FOOD CHEMISTRY
·
2016
·
IF 4.052
Mei-Jia Shi,Xiaoyi Wei,Jie Xu,Bing-Jie Chen,De-Yin Zhao,Shuai Cui,Tao Zhou
In order to improve the bioactivities of the polysaccharide from Enteromorpha prolifera (PE), crude PE (Mw 1400 kDa) was degraded to low molecular weight polysaccharide (44 kDa) in the presence of hydrogen peroxide/ascorbic acid, followed by carboxymethylation. The reaction conditions for carboxymethylation of degraded polysaccharide (DPE) were optimized by Response Surface Methodology. The carboxymethyled degraded polysaccharide (CDPE) obtained under optimized conditions, with a degree of carboxymethylation of 0.849, was characterized by FT-IR and 13 C NMR. The molecular weight of CDPE was measured to be 53.7 kDa. CDPE was evaluated for its antioxidant activity by determining the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radicals, and by determining the ferric reducing power. The antioxidant activity of CDPE was found to be greatly improved in comparison with degraded polysaccharide (DPE) and crude polysaccharide from Enteromorpha prolifera (PE).
研究领域:
生物化学
·
食品科学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Zhixiang Cai,Hongbin Zhang
The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.
研究领域:
生物化学
·
高分子科学
✓ 已验证
DOI
PubMed
高影响因子
Arabian Journal of Chemistry
·
2020
·
IF 4.762
Ludan Zhao,Peixiao Tang,Qiaomei Sun,Shuangshuang Zhang,Zili Suo,Huaqing Yang,Xiaoxiang Liao,Hui Li
In this study, a novel carboxymethyl functionalized β-cyclodextrin-modified graphene oxide (CM-β-CD-GO) adsorbent was designed and fabricated. The CM-β-CD-GO was applied to remove methylene blue (MB) from aqueous solutions. The adsorption mechanism was discussed in detail through the study of pH effect, kinetics, and isotherm models. The adsorption of CM-β-CD-GO for MB displayed high removal rates at the pH range of 6.0–10.0, and the removal efficiency is over 90% within 20 min. The pseudo-second-order model could well describe the kinetic process of MB adsorption, and the adsorption was determined by the multi-step process. The maximum uptake capability of CM-β-CD-GO towards MB was 245.70 mg g −1 at 25 °C according to Langmuir isotherm model. A possible adsorption mechanism that electrostatic attraction, π-π interaction, and host-guest supramolecular interactions supported MB adsorption was proposed. The adsorption capacity of CM-β-CD-GO showed no significant change after five cycles. The structure and morphology of CM-β-CD-GO were characterized by XPS, FT-IR, TGA, PXRD, AFM, SEM, zeta (ζ) potential determination, and Raman spectroscopy. This work provides valuable information for the design of novel adsorbents that specifically and efficiently adsorb cationic dyes contaminants.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Jing Liao,Hongjie Dai,Huihua Huang
Carboxymethyl chitin hydrogels with different degree of substitution (DS) were prepared by the homogeneous carboxymethylation of chitin extracted from Hericium erinaceus residue. The effect of DS on gel structure and property were studied. Results showed that the DS of carboxymethyl chitin hydrogels can be increased by increasing the amount of sodium chloroacetate. The equilibrium swelling degree and pH swelling sensitivity of the hydrogels were enhanced as the increase of DS. Zeta potential, low-field nuclear magnetic resonance, contact angle and molecular dynamics simulation results suggested that the introduction of carboxymethyl functional group enhanced the negative charge, water mobility, surface hydrophilicity and the ability to form hydrogen bonds with water of the hydrogels, resulting in an increased swelling degree of the hydrogels. Moreover, the prepared hydrogels showed different adsorption capability to various dyes, and the adsorption performance of the prepared hydrogels for cationic dyes could be enhanced as the increase of DS.
研究领域:
生物材料学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Wen-Xuan Hu,Liang-Sen Liao,Le Shi,Qian-Ru Su,Jia-Yang Fu,Xiuzhu Yu,Shuang-kui Du
Herein, oxidation and carboxymethylation were employed to improve the dispersibility and stability of starch nanocrystal (SNC) in aqueous solution by enhancing intermolecular electrostatic repulsion between SNCs, as well as to promote their protein loading capacity. FT-IR, XPS, and NMR analyses confirmed the successful surface modification of SNC, with oxidation likely occurring at the C6-OH position of anhydroglucose units. Oxidation selectively degraded the amorphous parts with small molecular weight, while carboxymethylation removed surface hydrocarbons, promoting relative crystallinity, crystalline lamellae thickness, and structural compactness in the oxidized and carboxymethylated SNC (OSNC and CSNC). Morphologically, OSNC and CSNC exhibited regular square shapes, with CSNC showing a more uniform appearance. Both OSNC and CSNC displayed small hydrodynamic size and high zeta potential, along with high transparency suspensions at pH 7, indicating good dispersibility and stability driven by electrostatic repulsion. Only OSNC, with the highest degree of oxidation, maintained stability at pH 3, due to its strong buffer capacity against protonation. Furthermore, both OSNC and CSNC showed enhanced protein loading capacity, with OSNC achieving higher capacity than CSNC, suggesting its potential as a protein delivery carrier. This work offers alternative strategies to reduce interparticle aggregation in SNCs, broadening their industrial applications.
研究领域:
食品科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Guangrui Ma,Wenqi Yin,Zhijun Shi,Yan Xu,Guang Yang
Carboxymethylation-modified cellulose nanofibrils (CMCNF) were prepared from bamboo fibers through a pretreatment process using a ternary deep eutectic solvent (DES) system consisting of chloroacetic acid, urea, and choline chloride. Grinding treatment was also employed. The properties of the resulting CMCNF were characterized using various analytical instruments including a fiber image analyzer, field-emission scanning electron microscope, X-ray diffractometer, and atomic force microscope. The results indicated that ternary DES pretreatment has the capability to carboxymethylate-modify the raw fiber material while maintaining the crystalline structure of cellulose. Additionally, it induced a wetting and swelling effect on the fibers, leading to the successful disruption of strong hydrogen bonds and the rapid production of cellulose nanofibrils during mechanical treatment. The carboxymethylation alteration enhanced the ability of the resultant CNF to disperse and increased the stability of the suspension. Furthermore, extending the duration of DES pretreatment enhances the process of fiber fibrillation and diminishes fiber polymerization. The CMCNF produced exhibited a high aspect ratio, with diameters ranging from 10 to 50 nm and lengths extending to a few micrometers. This study presents a novel approach and concept for producing carboxymethylated nanofibrillated cellulose. It also introduces a straightforward, environmentally friendly, and effective method for mass production of bamboo pulp nanofibrillated cellulose. This advancement is anticipated to enhance the processing and utilization of bamboo fiber resources, thereby contributing to an increased overall value.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Ning Yan,Xiao-Fang Wan,Xin-Sheng Chai
This study reported a new headspace gas chromatography (HS-GC) for simultaneously determining the degree of deacetylation (DD) and the degree of substitution (DS) in carboxymethyl chitosan (CMCS), which were based on HS-GC measuring the amounts of CO2 released from both the bicarbonate decomposition suppressed by -NH2 and the reaction between the bicarbonate and the acidified carboxymethyl and amino groups in CMCS. The results showed that the present method has a good measurement precision (RSD < 2.55%) and accuracy (relative differences <5.90%). Compared with the current titration-based method, the present HS-GC techniques provide a more reliable testing in the quantification of amino and carboxymethyl contents in CMCS. Moreover, since the HS-GC can perform an automated sample reaction equilibration and measurement, it could be much more efficient than the existing methods in the batch sample analysis.
研究领域:
分析化学
·
生物材料学
✓ 已验证
DOI
高影响因子
FIBERS AND POLYMERS
·
2017
·Vol. 18
·期 7
·1235-1242
·
IF 1.113
Weng Rengui,Chen Lihui,Xiao He,Huang Fang,Lin Shan,Cao Shilin,Huang Liulian
Bamboo cellulose (BC) is hydrophilic, biodegradable and inexhaustible. The bamboo cellulose membrane (BCM) is one of the best materials to replace petroleum-based polymer film for water purification. In this study, the N-methylmorpholine-N-oxide (NMMO) was used as a solvent to dissolve cellulose 6 wt.%, and regenerated cellulose membrane was prepared by phase inversion. A new kind of cellulose nanofiltration membrane (BC-NFM) was obtained by the hydrolysis and carboxymethylation of dense cellulose membrane (BCM). The modification was carried out through hydrolysis followed by carboxymethylation. The BC-NFM was characterized by XRD, FT-IR, SEM and thermal analysis. BC-NFM performance evaluation instrument were used to evaluate retention rate and water flux of nanofiltration membrane. BCM was immersed in 1 mol/ l NaOH and 3 wt/v.% chloroacetic acid solution to obtain BC-NFM. By calculating, pore size of nanofiltration membrane was 0.63 nm. With a pressure of 0.5 MPa, the water flux of nanofiltration membrane for Na 2 SO 4 solution was 10.32 l /m 2 h, and the retention rate was 68.4 %. The water flux for NaCl solution was 13.12 l /m 2 h, and the retention rate was 34.9 %. And the retention rates were 93.0 % and 98.9 % for methyl orange and methyl blue, respectively. The stability of the nanofiltration membrane was measured by the thermal analyzer, following the order of BC>BCM>BC-NFM. The prepared cellulose nanofiltration membrane exhibited good stability in water treatment process, and can be used to remove organic compounds in aqueous solutions.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2018
·
IF 3.849
Yushuang Zhao,Shuangshuang Jing,Xiaoting Zhang,Zehong Chen,Hao Zhuo,Yijie Hu,Qingzhong Liu,Linxin Zhong,Xinwen Peng,Runcang Sun
Although hemicelluloses have demonstrated their promising application as paper strengthening agents, the influences of different hemicellulosic fractions on the mechanical properties of paper are not clear. Revealing the reinforcing effect of hemicellulosic fractions on the mechanical properties of paper is very helpful to better utilize hemicelluloses. For this purpose, four hemicellulosic fractions (HC pH5.5 , HC 15% , HC 30% , and HC 75% ) were extracted from corncob, and then chemically modified (carboxymethylation) as paper strengthening agents. We demonstrated that the hemicellulosic fraction HC 15% obtained from 15% ethanol was difficult to be modified; while HC 75% obtained from 75% ethanol was more easily chemically modified. Furthermore, the carboxymethylated hemicellulosic fraction CHC 30% with fewer branches and the highest molecular weight had a more significant effect on improving paper strength. Therefore, isolation of desirable hemicellulosic fraction is extremely important to more effectively apply hemicelluloses as paper strengthening agents.
研究领域:
制浆造纸工程
·
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 1
·160
·
IF 5.719
Rongrong Si,Yehong Chen,Daiqi Wang,Dongmei Yu,Qijun Ding,Ronggang Li,Chaojun Wu
In the present study, carboxymethyl cellulose nanofibrils (CMCNFs) with different carboxyl content (0.99–2.01 mmol/g) were prepared via controlling the ratio of monochloroacetic acid (MCA) and sodium hydroxide to Eucalyptus bleached pulp (EBP). CMCFs-PEI aerogels were obtained using the crosslinking reaction of polyethyleneimine (PEI) and CMCNFs with the aid of glutaraldehyde (GA). The effects of pH, contact time, temperature, and initial Cu2+concentration on the Cu2+removal performance of CMCNFs-PEI aerogels was highlighted. Experimental data showed that the maximum adsorption capacity of CMCNF30-PEI for Cu2+was 380.03 ± 23 mg/g, and the adsorption results were consistent with Langmuir isotherm (R2> 0.99). The theoretical maximum adsorption capacity was 616.48 mg/g. After being treated with 0.05 M EDTA solution, the aerogel retained an 85% removal performance after three adsorption–desorption cycles. X-ray photoelectron spectroscopy (XPS) results demonstrated that complexation was the main Cu2+adsorption mechanism. The excellent Cu2+adsorption capacity of CMCNFs-PEI aerogels provided another avenue for the utilization of cellulose nanofibrils in the wastewater treatment field.Keywords:carboxymethylation;cellulose nanofibrils;aerogel;adsorption
研究领域:
材料科学
·
环境工程
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Lunlun Shi,Xiupeng Chen,Aitao Li,Xiaoling Wu,Xian Kong,Hongming Lou,Zhixian Li
Covalent organic frameworks (COFs) offer a promising platform for enzyme immobilization due to their abundant and chemically modifiable functional groups alongside finely tunable pore structures. Utilizing carboxymethylation, we successfully tailored the microenvironment of COFs and subsequently immobilized the enzyme via adsorption. This strategic modification induces a localized reduction in pH within the COF, significantly enhancing the enzyme’s catalytic activity. Notably, the relative activity of Cyt c@cmCOF-TATP attained 134.8% of its free counterpart, and its catalytic efficiency (kcat/KM) reached 278% relative to the free Cyt c. MD simulations indicate that the heightened enzyme activity and stability at low pH for Cyt c@cmCOF-TATP are related to a more stable backbone framework and active site. Additionally, a more compact packing within the active site side chains may also contribute to these favorable characteristics. Furthermore, the intrinsic photocatalytic capability of cmCOF-TATP complemented the Cyt c catalysis, yielding a relative activity of 165.7% under the conditions of lighting. Impressively, the enzyme demonstrated enhanced stability, preserving 83.7% activity after six cycles, and exhibited elevated solvent tolerance and pH robustness compared to the free enzyme.
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2021
·
IF 4.598
Jia Zeng,Dongqiao Zhang,Weifeng Liu,Jinhao Huang,Dongjie Yang,Xueqing Qiu,Shenhui Li
High efficiency lignin-grafted cationic polyacrylamide multifunctional flocculant (CL-CPAs) was synthesized via “grafting to” strategy using carboxymethylated lignin (CL), acrylamide (AM) and methylacryloyloxyethyltrimethyl ammonium chloride (DMC) as raw materials. The synthesized CL-CPAs showed high flocculation efficiency. Only a small dosage between 3.6 and 4.2 mg‧L −1 of CL-CPAs and a short flocculation time of 1–2 min were needed for sedimentation of kaolin suspension. Meanwhile, the carboxyl groups on the modified lignin endowed CL-CPAs with good copper ion capture function through complexation and electrostatic interaction. In addition, simultaneous flocculation of kaolin suspension and removal of copper ion was achieved for CL-CPAs attributing to the charge neutralization, bridging, and electrostatic complexation. The synthesized carboxymethylated lignin-based flocculants are cheap, environmentally friendly and technically feasible, showing broad prospects in wastewater treatment.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）