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排序方式: 共有150条查询结果,搜索用时 15 毫秒
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In the present study, peanut shell, a green waste raw material, was used to prepare biochar (BC) and to obtain BC-supported nano-palladium/iron (BC-nPd/Fe) composites for removing 2,4-dichlorophenoxyacetic acid (2,4-D) from water. Characterization analysis demonstrated that nPd/Fe particles were well dispersed on the BC surface with weakened magnetic properties. The average particle diameter and specific surface area of nPd/Fe were 101.3 nm and 6.7 m2 g−1, whereas the corresponding values of the BC-nPd/Fe materials were 88.8 nm and 14.8 m2 g−1, respectively. Several factors were found to influence the dechlorination of 2,4-D, including the weight ratio of BC to Fe, Pd loading ratio, initial solution pH, 2,4-D concentration, and reaction temperature. Dechlorination results indicated that the 2,4-D removal and phenoxyacetic acid (PA) generation rates were 44.1% and 20.1%, respectively, in the nPd/Fe system, and 100.0% and 92.1%, respectively, in the BC-nPd/Fe system. The dechlorination of 2,4-D was well described by the pseudo-first-order kinetic model (R2 > 0.97), and the observed rate constants kobs were 0.0042 min (nPd/Fe) and 0.0578 min (BC-nPd/Fe), respectively. The reaction mechanism indicated that the dechlorination hydrogenation was the main process to remove 2,4-D from water in the BC-nPd/Fe system. In addition, BC inhibited the formation of a passivation layer on the particle surface during the reaction, thus maintaining the high reactivity of BC-nPd/Fe. The easy preparation technique, high 2,4-D dechlorination capacity, and mild reaction conditions suggest that BC-nPd/Fe may be a promising alternative composite to remove 2,4-D from water. 相似文献
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Large-area surface-plasmon polariton (SPP) interference lithography is presented, which uses an attenuated total reflection-coupling mode to excite the interference of the SPPs. The interference of the SPPs causes a highly directional intensity range in a finite depth of the electric field, which is good for noncontact. Finite-difference time-domain simulations of the interference on a thin resist layer show that broad-beam illumination with a p-polarized light at a wavelength of 441 nm can produce features as small as 60 nm with high contrast, smaller than lambda/7. Our results illustrate the potential for patterning periodic structures over large areas at low cost. 相似文献
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Wheat gluten (WG) and Attapulgite (ATP) was mixed in acidic solution and freeze-dried, thermally compression-molded to form nanocomposite sheet. The influences of reduction and sonication on structure of wheat gluten were examined by Raman spectrum. The variation of disulfide bonding in wheat gluten show that the sonication is more effective than reduction on the breakage of disulfide bonds, whereas the content of disulfide bonds in the WG sheet molded by sonicated WG powder is the highest in the molded sheets. FT-IR analysis displays that the bands in the range of 1700-1600 cm−1 shift to higher frequency after mixing WG and ATP powders and molding the nanocomposite. The tensile and bending properties of the WG sheet increase with addition of ATP powder, and the properties of the sheet molded by sonicated WG powder decrease for the reduction of the disulfide bonding, but the properties of the sheet can be improved by addition of ATP. The WG/ATP nanocomposite images observed by SEM and TEM show that rod-like ATP particles are evenly dispersed in WG matrix, but the crystal structure of ATP is impervious. The viscoelasticity of the WG sheet declines with addition of ATP particle, and that the α-relaxation of the WG sheet molded by sonicated WG powder shift to high temperature and become broad. Both mass and bending strength of 7 wt% WG/ATP nanocomposite sheet show a decline over a soil exposure time of 20 days. 相似文献
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HL—1M装置的真空进展 总被引:5,自引:2,他引:3
总结了1994 至1998 年度HL-1M 装置的真空进展,包括真空壁条件、真空运行参数、放电进展、影响壁条件的主要因素及其控制指标等 相似文献
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Yongkang Ye Shun Ding Yingwang Ye Houchuan Xu Xiaodong Cao Sheng Liu Hanju Sun 《Mikrochimica acta》2015,182(9-10):1783-1789
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Yongkang Xi Bo Liu Shuxin Wang Xiaonan Huang Hang Jiang Shouwei Yin To Ngai Xiaoquan Yang 《Chemical science》2021,12(11):3885
Chemo-enzymatic cascade processes are invaluable due to their ability to rapidly construct high-value products from available feedstock chemicals in a one-pot relay manner. However, they have proven to be challenging because of the mutual inactivation of both catalysts. A conceptually novel strategy based on Pickering interfacial catalysis (PIC) is proposed here to address this challenge. This study aimed to construct a protein-stabilized Pickering system for biphasic cascade catalysis, enabled by phosphorylated zein nanoparticles (ZCPOPs) immobilized in gold nanoparticles (Au NCs). Ultra-small Au NCs, 1–2 nm in diameter, were integrated into ZCPOPs at room temperature. Then, the as-synthesized ZCPOPs–Au NCs were used to stabilize the oil-in-water (o/w) Pickering emulsion. Besides their excellent catalytic activity and recycling ability in a variety of oil phases, ZCPOPs–Au NCs possess unpredictable catalytic activity and exhibit mimicking properties of horseradish peroxidase. Particularly, the cascade reaction is well achieved using a metal catalyst and a biocatalyst at the oil–water interface. The result showed that such a combination of chemo- and biocatalysis improved the catalytic yield more than two times compared with that of sole metal catalysis. This study opened a new avenue to design nanomaterials using the combination of chemo- and biocatalysis in a Pickering emulsion system for multistep syntheses.A robust chemo- and biocatalytic cascade PIC with a recovery catalyst and a separation product was developed. The results groundbreakingly highlighted the preliminary applications of artificial enzymes and bio-enzymes in a one-pot cascade PIC. 相似文献
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