The invention is a device for purifying drinking water that has at least one fibrous structure. Preferably, there is an upstream and downstream fibrous structure. Each fibrous structure is a mixture of nano alumina fibers and second fibers arranged in a matrix to create asymmetric pores and to which fine, ultrafine, or nanosize particles are attached. Preferably, the device has an upstream antimicrobial for sterilization of retained microbes. The device is substantially more efficient at removing soluble contaminants such as halogens from a fluid stream than those previously available and is also able to retain turbidity, bacteria, and virus.