基于尿素电氧化技术的空间站新型污水回用系统设计

空间站中水资源的补充对实现宇航员长期在轨驻留至关重要。将航天员的尿液处理后循环回用是供水的必要途径之一, 其占据了回收水量的绝大部分。然而, 传统尿液处理方法存在设备庞大、流程复杂和原子利用率低等问题。因此设计了新型污水处理及回用系统: 基于尿素电氧化技术处理尿液, 引入甲烷燃料电池与Sabatier反应器和氢氧燃料电池联用, 以进一步利用尿液处理产物, 通过设计分级处理及动态调控系统, 精准配置空间站内水资源。该设计系统有助于节省宝贵空间并降低处理能耗, 有望提高水的回收率同时实现资源的优化配置, 为空间站内水资源的循环利用提供新思路。 The replenishment of water resources in a space station is essential for achieving an astronaut's long-term and on-orbit residence. Recycling his or her urine is one of important and major ways of wastewater recovery. However, traditional urine treatment methods have the disadvantages of equipment that takes large space, complex procedures and low atomic utilization. Therefore, this paper designs a novel wastewater reuse system that treats urine based on urea electrooxidation technology, introduces methane fuel cell coupled with the Sabatier reactor and hydrogen-oxygen fuel cell to further utilize urine treatment products and to allocate water resources precisely in the space station through designing grading treatment and dynamic control systems. The wastewater reuse system designed in the paper contributes to saving valuable space and reducing energy consumption during urine treatment, thus improving water recovery rate and optimizing resource allocation. ©2024 Journal of Northwestern Polytechnical University

碳化钒改性镍基催化剂的尿素电氧化性能

尿素电解法以其在含尿素废水处理及制氢领域的节能环保前景而受到广泛关注，关键在于设计高效稳定的尿素电氧化催化剂。文中设计开发一种VC(碳化钒)改性的Ni-VC/MWCNTs(Ni基纳米复合催化剂)用于尿素电氧化可达到343.3 mA/mg的优异电流密度，其与Ni/MWCNTs催化剂相比具有更小的Tafel斜率和更低的电荷转移电阻。此外，在稳态条件下，Ni-VC/MWCNTs催化剂的电流密度也得到提高。X射线光电子能谱测试表明引入VC使得Ni更易失电子生成活性组分NiOOH,从而增强尿素电氧化性能。此外，在尿素电解池中，达到10 mA/cm~2的电流密度，以Ni-VC/MWCNTs作为阳极催化剂所需的电压比Ni/MWCNTs降低了近100 mV。结果表明Ni-VC/MWCNTs是一种优良的尿素电解催化剂，有望实现高效制氢和废水资源化利用。 Urea electrolysis has attracted wide attention for its energy-saving and environmentally friendly prospects in the fields of urea-containing wastewater treatment and hydrogen production. The key issue is the design of efficient and stable catalysts for urea electrooxidation. The synthesis of VC (vanadium carbide) modified nickel- based catalysts supported on multi-walled carbon nanotubes (Ni-VC/MWCNTs) for UOR (urea electrooxidation reaction) was reported. Ni-VC/MWCNTs has a superior current density of 343. 3 mA/mg. Particularly, Ni-VC/ MWCNTs has a smaller Tafel slope and a lower charge transfer resistance compared with Ni/MWCNTs. Moreover, the current density under the steady state of Ni-VC/MWCNTs is also enhanced. XPS (X-ray photoemission spectroscopy) demonstrates that the introduction of VC makes Ni more susceptible to lose electrons to form the active component NiOOH, which improves the UOR performance. Furthermore, in the urea electrolytic cell, the voltage required to supply 10 mA/cnr with Ni-VC/MWCNTs as the anode is reduced by nearly 100 mV compared with Ni/MWCNTs. The result suggests Ni-VC/MWCNTs is an efficient catalyst for urea electrolysis, which is expected to high-efficiency hydrogen production and resourceful utilisation of wastewater. © 2024 Editorial Office of Chemical Engineering (China). All rights reserved

直接尿素燃料电池研究进展

Direct urea fuel cells (DUFCs) can simultaneously treat urea-containing wastewater (urine, etc.) and generate electricity. Ni-based materials are effective catalysts for anodic urea electrooxidation reaction (UOR). However, the complex and sluggish kinetics of UOR lead to low activity and poor stability of Ni-based catalysts, resulting in generally lower power density of DUFCs. The key to realizing the application of DUFCs lies in the modification of Ni-based catalysts, constructing efficient and stable catalyst layers and the related membrane electrode assemblies (MEA). Therefore, the research progress of anode catalysts assembled into DUFCs was reviewed in detail. Furthermore, the effect mechanism (including the support effect and synergistic effect) on the DUFC performance of the composition structure for the modified catalysts was deeply analyzed. The review aims to provide a scientific basis for the efficient and stable UOR catalyst design. In addition, the research progress of the membrane materials in DUFC systems and the fabrication of the MEA were described. Finally, the research priorities and future directions in this field were summarized and proposed, which contributed to the development of high-performance DUFCs achieving commercialization. © 2023 Editorial Office of Chemical Engineering (China). All rights reserved