Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 4

年份

2022 1

2020 1

2013 1

2008 1

关键词

检索范围：

排序：展示方式：

Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes

GAO Qijun, HUANG Mianyan, WANG Yuxin, CAI Yuquan, XU Li

《化学科学与工程前沿（英文）》 2008年第2卷第1期页码 95-101 doi: 10.1007/s11705-008-0012-5

摘要： Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells. However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature. This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this contradictory situation, insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC)) powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60°C. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability and proton conductivity. Results showed significant improvement not only in temperature tolerance, but also in methanol resistance of the SPEEK/Zr(PBTC) composite membranes. The membranes containing 30 wt-% ∼ 40 wt-% of Zr(PBTC) had their methanol permeability around 10 cm·s at room temperature to 80°C, which was one order of magnitude lower than that of Nafion115. High proton conductivity of the composite membranes, however, could also be achieved from higher temperature applied. At 100% relative humidity, above 90°C the conductivity of the composite membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion115 membrane and even reached a high value of 0.36 S·cm at 160°C. Improved applicable temperature and high conductivity of the composite membrane indicated its promising application in DMFC operations at high temperature.

关键词： homogeneous mixture PBTC zirconium tricarboxybutylphosphonate Nafion115 DMFC

HTML PDF 收藏

Evaluation of precipitation behavior of zirconium molybdate hydrate

Liang ZHANG, Masayuki TAKEUCHI, Tsutomu KOIZUMI, Izumi HIRASAWA

《化学科学与工程前沿（英文）》 2013年第7卷第1期页码 65-71 doi: 10.1007/s11705-013-1314-9

摘要： In the dissolution step of spent nuclear fuel, there is a world-concern problem that zirconium molybdate hydrate precipitates as a byproduct, and accumulates in some reprocessing equipments. In order to prevent this accumulation, we have developed a new method based on the controlled reaction crystallization of zirconium molybdate hydrate (ZMH) in the reprocessing solution, followed by solid liquid separation. In order to measure the particle size of ZMH, batch crystallization experiments were conducted by varying nitric acid concentration and operating temperature. In result, almost all particle sizes scatter around 1 μm on average, despite the higher concentration of nitric aid and operating temperature, and then small particles grow up as an aggregate sticking to the crystallizer. Moreover, polymorph and color changing were observed by varying the concentration of nitric acid and reaction time. These results suggest that crystal color and adhesiveness are closely related to the particle size of ZMH. And the control of nitric acid concentration and small particle growth would be the useful technique to prevent the ZMH sticking.

关键词： spent nuclear fuel zirconium molybdate hydrate cleaning method accumulation

HTML PDF 收藏

Flow synthesis of a novel zirconium-based UiO-66 nanofiltration membrane and its performance in the removal

Feichao Wu, Yanling Wang, Xiongfu Zhang

《化学科学与工程前沿（英文）》 2020年第14卷第4期页码 651-660 doi: 10.1007/s11705-019-1819-y

摘要： In this work, a thin zirconium-based UiO-66 membrane was successfully prepared on an alumina hollow fiber tube by flow synthesis, and was used in an attempt to remove -nitrophenol from water through a nanofiltration process. Two main factors, including flow rate and synthesis time, were investigated to optimize the conditions for membrane growth. Under optimal synthesis conditions, a thin UiO-66 membrane of approximately 2 µm in thickness was fabricated at a flow rate of 4 mL·h for 30 h. The -nitrophenol rejection rate for the as-prepared UiO-66 membrane applied in the removal of -nitrophenol from water was only 78.1% due to the existence of membrane defects caused by coordinative defects during membrane formation. Post-synthetic modification of the UiO-66 membrane was carried out using organic linkers with the same flow approach to further improve the nanofiltration performance. The result showed that the -nitrophenol rejection for the post-modified membrane was greatly improved and reached over 95%. Moreover, the post-modified UiO-66 membrane exhibited remarkable long-term operational stability, which is vital for practical application.

关键词： UiO-66 membrane flow synthesis nanofiltration p-nitrophenol removal

HTML PDF 收藏

Engineering zirconium-based metal-organic framework-801 films on carbon cloth as shuttle-inhibiting interlayers

《化学科学与工程前沿（英文）》 2022年第16卷第4期页码 511-522 doi: 10.1007/s11705-021-2068-4

摘要： Lithium-sulfur batteries have been regarded as the next-generation rechargeable batteries due to their high theoretical energy density and specific capacity. Nevertheless, the shuttle effect of lithium polysulfides has hindered the development of lithium-sulfur batteries. Herein, a novel zirconium-based metal-organic framework-801 film on carbon cloth was developed as a versatile interlayer for lithium-sulfur batteries. This interlayer has a hierarchical porous structure, suitable for the immobilization of lithium polysulfides and accommodating volume expansion on cycling. Moreover, the MOF-801 material is capable of strongly adsorbing lithium polysulfides and promoting their catalytic conversion, which can be enhanced by the abundant active sites provided by the continuous structure of the MOF-801 films. Based on the above advantages, the lithium-sulfur battery, with the proposed interlayer, delivers an initial discharge capacity of 927 mAh·g^–1 at 1 C with an extremely low decay rate of 0.04% over 500 cycles. Additionally, a high area capacity of 4.3 mAh·cm^–2 can be achieved under increased S loading.

关键词： lithium-sulfur batteries metal-organic framework-801 film interlayer shuttle effect