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857 results on '"Liu, Guifeng"'

205. Functionalized lignin-based magnetic adsorbents with tunable structure for the efficient and selective removal of Pb(II) from aqueous solution

Author

Guomin Wu, Xuan Zhou, Jin Can, Kong Zhenwu, Liu Guifeng, and Huo Shuping

Subjects
Aqueous solution, Chemistry, General Chemical Engineering, Cyanuric chloride, Nanoparticle, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Endothermic process, Industrial and Manufacturing Engineering, 0104 chemical sciences, chemistry.chemical_compound, Adsorption, Chemical engineering, Environmental Chemistry, Magnetic nanoparticles, 0210 nano-technology, Selectivity, Superparamagnetism
Abstract

With the increasing concern in sustainable development and environmental governance, the biomass-based magnetic materials containing sufficient active sites and regular structure can be regarded as the high-performance adsorbents for removal of heavy metal pollutants from wastewater. In this study, we reported the tunable covalent binding of lignin onto amine-functionalized magnetic nanoparticles (AMNP) using cyanuric chloride as a chemoselective cross-linker. The chemical structures, morphologies, and magnetic properties of the synthesized lignin-based magnetic adsorbents (L1@MNP and L2@MNP) were comprehensively characterized. Batch adsorption experiments were conducted to investigate various effecting factors, including pH, contact time, solution concentration and temperature. With the higher component ratio of AMNP/lignin, L1@MNP displayed higher adsorption affinity (qmax = 111.23 mg/g) and selectivity towards Pb(II) than L2@MNP (qmax = 81.97 mg/g). The adsorption kinetics agreed well with the pseudo-second-order kinetic model, and the thermodynamic adsorption behaviors were found to be an endothermic and spontaneous process. In addition, the presence of magnetic cores in the network facilitated the fast recovery of both two magnetic adsorbents after the adsorption process, owing to the good superparamagnetic properties for L1@MNP (40.06 emu/g) and L2@MNP (26.95 emu/g). Furthermore, the core–shell magnetic adsorbents also showed superior stability even in an acidic solution, of which the removal efficiency could well maintain over 85% after 5 cycles. This work provides a facile strategy for the design and synthesis of lignin-based adsorbents with flexible nanoparticles as a building block for the potential application prospects in Pb(II) removal from wastewater.

Published
2021

213. The contribution of hereditary cancer-related germline mutations to lung cancer susceptibility

Author

Liu, Mengyuan, primary, Liu, Xinyi, additional, Suo, Peisu, additional, Gong, Yuan, additional, Qu, Baolin, additional, Peng, Xiumei, additional, Xiao, Wenhua, additional, Li, Yuemin, additional, Chen, Yan, additional, Zeng, Zhen, additional, Lu, Yinying, additional, Huang, Tanxiao, additional, Zhao, Yingshen, additional, Liu, Ming, additional, Li, Lifeng, additional, Chen, Yaru, additional, Zhou, Yanqing, additional, Liu, Guifeng, additional, Yao, Jianfei, additional, Chen, Shifu, additional, and Song, Lele, additional

Published
2020
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229. Preparation and properties of thermoset composite films from two-component waterborne polyurethane with low loading level nanofibrillated cellulose

Author

Zhenwu Kong, Liu Guifeng, Guomin Wu, and Chen Jian

Subjects
Materials science, Nanocomposite, Scanning electron microscope, General Chemical Engineering, Organic Chemistry, Composite number, Thermosetting polymer, 02 engineering and technology, Dynamic mechanical analysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, chemistry.chemical_compound, chemistry, Ultimate tensile strength, Materials Chemistry, Composite material, 0210 nano-technology, Glass transition, Polyurethane
Abstract

Thermoset nancomposite films were prepared from a two-component waterborne polyurethane (2K-WPU) incorporated with different contents of high aspect ratio nanofibrillated cellulose (NFC). Effects of NFC addition on viscosity and particle size distribution of the 2K-WPU dispersion were investigated by rotational rheometer and laser particle size analyzer, respectively. Viscosities of the 2K-WPU/NFC dispersions increased sharply and particle sizes of the 2K-WPU/NFC dispersions increased slightly with the increase of NFC content. Fractography images from scanning electron microscopy (SEM) showed rough structures appearing in the nancomposites structure, which corresponded to the microphase separation between NFC nano-filler and the 2K-WPU matrix. This microphase separation phenomenon led glass transition temperature ( T g ) and break elongation of the 2K-WPU/NFC nanocomposite films decreased with the increase of NFC content. Tensile tests and dynamic mechanical analysis (DMA) indicated all the 2K-WPU/NFC nanocomposite films showed simultaneous enhancements in modulus and tensile strength, compared with those for the neat 2K-WPU (0 wt%). The enhancements can be attributed to strong interactions resulting from the formation of hydrogen bonds and chemical grafting between NFC nano-filler and the 2K-WPU matrix.

Published
2017

230. Clickable Synthesis of 1,2,4-Triazole Modified Lignin-Based Adsorbent for the Selective Removal of Cd(II)

Author

Guomin Wu, Zhenwu Kong, Xueyan Zhang, Junna Xin, Liu Guifeng, Jinwen Zhang, and Can Jin

Subjects
Addition reaction, Langmuir, Renewable Energy, Sustainability and the Environment, General Chemical Engineering, Metal ions in aqueous solution, Inorganic chemistry, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Metal, chemistry.chemical_compound, Adsorption, chemistry, visual_art, visual_art.visual_art_medium, Click chemistry, Environmental Chemistry, Lignin, Fourier transform infrared spectroscopy, 0210 nano-technology
Abstract

Development of bioadsorbents for efficient removal of heavy metal ions from contaminated water is of great interest but still challenging. In this study, a 1,2,4-triazole-3-thiol modified lignin-based adsorbent (LBA) was synthesized through a UV-initiated thiol-yne click reaction chemistry for Cd(II) adsorption. The structure of LBA, prepared by thiol-yne addition reaction, was confirmed and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and elemental analysis. Effects of pH, contact time, initial metal concentration, and temperature on the adsorption of Cd(II) on LBA were studied. Due to multiple thio-triazole units as binding sites, LBA was found to exhibit an adsorption capacity that was 8.6 times that of the raw lignin for Cd(II) adsorption. Pseudo-second-order and Langmuir models were utilized to describe the adsorption kinetics and isotherms, respectively. Furthermore, the study of adsorption selectivity suggested that LBA had high selectivity for adsorbing Cd(...

Published
2017

231. Research on pipeline leakage identification method based on Lyapunov exponent spectrum

Author

Liu, Guifeng, Liu, Jingbin, Wang, Ji, Liu, Shuyong, Liu, Guifeng, Liu, Jingbin, Wang, Ji, and Liu, Shuyong

Abstract

In terms of resource transportation, pipelines play a very important role, however, it’s leakage is almost inevitable, so leakage monitoring has always been a research hotspot. The leakage identification of water supply pipeline is studied in this paper. The vibration caused by turbulence and cavitation at the leak point has chaotic characteristics, and the spectral distribution of which has its own special area. Chaos can be judged by the Lyapunov exponent, this means that the occurrence of the leak is judged. By this method, the leakage can be effectively identified. The above theory is verified by experiments in this paper.

Published
2019

232. Constructing polyurethane foams of strong mechanical property and thermostability by two novel environment friendly bio-based polyols

Author

Zhenwu Kong, Chen Jian, Guomin Wu, Huo Shuping, and Liu Guifeng

Subjects
Cardanol, Diethanolamine, Materials science, Scanning electron microscope, General Chemical Engineering, Dispersity, 02 engineering and technology, General Chemistry, Epoxy, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Chemical engineering, visual_art, Polymer chemistry, visual_art.visual_art_medium, Reactivity (chemistry), 0210 nano-technology, Polyurethane, Thermostability
Abstract

Two novel cardanol-based polyols were synthesized and used to construct polyurethane (PU) foams. The cardanol-based polyols with high reactivity were obtained from the epoxidation of cardanol, followed by the ring opening reaction of epoxy group with diethanolamine (DEA). Subsequently, PU foams were synthesized by these cardanolbased polyols. Compared with petroleum-based (PEG) PU foams, these green cardanol-based PU foams exhibit better mechanical property and higher thermostability. Scanning electron microscopy (SEM) tests show that the cells of cardanol-based PU foams are monodisperse, with fairly uniform spherical shape and regular size.

Published
2016

233. Synthesis and properties of POSS-containing gallic acid-based non-isocyanate polyurethanes coatings

Author

Liu Guifeng, Zhenwu Kong, Guomin Wu, Jin Can, Chen Jian, and Huo Shuping

Subjects
chemistry.chemical_compound, Materials science, Polymers and Plastics, chemistry, Water resistance, Mechanics of Materials, Materials Chemistry, Thermal stability, Izod impact strength test, Gallic acid, Composite material, Condensed Matter Physics, Isocyanate
Abstract

A series of novel biomass-based nonisocyanate polyurethanes (NIPUs) coatings were successfully prepared via the reactions of gallic acid-based cyclic carbonate with diamines. Then the NIPUs were modified with epoxy-functionalized POSS to form NIPU/POSS coatings with chemically linked POSS groups. The properties of the NIPUs and NIPU/POSSs were determined, and the influences of POSS on mechanical and thermal properties of the resulting coatings were investigated. The results showed that the gallic acid-based NIPU coatings have excellent impact strength, adhesion, flexibility, pencil hardness and thermal stability, but suffering from low water resistance. By introducing POSS into the NIPU networks, the pencil hardness, water resistance and thermal stability of the NIPU/POSS coatings were improved, while the adhesion of the coatings were observed to be slightly decreased.

Published
2015

236. A novel synthetic-genetic-array–based yeast one-hybrid system for high discovery rate and short processing time

Author

Yeh, Chung-Shu, primary, Wang, Zhifeng, additional, Miao, Fang, additional, Ma, Hongyan, additional, Kao, Chung-Ting, additional, Hsu, Tzu-Shu, additional, Yu, Jhong-He, additional, Hung, Er-Tsi, additional, Lin, Chia-Chang, additional, Kuan, Chen-Yu, additional, Tsai, Ni-Chiao, additional, Zhou, Chenguang, additional, Qu, Guan-Zheng, additional, Jiang, Jing, additional, Liu, Guifeng, additional, Wang, Jack P., additional, Li, Wei, additional, Chiang, Vincent L., additional, Chang, Tien-Hsien, additional, and Lin, Ying-Chung Jimmy, additional

Published
2019
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