In this work, influences of particle hydrophilicity and morphology on its removal by electrically neutral and positively charged water droplets were investigated experimentally in a home-made chamber. Potassium chloride (KCl) and Di-Ethyl-Hexyl-Sebacate (DEHS) and agglomerated KCl aerosols were successively adopted as representative testing cases and each test was carried out batchwise. The results showed that minimal collection efficiency of DEHS particles (hydrophobic) could be improved from 38% to 82% due to droplet charging after spray for ten minutes, which is a significantly greater increment than that of KCl particles (hydrophilic) after same charging-spray time. Additionally, droplet charging enhances the operational stability of traditional spray to collect DEHS particles in tested sizes while contributes most to removal of KCl particles only in low concentration and intermediate size. As a comparison with nearly spherical particles (KCl), a higher collection efficiency by electrically neutral droplets corresponds to loose agglomerates in low particle concentration due to interception mechanism, but the difference could be weakened by an addition of electric field onto water spray.
Bibliographical noteFunding Information:
The authors thank the support of members of the Center for Filtration Research: 3M Corporation, A.O. Smith Company, Applied Materials, Inc., BASF Corporation, Boeing Company, Corning Co., China Yancheng Environmental Protection Science and Technology City, Cummins Filtration Inc., Donaldson Company, Inc., Entegris, Inc., Ford Motor Company, Guangxi Wat Yuan Filtration System Co., Ltd, MSP Corporation; Samsung Electronics Co., Ltd., Xinxiang Shengda Filtration Technology Co.,Ltd., TSI Inc., W. L. Gore & Associates, Inc., Shigematsu Works Co., Ltd., and the affiliate member National Institute for Occupational Safety and Health (NIOSH). The author also thanks the project of China General Administration of Quality Supervision, Inspection and Quarantine (2017QK178) and the financial aid from the program of China Scholarship Council (CSC).
- Droplet charging
- Particle morphology