A magnetic mesoporous SiO2/Fe3O4 hollow microsphere with a novel network-like composite shell: synthesis and application on laccase immobilization

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

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Synthesis and upconversion luminescent properties of Bi2MoO6:20%Yb3+, 2%Er3+ hollow microsphere with different W6+ ions doping

Journal of Solid State Chemistry ◽

10.1016/j.jssc.2021.122064 ◽

2021 ◽

Vol 297 ◽

pp. 122064

Author(s):

Wen Ge ◽

Kong Liu ◽

Peizhi Yang ◽

Shukang Deng ◽

Lanxian Shen

Keyword(s):

Hollow Microsphere ◽

Luminescent Properties

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Sublimation of composite ice and its influence on performance of ice shells

International Journal of Space Structures ◽

10.1177/09560599211011863 ◽

2021 ◽

Vol 36 (1) ◽

pp. 67-77

Author(s):

Yue Wu ◽

Junkai Huang ◽

Jiafeng Chen

Keyword(s):

Numerical Simulation ◽

Shell Structure ◽

Composite Shell ◽

Engineering Practice ◽

Sublimation Rate ◽

Long Span ◽

Static Performance ◽

New Type ◽

Ice Sublimation ◽

Composite Shell Structure

The long-span ice composite shell structure is a new type of ice and snow structure developed in recent years. The engineering practice of ice composite shell shows that sublimation is one of the important reasons for its damage and even collapse. In this paper, we firstly supplemented the existing H-K equation and obtained the revised ice sublimation equation through indoor evaporative plate experiment considering the influence of admixtures and wind speed. Afterwards, combining the simulations of solar radiation and CFD, the numerical simulation of sublimation distribution on the surface of were realized by programming in Grasshopper platform. During sublimation, the thickness of the ice composite shell decreases by 0.38 mm every 10 days and the sublimation rate on the sunny side was 1.7 times that on the shady side. Finally, the static performance and stability of the sublimated ice composite spherical shell were analyzed. After 70 days of sublimation, the thickness of the ice composite shell structure becomes thinner and uneven, which leads its sensitivity to external load increases.

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Preparation and characterization of polydopamine/melamine microencapsulated red phosphorus and its flame retardance in epoxy resin

RSC Advances ◽

10.1039/d1ra03164c ◽

2021 ◽

Vol 11 (33) ◽

pp. 20391-20402

Author(s):

Chen Cheng ◽

Yanling Lu ◽

Weining Ma ◽

Shaojie Li ◽

Jun Yan ◽

...

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Shell Structure ◽

Composite Shell ◽

Intumescent Flame Retardant ◽

Smoke Suppression ◽

Flame Retardance ◽

Red Phosphorus ◽

Composite Shell Structure

Red phosphorus was coated by a polydopamine/melamine composite shell structure, which constituted an intumescent flame retardant with superior flame retardance and smoke suppression performance for epoxy resin.

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An Optimum Fatigue Design of Polymer Composite Compressed Natural Gas Tank Using Hybrid Finite Element-Response Surface Methods

Polymers ◽

10.3390/polym13040483 ◽

2021 ◽

Vol 13 (4) ◽

pp. 483

Author(s):

Kazem Reza Kashyzadeh ◽

Seyed Saeid Rahimian Koloor ◽

Mostafa Omidi Bidgoli ◽

Michal Petrů ◽

Alireza Amiri Asfarjani

Keyword(s):

Finite Element ◽

Fatigue Life ◽

Natural Gas ◽

Response Surface ◽

Polymer Composite ◽

Wall Thickness ◽

Composite Shell ◽

Compressed Natural Gas ◽

Fiber Angle ◽

Composite Tank

The main purpose of this research is to design a high-fatigue performance hoop wrapped compressed natural gas (CNG) composite cylinder. To this end, an optimization algorithm was presented as a combination of finite element simulation (FES) and response surface analysis (RSA). The geometrical model was prepared as a variable wall-thickness following the experimental measurements. Next, transient dynamic analysis was performed subjected to the refueling process, including the minimum and maximum internal pressures of 20 and 200 bar, respectively. The time histories of stress tensor components were extracted in the critical region. Furthermore, RSA was utilized to investigate the interaction effects of various polymer composite shell manufacturing process parameters (thickness and fiber angle) on the fatigue life of polymer composite CNG pressure tank (type-4). In the optimization procedure, four parameters including wall-thickness of the composite shell in three different sections of the CNG tank and fiber angle were considered as input variables. In addition, the maximum principal stress of the component was considered as the objective function. Eventually, the fatigue life of the polymer composite tank was calculated using stress-based failure criterion. The results indicated that the proposed new design (applying optimal parameters) leads to improve the fatigue life of the polymer composite tank with polyethylene liner about 2.4 times in comparison with the initial design.

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Variability and improvement of optical and antimicrobial performances for CQDs/mesoporous SiO2/Ag NPs composites via in situ synthesis

Green Processing and Synthesis ◽

10.1515/gps-2021-0035 ◽

2021 ◽

Vol 10 (1) ◽

pp. 403-411

Author(s):

Youliang Cheng ◽

Mingjie Wang ◽

Changqing Fang ◽

Ying Wei ◽

Jing Chen ◽

...

Keyword(s):

Uv Light ◽

Carbon Quantum Dots ◽

Diffusion Method ◽

Ag Nps ◽

Uniform Size ◽

High Antibacterial Activity ◽

Fluorescent Materials ◽

Potential Applications ◽

Mesoporous Sio2

Abstract To change the optical properties and improve the antibacterial performances of carbon quantum dots (CQDs) and Ag NPs, mesoporous SiO2 spheres were combined with them to form the composites. In this paper, CQDs with a uniform size of about 3.74 nm were synthesized using glucose as carbon source. Then, CQDs/mesoporous SiO2/Ag NPs composites were obtained in situ under UV light irradiating by using mesoporous SiO2 and Ag NO3 as the carrier and silver resource, respectively. The diameter of CQDs/mesoporous SiO2/Ag NPs particles was in the range of 200–250 nm. With the increase in irradiating time, the red-shift in the UV-Vis spectrum for as-prepared CQDs/mesoporous SiO2/Ag NPs composites was found, and the adsorption peak was widened. In addition, the composites showed a high antibacterial activity against Staphylococcus aureus and Escherichia coli via disc diffusion method. These results indicated that inhibition circles for Ag NPs/mesoporous SiO2/CQDs and mesoporous SiO2/Ag NPs were similar in diameter. Furthermore, the two composites had a better bactericidal performance compared with other particles. Therefore, as-prepared CQDs/mesoporous SiO2/Ag NPs composites in this paper have great potential applications for fluorescent materials and antibacterial materials.

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