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Chemically modified magnetic chitosan microspheres for Cr（VI） removal from acidic aqueous solution

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Particuology 2016年第3期14卷 79-86页

作者： xitong sun Qian Li Liangrong Yang Huizhou Liua CAS Key Laboratory of Biobased Materials Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China School of Biological Engineering Dalian Polytechnic University Dalian 116034 China CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China

A bioadsorbent composed of magnetic silica nanoparticles encapsulated by chitosan microspheres was prepared by the emulsion cross-linking method, and it was then modified with quaternary ammonium groups by reaction with ethylenediamine and glycidyl trimethylammonium chloride. Characterization of the bioadsorbent indicated that it was highly acid resistant and magnetically responsive. The bioadsor- bent was then used to remove Cr（VI） from acidic aqueous solution. The results of batch experiments indicated that the optimal pH value was 2.5, and the adsorbent exhibited low pH dependence. The maximum adsorption capacity was 233.1mg/g at pH 2.5 and 25 ℃, and the equilibrium time was deter- mined to be 40-120 min depending on the initial Cr（VI） concentration. The adsorbent could be effectively regenerated using a mixture of 0.3 mol/L NaOH and 0.3 mol/L NaCI with a desorption efficiency of 95.6%, indicating high reusability. In conclusion, the bioadsorbent shows potential for Cr（VI） removal from acidic

关键词： Chitosan Quaternary ammonium Magnetic Adsorption Cr(VI)

A first-principles microkinetic study on the hydrogenation of carbon dioxide over Cu(211) in the presence of water

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Science China Chemistry 2019年第12期62卷 1686-1697页

作者： xitong sun Peng Wang Zhengjiang Shao Xiaoming Cao P.Hu Key Laboratories for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Chemical Engineering Queen's University of BelfastBelfast BT95AGUK

The hydrogenation of carbon dioxide(CO2)is one of important processes to effectively convert and utilize CO2,which is also regarded as the key step at the industrial methanol *** is likely to play an important role in this process,but it still remains *** systematically understand its influence,here we computationally compare the reaction mechanisms of CO2 hydrogenation over the stepped Cu(211)surface between in the absence and presence of water based on microkinetic simulations upon density functional theory(DFT)*** effects of water on each hydrogenation step and the whole activity and selectivity are checked and its physical origin is *** is found that the water could kinetically accelerate the hydrogenation on CO2 to COOH,promoting the reverse water gas shift reaction to produce carbon monoxide(CO).It hardly influences the CO2 hydrogenation to methanol *** addition,the too high initial partial pressure of water will thermodynamically inhibit the CO2 conversion.

关键词： CO2 activation microkinetic modeling DFT CH3OH selectivity

General trends in Horiuti-Polanyi mechanism vs non-Horiuti-Polanyi mechanism for water formation on transition metal surfaces

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Chinese Journal of Catalysis 2020年第2期41卷 294-301页

作者： xitong sun Jianfu Chen PHu Key Laboratory for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Chemical Engineering Queen’s University BelfastBelfast BT95AGUK

It is generally acknowledged in heterogeneous catalysis that hydrogenation follows the so-called Horiuti-Polanyi(HP) mechanism. In this work, a thorough investigation of the mechanism of hydrogenation of hydroxyl groups and O catalyzed by a series of transition metals was carried out through density functional theory calculations, as surface hydroxyls and O are very common species in many catalytic systems. It is found that different metal catalysts exhibit different mechanisms. On some metal catalysts, the non-HP mechanism is preferred, whereas the classic HP mechanism is favored on other catalysts. Detailed analyses of the metal-dependent mechanism shows that the activity toward the dissociation of H2 decides which mechanism is preferred. On active catalysts, such as Ni and Pt, H2 prefers to dissociate with strong H adsorption energies, which lead to the classic HP mechanism being favored. On inactive surfaces, on the other hand, the adsorption of H is weak, which results in the non-HP mechanism being preferred. The parameter η, which is a structural descriptor, was defined to understand the different mechanisms.

关键词： Hydrogenation Horiuti-Polanyi mechanism Water formation Transition metal Density functional theory

Gas-assisted magnetic separation for the purification of proteins in batch systems

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Particuology 2016年第1期14卷 170-176页

作者： Zhini Liu Liangrong Yang Tingting Dong Wensong Li xitong sun Menghao Zhu Zhengkang Duan Qingfen Liu Huizhou Liu College of Chemical Engineering Xiangtan University Xiangtan 411105 China Key Laboratory of Green Process and Engineering State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy ofSciences Beijing 100190 China

In this paper, gas-assisted magnetic separation （GAMS）, a technique that combines magnetic separation with flotation, was investigated for the potential large-scale separation of proteins, The GAMS process includes adsorption of target proteins and magnetic separation to recover protein-loaded magnetic particles from the dilute biosuspension with the assistance of bubbles, Microsized ethylenediamine- functionalized poly（glycidyl methacrylate） superparamagnetic microspheres （MPMs） and bovine serum albumin （BSA） were used as a model system. The feasibility of GAMS for capturing BSA-loaded MPMs from an appropriate medium was shown, High recovery of BSA-loaded MPMs was obtained by simple adjustment of the initial solution pH without extra detergents and antifoaming agents. The GAMS con- ditions were consistent with the adsorption conditions, and no proteins were desorbed from the MPMs during this process. Under the optimal conditions, the separation rate and recovery percentage reached 410 mL/min and 98% in 0.61 min, respectively. Conformational changes of BSA during the GAMS process were investigated by fluorescence spectroscopy and circular dichroism spectrometry,

关键词： Adsorption Magnetic separation Flotation Recovery BSA conformation

Polystyrene microsphere-immobilized palladium(Ⅱ)porphyrin as mild,reusable,and highly efficient catalyst for Heck reaction

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Particuology 2015年第5期13卷 128-133页

作者： Yinbin Huang Liangrong Yang Minghui Huang Jian Wang Lin Xu Wensong Li Huacong Zhou xitong sun Huifang Xing Huizhou Liu Key Laboratory of Green Processes and Engineering Institute of Process EngineeringChinese Academy of Sciences Agricultural & Biosystems Engineering South Dakota State University Art College Hubei University of Economics

A novel Heck reaction catalyst consisting of a palladium（ll） complex of meso-tetra（p- hydroxyphenyl）porphyrin （MTP） and cross-linked chloromethylated polystyrene microspheres （PMs） was successfully prepared via covalent ether bonds between the chloride groups in the PMs and the hydroxyl groups in MTP. The catalyst was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and inductively coupled plasma atomic emission spectroscopy （ICP-AES）. This polystyrene-supported palladium-complex was an efficient heterogeneous catalyst for cross-coupling of aryl iodides with ethyl acrylate. The reaction of iodobenzene and ethyl acrylate under N2 at 100 °C and a catalyst concentration of 0.1% gave a gas chromatography product yield of 99.8%, which is much higher than that achieved using a free palladium（II） complex of MTP as the catalyst （41.3%）. The catalyst was recycled up to six times without significant loss of catalytic activity. These results suggest that the immobilized palladium（II） MTP catalyst has potential applications in synthetic and industrial chemistry.

关键词： Heterogeneous catalyst Palladium-porphyrin Polystyrene microspheres Heck reaction

Kinetically accelerated and high-mass loaded lithium storage enabled by atomic iron embedded carbon nanofibers

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Nano Research 2022年第7期15卷 6176-6183页

作者： Qian Xu Yanan Li Chenghao Wu xitong sun Qiang Li Huabin Zhang Le Yu Yuanyuan Pan Yujuan Wang Shiwei Guo Mengdi Zhang Han Hu Mingbo Wu State Key Laboratory of Heavy Oil Processing Institute of New EnergyCollege of Chemistry and Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580China College of Physics Center for Marine Observation and CommunicationsQingdao UniversityQingdao 266071China KAUST Catalysis Center(KCC) Physical Sciences and Engineering DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Beijing Advanced Innovation Center for Soft Matter Science and Engineering State Key Lab of Organic-Inorganic CompositesBeijing University of Chemical TechnologyBeijing 100029China

Carbonaceous materials represent the dominant choice of materials for anodic lithium storage in many energy storage ***,the nonpolar carbonaceous materials offer weak adsorption toward Li+that largely denies the high-rate Li+***,the atomic Fe sites decorated carbon nanofibers(AICNFs)facilely produced by electrospinning are reported for kinetically accelerated Li+*** calculation reveals that the atomic Fe sites possess coordination unsaturated electronic configuration,enabling suitable bonding energy and facilitated diffusion path of Li+.As a result,the optimal structure displays a high capacitive contribution up to 95.9%at a scan rate of 2.0 mV·s^(−1).In addition,ultrahigh capacity retention of 97%is afforded after 5,000 cycles at a current density of 3 A·g^(−1).Moreover,the interlaced fiber structure enabled by electrospinning benefits structural stability and improved conductivity even at thick electrodes,thus allowing a high areal capacity of 1.76 mAh·cm−2 at a loading of 8 mg·cm−*** of these structure and performance merits,the lithium-ion capacitor containing the AICNF-based anode delivers a high energy density and large power density.

关键词： atomic iron pseudocapacitance high-mass loading electrospinning lithium storage

直流电场对脱硫菌红串红球菌NCC-1生长及脱硫性能的影响

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石油化工 2010年第6期39卷 669-674页

作者：刘镔马洁孙西同孙晓彦首都师范大学化学系北京100048

以专一性降解二苯并噻吩(DBT)的红串红球菌NCC-1为脱硫菌,以DBT为硫源,考察了加直流电场对脱硫菌在不同浓度DBT水相中生长和脱硫性能的影响,以及调控菌液pH对脱硫菌生长和脱硫性能的影响;同时考察了脱硫菌对柴油的脱硫性能。实验结果表... 详细信息

以专一性降解二苯并噻吩(DBT)的红串红球菌NCC-1为脱硫菌,以DBT为硫源,考察了加直流电场对脱硫菌在不同浓度DBT水相中生长和脱硫性能的影响,以及调控菌液pH对脱硫菌生长和脱硫性能的影响;同时考察了脱硫菌对柴油的脱硫性能。实验结果表明,当电流密度为0.52～1.01A/m2时,能有效促进脱硫菌生长,提高脱硫效率,最佳电流密度为0.72A/m2,当DBT初始浓度为0.20mmol/L时,DBT完全降解的时间为120h,比不加电场时缩短了24h;当DBT初始浓度为1.00mmol/L时,DBT浓度降至0.31mmol/L所需时间为72h,比不加电场时缩短了96h。此外,调控菌液pH能有效促进脱硫菌生长。脱硫菌用于柴油脱硫时,在电流密度为0.72A/m2、柴油与菌液体积比1∶9的条件下,总硫含量从606mg/L降至269mg/L,脱硫率为55.7%,比不加电场时高出12.9个百分点。

关键词：直流电场红串红球菌NCC-1 二苯并噻吩柴油生物脱硫

大肠杆菌在直流电场刺激作用下的生长机理研究

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化学通报 2010年第3期73卷 252-256页

作者：马洁孙西同刘镔孙晓彦首都师范大学化学系北京100048

以钛网电极和铂网电极对培养瓶中大肠杆菌生长过程进行加电刺激,考察其在直流电场作用下的生长情况,并结合盐桥、循环伏安扫描、恒电流等技术对电场作用机理进行研究。结果表明,在电流密度为0.2275mA/cm2时,直流电场能有效促进大肠杆菌... 详细信息

以钛网电极和铂网电极对培养瓶中大肠杆菌生长过程进行加电刺激,考察其在直流电场作用下的生长情况,并结合盐桥、循环伏安扫描、恒电流等技术对电场作用机理进行研究。结果表明,在电流密度为0.2275mA/cm2时,直流电场能有效促进大肠杆菌的生长,且随着电流密度的增大,菌体的生长速度逐步加快;当使用盐桥屏蔽电极反应产物时,单纯的离子电流对细胞的生长没有显著影响,水的阴极电解产物是促进微生物生长的主要因素。通过对析氢活性不同的铂网电极与钛网电极加相同电流密度0.0455mA/cm2的电场后,起促进生长作用的主要是阴极电解产物吸附氢和氢气,其中对摇瓶培养的细菌氢气的促进作用显著。

关键词：大肠杆菌直流电场盐桥吸附氢氢气

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电磁感应通信信号采集与存储系统设计

现代电子技术 2017年第19期40卷 14-17,21页

作者：孙希彤刘秋生军械工程学院三系河北石家庄050003

设计了一套感应通信信号采集与存储系统。阐述电磁感应通信基本原理,针对信号特点,明确系统参数,对系统进行总体设计,并对信号调理模块、A/D采集模块、SRAM及SD卡、主控芯片及网络通信模块等进行详尽的分析。系统采用金属线圈感应信号,S... 详细信息

设计了一套感应通信信号采集与存储系统。阐述电磁感应通信基本原理,针对信号特点,明确系统参数,对系统进行总体设计,并对信号调理模块、A/D采集模块、SRAM及SD卡、主控芯片及网络通信模块等进行详尽的分析。系统采用金属线圈感应信号,STM32F407ZGT6微处理器作为主控芯片控制采集与存储,通过RJ45网口将数据转存给上位机。试验结果表明,该采集系统能够有效实现感应通信信号的高保真采集。

关键词：信号采集感应通信 STM32F407ZGT6 数据传输