ACS Applied Bio Materials
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2018
·
IF 0
Huimin He,Jinyang Li,Xiaodong Cao,Changshun Ruan,Qi Feng,Hua Dong,Gregory F. Payne
Chitosan is an aminopolysaccharide that can be physically cross-linked through two independent, reversible, and pH-switchable mechanisms. At high pH, neutral chitosan chains can self-assemble to form crystalline domains that serve as one type of physical cross-link (such cross-linked hydrogels are designated Chit0). At low pH, the chains are cationic and dis-assembled from each other but can be electrostatically cross-linked by multivalent anionic micelles of sodium dodecyl sulfate (such cross-linked hydrogels are designated SDS-Chit-H+). Here, we report that the ability to reversibly reconfigure cross-linking mechanisms provides a means to fuse separately prepared chitosan films. Experimentally, neutral Chit0 hydrogel films were first prepared by cathodic electrodeposition, and then separately prepared Chit0 films were fused by overlapping them in the presence of SDS and acid. Qualitative evidence demonstrates fusion across the interface at both the microscale (e.g., SEM) and macroscale. Mechanical testing (e.g., tear test) demonstrates that fusion leads to strong bonding with failure occurring in the bulk region of the film and not at the joint. Potentially, the ability to fuse separately prepared films may provide new opportunities for additive manufacturing of biobased materials.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2018
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IF 3.909
Jianzhe Ma,Yang Lei,Muhammad Asim Khan,Fengyun Wang,Yuting Chu,Wu Lei,Mingzhu Xia,Sidi Zhu
This paper describes a modification method of Na-montmorillonite (Na-Mt) with carboxymethyl-chitosan (CMC). The as-prepared samples were analyzed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analyzer and thermogravimetric analysis (TGA). Two common tetracycline antibiotics, tetracycline (TET) and chlortetracycline (CTC), were selected as the represented pollutants and adsorbed by CMC-Mt under different experimental conditions. The intercalation of CMC obviously amplified the basal spacing of the interlayers confirmed by XRD measurements and improved the adsorption capacities of montmorillonite to some degree. The results showed that the tetracycline antibiotic sorption onto CMC-Mt was mainly dependent on pH and was not affected by temperature. Besides, the removal of TET and CTC rapidly attained an equilibrium within 2 h of contact time. The kinetic data of adsorption was determined by first-order, second-order kinetics and intraparticle diffusion models. The kinetic study indicates that the TET and CTC adsorption processes obeyed the second-order kinetics. The Freundlich isotherm study was in agreement with the practical data, suggesting a heterogeneous sorption process. Furthermore, the thermodynamic studies revealed that the removal process was more spontaneous at a lower temperature, implying it an exothermic reaction. The synthesized adsorbent CMC-Mt can be widely used in the treatment of wastewater.
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高影响因子
Journal of Materials Research and Technology-JMR&T
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2018
·
IF 3.398
Bo Feng,Jinxiu Peng,Wei Guo,Guodong Luo,Wenpu Zhang,Huihui Wang
The separation of scheelite and calcite by froth flotation is difficulty as these two minerals have similar physicochemical characteristics. To solve this problem, the role of carboxymethyl chitosan in the flotation separation of scheelite from calcite has been studied and the depression mechanism has been discussed. Micro-flotation tests show that carboxymethyl chitosan has strong depression effect on calcite and the depression effect decreased with the increase of pH. However, its depression effect on scheelite is weak. A concentrate with WO 3 grade of 65.21% and WO 3 recovery of 77.48% can be achieved in the mixed minerals flotation when carboxymethyl chitosan was used. The adsorption tests show that carboxymethyl chitosan has adsorbed on the calcite surface and the adsorption amount increased with the increase of added amount. The adsorption mechanism of carboxymethyl chitosan on calcite surface was analyzed through the X-ray photoelectron spectroscopy (XPS) tests and the results revealed that carboxymethyl chitosan adsorbed on calcite surface mainly through chemical interaction.
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高影响因子
JOURNAL OF FOOD ENGINEERING
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2018
·
IF 3.197
Tiantian Wu,Yuan Li,Ni Shen,Chunhong Yuan,Yaqin Hu
The objective of this study was to study the effect of calcium ions on the binding of lysozyme to chitosan (CS)/sodium alginate (SA) complexes (CS-SA-Ps), in order to develop a complex system for lysozyme delivery which might be of practical interest in the field of food preservatives . Result showed that with the increase of calcium ions (Ca 2+ ) concentration, the value of Z-Ave decreased while the value of ζ-potential and LE increased, where the addition of 5.0 mM Ca 2+ contributed to uniform distribution of the complexes. Sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that there was no significant difference of molecular integrity when lysozyme was released from CS-SA-Ps. The exothermic interaction between lysozyme and SA were proved by thermodynamic measurements, in which the binding stoichiometry showed a slight decrease in the presence of calcium chloride. Moreover, the release rate of lysozyme from CS-SA-Ps could be slowed by the increase of Ca 2+ addition concentration.
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 9
·6817-6823
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IF 3.201
Zhenliang Li,Zunli Mo,Pengji Yan,Shujuan Meng,Ruijuan Wang,Xiaohui Niu,Nijun Liu,Ruibin Guo
Inspired by amino acids with amphoteric groups for electrochemical enantiorecognition, amphoteric chitosan (ACCS) was prepared with chloroacetic acid and CS, and has perfect solubility in alkaline and acid solution, compared with CS. ACCS was linked to the ethylenediamine-functionalized multiwalled carbon nanotubes (MWCNTs–EA) through covalent bonding. Chiral interfaces were fabricated with MWCNTs–EA–ACCS and used for the electrochemical enantiorecognition of phenylalanine (Phe) enantiomers. The ACCS chiral interfaces showed excellent selectivity toward the Phe enantiomers. Also, the optimization of parameters such as pH, temperature and response time was carried out for the electrochemical recognition. Furthermore, the ACCS is capable of determining the percentage of enantiomers in mixed solutions. The electrochemical recognition of amino acid enantiomers with different functional groups was investigated, and it was found that the amphoteric functional groups of ACCS play an important role in the enantioselective discrimination.
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Chemistry Central Journal
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2013
·Vol. 7
·期 1
·1-11
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IF 1.312
Zuo Ping-Ping,Feng Hua-Feng,Xu Zhi-Zhen,Zhang Ling-Fan,Zhang Yu-Long,Xia Wei,Zhang Wen-Qing
Background Graphene oxide (GO)can be dispersed through functionalization, or chemically converted to make different graphene-based nanocomposites with excellent mechanical and thermal properties. Chitosan, a partially deacetylated derivative of chitin, is extensively used for food packaging, biosensors, water treatment, and drug delivery. GO can be evenly dispersed in chitosan matrix through the formation of amide linkages between them, which is different from previous reports focusing on preparing GO/chitosan nanocomposites through physical mixing. Results In this study, free-standing graphene oxide-chitosan (GO-chitosan) nanocomposite films have been prepared. The GO-chitosan films are biologically compatible and mechanically reinforced. Through the formation of amide linkages between GO’s carboxylic acid groups and chitosan's amine groups, GO could be evenly dispersed within the chitosan matrix. We also characterized the GO-chitosan composite films using element analysis, Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, differential scanning calorimetry, and thermo gravimetric analysis. Compared to pristine chitosan film, the tensile strength of GO-chitosan film is improved by 2.5 folds and Young’s modulus increases by nearly 4.6 folds. The glass transition temperature of GO-chitosan composite film shifts from 118°C to 158°C compared to the pristine chitosan, indicating its enhanced thermal stability. GO-chitosan composite film was also evaluated for its biocompatibility with C3H10T1/2 cells by in vitro fluorescent staining. The graphene oxide-reinforced chitosan composite films could have applications in functional biomaterials. Conclusion The present study describes a useful and simple method to chemically attach biocompatible chitosan onto graphene oxide. We envision that the GO-chitosan film will open avenues for next-generation graphene applications in the realm of functional biomaterial.
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高影响因子
JOURNAL OF FOOD SCIENCE
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2013
·Vol. 78
·期 1
·M90
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IF 1.775
Xiaodong Geng,Ronghua Yang,Jianying Huang,Xiao Zhang,Xiangyang Wang
Total of 3 water-soluble quaternary-based chitin/chitosan derivatives, which have an identical molecular weight and anion, were synthesized and characterized. Their antibacterial activities against Salmonella cholerae-suis and Bacillus subtilis were evaluated in vitro . The polysaccharides exhibited the antibacterial efficiency. Their minimum inhibitory concentration (MIC) values vary from 0.02 to 20.48 mg/mL, and their minimum bactericidal concentration (MBC) values vary from 0.08 to 40.96 mg/mL against S. cholerae-suis and B. subtilis , respectively. Futhermore, the extent of Bacillus subtilis cells damage was examined via transmission electron microscopy (TEM) to show how N,N,N -trimethylchitosan (TMC) gradually destroyed and killed B. subtilis cells when they were treated with TMC. One of those quaternary polymers, O -([2-hydroxy-3-trimethylammonium])propyl chitin (OHT-chitin), which can be directly and easily synthesized from chitin in bulk quantities, also was demonstrated its antibacterial activity. These water soluble quaternary-based chitin/chitosan derivatives that have antibacterial effect should be potentially used as antimicrobial agents in many fields. Practical Application: The main practical application behind the investigation and evaluation antibacterial activity of 3 water-soluble quaternary-based chitin/chitosan derivatives could be potentially used as antimicrobial agents in many fields. These polysaccharides represent a renewable source of natural biodegradable polymers and meet with the emergence of more and more food safe problems.
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高影响因子
Science China-Materials
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2015
·Vol. 58
·期 10
·811-818
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IF 0
Zhao Heng,Jiao Tifeng,Zhang Lexin,Zhou Jingxin,Zhang Qingrui,Peng Qiuming,Yan Xuehai
Graphene oxide (GO)-chitosan composite hydrogels were successfully prepared via the self-assembly of chitosan molecules and GO. These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The adsorption capacity results demonstrate that the prepared GObased composite hydrogels can efficiently remove three tested dye molecules, Congo red, methylene blue and Rhodamine B, from wastewater in accordance with the pseudo-second-order model. The dye adsorption capacity of the obtained hydrogels is mainly attributed to the GO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. The present study indicates that the as-prepared composite hydrogels can serve as good adsorbents for wastewater treatment as well as the removal of harmful dyes.
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RSC Advances
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2015
·Vol. 6
·期 4
·2678-2686
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IF 3.84
Chunzhen Fan,Kan Li,Yalin Wang,Xufang Qian,Jinping Jia
Magnetic chitosan beads (MCBs) synthesized through a common embedding method and crosslinked with glutaraldehyde were studied for the adsorption of Cu2+ in aqueous solution. MCBs were investigated by means of hysteresis curves, thermo-magnetization curves, TGA, FTIR and XRD. Kinetic, isothermal and thermodynamic studies were applied to investigate the adsorption of Cu2+ by the MCBs. The effects of the pH value and the coexisting ions on the adsorption of Cu2+ were explored. Subsequently, the stability of the MCBs including the adsorption capacity (Qe) and the saturated magnetization (Ms) stability was investigated under various conditions. Simultaneously, FTIR and XRD were utilized to further analyze the change in the MCBs in the stability studies. The results suggested that the MCBs showed good stability without a significant loss in Qe and Ms after regeneration from five sequential cycles. The MCBs presented excellent storage stability while stored in a drying vessel for ten months. For thermal stability, the Qe and Ms of the MCBs presented similar variations after being heated in the atmosphere and in a vacuum at different temperatures for 30 h. The Qe changed slightly after being heated at 50 and 100 °C, and decreased sharply at 150 and 200 °C. The magnetization was stable in the lower temperature range (50–150 °C) and increased slightly at 200 °C. Different magnetic fields had little effect on the stability of the MCBs.
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CARBON
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2013
·
IF 5.868
Xiangqian Fan,Lingxia Zhang,Guobin Zhang,Zhu Shu,Jianlin Shi
Nitrogen-doped microporous carbons were fabricated by a simple chemical activation strategy in which chitosan and K 2 CO 3 were employed as the precursor and activation agent, respectively. The textural and chemical properties of the porous carbons could be easily tuned by changing the ratio of K 2 CO 3 /chitosan and activation temperature. Due to their large pore volume , well-defined microporosity and relatively high nitrogen content, these porous carbons were applied as adsorbents for CO 2 capture and demonstrated excellent CO 2 uptake performances. In particular, the sample prepared at 635 °C with K 2 CO 3 /chitosan ratio = 2 shows a CO 2 uptake as high as 3.86 mmol g −1 at 25 °C, 1 atm. Furthermore, the CO 2 uptake remains almost constant in five consecutive adsorption–desorption cycles, indicating this material has great stability and recyclability as a CO 2 sorbent . In addition, an extraordinary separation selectivity against N 2 (CO 2 /N 2 selectivity of ca. 21) was also observed.
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Chemistry-An Asian Journal
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2016
·Vol. 11
·期 6
·893-899
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IF 4.592
Yang Yang,Chen Sun,Hin-Lap Yip,Runcang Sun,Xiaohui Wang
Graphical Crystal palace : Perovskite crystals with controlled morphology and properties are formed in a chitosan template by three steps including electrostatic adsorption/chelation, nucleation, and growth. The exposed functional groups of chitosan coordinate strongly with Pb 2+ and some of these stabilized Pb 2+ ions interact with I − ; nucleation occurs and perovskite crystals start to grow in the chitosan network. Biomimetic mineralization is a powerful approach for the synthesis of advanced composite materials with hierarchical organization and controlled structure. Herein, chitosan was introduced into a perovskite precursor solution as a biopolymer additive to control the crystallization and to improve the morphology and film-forming properties of a perovskite film by way of biomineralization. The biopolymer additive was able to control the size and morphology of the perovskite crystals and helped to form smooth films. The mechanism of chitosan-mediated nucleation and growth of the perovskite crystals was explored. As a possible application, the chitosan–perovskite composite film was introduced into a planar heterojunction solar cell and increased power conversion efficiency relative to that observed for the pristine perovskite film was achieved. The biomimetic mineralization method proposed in this study provides an alternative way of preparing perovskite crystals with well-controlled morphology and properties and extends the applications of perovskite crystals in photoelectronic fields, including planar-heterojunction solar cells.
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高影响因子
APPLIED CLAY SCIENCE
·
2016
·
IF 2.586
Xiaoyu Li,QianYang,Jing Ouyang,Huaming Yang,Shi Chang
Natural halloysite (Hal) nanotubes were well dispersed and thoroughly emulsified to prepare the porous microspheres Hal-chitosan (Hal-CTS) in a water/oil microemulsion, which was further loaded with aspirin (Asp) as a model drug to investigate the drug release behavior. The charge-mediated adsorption of molecules to the surface of Hal could facilitate the dispersion of Hal in aqueous media and enabled Hal to assemble into microspheres. The microspheres had interconnected pores, large pore volume, high specific surface area and hierarchical pore distribution, which was beneficial to the entrance of Asp molecules. The porous microspheres showed excellent loading capacity for Asp as high as 42.4 wt%, around 20 times higher than the pristine Hal (2.1 wt%). The release results indicated that Hal-CTS/Asp nanocomposites had the lower release in the simulated gastric fluid, whereas more rapid release rate and higher release amount in the simulated intestinal fluid, which could help to maintain effective concentration of Asp in the body and reduce the maximum extent of the side effects to the stomach. The as-prepared Hal-CTS/Asp nanocomposites could have potential application in the drug carrier systems due to their natural and excellent biocompatibility.
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