Design and Performance Evaluation of Electropositively Charged Filters for Removing Fine Particles in Liquid Filtration

摘要

The main aim of the present work is to modify positively the surface of filtermedia for capturing negatively charged contaminants mainly bacteria and virus from water. In order to reduce the pressure drop and increase the filtration efficiency, the filter media modified by charge modifier having positive functional groups is developed and evaluated. The apparatus for manufacturing of the filter media consists of a mixing tank, a vacuum pumping system, an injection nozzle, a roller press and a controller. The filter media was composed of glass fiber (50～900 nm), cellulose fiber (10～20 ㎛) and charge modifier. Scanning electron microscope (SEM) and atomic force microscopy (AFM) were employed to characterize the modified surface. Also, the performance evaluation of modified filters was conducted to investigate the characteristics of charge modification quantified in terms of surface zeta potential and filtration efficiency. The surface of filtermedia modified by resins was irregularly rough and the average diameter of fibers was increased. The zetapotential value and separation efficiency of the modified filtermedia were +45 mV at pH 7 and 91% for PSL particles of 0.11 ㎛, respectively. The positively charged filter media showed the potential to be an effective method for removing fine particles (such as virus, bacterium, and so on) from the contaminated water for liquid filtration.