The invention provides a novel type of filter media that offers efficient disinfection effects, while achieving a low water pressure drop and a high water flow rate when in use. Specifically, the filter media of the invention comprises a microorganism-killing membrane containing electrospun nanofiber fabrics loaded with biocidal nano-particles. The filter media of the invention is adhesive-layer free and contains at least one thermal binding layer that are made of spunbonded nonwoven polymeric fabrics. The invention also provides a water-purification cartridge and a portable water system thereof.