Wang Youfeng, Cai Rongrong, Chen Lan, Cai Xiaoyong, Chen Rui, Chen Chunying, Ge Guanglu
CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China.
Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education Ministry, School of Chemistry and Chemical Engineering , South China University of Technology , Guangzhou 510640 , P. R. China.
Environ Sci Technol. 2018 Aug 7;52(15):8733-8744. doi: 10.1021/acs.est.8b02010. Epub 2018 Jul 25.
The filtration performance of a fibrous filter in removing nano-SiO aerosols atomized using different solvents including methanol, ethanol, 1-propanol, water, and the ethanol/water mixture has been investigated. Through discrete element method (DEM) simulation and filtration experiments, the efficiency variation caused by the combinative interaction of the particle-filter adhesion and interparticle attraction has been analyzed and verified. The adhesion force between the solvent-coated nanoparticles and the filter is considered as the key factor to influence their initial filtration efficiency and can be balanced by their interparticle interaction. The stronger the adhesion, the higher the initial filtration efficiency. Primary aggregate is formed through the particle-fiber interaction, and further agglomerate is caused by particle migration on the fibers, i.e. secondary aggregate. Hydrogen bonding interaction is considered as the main factor causing interparticle secondary agglomeration, and plenty of OH groups existing in the nano-SiO aerosols yielded from alcohol promotes the particle secondary aggregation. As a result, the Brown diffusion capture of the filter is significantly abated, and the as-formed agglomerate is scraped off the filter surface by the alcohol molecules, causing the filtration efficiency decreases. This study highlights the surface affinity properties of nanoaerosols and their balance between particle-particle and particle-fiber interactions in the filtration process.
研究了纤维过滤器在去除使用不同溶剂（包括甲醇、乙醇、1-丙醇、水以及乙醇/水混合物）雾化的纳米二氧化硅气溶胶方面的过滤性能。通过离散元法（DEM）模拟和过滤实验，分析并验证了颗粒与过滤器之间的粘附以及颗粒间吸引力的联合作用所导致的效率变化。溶剂包覆的纳米颗粒与过滤器之间的粘附力被视为影响其初始过滤效率的关键因素，并且可以通过颗粒间的相互作用来平衡。粘附力越强，初始过滤效率越高。通过颗粒与纤维的相互作用形成初级聚集体，而颗粒在纤维上的迁移会导致进一步的团聚，即次级聚集体。氢键相互作用被认为是导致颗粒间次级团聚的主要因素，由醇类产生的纳米二氧化硅气溶胶中存在的大量羟基促进了颗粒的二次聚集。结果，过滤器的布朗扩散捕获显著减弱，并且形成的聚集体被醇分子从过滤器表面刮落，导致过滤效率降低。本研究突出了纳米气溶胶的表面亲和特性及其在过滤过程中颗粒 - 颗粒和颗粒 - 纤维相互作用之间的平衡。
