The hollow fiber membrane resembles thin straws, with hundreds to thousands of them bundled together, ranging from 1 to 3.5mm in width. They are securely fixed within a PVC shell. These membranes, typically made from polymers like polyethylene, polypropylene, polysulfone, or polyvinylidene fluoride (PVDF), form a semi-permeable barrier. Their porous structure contains minuscule pores or channels that permit the passage of certain substances, usually smaller molecules, while effectively blocking larger molecules or particles. This technology finds wide application across industries due to its efficient filtration capabilities and compact design.