CELLULOSE
·
2021
·Vol. 28
·期 7
·4151-4164
·
IF 5.044
Sun Tingting,Wang Huimin,Liu Jiaye,Chu Xiaomeng,Xing Xuteng,Liu Shaojie,Tang Erjun,Liu Xinying,Hildebrandt Diane
In this work, a recoverable acrylamide-vinylamine copolymer immobilized TEMPO [P(AM-co-VAm)-T] catalyst for selective oxidation of cellulose with good catalytic performance and low cellulose degradation was developed. Firstly, the acrylamide-vinylamine copolymer [P(AM-co-VAm)] was prepared by Hofmann degradation of polyacrylamide (PAM). Then, the condensation reduction reaction between amine groups of P(AM-co-VAm) and carbonyl groups of 4-oxo-TEMPO yielded P(AM-co-VAm)-T. P(AM-co-VAm)-T was used as a catalyst for selective oxidation of C6 primary hydroxyl groups of cellulose to carboxyl groups. The carboxyl content of obtained oxidized cellulose was up to 1.114 mmol/g, which was equivalent to 76% of the free TEMPO level. This macromolecular catalyst was easily recycled and the recycling performance was excellent. Interestingly, it was found that P(AM-co-VAm)-T could effectively reduce the degradation of oxidized cellulose. The corresponding degradation degree was 21–27%, which was much lower than the degradation degree of free TEMPO (61–66%) and other macromolecular TEMPO catalysts, such as polyacrylic acid immobilized-TEMPO (41–53%) and polyamidoamine supported TEMPO (28–44%). P(AM-co-VAm)-T with positive charge and suitable size could effectively inhibit the formation of C6 aldehydes and C2/C3 ketones, which was the main reason that it could significantly inhibit cellulose degradation.
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高影响因子
Marine Life Science & Technology
·
2020
·Vol. 3
·期 1
·85-93
·
IF 0
Chen Rui,Huang Wen-Can,Wang Wei,Mao Xiangzhao
Chitin nanofibers have recently received increased attention and are considered to be a promising material for a wide range of applications because of their excellent characteristics. In this study, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized chitin nanofibers (CNFs) with various oxidation times were prepared and characterized. CNFs with different oxidation times were then utilized for enzyme immobilization, using chymotrypsin as a model enzyme. The effects of oxidation time on enzyme immobilization were explored. Results showed characteristics of chitin nanofibers can be controlled by adjusting oxidation time. CNFs treated with TEMPO for 360 min showed the lowest crystallinity (79.13 ± 1.43%), the shortest length (241.70 ± 74.61 nm), the largest width (12.67 ± 3.43 nm), and the highest transmittance (73.01% at 800 nm). The activity of immobilized enzymes and enzyme loading showed good correlation to the carboxylate content of CNFs. The enzyme efficiency based on CNFs and the content of carboxylate groups peaked at the oxidization time of 60 min. When the additional amount of chymotrypsins (CTs) was 500 or 2000 mg/g carrier, the highest loading amount of CTs was 307.17 ± 4.08 or 726.82 ± 12.05 mg/g carrier, respectively.
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PubMed
CATALYSIS TODAY
·
2018
·
IF 4.667
Mei Cui,Renliang Huang,Wei Qi,Rongxin Su,Zhimin He
2,5-Diformylfuran (2,5-DFF) is an important furan-based chemical with broad application potential. To address the difficulties in isolating/purifying the product and recycling the 2,2,6,6- tetramethylpiperidine-1-oxy (TEMPO)-based catalysts, we employed a solvent with a low boiling point in which TEMPO has a low solubility to investigate the effects of TEMPO and its analogs on catalyzing the oxidation of 5-hydroxymethylfurfural (5-HMF). The results indicated that in ethyl acetate with the substitution of one H of TEMPO at the C4 position with either an acetamido ( NH-Ac), methoxy ( OCH 3 ), hydroxy ( OH) or isothiocyanato ( N C S) group, the resulting compound had a product selectivity similar to that of TEMPO (>86%), except for the 4-isothiocyanato-TEMPO-catalyzed reaction. However, after two Hs were substituted with an oxo group ( O), the catalytic efficiency significantly decreased (product yield 16%, selectivity 52%). Based on both the catalytic efficiency and catalyst solubility, a highly efficient method for preparing 2,5-DFF was established using ethyl acetate as the solvent, 4-acetamido-TEMPO as the catalyst and Fe(NO 3 ) 3 and NaCl as cocatalysts. At 40 °C with a substrate concentration of 0.125 mol/L, 5-HMF was completely converted in 2 h, and the yield of 2,5-DFF was 89%. Moreover, when the substrate concentration increased to 0.25 mol/L, the yield of 2,5-DFF was 87%. When 4-acetamido-TEMPO was recovered by centrifugation, the product yield remained as high as 86% after three cycles, demonstrating good recyclability.
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高影响因子
CARBOHYDRATE POLYMERS
·
2025
·
IF 12.5
Fang Tian,Wenyuchu Chen,Weiliang Guan,Yujin Li,Zan Ni,Chongsheng Zhang,Xiaona Wang,Luyun Cai
Surimi is widely appreciated for its preferred texture and nutritional profile. However, maintaining its superior gel-forming properties while preventing nutrient loss caused by the washing process remains challenging. In this study, pre-emulsions made from pea protein isolate (PPI), pterostilbene (PTE), TEMPO-oxidized cellulose (TOC), and coconut oil (CO) were used as a fat substitute to improve the gel properties of surimi. These were incorporated into brown croaker ( Miichthys miiuy ) surimi. The results showed that the PPI-CO-TOC-PTE pre-emulsion (P-C-T-P) had a small d 4,3 particle size (283.5 nm). Molecular docking simulations demonstrated that TOC enhanced hydrogen bonding interactions between PPI and PTE. Adding P-C-T-P significantly improved the gel strength (2002.33 ± 48.74 g × mm) and water-holding capacity (91.40 ± 0.37 %) of the surimi gels. Furthermore, the protein network structure was denser in the P-C-T-P group. The surimi with P-C-T-P showed higher storage and loss moduli and the highest levels of hydrogen bonding, hydrophobicity, and β-sheet content. Thus, P-C-T-P addition improved surimi gel properties compared with directly supplying lipids to surimi.
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高影响因子
Energy Materials
·
2025
·Vol. 5
·期 7
·N
·
IF 11.2
Feiyang Hu,Zhiwen Cui,Zhen Dong,Liyuan Jiang,Nwaji Njemuwa Njoku,Wenzhang Dong,Hao Fan,Mahalingam Ravivarma,Jianbao Wu,Duanyang Kong,Jiangxuan Song
Aqueous Zn-based flow batteries often face issues such as poor reversibility and short lifespan due to irregular Zn deposition and detrimental side reactions. To address these challenges, we developed a zwitterionic gemini additive, N,N′-bis(3-propanesulfonic acid)-3,3′-bipyridinium (SPr-Bpy), to enhance Zn plating/stripping behavior and optimize the Zn2+ solvation structure. The dual sulfonate groups influence the Zn2+ solvation shell and anchor SPr-Bpy to the Zn surface through multi-site interactions. Additionally, the bipyridinium structure forms an electrostatic shielding layer, suppressing excessive Zn2+ accumulation, promoting uniform Zn deposition, and thus mitigating dendrite formation and hydrogen evolution. Consequently, the Zn||Zn symmetric cells exhibit an impressive lifespan of 250 h, while the Zn||Cu asymmetric cells achieve a high average Coulombic efficiency of 99.8% over 450 cycles. Moreover, SPr-Bpy significantly improves Zn/TEMPO flow battery performance, achieving a high areal capacity of 24.4 mAh cm-2 with an exceptional capacity retention of 99.992%/cycle over 500 cycles.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2025
·
IF 6.2
Ming Zeng,Qionghao Xu,Jiangang Yu
Nanocelluloses (NCs)-based aerogels with hierarchical microarchitecture are highly sought after for their extraordinarily thermal insulation and adsorption properties. Nevertheless, their intrinsic flammability, complex manufacturing processes, and inadequate mechanical characteristics substantially restrict their extensive practical applications. Herein, a Pickering emulsion templated sequential reaction strategy is employed to fabricate elastic NCs-based aerogels with hierarchically porous structures. The pivotal aspect of this synthesis resides in the Pickering emulsion phases, facilitating the in-situ construction of a polyvinyltrimethoxysilane (PVTMS) decorated framework. The resultant aerogels feature a low density and exhibit exceptional resilience. The material also displays exceptional anisotropic thermal insulating properties, with a peak value of 11.5 mW·m −1 ·K −1 along the axial direction and a value ten times greater, reaching 115.2 mW·m −1 ·K −1 , along the radial direction. Such a preparation method for the hybrid aerogels will offer noval perspectives in the field of advanced materials for multifunctional applications.
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高影响因子
ENVIRONMENTAL POLLUTION
·
2024
·
IF 7.6
Hiba Shaghaleh,Yousef Alhaj Hamoud,Qin Sun
Hydrogel adsorbents are promising tools for reducing heavy metals' bioavailability in contaminated soil. However, their practical feasibility remains limited by the low stability, inefficient removal efficiency, and potential secondary pollution. Optimizing the adsorption operation and the functional properties of hydrogel adsorbents could eliminate this method's drawbacks. Herein, three innovative in-situ remediation strategies for Pb/Cu-contaminated soil were adopted based on the concept of novel TEMPO-cellulose (TO-NFCs)/lignin/acrylamide@MIL-100(Fe) nanocomposite hydrogel adsorbent (NCLMH). Characteristic analyses revealed ideal Pb/Cu adsorption mechanisms by swelling, complexation, electrical attraction, and ion exchange via carboxyl/hydroxyl/carbonyl groups and unsaturated Fe(III) sites on ANCMH besides FeOOH formation. The highest maximum theoretical adsorption capacities of Pb(II) and Cu(II) on ANCMH were 416.39 and 133.98 mg/g, under pH 6.5, governed by pseudo-second-order/Freundlich models. Greenhouse pot experiments with contaminated soils amended with two-depth layers of 0.5% NCLMHs (SA@NCLMH) displayed a decline in Pb and Cu bioavailability up to 85.9% and 74.5% within 45 d. Soil column studies simulating continuous water soil flushing coupled with NCLMH layers, instead of conventional extractant fluids, and connected to NCLMH-sand column as purification unit (CF@NCLMH) achieved higher removal rates for Pb, and Cu of 89.5% and 77.2% within 24 h. Alternatively, conducting multiple-pulse soil flushing mode (MF@NCLMH) gained the highest Pb and Cu removal of 96.5% and 85.4%, as the water flushing-stop flux events allowed adequate water movement/residence period, promoting Pb/Cu desorption-adsorption from soil to NCLMH. Also, the NCLMH-sand column conducting and easy separation of the stable/reusable NCLMHs prevented the potential secondary pollution. Interestingly, the three remediated soils reached the corresponding regulation of the permissible limits for Pb and Cu residential scenarios in medium-to-heavily agricultural polluted soils, alleviating the Pb/Cu bioaccumulation and phytotoxicity symptoms in cultivated wheat, especially after MF@NCLMH treatment. This study introduces promising alternative remediation strategies with high sustainability and feasibility in acidic-to-neutral heavy metal-contaminated agricultural soil.
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高影响因子
RSC Advances
·
2023
·Vol. 13
·期 15
·10204-10214
·
IF 3.9
Meilin Li,Bei Jiang,Shuoang Cao,Xinyi Song,Yuanqiao Zhang,Lijun Huang,Quanping Yuan
High-performance flexible barium titanate (BaTiO3)-based piezoelectric devices have gained much attention. However, it is still a challenge to prepare flexible polymer/BaTiO3-based composite materials with uniform distribution and high performance due to the high viscosity of polymers. In this study, novel hybrid BaTiO3 particles were synthesized with assistance of TEMPO-oxidized cellulose nanofibrils (CNFs) via a low-temperature hydrothermal method and explored for their application in piezoelectric composites. Specifically, Ba2+ was adsorbed on uniformly dispersed CNFs with a large amount of negative charge on their surface, which nucleated, resulting in the synthesis of evenly dispersed CNF-BaTiO3. The obtained CNF-BaTiO3 possessed a uniform particle size, few impurities, high crystallinity and dispersity, high compatibility with the polymer substrate and surface activity due to the existence of CNFs. Subsequently, both polyvinylidene fluoride (PVDF) and TEMPO-oxidized CNFs were employed as piezoelectric substrates for the fabrication of a CNF/PVDF/CNF-BaTiO3 composite membrane with a compact structure, displaying the tensile strength of 18.61 ± 3.75 MPa and elongation at break of 3.06 ± 1.33%. Finally, a thin piezoelectric generator (PEG) was assembled, which output a considerable open-circuit voltage (4.4 V) and short-circuit current (200 nA), and could also power a light-emitting diode and charge a 1 μF capacitor to 3.66 V in 500 s. Its longitudinal piezoelectric constant (d33) was 5.25 ± 1.04 pC N−1 even with a small thickness. It also exhibited high sensitivity to human movement, outputting a voltage of about 9 V and current of 739 nA for only a footstep. Thus, it exhibited good sensing property and energy harvesting property, presenting practical application prospects. This work provides a new idea for the preparation of hybrid BaTiO3 and cellulose-based piezoelectric composite materials.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Zuwu Tang,Xinxing Lin,Yalan Chen,Yuwei Pan,Yuqing Yang,Ajoy Kanti Mondal,Meiqiong Yu,Hui Wu
Water pollution is an ongoing trouble that is of significant urgency to resolve worldwide. However, traditional materials used in the process of water purification are costly and energy intensive. The preparation of low-cost, green and sustainable aerogels with low density, high porosity and high specific surface area (SSA) is a great challenge. In this paper, a mussel-inspired, low-cost, polydopamine (PDA)-functionalized TEMPO-oxidized cellulose nanofiber (TOCNF) PDA/TOCNF composite aerogel has been rationally designed and fabricated with low-density, high porosity and high SSA. The PDA/TOCNF composite aerogel shows low density (18.2 mg/cm 3 ), high porosity (98.7 %), and large surface areas (41.3 m 2 /g). The resulting PDA/TOCNF composite aerogel could adsorb a maximum of 314.6 mg/g of methylene blue (MB). The recycle experiment for reusing of adsorbent showed that after five consecutive cycles, the removal ability of MB by the PDA/TOCNF composite aerogel still maintained higher than 90 %. In addition, the PDA/TOCNF composite aerogel also had a high adsorption capacity of heavy metal ions, for example, it adsorbs 446.0 mg/g of Cu 2+ , 222.0 mg/g of Pb 2+ , 267.0 mg/g of Cd 2+ , and 600.0 mg/g of Fe 3+ , respectively. The possible adsorption mechanisms imply that the PDA/TOCNF composite aerogel adsorbs MB due to the synergistic binding interactions, such as electrostatic attraction, π-π stacking interaction, Vander waals force, and hydrogen bonding. Similarly, the PDA/TOCNF composite aerogel adsorbs metal ions due to the electrostatic attraction and chelation of metal ions with the PDA/TOCNF aerogel. Therefore, PDA/TOCNF composite aerogels may have potential applications in wastewater treatment because of their sustainability and low energy consumption.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Baolong Huo,Man Du,Ao Shen,Mengwen Li,Yaru Lai,Xue Bai,Aijun Gong,Leqiu Fang,Yunxu Yang
A highly selective and sensitive fluorescence “light-up” probe PTH for ClO − has been developed, which is designed by a new strategy based on TEMPO-oxidation for the first time. PTH exhibits excellent properties including quick response (within 2 min), lower detection limit (63.7 nM), good linearity ( R 2 = 0.9863) and specific selectivity. More importantly, its application of detection ClO- in real samples has also been achieved.
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高影响因子
CELLULOSE
·
2017
·Vol. 24
·期 6
·2415-2425
·
IF 3.417
Sang Xiankui,Qin Chengrong,Tong Zhangfa,Kong Song,Jia Zhuan,Wan Guangcong,Liu Xinliang
2,2,6,6-Tetramethylpiperidine-1-oxyl radical (TEMPO) can selectively oxidize primary hydroxyl groups of cellulose to carboxyl groups. However, the depolymerization also occurs during the process. The kinetics and mechanism of carboxyl group formation on the surface of cellulose fiber oxidized by TEMPO/NaClO 2 /NaClO were discussed. The oxidization and depolymerization of cellulose occurred simultaneously, according to analysis of FTIR and 13 C CP/MAS NMR. The glucuronic acid and some small molecular fragments, formed by hydrolysis or β-elimination during the oxidation, are also discussed. The crystallization index increased and crystal size decreased, as shown by X-ray analysis. The degradation steps in the TEMPO/NaClO 2 /NaClO system was discussed, according to carbon conversion analyzed by 13 C CP/MAS NMR. The oxidation of cellulose can be described well by the kinetics model established based on the degradation of cellulose. It was found that temperature is one of the key parameters for controlling the oxdation and degradation level. The possible mechanism for oxidation of cellulose was composed.
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高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Badusha Mohamad Ali,Ziqi Yu,Zhengyuan Tao,Tangxin Zhang,Lei Wang,Chenbing He,Hao Zhang,Jianli Wang
The novel 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) groups immobilized on functional polymers or nanoparticles emerged as potential Pickering interfacial catalysts (PICs) for effective catalysis in biphasic systems. In this study, a snowman-shaped Janus-structured polymer with TEMPO-anchored nanohybrid particles (SM-JPP-TEMPO) was prepared and employed as a potential PIC in the Anelli–Montanari system for the selective oxidation of alcohol. The amphiphilic character of SM-JPP-TEMPO particles plays a dual role as an emulsifier and catalyst in the Pickering emulsion. As a result, it enables smaller droplets (102 μm) at the water-in-oil (W/O) interface and reduces the interfacial tension from 26.58 to 17.38 mN/m, which improves the stability of the Pickering emulsion system. This constructed Pickering emulsion microreactor offers a larger interface contact area and shortens the mass transfer distance of the substrate of cinnamyl alcohol, which significantly enhances the catalytic conversion at the Anelli–Montanari oxidation system, thus achieving remarkable conversion efficiency of (92.3%) with excellent selectivity (99%) in static (stirring-free) condition. It was found that the Janus nanohybrid catalyst (SM-JPP-TEMPO) enhanced 1.29-fold catalytic efficiency compared to the TEMPO grafted spherical polystyrene nanoparticle (PS-NPs-TEMPO) catalyst (72%). Moreover, after seven consecutive cycles, the Janus nanocatalyst (SM-JPP-TEMPO) maintained the conversion significantly. Hence, these results collectively highlight that the amphiphilic SM-JPP-TEMPO catalyst provides an efficient and eco-friendly strategy for the intensification of liquid–liquid biphasic reaction systems for potential applications in industries.
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高影响因子
危险品化学品经营许可证（带存储）