| Air quality can directly affect people’s physical and mental health.In recent years,air pollution problems,such as PM2.5 pollution,indoor formaldehyde pollution and the COVID-19 epidemic which can spread by the aerosol route,have raised further concerns of the public on the harmful substances transported by air medium.How to improve air quality or to prevent harmful pollutants from entering human body through air have also become a social focus and research hotspot.Besides the long-term control strategy focusing on eliminating the pollution sources,the most effective air pollution control method is the application of suitable air purification devices.However,due to many problems such as high cost,poor practicability,and unenvironmental raw materials,the state-of-the-art air purification technology together with the derived air purification products in the market cannot fully satisfy people’s needs for purification of current air pollution that consists of complex components.Therefore,the research and development of new air purification technology and more comprehensive air purification products is not only a scientific challenge,but also an urgent need to build a livable environment and protect human health.This dissertation focuses on the purification strategy of indoor air pollution,which is the most harmful to the human body among various air pollution types.Aiming at the problems of many release sources and long release periods of indoor formaldehyde gaseous pollutants,we have designed a high-efficiency and low-energy consumption hermocatalytic degradation filter that can be used in indoor environments;aiming at the problem that the existing PM2.5 filter material has a single function and the material itself is not degradable,we have developed an environmental friendly cellulose based dual network PM2.5 filter with high thermal sterilization and disinfection efficiency;in addition,a highly sensitive wearable volatile organic pollutants(VOCs)detector was developed for the real-time monitoring of indoor organic volatiles.Finally,through the new breakthroughs in the above technologies and materials,the effect of comprehensive control of indoor air pollution prevention and control has been achieved.The main research results are as follows:1.We integrated graphene flakes with high joule heat conversion efficiency,threedimension porous sponge with high specific surface area and high-performance thermocatalysts via macroscopic assembly of nanomaterials and successfully obtained a local heating microstructure reactor(LH-MSR)for indoor formaldehyde and VOCs purification.This novel thermocatalytic degradation filter ultimately retains the threedimension highly porous sponge framework,which ensures efficient mass transfer efficiency.Furthermore,the graphene flakes as heat source coated on the sponge skeleton can directly heat the catalysts after applying voltage,thus achieving a high heat transfer efficiency.It successfully crossed the technical barrier of thermocatalytic degradation of indoor air purification and provided an effective solution for treating indoor formaldehyde pollutants.2.We compounded the nano-scale porous cellulose film onto the micron-scale pores in the three-dimension sponge through the liquid film freeze-drying process and obtained an environment-friendly double-network three-dimension porous filter with a"window screen" structure.This three-dimension non-vertically stacked structure of single-layer nanocellulose porous films with high surface area highly increase the efficiency of single filtration and improves the utilization efficiency of nanocellulose,which further improves the service life of the filter.In addition,our double-network three-dimension porous filter can realize the thermal sterilization function by using graphene warped sponge.This work has laid an essential foundation for the development of the next-generation eco-friendly and multi-functional PM2.5 purification filter.3.A high sensitivity VOCs detection sensor with the controllable cross-linked network was realized by using the synthetic method of hydrothermal polymerization curing.Under the premise of not changing the chemical composition of polydimethylsiloxane(PDMS),only by introducing the good solvent of PDMS and using the synthetic method of hydrothermal polymerization curing,the internal polymerization network structure can be optimized to obtain the highly soft,high sticky and highly stretchable(the elongation can be up to 3000%)PDMS rubber with controllable mechanical properties.Also,the prepared PDMS showed strong adhesion to metal,skin and rubber products.This signal sensor with high sensitivity for different organic solvents shows great application potential in the field of real-time detection of indoor gaseous VOCs pollution. |
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