Nanomaterials and devices for water and air
- One of the challenges in sustainable development is to conserve the natural resources and environment. Fresh water and clean air are the foundation to the public health. However, the long existing and new emerging pollution problems have raised serious concerns. In my Ph.D. study, I worked on developing nanomaterials and nanotechnologies to provide new solutions to the environmental problems from rational design to device realization. In chapter one and two, I will introduce the air pollution problem, air filtration background and how we use nanotechnology to solve the air pollution problems. A transparent air filter is introduced for highly efficient PM2.5 capture to protect indoor air quality. During haze occurrence, although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. We demonstrate a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with > 95.00% removal of PM2.5 under extreme hazardous air-quality conditions. A field test in Beijing shows that our transparent air filter can removal 98.69% of PM2.5 at high transmittance of ~77% during haze occurrence. In chapter three to six, I will focus on water pollution problem, especially on pathogen pollutions, and introduce two nanotechnology enabled methods for water disinfection. Safe water scarcity occurs mostly in developing regions that also suffer from energy shortages and infrastructure deficiencies. Hence, high-speed, low-cost and energy efficient water disinfection are in great need to solve the water problem in these regions. In chapter four and five, one dimensional nanomaterial assisted electroporation was introduced for fast water disinfection. With conducing filter made from AgNW or CuONW, we have achieved > 99.9999% disinfection of model bacteria and viruses with contact time of only 1s. The filtration device that relies only on high electric field for water disinfection can be powered by battery or motion generated static electricity. Finally in chapter six, I will introduce a visible light photocatalytic water disinfection. Finding a good photocatalyst that can harvest visible sunlight for the generation of reactive oxygen species will enhance the solar energy usage for water disinfection in the developing areas. I show that vertical aligned few layers of MoS2, as a new photocatalyst, can successfully disinfect bacteria using the full range of visible light. With the rational selection of catalyst to promote electron-hole separation and reactive oxygen species generation, MoS2-Cu can achieve 99.999% bacteria disinfection in 20 min.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Materials Science and Engineering.
|Cui, Yi, 1976-
|Cui, Yi, 1976-
|Statement of responsibility
|Submitted to the Department of Materials Science and Engineering.
|Thesis (Ph.D.)--Stanford University, 2015.
- © 2015 by Chong Liu
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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