membranfiltre

Membranfiltre (membrane filters) are devices or components that use a semi-permeable membrane to separate components in a liquid by applying pressure or a concentration gradient. The membrane acts as a barrier that allows certain molecules or ions to pass while retaining others, enabling filtration without phase change.

Membranfiltre are typically categorized by pore size and separation mechanism into microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). MF generally removes bacteria and suspended solids with pore sizes around 0.1–10 micrometres; UF removes macromolecules and colloids with roughly 1–100 nanometres; NF targets multivalent ions and small organic molecules; RO provides near-complete rejection of salts with dense membranes.

Materials commonly used include polymeric membranes (polypropylene, polysulfone, polyvinylidene fluoride, cellulose acetate) and ceramic membranes. Modules come in hollow-fiber, spiral-wound, tubular, and flat-sheet configurations.

Applications are wide: drinking water and wastewater treatment, food and beverage processing (concentration and clarification), pharmaceutical and bioprocessing, and medical dialysis. Membranes can operate at ambient or elevated temperatures and are often integrated into cross-flow systems to reduce fouling.

Operation and challenges: fouling by particulates, biofilms, or scaling reduces flux; pretreatment and periodic cleaning are used. Energy consumption depends on pressure requirements and membrane type. Advances focus on fouling resistance, higher flux, and durable materials.

History: early membrane development accelerated in the mid-20th century with improvements in membrane chemistry and module design, expanding the role of membranfiltre across industries.