surface charge density
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Author(s):  
Fangxin Wang ◽  
Yongyang Sun ◽  
Guanggong Zong ◽  
Wenyan Liang ◽  
Bin Yang ◽  
...  

2021 ◽  
Vol 11 (02) ◽  
pp. 69
Author(s):  
Frederikus Tunjung Seta ◽  
Xingye An ◽  
Hongbin Liu

Cellulose and chitin are two of the most abundant biopolymer on earth, have been attracted a lot of interest from many researchers, especially related to their nanoparticles form. Recently the method to extract them into nanoscale materials mostly by mineral or liquid acid hydrolysis, such as sulfuric and hydrochloric acid. Despite their high yield production, many disadvantages are produced by their use as a hydrolysis catalyst, such as low thermal stability and are difficult to be functionalized due to the presence of sulfate groups, tendency to be aggregated due to the bare surface charge density, the potential excessive degradation of cellulose; and large amounts of effluent will be produced due to the neutralization stage and corrosion hazards to the equipment and environment. To overcome the drawback of those acids, solid acid can be used to produce cellulose (CNC) and chitin nanocrystals (ChNC). Their ability to recrystallize and recycle makes them more environmentally friendly, furthermore, most of the acid can do esterification on the surface of cellulose and chitin. The purpose of this paper is to provide a critical review of recent progress related to solid acid hydrolysis since they have interesting characterization even some of their attribute is better than the conventional method.


2021 ◽  
Author(s):  
Sheng Zhang ◽  
Qiuxiao Zhu ◽  
Tingting Wang ◽  
Xuchong Wang ◽  
Xiaoping Sun ◽  
...  

Abstract As a green material, cellulose is widely used in friction triboelectric nanogenerators (TENGs). However, the weak polarity of the cellulose surface leads to its weak contact electrification performance, which is not conducive to its utilization in TENGs. In this study, epoxy chloropropane and ethylenediamine were grafted onto cellulose to form paper and were assembled with an FEP film. The output voltage, current, and surface charge density were 34.9%, 26.7%, and 16.7% higher than those of ordinary paper, respectively. When 20% nano TiO2 filler was added to the paper made from amino-modified cellulose, the output voltage, current, and surface charge density of the TENG increased by 70.9%, 226.7%, and 122.2%, respectively, compared with ordinary paper. As the air humidity of the TENG increased from 60% to 90%, the output voltage, current, and surface charge density were maintained at 53.7%, 38.9%, and 61.0%, respectively. When a 5 × 107 Ω resistor was connected to the working circuit, its output power reached 13.78 μ W·cm2. This showed that cellulose as a green material has wide application prospects in the field of TENG.


2021 ◽  
pp. 152225
Author(s):  
Youna Kim ◽  
Moonhyun Choi ◽  
Jiwoong Heo ◽  
Sungwon Jung ◽  
Dongwon Ka ◽  
...  

2021 ◽  
Vol 9 ◽  
Author(s):  
Ning Guan ◽  
Weijian Chen ◽  
Yan Gao

Alkali metal thermoelectric converter (AMTEC) is a clean energy converter that can be coupled with biomass for power generation. In present research, the transport of heat and cation was investigated in NaK-BASE tubes prepared at different sintered temperatures. The heat conduction and the fractal model were employed to investigate the temperature distributions based on the microstructures of the NaK-BASE tubes sintered at different temperatures, and the transport of Na+ and K+ in NaK-BASE tube was simulated by Poisson-Nernst-Planck multi-ions transport model, and the cation concentrations and surface charge densities were obtained in the NaK-BASE tubes with different temperatures. The results showed that microstructure of the NaK-BASE was related to the sintered temperature, and the microstructure of the NaK-BASE impacted the temperature distribution, the cation concentration and the surface charge density of Na+ and K+ in the NaK-BASE tubes. At the same heat source temperature, the average temperature in the NaK-BASE prepared at high sintered temperature was higher than that prepared at low sintered temperature. In addition, the increase of the average temperature resulted in the increase of the cation concentration and the surface charge density of Na+ and K+ in the NaK-BASE, therefore, the performance of the NaK-AMTEC could be enhanced by increasing the sintered temperature and the average temperature of the NaK-BASE.


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