检索结果-南通市图书馆

Dyes adsorption using a synthetic carboxymethyl cellulose-acrylic acid adsorbent

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第5期26卷 1203-1211页

作者： Genlin Zhang Lijuan Yi Hui Deng Ping Sun School of Chemistry and Chemical Engineering Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan Shihezi University

Removal of noxious dyes is gaining public and technological attention. Herein grafting polymerization was employed to produce a novel adsorbent using acrylic acid and carboxymethyl cellulose for dye removal. Scanning electron microscopy and Fourier-transform infrared spectroscopy verified the adsorbent formed under optimized reaction conditions. The removal ratio of adsorbent to Methyl Orange, Disperse Blue 2BLN and malachite green chloride reached to 84.2%, 79.6% and 99.9%, respectively. The greater agreement between the calculated and experimental results suggested that pseudo second-order kinetic model better represents the kinetic adsorption data. Equilibrium adsorptions of dyes were better explained by the Temkin isotherm. The results implied that this new cellulose-based absorbent had the universaiity for removal of dyes through the chemical adsorption mechanism.

关键词： adsorption dye grafting polymerization carboxymethyl cellulose acrylic acid

PREPARATION OF POLY(ETHYLENEGLYCOL-co-acrylic acid) MICROSPHERES WITH DIVINYLBENZNE AS CROSSLINKER BY DISTILLATION-PRECIPITATION POLYMERIZATION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2007年第3期25卷 303-309页

作者：杨新林黄文强 Key Laboratory of Functional Polymer Materials the Ministry of EducationInstitute of Polymer ChemistryNankai UniversityTianjin 300071China

Monodisperse poly（poly（ethyleneglycol） methyl ether acrylate-co-acrylic acid）（poly（PEGMA-co-AA）） microspheres were prepared by distillation-precipitation polymerization with divinylbenzene （DVB） as crosslinker with 2,2＇- azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%. The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.

关键词： Distillation-precipitation polymerization Monodisperse microspheres Divinylbenzene Poly(ethyleneglycol) methyl ether acrylate acrylic acid Hydrogen bonding.

Effect of preparation conditions on selective oxidation of propane to acrylic acid

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2009年第S02期19卷 476-479页

作者： YU Zhen-xing ZHENG Wei XU Wen-long ZHANG Yu-hang FU Hong-ying ZHANG Ping Daqing Nanyuan Group Co. LtdDaqing 163517China

The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were *** the catalysts studied,Mo_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_(x) catalyst calcined in inert atmosphere at 600℃shows the best performance in terms of propane conversion and selectivity to acrylic *** results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure,chemical composition,which are related to their catalytic performances;and 51.0%propane conversion and 30.5%one-pass yield to acrylic acid can be achieved at the same time.

关键词： selective oxidation propane oxidation catalysts preparation acrylic acid propane

TEMPERATURE AND pH RESPONSE,AND SWELLING BEHAVIOR OF POROUS ACRYLONITRILE-acrylic acid COPOLYMER HYDROGELS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2006年第2期24卷 195-203页

作者：包永忠 State Key Laboratory of Polymer Reaction Engineering Zhejiang University

Macroporous acrylonitrile-acrylic acid （AN-AA） copolymer hydrogels were synthesized by flee-radical solution polymerizations, using ammonium persulfate （APS）/N,N,N＇,N＇-tetramethylethylenediamine （TEMED） redox initiator system and alcohols porogens. The morphology, temperature and pH sensitive swelling behavior, and swelling kinetics of the resulting hydrogels were investigated. It was found that alcohol type and concentration had great influences on the pore structure and porosity of hydrogels. The pore size of hydrogel increases with the moderate increase of the length of alcohol alkyl chain. However, a further increase of alkyl length would result in the formation of cauliflower-like structure and the decrease of pore size. The porosity of hydrogels increases with the increase of porogen concentration in the polymerization medium. The hydrogels with macroporous structure swell or shrink much faster in response to the change of pH in comparison with the conventional hydrogel without macroporous structure. Furthermore, the response rate is closely related to the porosity of the hydrogels, which could be easily controlled by modulating the concentration of the porogen in the medium. The circular swelling behavior of hydrogels indicated the formation of a relaxing three-dimensional network.

关键词： Acrylonitrile acrylic acid Porous hydrogel Swelling behavior

Oxidation of propane to acrylic acid and acetic acid over alkaline earth-doped Mo-V-Sb-O_x catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2010年第6期19卷 593-599页

作者： Chandan S.Chaudhari Shailesh S.Sable Hanumant Gurav Ashutosh A.Kelkar Vilas H.Rane Chemical Engineering and Process Development Division National Chemical Laboratory Catalysis Division National Chemical Laboratory

Alkaline earth metal （Mg,Ca,Sr and Ba）-doped Mo-V-Sb-O x catalysts,prepared by a dry-up method,have been investigated for their catalytic performance in the oxidation of propane under different reaction *** catalysts have been characterized by N2 adsorption-desorption,temperature-programmed desorption （TPD） of NH3,SEM and *** of water vapor on the catalytic performance,particularly on the selectivities to acetic acid and acrylic acid,has also been *** selectivity to acrylic acid was improved significantly by the doping of alkaline earth metals to Mo-V-Sb-O x *** surface acidic sites of the catalyst decreased with the doping of the catalyst with alkaline earth metals,which ultimately was found to be beneficial for obtaining high selectivity to acrylic *** catalytic activity and product selectivities were found to be influenced by the reaction temperature,C3H8/O2 ratio and space velocity.A significant improvement in the selectivity to acrylic acid has also been observed by the addition of water vapor in the feed of propane and oxygen in the oxidation of propane.

关键词： oxidation of propane surface acidity alkaline earth doped Mo-V-Sb-Ox catalysts acrylic acid acetic acid

Graft Copolymerization of acrylic acid onto Fungal Cell Wall Structural Polysaccharide

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2001年第1期9卷 97-99页

作者：张诚孟琴吕德伟 Zhejiang Univ Inst Mat & Chem Engn Hangzhou 310027 Peoples R China

acrylic acid was graft-copolymerized onto Rhi. oryzae's cell wall structural polysaccharide directly and efficiently in aqueous solution with eerie ammonium nitrate as initiator. The maximal grafting percentage of 135.5% was obtained under the condition of [Ce4+]=5mmol·L-1, [AA]=lmol·L-1, T=60℃ and t=3h. Graft copolymerization was suggested to proceed through free radical reaction mechanism. Grafting occurred primarily on chitosan. acrylic acid was also attempted to be grafted onto Asp. niger cell wall structural polysaccharide, and only 44.2% of grafting percentage was resulted.

关键词： graft Rhi. oryzae cell wall acrylic acid ceric ammonium nitrate

Selective oxidation of propane to acrylic acid over mixed metal oxide catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2008年第2期17卷 191-194页

作者： Wei Zheng Zhenxing Yu Ping Zhang Yuhang Zhang Hongying Fu Xiaoli Zhang Qiquan Sun Xinguo Hu School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150001 Heilongjiang China Daqing Petroleum Co Ltd Daqing 163453 Heilongjiang China

The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.

关键词： propane oxidation catalysts preparation acrylic acid selective oxidation

Catalytic Cracking of Polylactic acid to acrylic acid

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第17期41卷 2071-2076页

作者： Yuchen Jiao Meng Wang Ding Ma Beijing National Laboratory for Molecular Sciences New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Comprehensive Summary,As a typical type of sustainable plastic,polyesters can be recycled or upcycled into value-added chemicals in a variety of ***,excess reagents are required for most of the depolymerization and upcycling processes,causing the emission of environmental pollutants and the waste of chemical *** we demonstrate a one-pot catalytic process to directly crack polylactic acid into acrylic acid by acid catalyst with the assistance of an ionic liquid,*** acid is attacked by the Br–from Bu4PBr and the H+from acid to form oligomers containing Br or acryloyl group,and these oligomers serve as intermediates to produce acrylic acid during their mutual *** acrylic acid is vaporized directly from the reactor and obtained in a collector with a selectivity around 90%when polylactic acid is fully *** green process shows great advantages in atom economy compared to the conventional recycling/upcycling methods for polyesters,in addition.

关键词： Polylactic acid acrylic acid Atom economy Upcycling lonic liquid Commodity polymers Plastics Green chemistry

Preparation and Characterization ofβ-Cyclodextrin/Poly(acrylic acid)/Permutite Hydrogel Composite for U(Ⅵ)Adsorption

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第10期39卷 1795-1806,1742页

作者： ZHANG Zi-Hui ZHANG Wen XU Xiao-Ping OU Min-Rui College of Chemistry Fuzhou UniversityFuzhou 350116China College of Chemical Engineering Fuzhou UniversityFuzhou 350116China

Uranium in the environment can damage human health and *** is a need for excellent adsorbents to remove U(Ⅵ)from aqueous *** we synthesized a novelβ-cyclodextrin/poly(acrylic acid)/permutite(CAP)hydrogel composite by a simple *** characterizations of the materials were conducted by XRD,FTIR,SEM,EDX,and *** effect of pH value,contact time,initial U(Ⅵ)concentration,and temperature were researched.A pseudo-second-order kinetic model,intra-particle diffusion model,and Langmuir isotherm model were used to describe the U(Ⅵ)adsorption behavior,and the maximum adsorption capacity of U(Ⅵ)was 833.33 mg/g at 25℃.Thermodynamic analysis showed that the adsorption process of U(Ⅵ)was endothermic and ***,the excellent reusability indicated that CAP hydrogel composite could be potentially used as a promising sorbent for the removal of U(Ⅵ)in wastewater.

关键词： β-cyclodextrin acrylic acid hydrogel adsorption U(Ⅵ)