Table of Content

10 March 2021, Volume 42 Issue 3

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Cover and Content of Chemical Journal of Chinese Universities Vol.42 No.3(2021)

2021, 42(3):  1-8. 

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Review

Synthesis and Application of Silica/carbon-based Large-pore Mesoporous Nanomaterials

SHE Peihong, XU Wenzhou, GUAN Buyuan

2021, 42(3):  671-682.  doi:10.7503/cjcu20200533

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In the past decade， large-pore mesoporous nanomaterials have attracted considerable research interests because of their ultra-large open channels， abundant chemical compositions and potential wide range of applications. Soft-templating and hard-templating methods are two most effective approaches to synthesize high-quality mesoporous nanoparticles with highly accessible large channels. Through these two approaches， amphiphilic molecular template/framework precursor composite micelles or inorganic nanoparticles serve as struc-tural subunits， respectively， for the formation of mesostructured nanoparticles. In this review， we provide a comprehensive overview of the synthesis methods of large-pore mesoporous nanoparticles. Afterwards， we discuss their applications in catalysis， energy storage and conversion， as well as biomedical applications. Lastly， we outline the research challenges and possible development directions of mesoporous nanomaterials with ultra-large pores for various applications.



Inorganic Chemistry

Morphology Control of SAPO Molecular Sieves under the Assistance of Organosilane

WANG Ye, ZHANG Xiaosi, SUN Lijing, LI Bing, LIU Lin, YANG Miao, TIAN Peng, LIU Zhongyi, LIU Zhongmin

2021, 42(3):  683-690.  doi:10.7503/cjcu20200668

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SAPO-5 and SAPO-34 molecular sieves with special morphology were synthesized by employing isopropylamine（IPA） as the organic-structure directing agent and 3-piperazinylpropylmethyldimethoxysilane（PZPMS） as a mesoporogen. The effects of the amounts of organosilane and silica source were systematically investigated which may change both crystalline phase and the crystal morphology. The products were SAPO-14， SAPO-5 and SAPO-5/SAPO-34 in turn as the addition and increase of PZPMS. SAPO-5 will transfer to SAPO-34 with the increased dosage of TEOS. The synthesized samples were well characterized， and the pre-sence of PZPMS in the product was confirmed. Hierachical channels formed after removal of the organics， and the MTO catalytic performance of SAPO-34 molecular sieve was significantly improved. Furthermore， it exhi-bited 86.95% selectivity for ethylene and propylene. The hydrogen bond interaction between PZPMS and IPA is the key to synthesize SAPO with special morphology. This work provides an effective strategy to control the morphology of SAPO molecular sieves.



Synthesis， Structure and Dielectric Properties of One-dimensional Chain Hydrogen Glycine Supramolecular Compound ［（Gly）₂⁺（18-crown-6）₂（MnCl₄）^2‒］

WANG Le, QIN Liulei, LIU Yang, REN Li, XU Huiting, LIU Zunqi

2021, 42(3):  691-699.  doi:10.7503/cjcu20200594

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A new phase transition one-dimensional chain hydrogen-bonding glycine supramolecular ［（Gly）₂⁺（18-crown-6）₂（MnCl₄）^2?］（1） was prepared by evaporation method with the reaction of glycine（Gly）， 18-crown-6， transition metal compound MnCl₂ and hydrochloric acid. Compound 1 was characterized and analyzed by means of elemental analysis， variable temperature X-ray single crystal diffraction and dielectric constant measurements. The results showed that crystal of the title complex belonged to monoclinic crystal system， space group changed from P2₁/c（100 K， low temperature） to C2/c（293 K， room temperature）. ［MnCl₄］^2? anion displayed a double tetrahedral structure with common edges in a disordered state with the temperature increasing. Dynamic oscillations occured between the protonated glycine molecule and the intramolecular hydroxyl group（—OH）， and built one-dimensional O—H…Cl hydrogen bonds chain with obvious stretching motion. These caused the structural phase transition and dielectric anomaly of compound 1 in a certain temperature range.



Seedless Synthesis of Gold Nanorods with Narrow Absorption Using Binary Surfactant Mixture

LU Feng, GONG Yi, ZHAO Ting, ZHAO Ning, JU Wenwen, FAN Quli, HUANG Wei

2021, 42(3):  700-708.  doi:10.7503/cjcu20200561

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A seedless synthetic method was developed for the preparation of high-quality gold nanorods（AuNRs） using binary surfactant mixture containing hexadecyltrimethylammonium bromide（CTAB） and sodium oleate（NaOL）. The morphologies， optical properties and photothermal performances were charac- terized by means of transmission electron microscopy（TEM）， UV-Vis-NIR spectroscopy and infrared thermal imaging system. The results indicate that uniform AuNRs can be obtained with a NaOL concentration between 8.21—11.5 mmol/L， and their longitudinal surface plasmon resonance（LSPR） wavelength can be tuned from 650 nm to 1150 nm. The AuNRs prepared with this method exhibited narrow LSPR peak， especially in the second near infrared-Ⅱ region（NIR-Ⅱ， λ>1000 nm）. Under the irradiation of 1064 nm laser， the temperature of AuNRs solution can increase to 67 ℃， with a photothermal conversion efficiency of 31.5%. The AuNRs also exhibited excellent photothermal stability under laser irradiation， which can be useful for photoacoustic imaging and photothermal therapy in the second near-infrared region.



Atropisomerism and Magnetic Properties of an in situ Synthesized Chiral Nickel Complex

RUAN Zeyu, DU Shannan, HUANG Guozhang, TONG Mingliang, LIU Junliang

2021, 42(3):  709-716.  doi:10.7503/cjcu20200475

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Atropisomers refer to a subclass of chiral compounds that cannot be superposed with its mirror image. For a long time， chiral complexes play an important role in the fields of medicine， dyes， materials and natural products. Metal complexes as atropisomers have widespread applications in asymmetric catalysis. In contrast， fewer examples are known as obtaining atropisomers from achiral substrate， while it is even rarer to use non-axial-chirality ligand to achieve atropisomers. In general， acetonitrile is reactive inert and difficult to break the C—H bond in acetonitrile， so it is usually not a good nucleophilic reagent precursor. Activation of acetonitrile molecules assisting with transition-metal ions is an effective approach for introducing cyanomethyl groups. Herein we demonstrate a pair of atropisomers obtained through in?situ assembly under the coordination of Ni^II and K^I， where the non-axial-chirality ligand dpkMeCN-H［dpkMeCN=cyanomethyl-di（pyridin-2-yl）methanol］ containing a cyanomethyl group was introduced by the reaction with acetonitrile. From the magnetic measurements and analysis， the ferromagnetic coupling between two Ni^Ⅱ ions was revealed. Accompanied with zero-field splitting from the distorted octahedral Ni^Ⅱ ions， magnetic anisotropy was preserved for the chiral nickel complexes.



Analytical Chemistry

Arginine Functionalized Magnetic Nanoparticles and Its Application in Phosphopeptides Enrichment

ZHENG Haijiao, JIANG Liyan, JIA Qiong

2021, 42(3):  717-724.  doi:10.7503/cjcu20200685

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Arginine modified magnetic nanoparticles（Mag-Arg） were synthesized and used as themagnetic carrier of magnetic solid phase extraction（MSPE） platform. The prepared magnetic nanoparticles were applied to the enrichment of phosphopeptides from complex samples coupled with MALDI-TOF MS. Mag-Arg was characterized by means of scanning electron microscopy， particle size analysis， Zeta potential measurement， infrared spectroscopy， vibrating sample magnetometer and X-ray diffraction. Under the optimal adsorption desorption conditions， the MSPE-MS platform could achieve high selectivity and sensitivity（the detection limit was determined to be as low as 0.1 fmol） for phosphopeptides. Finally， the method was applied to the determination of phosphopeptides in nonfat milk， showing great potential in the detection of low-abundance phosphopeptides in real complex biological samples.



Development of Small Animals in vivo Fluorescence-photothermal Dual Mode Imaging System

CHEN Hongda, ZHANG Hua, WANG Zhenxin

2021, 42(3):  725-730.  doi:10.7503/cjcu20200640

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This study reports a small animal in vivo fluorescence-photothermal dual-mode imaging system， which has dual functions of fluorescence imaging and thermal imaging. The system has high imaging sensiti- vity， fast acquisition speed（≤51 frame/s）， and large tissue penetration depth（near infrared fluorescence up to 10 mm during imaging）， and a thermal imaging resolution of 0.1 ℃. The system can not only achieve fluorescence imaging of small animal subcutaneous tumors and deep tissues/organs， but also integrates thermal imaging to monitor temperature changes in photothermal therapy in real time， as well as the controlled release process of drugs to achieve precise treatment.



Interactions of Pyrene with Human Serum Albumin and Bovine Serum Albumin： Microenvironmental Polarity Differences at Binding Sites

LI Mengshuo, ZHANG Jing, LIU Dan, ZHU Yaxian, ZHANG Yong

2021, 42(3):  731-735.  doi:10.7503/cjcu20200559

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The interactions of pyrene（Pyr）， a microenvironmental hydrophobic fluorescent probe， with human serum albumin（HSA） or bovine serum albumin（BSA） were investigated using steady-state fluorescence， fluorescence resonance energy transfer technology， and molecular docking methods. It was observed that the average values of I₁/I₃ of the Pyr in the presence of HSA or BSA are 1.36 and 0.92， respectively. The binding constants of Pyr with HSA or BSA has been decreased from 1.86×10⁷ L/mol ^{to 1.71×105 L/mol. The apparent distances of Pyr to tryptophan residues in HSA or BSA were calculated to be 2.37 and 2.34 nm. The binding sites of Pyr in HSA or BSA were located in subdomain ⅠB and subdomains ⅠA， respectively. The polarity of amino acid residues around the binding sites was one of the main factors affecting the I₁/I₃ value of Pyr. The experimental results suggested that there were significant differences in the binding sites and its microenvironmental polarity of BSA and HSA with Pyr.}



Controllable Assembling of Silver Nanosheets on Non-woven Fabric Fibers and Its SERS Effect

LI Qi, TIAN Du, CHEN Shaoyun, ZHONG Min, HU Chenglong, CHEN Jian

2021, 42(3):  736-744.  doi:10.7503/cjcu20200453

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A two-step chemical synthesis method was used to in situ construct Ag nanosheets（AgNS） with a nanogap of 20—110 nm on the non-woven fabrics fiber（NWF）（marked with AgNS@NWF）. Scanning electron microscopy showed that the AgNS@NWF micro-nano structure had a hierarchical structure， and it was used for the study of surface-enhanced Raman scattering（SERS）. The experimental results showed that the as- prepared AgNS@NWF micro-nano structure had a good SERS sensitivity and excellent signal reproducibility. Rhodamine 6G（R6G） was used as the probe molecule for SERS detection， and the logarithmic plot of SERS intensity versus loading concentration of R6G played a small slope of 0.32±0.03， indicating that the AgNS@NWF micro-nano structure offers sufficient binding sites for the efficient capture of the analyte from the loading solution， even at a low concentration of 1×10^-10 mol/L， the Raman peaks of R6G at band of 610， 773， 1361 and 1648 cm^-1 could still be clearly observed. The relative standard deviations of the Raman scattering intensities at band of 610 cm^-1 were 3.57%， 3.67% and 8.46%， respectively， when the concentration of R6G was reduced by an order of magnitude in the range of 1×10^?5―1×10^?7 mol/L， which was better than or close to previous studies. The AgNS@NWF micro-nano structure was used to detect low-activity 3-mercaptopropionic acid and melamine molecules， and the minimum detection limits were 1×10^?5 mol/L and 1×10^-6 mol/L， respectively. This method offered an easy， rapid， and low-cost way to prepare highly sensitive and reproducible SERS substrates and made the SERS more practicable.



Sensitive and Electrochemical Detection of Telomerase Activity Based on the Signal Amplification of Strand Displacement Reaction

MA Yanrong, JIANG Shengnan, JIN Yan

2021, 42(3):  745-751.  doi:10.7503/cjcu20200435

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An electrochemical method was developed for sensitive detection of telomerase activity based on strand displacement reaction. A ferrocene（Fc）-labeled DNA probe（T-DNA） was designed as signal probe. The thiolated hairpin DNA（H-DNA） was used as capture probe and was self-assembled on the Au electrode surface via Au-S bond. Assisted DNA（A-DNA） partially hybridized with T-DNA to form AT-DNA duplex. In the presence of telomerase， telomerase substrate（TS） primer was elongated by adding multiple TTAGGG repeats at its 3′ terminal. The elongated DNA hybridized with A-DNA to displace T-DNA which can hybridize with H-DNA. As a result， the Fc tags are close to the Au electrode surface， producing an electrochemical signal. One elongated DNA can displace multiple T-DNAs， leading to the enrichment of Fc onto the Au electrode for signal amplification. Based on this， the peak current is linearly related with the number of HeLa cells in the range of 5―100 cells， and detection limit is down to 5 HeLa cells. Therefore， it provides a simple and sensitive approach for detecting telomerase activity.



Physical Chemistry

Theoretical Study on Photoinduced Stepwise Dearomatization of Benzenoid Arenes with Different States

TENG Yunyang, QU Zexing, ZHOU Zhongjun, HUANG Xuri

2021, 42(3):  752-757.  doi:10.7503/cjcu20200766

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A class of important dearomatization reaction of benzenoid arenes with heteroatoms via a photocatalysis were investigated with density functional theory（DFT） and time-dependent density functional theory（TD-DFT）. The results show that the dearomatization is a stepwise ［4 + 2］ cycloaddition reaction， that is， the first step occurs in the triplet state， and while the second step occurs in the singlet ground state. Here， the aetophenone group can be regarded as the receiving device of light， and after absorbing light， the system can reach the triplet state with a barrierless process via internal conversion and intersystem crossing， and subsequently complete the proton transfer in the triplet state to generate the reactive diradical， and finally trigger cause the subsequent dearomatization reaction. More importantly， by analyzing the potential energy surface， it is found that this reaction has a high stereoselectivity， which is in well agreement with the experimental results.



Theoretical Study on the Unbinding Pathway of Xanthine Oxidase Inhibitors Based on Steered Molecular Dynamics Simulation

QI Renrui, LI Minghao, CHANG Hao, FU Xueqi, GAO Bo, HAN Weiwei, HAN Lu, LI Wannan

2021, 42(3):  758-766.  doi:10.7503/cjcu20200752

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At present， Xanthine Oxidase（XO） inhibitors are the main drugs used to treat gout and hyperuricemia. The interaction between XO and inhibitors is a hot study spot. The unbinding pathway of XO inhibitors（Allopurinol and Puerarin） were analysed via steered molecular dynamics simulation. Molecular docking results showed that allopurinol and puerarin were bound to the MO-pt center of XO. Alanine scanning results indicted that Val789， Arg880， Phe911， Phe914 and Val1081 played very important roles for inhibitors binding to XO. The tunnel analysis based on CAVER 3.0 illustrated the shape of the tunnel was relatively regular， which was beneficial to the dissociation of the inhibitors. The steered molecular dynamics simulation results revealed that compared to puerarin， allopurinol needed more external force and longer time to escape from XO. In addition， Phe1009， Arg880， Ala1079， Val1011 and Thr1010 all played important roles in maintaining the structural stability of the two compounds binding to XO， Phe649 and Phe1013 functioned a gating role in the process of inhibitor dissociation， and His875 played a blocking role in inhibitors dissociation. The results provided some theoretical clues for the study of the interaction between inhibitors and XO. Puerarin can be developed as a mild candidate medicine for the treatment of gout in the future.



Transient Absorption and Decay Kinetic Properties of Photo-excited Metal Coordinated Tetraphenylporphyrin

MA Zihui, WANG Mengyan, CAO Hongyu, TANG Qian, WANG Lihao, ZHENG Xuefang

2021, 42(3):  767-775.  doi:10.7503/cjcu20200736

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The naturally selected chlorophyll and heme， and zinc or nickel coordinated porphyrin photosensitizer showed excellent photochemical and photophysical properties. Photoexcitation of metalloporphyrin to the excited state is the first step of reaction， which is the research priorities and challenges. The classical template molecules of porphyrins tetraphenylporphyrin（TPP-2H）， and four metal-coordinated tetraphenylporphyrins， TPP-FeCl， TPP-Ni， TPP-Mg and TPP-Zn， were chosen for the investigations of their photochemical and photophysical properties. The Soret band absorption peak intensities of photoexcited TPP-2H， TPP-Zn and TPP-Mg decreased significantly in steady state absorption spectrum， while the counterpart peak of TPP-Ni increased obviously from 0.3 a.u. to 1.3 a.u.. However， the peak location and intensity of TPP-FeCl remained almost the same. According to the transient absorption spectrum， the Soret band negative peaks of TPP-2H， TPP-Mg and TPP-Zn had the negativeΔOD values for the lower molar absorption coefficient ε_t than ε_G of ground state compounds. The positive and negative absorption peaks microsecond lifetime decay kinetics of TPP-2H， TPP-Mg and TPP-Zn confirmed the relatively stable transient excited states after the photoexcitation. All the experimental and theoretical data manifested that the unoccupied orbitals and electron distribution of metal ion in the center of porphyrins would induce the diversification of porphyrin photochemical and photophysical properties. The experimental research further assists to comprehend photosynthesis process and provides an important basis for the selection of coordination metal in the porphyrin application research field of photoelectric conversion.



Effect of Aqueous Solution pH on the Oxidation of Methane to Methanol at Low Temperature

LI Jian, YU Mingming, SUN Yuan, FENG Wenhua, FENG Zhaochi, WU Jianfeng

2021, 42(3):  776-783.  doi:10.7503/cjcu20200703

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This study investigated the effect of different aqueous solution pH on the reactivity of the Fe/ZSM-5 zeolite in the process of selective oxidation of methane to methanol using H₂O₂ as oxidant at low temperature. Fe/ZSM-5 catalyst was prepared by solid ion exchange method， and its structure and physical properties were characterized by means of X-ray diffraction（XRD）， inductively coupled plasma（ICP）， diffuse reflectance ultraviolet/visible spectroscopy（DR UV-Vis）， Raman spectroscopy（Raman）， and solid-state nuclear magnetic resonance（Solid-state NMR）. H₂SO₄ and NaOH were used to adjust the pH of the reaction solution， and the products were quantitatively analyzed by gas chromatography and liquid NMR. The influences of different aqueous solution pH on the reactivity of the reaction were systematically investigated. Besides， the effects of the aqueous solution pH on the metal leaching out of the Fe/ZSM-5 catalyst and the residual concentration of H₂O₂ were further investigated. It is expected that the obtained experimental results could provide guidance for further optimization of the selective oxidation of methane to methanol reaction.



Experimental Set-up and Application Research of Solid-State Nuclear Magnetic Resonance Multiple-CP Technique

ZHANG Zhilan, WANG Ning, TANG Dandan, SHU Jie, LI Xiaohong

2021, 42(3):  784-793.  doi:10.7503/cjcu20200698

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The quantitative solid-state nuclear magnetic resonance（NMR） multiple-cross polarization（CP） technique attracts enormous interest of the material researchers. With proper setting of experimental parameters， Multiple-CP is capable to determine the molecular chemical structure， multi-phase composition and the component contents of blends. However， the accuracy of the testing results is sensitive to the experimental parameters which are tuned by the system parameters of the measuring samples. To gain the accurate results with high efficiency， it is necessary to reveal the influence behavior of the system parameters on experimental parameters. In this work， L-alanine， L-valine and their mixture were chosen as the model samples. Firstly， system parameters of spin-lattice relaxation time of ¹H（T_1，H）， cross relaxation time（T_CH） and spin?lattice rela-xation time of ¹H in the spin?locking field(T_{\mathrm{1}\rho }^{\text{?}\mathrm{H}\text{?}}) were measured. Meanwhile， the accuracy of Multiple-CP results was evaluated with the variation of three experimental parameters， including relaxation recovery time（t_d）， cross-polarization contact time（t_p）， and cross-polarization times（n）. By comparing the data of different ¹³C groups， it is revealed that the setting of t_p is essential to the result accuracy， which is tuned by T_CH and \text{?}{T}_{\mathrm{1}\rho }^{\text{?}\mathrm{H}\text{?}} of the system. Moreover， the values of the parameter difference between the molecular groups or blended components also affects the Multiple-CP results. Therefore， Multiple-CP is recommended to study the systems with similar T_CH and \text{?}{T}_{\mathrm{1}\rho }^{\text{?}\mathrm{H}\text{?}} values. For the blends or mixtures， the identical unit of each component is suggested chosen for determining the contents.



In⁃situ Growth NiS/nickel Foam as Cathode Current Collector of Magnesium-sulfur Batteries

HUANG Yan, ZHANG Shuxin, NULI Yanna, WANG Baofeng, YANG Jun, WANG Jiulin

2021, 42(3):  794-802.  doi:10.7503/cjcu20200693

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Nickel foam in situ grown NiS and Cu foil were respectively used as the cathode current collectors of magnesium-sulfur（Mg-S） batteries with S@MC cathode and（PhMgCl）₂-AlCl₃+LiCl/THF hybrid electrolyte. The constant-current discharge-charge cycling and rate performances of the Mg-S batteries were compared and the reason of different performance was analyzed. When using copper foil collector， the cracks were observed on the cathode and obvious uneven distribution with slightly higher sulfur content on magnesium anode. In the case of NNF， the morphology of the cathode can be basically maintained because the pore structure of nickel foam buffers the volume changes of sulfur active material. Importantly， NiS in situ growing on NNF can accele-rate the conversion of polysulfide intermediates， reduce the formation of polysulfides and suppress the shuttle， and hardly interfere the electrochemical reaction on the magnesium anode， resulting in more uniform magnesium surface. As a result， the Mg-S battery with NNF cathode current collector exhibits significantly improved cycle stability and rate performance.



Construction of Fe-aminoclay-glucose Oxidase Nanocomposite Catalyst and Its Multi-enzyme Cascade Analysis

LI Liu, SUN Shiyong, LYU Rui, GOLUBEV Yevgeny Aleksandrovich, WANG Ke, DONG Faqin, DUAN Tao, KOTOVA Olga Borisovna, KOTOVA Elena Leonidovna

2021, 42(3):  803-810.  doi:10.7503/cjcu20200635

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Glucose oxidase（GO_x） and Fe-aminoclay（FeAC） were combined to construct a mimic multi- enzyme system（FeAC-GO_x） for cascade reaction. FeAC exhibit peroxidase-like activity which can catalyze H₂O₂ generated by GOx and trigger color reaction. The obtained FeAC-GO_x was characterized by scanning electron microscope（SEM）， X-ray diffraction（XRD）， and fourier transform infrared spectroscopy（FTIR）. The enzymatic kinetics， catalytic stability and reusability were evaluated. As a result， the immobilization efficiency of GO_x could reach to 76.4%， and FeAC-GO_x exhibited excellent cascade catalysis activity. Compared with the free enzyme， FeAC not only possessed a strong tolerance toward temperature and pH， but also presented excellent reusability. The catalytic activity of reused FeAC barely changed after six repetitions. This strategy may lay the foundation to the development of a new glucose biosensor， and provide a novel approach to design multi-enzyme cascade system.



Fabrication of Antifouling-antibacterial Dual Functional Polymer Coating via Dopamine-based Multiple Interactions

WANG Yupeng, ZHAO Yang, LI Mohan, SHI Suqing, GONG Yongkuan

2021, 42(3):  811-818.  doi:10.7503/cjcu20200567

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Biomedical device relating bacterial colonization has become a severe issue in clinical practice. To prevent the formation of bacterial biofilm， we develop a facile and versatile one-step codeposition method to readily fabricate an antifouling-antibacterial dual functional polymer coating by virtue of multiple interactions between dopamine derivatives and primary amines in zwitterionic polymer（PMA） and carboxymethyl chitosan（CMC）. The presence of DA drives the codeposition of polydopamine（PDA）， CMC and PMA， endowing the coating with good durability. While the multiple interactions among CMA， PMA and DA， i.e. hydrogen bonding， Michael addition and/or Schiff base reacions， are beneficial to regulate the oxidation and self- aggregation of DA， eventually achieving a uniformly codeposited polymer coating. Due to the coexistance of zwitterionic antifouling moieties and bactericidal CMC， the resultant CMC-PMA-PDA coating both has the capacity of resisting bacterial adhesion and killing the bacteria adhered on its surface， effectively inhibiting the bacteria biofilm formation.



High-low Temperature Properties of Ni-rich LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Material by Hydrothermal Synthesis with CTAB Assisted

ZHANG Huishuang, GAO Yanxiao, WANG Qiuxian, LI Xiangnan, LIU Wenfeng, YANG Shuting

2021, 42(3):  819-826.  doi:10.7503/cjcu20200507

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Using acetate as raw material， cetyltrimethyl ammonium bromide（CTAB） as dispersing agent， LiNi_0.6Co_0.2Mn_0.2O₂ cathode material was synthesized by hydrothermal method after high temperature two-step sintering. The experiments proved that proper addition of the dispersant CTAB can effectively adjust the particle morphology， reduce Ni²⁺/Li⁺ cation mixing and improve the electrochemical properties of the material. When 2%（mass fraction） CTAB was added， the LNi_0.6Co_0.2Mn_0.2O₂ cathode material had an ordered layered structure and the particles of the material were homogeneous and dispersed. Furthermore， and the optimal cycling performance and the high-low temperature performance were obtained. The retention rate of the material was 88.5 % after 100 cycles in the voltage range of 3.0—4.3 V at a rate of 1C and 25 ℃. The initial discharge specific capacity were 60.3， 168.5 and 207.2 mA·h/g， respectively， at a rate of 0.1C under the environmental conditions of ?20， 25 and 55 ℃， which provided a strong basis for the wider application of the material.



Molten-salt-assistance Synthesis and Photocatalytic Hydrogen Evolution Performances of g-C₃N₄ Nanostructures

GUI Chen, WANG Haolin, SHAO Baixuan, YANG Yujing, XU Guangqing

2021, 42(3):  827-833.  doi:10.7503/cjcu20200471

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Using urea as raw material， g-C₃N₄ nanostructures with adjustable bandgap were prepared in KCl-NaCl-BaCl₂ system by molten-salt-assistance thermal polymerization method. The structure， morphology， composition and optical properties of the products were characterized by X-ray diffraction， scanning electron microscope， X-ray photoelectron spectrometer， UV-Visible diffuse reflection spectrometer and fluorescence spectrometer， respectively. The photocatalytic performance of the products in visible light was tested， and the effects of different urea/molten salt ratios on the photocatalytic performance of g-C₃N₄ nanostructures were studied. The results show that the absorption spectra of g-C₃N₄ nanostructure prepared by molten-salt- assistance thermal polymerization manifest obvious broadening， and the absorption edge shifts from ca. 450 nm to ca. 500 nm， compared with the g-C₃N₄ prepared by ordinary thermal polymerization method. At the same time， the recombination rate of photogenerated carriers is obviously reduced， so the photocatalytic hydrogen production performance is effectively improved. The hydrogen evolution rate of the optimized g-C₃N₄（60） samples reach 12301.1 μmol?g^?1?h^?1， which is 4 times that of g-C₃N₄ prepared by ordinary thermal polymerization method.



Construction of Active Sites in Porous Organic Polymers for Various Heavy Metal Ions Capture

ZHAO Kaiqing, WU Ruoyu, LUO Yifeng, SHI Chunhong, HU Jun

2021, 42(3):  834-842.  doi:10.7503/cjcu20200467

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Heavy metal pollution is directly related to human health and life safety， and the development of broad-spectrum and high-efficiency heavy metal adsorbents is expected to solve the problem of coexistence of multiple heavy metal pollutants in industrial wastewater. A triptycene-based porous organic polymer（TPOP） with high specific surface area was produced by crosslinking three-dimensional rigid triptycene monomer through the simple Friedel-Crafts alkylation reaction. Then， a broad-spectrum heavy metal ions adsorption active site（TPOP-CH₂EDTA） was constructed in TPOP by grafting of ethylenediamine and sodium chloroacetate. The obtained TPOP-CH₂EDTA showed a micro/mesoporous structure， with the main micropore size of 1.6 nm and the BET surface area of 634 m²/g， which facilitates the transfer and coordination of heavy metal ions. TPOP-CH₂EDTA has a broad-spectrum adsorption for heavy metal ions， like Ag（Ⅰ）， Cu（Ⅱ）， Ni（Ⅱ）， Zn（Ⅱ）， Co（Ⅱ）， Sn（Ⅳ）， Pb（Ⅱ）， Cd（Ⅱ）， Fe（Ⅲ）， Cr（Ⅲ） are investigated， respectively， and the removal efficiency are all higher than 98%. Taking Pb（Ⅱ） as a typical heavy metal pollutant， the maximum adsorption capacity of Pb（Ⅱ） is calculated up to 184.5 mg/g by the Langmuir model. The kinetic study shows that it is a Pseudo-second-order adsorption， fast adsorption rate， and the kinetic constant k₂ of 0.0173 g·mg^-1·min^-1. After 5 recycling use， the removal efficiency of Pb（Ⅱ） is still as high as 95.8%. More significantly， the removal efficiency of Pb（Ⅱ） and Cu（Ⅱ） in their mixture solution is either higher than 99%. For the complex real water containing large amounts of inorganic salts， like Ca（Ⅱ）， Mg（Ⅱ）， K（Ⅰ）， Na（Ⅰ） ions， and organic compounds， the remo-val efficiency of Pb（Ⅱ） and Cu（Ⅱ） still maintains higher than 90%. Therefore， a broad-spectrum heavy metal ion adsorption active site is constructed by controlling the microstructure of porous organic polymers（such as specific surface area， pore size and adsorption site density）， which provides a scheme for the coordinated removal of mixed heavy metal ions in complex water systems.



Admicelles and Adsolubilization of Extended Surfactants on Alumina

HU Xueyi, HAN Lulu, FANG Yun, XIA Yongmei

2021, 42(3):  843-849.  doi:10.7503/cjcu20200433

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A series of sodium linear alkyl polyoxypropylene ether sulfates（C_cP_pS， c=8 or 16， p=9； c=12， p=3， 6 or 9） was synthesized and structurally identified to investigate the formation of admicelles of extended surfactants on alumina and the related adsolubilization. The formation of bilayer admicelles of C₁₂P₉S on alumina was identified by the adsolubilization result of cationic dye methylence blue（MB） in comparison with sodium dodecyl ether sulfate（SDS）， but the adsorption capacity of C₁₂P₉S and adsolubilization capacity of MB were both less than SDS for its rugby-shaped molecule caused by polyoxypropylene（PPO） spacer. On the contrary， C₁₂P₉S@Al₂O₃ showed stronger adsolubilization capacities of weak polar PA molecules and water-insoluble ST molecules than those of SDS evidently. Moreover， the adsolubilization capacity of PA by C₁₂P₉S@Al₂O₃ was 8.5 times of SDS@Al₂O₃， which means that PA molecules were adsolubilized as expected in the swollen PPO domains in bilayer admicelles of C₁₂P₉S on alumina， and makes extended surfactant modified alumina potential application prospects in some fields such as wastewater treatment and drug delivery systems.



Polymer Chemistry

Synthesis and Characterization of Thermoresponsive Polypeptide/polypeptoid Block Copolymers

LI Rongye, NI Yunxia, LIU Dandan, LI Zhi, CHENG Yuxin, XIA Mingxin, FU Xiaohui

2021, 42(3):  850-856.  doi:10.7503/cjcu20200651

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Thermoresponsive polymer refers to a type of polymer that can respond to external temperature and the molecular structure exhibit reversible or irreversible changes， that show great potential for both fundamental research and applications. In this work， both polypeptide and polypeptoid are involved to construct a new type of thermoresponsive block copolymers， which combine the structural advantages for tunable properties. We used n-hexylamine as an initiator and synthesized a series of thermoresponsitive diblock copolymer oligo（ethylene glycol） modified poly（γ-propargyl-L-glutamate）-block-poly（N-octylglycine）［（PPLG-g-EG₃）-b-PNOG］ with narrow molecular mass distribution by ring-opening polymerization and post-modification strategy. The crystallization behavior of the polymers was studied by differential scanning calorimetry. Circular dichroism（CD） spectrum was used to investigate the secondary structure of the polymer， and its self-assembly behavior in aqueous solution was further investigated. The results show that the thermoresponsitive polymers adopt α-helix at room temperature. As the temperature increases， the fraction of α-helix decreases. Additionally， the obtained polymers exhibit cylindrical nanostructure in aqueous solution.



Monte Carlo Simulation of the Transformation Control of ABC Triblock Copolymer Micelles from Multicompartment Structure to Multicore Structure

FAN Juanjuan, HAN Yuanyuan, CUI Jie

2021, 42(3):  857-865.  doi:10.7503/cjcu20200612

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The self-assembly behavior of ABC triblock terpolymers with hydrophobic-hydrophilic-hydrophobic（H-P-H） sequence in selective solvent of B blocks was studied by means of Monte Carlo simulation. The simulation results show that various micelles with different morphologies can be formed by adjusting the hydrophobicity and the incompatibility of A and C blocks. According to the characteristics of hydrophobic core structures in the micelles， these micelles can be generally divided into two types： multicore micelles and multicompartment micelles. By increasing the hydrophobicity of hydrophobic blocks or reducing the incompatibility between A and C blocks， the micelles formed by H-P-H type ABC triblock terpolymers can transform from multicore micelles to multicompartment micelles. Via further investigation on the chain conformations in typical micelles， it is found that there is competition between the hydrophobic interaction and the repulsion between A and C blocks， and this competition is the main factor that determines whether the multicore micelles or the multicompartment micelles can be formed by ABC triblock terpolymers with H-P-H sequence.



Synthesis of α，ω⁃End Alkynyl-functionalized Styrene-isoprene-styrene Polymer Based on Di-lithium Method

YANG Lincan, LENG Xuefei, HAN Li, LI Chao, ZHANG Songbo, LEI Lan, MA Hongwei, LI Yang

2021, 42(3):  866-874.  doi:10.7503/cjcu20200596

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Styrene-isoprene-styrene（SIS） triblock polymer is widely used thermoplastic elastomer（TPE） material. Establishing an efficient， precise and universal method for SIS functionalization has always been the key to improve the properties of TPE materials. Herein， the α，ω-end alkynyl-functionalized SIS polymer was synthesized efficiently by using the di-lithium initiation method and capped with alkynyl-functionalized monomer. First， the bi-functional di-lithium initiator was synthesized by the reaction of diene monomer with mono- functional initiator. Then， using lithium t-butoxide as the additive of the isoprene polymerization and potassium t-butoxide as the additive of the styrene polymerization， SIS triblock polymer with low vinyl content（5.8%） and narrow polydispersity index（<1.17） was synthesized. Whereafter， using di-lithium compound as initiator， adding alkynyl-functionalized 1，1-diphenylethylene（DPE） derivative for end-capping in one step， the α，ω-end alkynyl-functionalized SIS triblock "brick" polymer was synthesized with efficiency higher than 90%. Combined with the study of “click” reaction of alkynyl group， the preparation of thermoplastic elastomer materials with functional groups and topology could be realized.



Molecular Dynamics Simulation of Polymer/rod Nanocomposite

LIU Aiqing, XU Wensheng, XU Xiaolei, CHEN Jizhong, AN Lijia

2021, 42(3):  875-883.  doi:10.7503/cjcu20200593

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The effects of nanorods on the structural， dynamical， and rheological properties of polymer matrix were investigated under shear flow via nonequilibrium molecular dynamics simulation. By comparing the results of nanocomposites（with volume fractions from 0. 8% to 10%） and pure melts， it is found that the diffusion and relaxation of polymer chains are gradually limited with the increase of nanoparticles， while the polymer size keeps almost unchanged. Under shear flow， it is found that the structural properties such as the mean-square radius of gyration， main components of gyration tensor and the orientation resistance parameter are almost independent of the volume fractions of nanoparticles， from the perspective of Weissenberg number（W_i）， while the tumbling motion of polymer chains is restricted. In addition， we also find the shear viscosity curve of nanocomposites is essentially the same with that of the pure melt， that is， W_i=1 divides the curve into the plateau region and the shear thinning region. The introduction of nanorods merely changes the shear viscosity of the fluid quantitatively.



Studies on Viscosity and Chemical Structure Changes in Polycarbonate Melts under Nitrogen Protection

JIANG Lei, YAN Shengdi, LIN Yu, WU Guozhang

2021, 42(3):  884-893.  doi:10.7503/cjcu20200552

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Bisphenol A polycarbonate（PC） tends to degrade during high-temperature processing， resultting in yellowing and a gradual decrease in viscosity. Here， we report that some kinds of PC melts have a viscosity increase effect under N₂ protection. Seven grades of PCs were used to check the change in melt viscosity under high temperature in N₂ by means of dynamic rheological measurements， and their evolutions in molecular structure were analyzed by high performance liquid chromatography（HPLC） and nuclear magnetic resonance spectroscopy（NMR）. Results show that， unlike PCs synthetized by phosgene method where the viscosity of PC melts decreases firstly and later increases slowly， PCs synthetized by transesterification method present an increase in melt viscosity and melt strength with annealing time and exhibit serious shear thinning effect. Molecular structure characterization confirms that PC molecular chains are branched and cross-linked under anaerobic conditions， thus forming a high molecular weight gel. The gelation speed of PCs synthetized by transesterification method is higher than that of PCs synthetized by phosgene method， resulting in higher shear viscosity and melt strength in the low frequency region. We propose that the terminal hydroxyl content may be the main factor causing the difference in gelation of different PCs.



Fabrication of Superwetting Porous Shape Memory Sponge and Its Application in Oil-water Separation

LIU Pengchang, LAI Hua, CHENG Zhongjun, LIU Yuyan

2021, 42(3):  894-901.  doi:10.7503/cjcu20200549

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Owing to the shape memory properties of trans-1，4-polyisoprene（TPI）， TPI was coated onto the Polyurethane（PU） sponge to fabricate a hydrophobic and superoleophilic porous shape memory sponge. As the shape of the porous sponge was repeatedly pressed/recovered based on the good shape memory property， the pore size of the sponge could be controlled from about 450 nm to about 875 μm. Based on the superwetting performances and tunable pore size， the sponge was further applied in oil-water separation. Experimental results indicate that larger pore size was favorable for fast separation of immiscible oil-water mixture， and the small pore size was effective to realize the separation of emulsions， finally achieving the separation of different oil-water mixtures on the same material.



Highly Solvatochromic Terpyridine Compounds for Identification of Butanol Isomers

CHANG Hui, YAO Shuangquan, HAN Wenjia, KANG Xiena, ZHANG Li, LI Xinping, ZHANG Zhao

2021, 42(3):  902-909.  doi:10.7503/cjcu20200538

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N，N-Dimethyl functional group was introduced into the terpyridine molecule to realize the locally excited state luminescence of the terpyridine molecule. It was found that the polarity of the solvent induced a change in the dipole moment of terpyridine， achieving solvent-induced fluorescence discoloration from deep blue light（λ_max=384 nm） to yellow light（λ_max=558 nm）. As the fluorescence of terpyridine is easily quenched by the oscillation of —OH group in alcohol solvent， the n-butanol， iso-butanol， sec-butanol and tert-butanol solvents with different steric hindrances make the light color of terpyridine close， while the luminous intensity difference is greater. The terpyridine is further coordinated with ZnCl₂ to obtain the terpyridine-Zn（Ⅱ） complex. The coordination of the metal ion Zn（Ⅱ） promotes the charge transfer within the terpyridine molecule. Since the N，N-dimethyl functional group， as the electron donor can undergo plane distortion， the butanol isomers can adjust the locally excited and twisted intramolecular charge transfer of terpyridine-Zn（Ⅱ）， and then realize the adjustment of its light color in butanol isomer solvent. Terpyridine and terpyridine-Zn（Ⅱ） have good solvent-induced fluorescence discoloration properties， and can be used to identify four butanol isomers.



In⁃situ Study of the Epitaxial Crystallization of PCL/RGO at High Shear Rate

MIAO Weijun, WU Feng, WANG Yong, WANG Zongbao

2021, 42(3):  910-918.  doi:10.7503/cjcu20200493

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Polycaprolactone（PCL）/reduced graphene oxide（RGO） composites were used as the research object to study the evolution of the epitaxial crystalline structure and the influence on the formation of bulk crystal at the shear rate of 75 s^?1 by in?situ small-angle X-ray scattering（SAXS） and wide-angle X-ray diffraction（WAXD） in this paper. The experimental results show that PCL molecular chains start to form epitaxial crystal layer on the RGO surface at 160 s after shear， and part of PCL bulk crystal is formed simultaneously. In the isothermal crystallization stage（200―480 s after shear）， a large number of PCL bulk crystals are formed， which promotes the formation of regular periodic structure. The PCL molecular chain is more likely to change from the extensional chain to the random coil at a higher shear temperature because of the reduced viscosity at 75 s^?1， which is not beneficial for PCL molecular chain to form surface crystal layer on RGO. The shear tempe-rature of 70 ℃ is more favorable for the formation of PCL epitaxial crystal layer on the RGO at shear rate of 75 s^?1.



Effect of Copolymerization Structure and Molecular Weight on Melt Fluidity and Thermal Properties of Thermoplastic Polyimide Resins

XU Xiaozhou, LIU Yi, HE Minhui, MO Song, LAN Bangwei, ZHAI Lei, FAN Lin

2021, 42(3):  919-928.  doi:10.7503/cjcu20200482

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A series of molecular-weight controlled thermoplastic polyimide（TPI） resins was synthesized based on 4，4'-（hexafluoroisopropylidene）diphthalic anhydride/p-phenylenediamine（6FDA/p-PDA） endcapped with phthalic anhydride（PA）， in which the aromatic diamides with rigid backbone and large free volume， i.e.，m-phenylenediamine（m-PDA）， 2，2'-bis（trifluoromethyl） benzidine（TFDB） and 9，9-bis（4-aminophenyl） fluorene（BAFL）， were incorporated respectively. The effects of copolymerization structure and molecular weight on the melt fluidity and thermal properties of TPI resins were investigated. The correlation between the aggregation structures of TPI resins and their melting performance was constructed. The mechanical properties of TPI resins were evaluated at ambient and elevated temperatures. The results indicated that incorporation of aromatic diamines with large free volume as copolymerization structure can effectively reduce the molecular chain stacking density and increase the free volume of polymer， as a result， providing the resin good melting performance. The melt processability of resins can be further improved by reducing their designed molecular weight. These TPI resins with rigid backbone have excellent thermal stability and mechanical properties. The glass transition temperatures of these resins were in the range of 308—338 ^oC. TPI-C-25k and TPI-D-25k resins with the copolymerization structure of TFDB and BAFL， respectively， revealed high strength and toughness. They gave the tensile strength and flexural strength exceeding 120 MPa and 190 MPa， respectively， and showed the elongation at break over 8.2%. These TPI resins also exhibited good thermal stability at 250^℃.



Preparation and Properties of Poly（vinyl alcohol）/polypyrrole Composite Conductive Hydrogel Strain Sensor

WANG Jie, LI Ying, SHAO Liang, BAI Yang, MA Zhonglei, MA Jianzhong

2021, 42(3):  929-936.  doi:10.7503/cjcu20200480

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PVA/PA/NP hydrogel was prepared via freeze-thaw cycle method using poly（vinyl alcohol）（PVA） as raw material， phytic acid（PA） and amino-polyhedral oligomeric silsesquioxane（NH₂-POSS， NP） as cross-linking agents. Then， PVA/PA/NP-PPy composite conductive hydrogel was prepared by in?situ polymerization of pyrrole， which overcomed the fragile and hydrophobic characteristics of polypyrrole materials， and further improved the conductivity and sensitivity of hydrogels. The cyclic tensile curve prove that the hydrogel has good self-recovery ability， the conductivity is as high as 7.53 S/m. It can be seen from the I-V curves that the highest detection current of the hydrogel as a flexible strain sensor can reach 9.029 mA and the gauge factor can reach 6.796. The results show that it can accurately monitor many kinds of tiny movements of human body through the change of current signal.



Synthesis of Micro- to Nano-scale Perovskite Calcium Hydroxytinate and Its Performance as a Flame Retardant in Epoxy Resin

DONG Luming, SU Yanyue, WANG Chunzheng, QIAO Yafei, CHEN Yajun, MA Haiyun

2021, 42(3):  937-945.  doi:10.7503/cjcu20200470

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Perovskite hydroxystannate is a new type of flame retardant and smoke suppressant with high efficiency that has appeared in recent years. In this paper， micro- to nano-scale perovskite-type calcium hydroxystannate［CaSn（OH）₆， CSH］ was synthesized by co-precipitation method. Scanning electron micros-copy， transmission electron microscopy， X-ray diffraction， infrared spectroscopy， and X-ray photoelectron spectroscopy were used to characterize its morphology and structure. The results show that the synthesized CaSn（OH）₆ was a pure regular hexahedron with an average particle size of 500 nm， and showed a uniform size and good dispersion. CSH/EP flame retardant composites were prepared by applying CaSn（OH）₆ to epoxy resin（EP）. Thermogravimetric analysis， limiting oxygen index and cone calorimeter tests were used to characte-rized its thermal degradation behavior and combustion performance， respectively， scanning electron micros-copy， infrared spectroscopy， X-ray diffraction and Raman spectroscopy were used to explore the carbonizing flame retardant mechanism of EP composites. The results show that CaSn（OH）₆ could significantly improve the high temperature stability， heat release rate， total heat release， total smoke release and limiting oxygen index value of the EP composites. Especially at very low addition levels（0.5%， mass fraction）， the flame retardant and smoke suppression performance were greatly improved， and the heat release rate， total heat release and carbon monoxide release were reduced by 45.8%， 25.1% and 31.3%， respectively. Moreover， due to the good dispersion of CaSn（OH）₆ in the EP matrix and the strong interface effect， the addition of CaSn（OH）₆ also improved the mechanical strength of the EP composite and enhanced its flame retarancy properties. The CaSn（OH）₆ synthesized in this paper can be used as a multi-functional high-efficiency flame retardant， smoke suppression as well as a reinforcing agent for EP resin.



Materials Chemistry

Preparation of Small Mesoporous SiO₂ Particles with Asymmetric Tunnel Structure and Fabrication of the Resulting Hybrid Membranes

TONG Cheng, WU Wentao, WANG Ting

2021, 42(3):  946-955.  doi:10.7503/cjcu20200527

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Through a soft template method using chiral anionic acid as a surfactant， small mesoporous SiO₂ particles with asymmetric tunnel structures were firstly prepared. Then， the small mesoporous SiO₂ particles were incorporated into polyvinylidene fluoride（PVDF） and polyimide（PI） to fabricate two kinds of organic-inorganic hybrid membranes. Fourier transform infrared spectrometer（FTIR）， transmission electron microscope（TEM）， Scanning electron microscope（SEM） and Brunner-Emmet-Teller（BET） measurement were employed to characterize the microstructure of the small mesoporous SiO₂ and the resulting organic- inorganic hybrid membranes. The performance of the PVDF and PI hybrid membranes were evaluated by ultrafiltration and gas permeation experiments， respectively. The results showed that the small mesoporous SiO₂ particles with a lot of hydrophilic groups on its surface had a regular and orderly arranged pore structure， which presented spiral twists and asymmetry. Addition of small mesoporous SiO₂ particles would significantly improve the polarity of the two kinds of hybrid membranes， thereby effectively enhancing the anti-pollution performance of the PVDF membranes and the performance of the PI membranes for CO₂ separation. Moreover， the tunnel structures of mesoporous SiO₂ could also introduce a confined mass transfer channel， which could accelerate the diffusion of CO₂ molecule through the PI hybrid membrane. Addition of too many mesoporous SiO₂ caused the formation of aggregates in the polymer membranes， which weakened the polarity and hydrophilicity of membranes， thereby depressing the performance of the two kinds of hybrid membranes.



Sulfonic Acid-functionalized Spherical Covalent Organic Framework with Ultrahigh Capacity for the Removal of Cationic Dyes

YAN Yanhong, WU Simin, YAN Yilun, TANG Xihao, CAI Songliang, ZHENG Shengrun, ZHANG Weiguang, GU Fenglong

2021, 42(3):  956-964.  doi:10.7503/cjcu20200443

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The development of porous covalent organic frameworks（COFs） as adsorbents for highly effective and selective removal of organic pollutants from aqueous solution is desirable but remains challenging. Herein， a β-ketoenamine-linked sulfonic acid-functionalized spherical COF， namely TFP-BDSA， was synthesized by the Schiff-base reaction of 1，3，5-triformylphloroglucinol（TFP） with 2，2′-benzidinedisulfonic acid（BDSA）. The anionic nature of the framework can rapidly adsorb the cationic dyes of MLB， CV， and RhB， while it is difficult for the adsorption of MO and FS anionic dyes， making it promising for the separation of cationic and anionic dyes based on a charge-dependent mode. The adsorption kinetics of cationic dyes on TFP-BDSA all followed the Pseudo-second-order adsorption kinetic model， and the adsorption process fitted well the the Langmuir adsorption model. The maximum adsorption capacities of TFP-BDSA for MLB， CV and RhB are 1116， 1429 and 1638 mg/g， respectively， in which those of CV and RhB rank as the highest values in comparison to the other reported COFs to date. This work may provide a useful idea for developing COFs-based adsorbents for fast adsorption and effective removal of organic pollutants from wastewater.