兰州大学机构库 >化学化工学院
双功能太阳能蒸发器的设计与性能研究
Alternative TitleStudy on designing and performance of dual-functional solar evaporator
杨洲立
Subtype硕士
Thesis Advisor陈凤娟
2023-05-31
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name理学硕士
Degree Discipline化学
Keyword太阳能淡化 Solar desalination VOCs 降解 VOCs degradation 非自由基活化 non-radical activation 锥状阵列结构 array conical structure 冷凝水收集 condensate collection
Abstract

水是生命之源,在人类日常生活和生产中起着至关重要的作用。但随着工业的发展和社会的进步,水资源短缺问题逐渐受到重视。太阳能是一种取之不尽用之不竭的清洁能源,太阳能驱动脱盐技术受到广泛关注。近年来,通过新型光热材料的开发和结构设计,太阳能驱动脱盐蒸发器的光-热性能和水蒸发性能都获得急剧提升。但是,实际水环境及其复杂,既含有可溶性盐类,也含有有机污染物。具有单一蒸发功能的太阳能蒸发器已无法满足实际应用的需求。此外,针对如何快速收集太阳能蒸发器产生的净水仍然存在挑战。基于上述问题,本论文进行了以下两个方面的研究:

(1) 设计并合成了一种双功能太阳能蒸发器,该蒸发器以生物质废料作为原材料,在管式炉内原位氨气刻蚀一步法合成了的石墨化-氮 (graphite-N, g-N) 掺杂的生物质蒸发器,可同时进行脱盐和挥发性有机污染物 (volatile organic contaminants, VOCs) 的降解。以木材生物质废料为例,其衍生的g-N掺杂碳化木材 (graphite-N doped wood carbon, g-N/WC) 蒸发器在1个太阳光照下蒸发量高达 1.31 kg m-2 h-1,收集到的净水中Na+,K+,Ca2+和Mg2+四种离子浓度远低于世界卫生组织 (world health organization, WHO) 定义的这些离子的饮用水标准限值。并且,g-N/WC可以活化过氧单硫酸钾 (peroxymonosulfate, PMS) 产生大量的单线态氧 (1O2) 从而分解VOCs,其大量的微孔可以吸附VOCs来促进催化反应的进行。对VOCs(包括苯酚、双酚A (BPA) 、4,4'-磺酰二酚 (BPS) 和对氯苯酚(4-CP) 的降解效率达到99.91%以上。生命周期循环评估 (life cycle assessment , LCA) 结果表明,与其他新兴材料相比,g-N/WC 蒸发器的所有类别的环境影响和 CO2 排放量分别减少了 98% 和 82%。我们设计的太阳能蒸发器利用生物质废物,以极低的碳足迹解决了水资源短缺的危机,有望实现绿色、可持续水资源循环利用。

(2) 我们设计了具有锥状阵列结构的蒸发和水收集一体化的太阳能蒸发器,通过背面蒸发技术,实现快速水蒸发与水收集。首先,采用3D打印技术,构建具有锥状凹槽的树脂模型;然后,配制掺杂有碳纳米管(Carbon Nanotube, CNT) 的聚二甲基硅氧烷 (polydimethylsiloxane, PDMS) 浆料,通过印刷技术,制备具有锥状阵列结构的碳纳米管掺杂的聚二甲基硅氧烷(cone array carbon nanotube doped polydimethylsiloxane, CA-C/P )。以无纺布作为水传输材料,CA-C/P作为光热和水收集材料,利用倾斜角度来增加蒸发面积,竖直结构来收集净水,构建了三角形的蒸发收集一体化装置。在蒸发层,CA-C/P密集排列的锥状阵列结构可以有效提高光吸收效率,并且倾斜放置的蒸发器不仅提高了水蒸发面积,还能增加环境的热供给,使蒸发效率达到了3.61 kg m-2 h-1。在冷凝层,CA-C/P快速冷凝蒸发层产生的水蒸气,水蒸气在锥状结构的尖端冷凝为小水滴,在拉普拉斯压差下自发在锥状结构底部聚集,最后由于重力作用流到整个一体化设备的底部。在运行过程中,可以稳定冷凝蒸发量的2/3。使用实际南海海水水样进行测试,整个一体化设备长期稳定运行七天,维持良好水蒸发和水收集性能,Na+,K+,Ca2+和Mg2+四种离子浓度都降低至WHO定义的饮用水标准限值以下。该蒸发器为同时实现高效水蒸发和水收集提供了一种借鉴方法。

Other Abstract

Water is the source of life and plays a vital role in human daily life and production. However, with the development of industry and social progress, the problem of water shortage has gradually received attention. Solar energy is an inexhaustible clean energy, and solar-driven desalination has received widespread attention. In recent years, through the development and structural design of new photothermal materials, the photo-thermal performance and water evaporation performance of solar-driven desalination evaporators have been greatly improved. However, the actual water environment and its complexity contain both soluble salts and organic pollutants. Solar evaporators with a single evaporation function can no longer meet the needs of practical applications. In addition, there are still challenges in how to quickly collect the clean water produced by solar evaporators. Based on the above problems, the following two aspects are studied in this paper:

(1) A dual-function solar evaporator was designed and synthesized, which uses biomass waste as raw material and synthesizes graphite-N (g-N) doped biomass evaporator by in-situ ammonia etching in a tube furnace, which can simultaneously carry out desalination and degradation of volatile organic contaminants (VOCs). Taking wood biomass waste as an example, the derived g-N doped wood carbon (g-N/WC) evaporator evaporates up to 1.31 kg m-2 h-1 under one sunlight.The concentration of Na+, K+, Ca2+ and Mg2+ ions in the collected clean water is much lower than that of the World Health Organization (WHO) Define the standard limits for drinking water for these ions. Moreover, g-N/WC can activate potassium peroxymonosulfate (PMS) to produce a large amount of singlet oxygen (1O2) to decompose VOCs. A large number of micropores can adsorb VOCs to promote the catalytic reaction. The degradation efficiency of VOCs (including phenol, bisphenol A (BPA), 4,4'-sulfonyldiol (BPS) and p-chlorophenol (4-CP)) reached more than 99.91%. Life cycle assessment (LCA) results show that all categories of g-N/WC evaporators have reduced environmental impact and CO2 emissions by 98% and 82%, respectively, compared to other emerging materials. The solar evaporators we designed to use biomass waste to solve the crisis of water scarcity with a very low carbon footprint, promising green and sustainable water recycling.

(2) We have designed a solar evaporator with a cone array structure that integrates evaporation and water collection, and realizes rapid water evaporation and water collection through the back evaporation technology. First, 3D printing technology is used to construct a resin model with conical grooves; Then, polydimethylsiloxane (PDMS) slurry doped with carbon nanotubes (CNTs) is prepared. Cone array carbon nanotube doped polydimethylsiloxane (CA-C/P) is prepared by printing technology. Using non-woven fabrics as water transmission materials, CA-C/P as photothermal and water collection materials, the inclination angle is used to increase the evaporation area, and the vertical structure is used to collect clean water. A triangular evaporation collection integrated device is constructed. In the evaporation layer, the cone array of CA-C/P densely arranged can effectively improve the light absorption efficiency. The inclined evaporator not only improves the water evaporation area, but also increases the heat supply of the environment, so that the evaporation efficiency reaches 3.61 kg m-2 h-1. In the condensation layer, the water vapor generated by the CA-C/P rapidly condenses the evaporation layer. The water vapor condenses into small water droplets at the tip of the conical structure, which spontaneously collects at the bottom of the conical structure under the Laplace pressure difference, and finally flows to the bottom of the entire integrated equipment due to gravity. During operation, 2/3 of the condensation evaporation can be stabilized. Using actual South China Sea sea water samples, the entire integrated equipment operated stably for seven days for a long time, maintaining good water evaporation and water collection performance, and the four ion concentrations of Na+, K+, Ca2+ and Mg2+ were reduced below the standard limits for drinking water defined by WHO. The evaporator provides a reference method for achieving efficient water evaporation and water collection at the same time.

Subject Area无机化学
MOST Discipline Catalogue理学 - 化学 - 无机化学
URL查看原文
Language中文
Other Code262010_220200923851
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/537777
Collection化学化工学院
Affiliation
兰州大学化学化工学院
Recommended Citation
GB/T 7714
杨洲立. 双功能太阳能蒸发器的设计与性能研究[D]. 兰州. 兰州大学,2023.
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