer-oriented SLA printer. The material properties of the resulting polymer was characterized and tested. The mechanical strength, stiffness, and the elongation of the resulting polymer decreased with the addition of GO. The thermal properties were also adversely affected upon the increase in the GO content based on differential scanning calorimetry and thermogravimetric analysis results. It was proposed that the GO agglomerates within the 3D printed composites, can result in significant change in both mechanical and thermal properties of the resulting nanocomposites. This study demonstrated the possibility for the development of the GO/elastomer nanocomposites after the optimization of the GO/“flexible” photoreactive resin formulation for SLA with suitable annealing process of the composite in future.

  • Encapsulation of 2-amino-2-methyl-1-propanol with tetraethyl orthosilicate for CO 2 capture
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2019-11-21
    Sidra Rama, Yan Zhang, Fideline Tchuenbou-Magaia, Yulong Ding, Yongliang Li

    Carbon capture is widely recognised as an essential strategy to meet global goals for climate protection. Although various CO2 capture technologies including absorption, adsorption and membrane exist, they are not yet mature for post-combustion power plants mainly due to high energy penalty. Hence researchers are concentrating on developing non-aqueous solvents like ionic liquids, CO2-binding organic liquids, nanoparticle hybrid materials and microencapsulated sorbents to minimize the energy consumption for carbon capture. This research aims to develop a novel and efficient approach by encapsulating sorbents to capture CO2 in a cold environment. The conventional emulsion technique was selected for the microcapsule formulation by using 2-amino-2-methyl-1-propanol (AMP) as the core sorbent and silicon dioxide as the shell. This paper reports the findings on the formulated microcapsules including key formulation parameters, microstructure, size distribution and thermal cycling stability. Furthermore, the effects of microcapsule quality and absorption temperature on the CO2 loading capacity of the microcapsules were investigated using a self-developed pressure decay method. The preliminary results have shown that the AMP microcapsules are promising to replace conventional sorbents.

  • Functional ferritin nanoparticles for biomedical applications.
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2018-03-06
    Zhantong Wang,Haiyan Gao,Yang Zhang,Gang Liu,Gang Niu,Xiaoyuan Chen

    Ferritin, a major iron storage protein with a hollow interior cavity, has been reported recently to play many important roles in biomedical and bioengineering applications. Owing to the unique architecture and surface properties, ferritin nanoparticles offer favorable characteristics and can be either genetically or chemically modified to impart functionalities to their surfaces, and therapeutics or probes can be encapsulated in their interiors by controlled and reversible assembly/disassembly. There has been an outburst of interest regarding the employment of functional ferritin nanoparticles in nanomedicine. This review will highlight the recent advances in ferritin nanoparticles for drug delivery, bioassay, and molecular imaging with a particular focus on their biomedical applications.

  • Enzyme-Instructed Self-Assembly of Peptides Containing Phosphoserine to Form Supramolecular Hydrogels as Potential Soft Biomaterials.
    Front. Chem. Sci. Eng. (IF 2.809) Pub Date : 2018-02-07
    Jie Zhou,Xuewen Du,Jiaqing Wang,Natsuko Yamagata,Bing Xu

    Enzyme-instructed self-assembly (EISA) offers a facile approach to explore the supramolecular assemblies of small molecules in cellular milieu for a variety of biomedical applications. One of the commonly used enzymes is phosphatase, but the study of the substrates of phosphatases mainly focuses on the phosphotyrosine containing peptides. In this work, we examine the EISA of phosphoserine containing small peptides for the first time by designing and synthesizing a series of precursors containing only phosphoserine or both phosphoserine and phosphotyrosine. Conjugating a phosphoserine to the C-terminal of a well-established self-assembling peptide backbone, (naphthalene-2-ly)-acetyl-diphenylalanine (NapFF), affords a novel hydrogelation precursor for EISA. The incorporation of phosphotyrosine, another substrate of phosphatase, into the resulting precursor, provides one more enzymatic trigger on a single molecule, and meanwhile increases the precursors' propensity to aggregate after being fully dephosphorylated. Exchanging the positions of phosphorylated serine and tyrosine in the peptide backbone provides insights on how the specific molecular structures influence self-assembling behaviors of small peptides and the subsequent cellular responses. Moreover, the utilization of D-amino acids largely enhances the biostability of the peptides, thus providing a unique soft material for potential biomedical applications.

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上海纽约大学William Glover