Jinghua Yu,Lei Ge,Ping Dai,Shenguang Ge,Shiquan Liu
In this work, hollow silica microspheres (HSMs), which have hollow interiors and nanoporous shells, were used in the immobilization of enzyme to establish a novel chemiluminescence biosensor. The immobilization behavior of enzyme in HSMs with different pore sizes has been studied. The results revealed that the pore size and the surface area of HSMs play important roles in their immobilization performance. Compared with traditional methods, this immobilization method not only provides tunable and consistent pore system and restricted microspaces for enzyme immobilization , but also exhibits a larger immobilization capacity and a higher adsorption rate. A rhodanine derivative-KMnO 4 -HCl-H 2 O 2 was used to replace traditional chemiluminescence system (luminol-horseradish peroxidase-H 2 O 2 ) to reach the purpose of high sensitivity, simple operation and pH expansion for chemiluminescence biosensor. The linear range of this novel method is 7.72 × 10 −6 to 2.54 × 10 −2 mol L −1 ( r = 0.9994). The detection limit is 8.0 × 10 −7 mol L −1 . The Michaelis–Menten constant of glucose oxidase was 0.3 mmol L −1 . With glucose oxidase as a test enzyme, the proposed method gave an accurate and satisfactory result once applied to the determination of glucose in four different human serum samples.
Improving the ablation and mechanical properties of ablative thermal protection composites by introducing modified fillers which simultaneously with an unavoidable increase in density. Balancing this increase in density while achieving lightweight properties is crucial for the development of effective ablative composites. In this paper, different contents of the hollow silicate glass microspheres (HSMs) are incorporated into MoSi 2 /mica-modified CF-BPR composites to investigate the impact of HSMs. The results show that HSMs play a positive role in reducing the density and thermal conductivity of the composite. The ablation and insulation properties of the 30 vol.% HSMs composites exhibit a mass ablation rate of 0.035 g/s and a linear ablation rate of 0.015 mm/s, alongside the lowest backside temperature. A significant improvement in flexural strength after static ablation at 1500 °C reached 82.59 MPa and maintained a relatively high level after 1600 °C. HSMs act as interlaminar skeletons, enhancing the shearing strength of the composite and facilitating the formation of a protective liquid phase around the carbon fibers to prevent oxidation. The increasing toughness of carbon fibers further enhances the mechanical strength of the composites.
Qiang Sun,Huaili Zheng,Xuebin Hu,Muhammad Salam,Manli Sun,Chun Zhao,Bing Bao
In this study, the coagulant was prepared by grafting polydopamine onto chitosan hydrogel which was doped with hollow silica nanoparticles loaded with permanganate and then was coated on the surface of the titanium tablet to realize simultaneous coagulation and degradation of diclofenac sodium (DCFS) combined with UV irradiation. The coagulation kinetics were simulated well with Pseudo-first order and pseudo-second order models compared with Weber-Morris model, inferring the cooperation of chemical and physical processes. The outcomes of isotherm trials were fitted well with Langmuir model except for that at 303.15 K, which was described both well with Langmuir and Tëмкин models, implying monolayer and unsaturated coagulation of DCFS. It was degraded at the copresence of ultraviolet and permanganate released from coagulant in acidic aqueous medium. Hydroxyl and Mn(V) radicals played an important role in DCFS degradation process. Additionally, the coagulant was used directly for DCFS removal for ten times without rinse process, which provided a potential application in environmental remediation.
Many heterogeneous reduction reactions are hampered by the generated intermediate products located at the interface of reactants, resulting in reducing the reaction area or slowing down the mass transfer and thereby shutting off or slowing down the reaction. Thus, removing the unwanted intermediate products from the reaction interface is key to enabling a rapid and sufficient reduction rate and rationally mediating the product sizes and structures. Herein, we employ solid NaCl to absorb the intermediate molten ZnCl 2 generated at the liquid Zn-SiCl 4 gas interface, making the reaction happen continuously and sufficiently at a relatively low temperature of below 450 °C. In addition to refreshing the reaction interface, NaCl acts as a buffer to absorb the reaction heat, ensuring the production of hollow Si inherited from the spherical liquid Zn template. As a result, the yield of Si reaches over 95% within 2 h and the Si particle size is below 200 nm. Further, the obtained Si anode has an initial Coulombic efficiency of 86.7% and delivers a capacity of 1580 mAh g −1 at 3 A g −1 after 350 cycles with a capacity retention of 90.6%. Overall, this paper provides an effective strategy for engineering the reaction interface and revalorizing waste SiCl 4 for making Li-storage Si anodes.
危险品化学品经营许可证（带存储）