A water filtration system utilizes a housing configured to utilize various types of filter media and having a press-sealed closing system. The closing system includes a head portion defining a head opening, a lock member, and a lid member. The lock member releasably engages the head portion such that an abutment section of the lock member projects into the head opening. The lid member is received by the head portion to cover the head opening, and has an outward-facing press section configured to abut an inward facing portion of the abutment section of the lock member when the lid member is covering the head opening. Pressure generated within the housing during water filtration presses the lid member in an outward direction and causes the lid member press section to press against the abutment section of the lock member to substantially prevent disengagement of the lock member from the head portion.

Described are filtration membranes that include a porous polyimide membrane and thermally stable ionic groups; filters and filter components that include these filtration membranes; methods of making the filtration membranes, filters, and filter components; and method of using a filtration membrane, filter component, or filter to remove unwanted material from fluid.