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991.
Lihao Shi Wenjun Yu Enfu Wang Weisheng Han Yu Miao Yipeng Liang Yifan Chen Wenbiao Zhang Ran Zhang Jingda Huang 《Journal of polymer science. Part A, Polymer chemistry》2024,62(9):1853-1863
In this work, we used cellulose nanofibers (CNF) as the skeleton, Fe3O4@ZnO composite particles as magnetic synergist particles, 3-(2-aminoethylamino) propyltrimethoxysilane (AS) and trimethoxy(octyl)silane (OTMS) as water-based hydrophobic modifiers to prepare magnetic and superhydrophobic cellulose nanofibers based-aerogel with low density and intricate three-dimensional structure. Fe3O4@ZnO confers magnetic properties (3.82 emu/g) and exceptional thermal stability (water contact angle of 150.1° at 200 °C) to the system, while the combination with OTMS/AS endows the system superhydrophobic (157.5°) and excellent mechanical properties (stress of 96.95 kPa at 80% strain). It is worth noting that in the process of modifying the system with OTMS/AS, no organic solvents and acidic substances are used in the solution. Benefiting from their synergies, the system demonstrates a notable oil absorption capacity (12.31–41.91 g/g) and outstanding oil selectivity (exceeding 90%), driven by gravity alone. Interestingly, this system, marked by its cost-effectiveness, simplicity, eco-friendliness, and heightened efficiency, holds promising prospects for diverse applications in different oil–water separation behavior and purifying industrial oil wastewater, as well as oil flooding incidents. 相似文献
992.
非钛醇盐溶胶-凝胶法制备高光活性纳米晶TiO2气凝胶 总被引:2,自引:0,他引:2
以TiCl4为前驱体,采用环氧丙烷快速成胶法合成了具有高光催化活性的纳米晶TiO2气凝胶,利用X射线衍射、N2物理吸附和透射电镜等手段考察了H2O/TiCl4摩尔比和热处理等制备参数对TiO2气凝胶织构性质的影响,并以苯酚的光催化降解为模型反应评价了样品的光催化活性. 结果表明, H2O/TiCl4摩尔比为3时体系的成胶过程较为缓慢,制备的纳米晶TiO2气凝胶样品具有最小的晶粒尺寸及最大的比表面积和孔容,并且具有最佳的光催化活性. 相似文献
993.
Sono-deviced rheometer,which enabled viscoelastic properties under ultrasound operation, was used to investigate for cellulosic hydrogels. The viscoelastic behavior was compared in cellulosic hydrogels prepared at 0.5, 1 and 2 wt% concentration in the DMAc/LiCl solution. The sono-deviced equipment could measure the effect of changes in storage modulus G’ and loss modulus G” under 43 kHz ultrasound exposure. It was noted that the 43 kHz ultrasound significantly changed the values of the G′, meaning that the hydrogel was soften under the exposure within few seconds. When the ultrasound exposed 50 W of the out-put power at 1% strain, the G′ value of 4.2x104 Pa was reduced to 4.0x103 Pa during 5 min of the US interval. The declined lowering value of G’ then returned to the original moduli value when ultrasound was stopped. The values of both G’ and G” values were measured at applied strain % during viscoelastic measurements of the cellulosic hydrogels without and with ultrasound exposure. The comparison indicated that the ultrasound has reinforced the effect of the mechanical deformation of the hydrogel structure at the smaller mechanical strain values applied during the ultrasound operation. The ultrasound soften effect on the viscoelastic change efficiently occurred in the 0.5 wt% sample and easily induced the structural deformation probably due to the breakage of hydrogen bonds in the cellulose hydrogels. 相似文献
994.
《Current Applied Physics》2020,20(11):1226-1236
Herein, we present a facile low-cost and eco-friendly approach for conversion of bamboo timber waste (Bf) derived cellulose nanocrystals (Bf-CNCs) into strong blue luminescent graphene quantum dots (Bf-GQDs) by hydrothermal route. The various properties of synthesized Bf-GQDs were investigated using different spectroscopic techniques. The probable mechanism of Bf-GQDs formation from Bf-CNCs and the effect of pH, particle size on the fluorescent properties of Bf-GQDs also executed. Furthermore, Bf-GQDs were used for the detection of curcumin in an aqueous environment which is the major prerequisite of the present study. The Bf-GQDs showed remarkable photoluminescence (PL) quenching kinetics toward the curcumin (LOD 30.0 nM L−1) assessed by Stern-Volmer plot. The practicability of the method assessed using ginger rhizome juice, while the selectivity of the Bf-GQDs evaluated against different metal ions and different biochemicals. The proposed method will support to establish the strategies for the detection of biochemicals from the aqueous system. 相似文献
995.
Many derivatives of industrially useful cellulose have hydroxyls of the anhydroglucose(AHG) units uncompletely substituted. Since each AHG unit of a cellulose molecule is a trihydric alcohol,consisted of one primary(position 6) and two secondary hydroxyl groups(positions 2 and 3), the distribution of substituents in these trihydric alcohol units could be different for different derivatives. The 相似文献
996.
近红外仪测试二醋酸纤维素醋化值 总被引:1,自引:0,他引:1
本文研究了近红外仪在近红外区域(1100-2500nm),多重线性回归测定二醋酸纤维素的醋化值的方法。并且就近红外仪测试二醋酸纤维素醋化值的测试结果与传统滴定结果进行了比较,对测量的重现性进行了考察,相对标准偏差为0.07%。 相似文献
997.
近年来,二维材料MXene因其优异的电化学性能引起了人们的关注,被广泛应用于电化学储能领域。然而,在组装电极过程中,MXene纳米片往往会产生严重的自堆积效应从而大幅限制了其电化学性能。设计三维结构的气凝胶是解决MXene自堆积问题同时开发高性能MXene基超级电容器电极材料的关键。本文利用氧化石墨烯(GO)改善了Ti3C2Tx气凝胶的力学强度,并通过双向冷铸和冷冻干燥、温和还原的方法制备了具有双向有序结构的Ti3C2Tx/rGO复合气凝胶(A-TGA)。A-TGA具有较好的力学性能和导电性,因此可直接作为超级电容器的电极材料。同时,双向有序的独特结构为电解质离子提供了无阻碍的传输通道,大幅提升了气凝胶的电化学性能。A-TGA在电流密度为1 A·g-1时的比电容为370 F·g-1,在100 mV·s-1扫速下经过5 000次循环后,电容保持率高达94%,表现出优异的循环稳定性。 相似文献
998.
Zhen Zhang Kunlin Song Yanjun Li 《International Journal of Polymer Analysis and Characterization》2014,19(4):332-341
Poly (vinylidiene fluoride) (PVDF)/poly (methyl methacrylate) (PMMA)/cellulose nanocrystal (CNC) nanocomposites were prepared by solution blending. Non-isothermal crystallization of PVDF/PMMA (70/30) blend and its composites was investigated using differential scanning calorimetry. It was found that the addition of CNCs played a positive role in both the crystallization rate and crystallization percentage. The addition of CNCs increased the initial crystallization temperature, peak crystallization temperature, and crystalline enthalpy. The Avrami index indicated that CNCs did not change the crystallization mechanism; while other parameters derived from Jeziorny theory and Mo's method, including Z c , F(t), and α, further verified the positive role played by CNCs. 相似文献
999.
Zhaoyang Wang Xiaobin Liao Zifeng Lin Prof. Fuzhi Huang Yalong Jiang Kwadwo Asare Owusu Prof. Lin Xu Ziang Liu Dr. Jiantao Li Prof. Yan Zhao Prof. Yi-Bing Cheng Prof. Liqiang Mai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4044-4051
It is extremely desirable to explore high-efficient, affordable and robust oxygen electrocatalysts toward rechargeable Zn–air batteries (ZABs). A 3D porous nitrogen-doped graphene encapsulated metallic Ni3Fe alloy nanoparticles aerogel (Ni3Fe-GA1) was constructed through a facile hydrothermal assembly and calcination process. Benefiting from 3D porous configuration with great accessibility, high electrical conductivity, abundant active sites, optimal nitrogen content and strong electronic interactions at the Ni3Fe/N-doped graphene heterointerface, the obtained aerogel showed outstanding catalytic performance toward the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Specifically, it exhibited an overpotential of 239 mV to attain 10 mA cm−2 for OER, simultaneously providing a positive onset potential of 0.93 V within a half-wave potential of 0.8 V for ORR. Accordingly, when employed in the aqueous ZABs, Ni3Fe-GA1 achieved higher power density and superior reversibility than Pt/C−IrO2 catalyst, making it a potential candidate for rechargeable ZABs. 相似文献
1000.
A simple synthetic chemical process to produce metal oxide loaded carbon papers was developed using bacterial cellulose gel, which consisted of nanometer-sized fibrous cellulose and water. Metal ions were successfully impregnated into the gel via aqueous solution media before drying and carbonization methods resulting in metal oxide contents that were easy to control through variations in the concentration of aqueous solutions. The papers loaded by molybdenum oxides were characterized as pseudocapacitor electrodes preliminary, and the large redox capacitance of the oxides was followed by a conductive fibrous carbon substrate, suggesting that a binder and carbon black additive-free electrode consisting of metal oxides and carbon paper was formed. 相似文献