filtrationsrate

Filtrationsrate is the rate at which a filtrate is produced through a filter or membrane. It denotes the amount of fluid that passes through per unit time and is typically expressed in volume per time, such as liters per minute (L/min) or cubic meters per second (m3/s). The filtrationsrate depends on the driving force across the filter, the properties of the membrane or filter medium, and the characteristics of the fluid.

In physiology, the concept is closely associated with the glomerular filtration rate (GFR), the kidney’s rate of filtrate formation from blood plasma. GFR is a key indicator of renal function and is normally about 120 mL/min in healthy adults (roughly 180 L/day). It depends on renal plasma flow, capillary permeability, and the filtration barrier's selectivity. Clinically, GFR is estimated from substances such as inulin or creatinine and used to assess kidney health.

In engineering and environmental applications, the filtrationsrate describes how fast a liquid or gas passes through a filtration medium in processes such as water treatment, chemical processing, or air filtration. The rate is influenced by pressure difference, membrane permeability, surface area, pore size, temperature, and fluid viscosity. The flux, defined as filtrate per unit area per unit time, is a common way to quantify it; often expressed as J = ΔP / R or J = Lp ΔP × A with appropriate constants.

Related topics include filtration, glomerular filtration rate, creatinine clearance, membrane permeability, and dialysis.