oxygentransfer

Oxygen transfer refers to the movement of molecular oxygen between materials or compartments, driven by differences in oxygen partial pressure and mediated by interfaces or membranes. It encompasses exchanges between gas and liquid phases, as well as transfer within biological systems or industrial processes. The term is used in physiology, environmental science, and chemical or biochemical engineering.

In respiratory physiology, oxygen transfer describes the uptake of O2 from inspired air in the lungs into the blood, through the alveolar-capillary membrane, and its carriage by hemoglobin to tissues. In aquatic environments, oxygen transfer is the process by which oxygen moves from the atmosphere into water, where it dissolves according to Henry’s law and supports aquatic life. Solubility decreases with higher temperature and salinity, and mixing and surface area influence the rate.

In engineering and industry, oxygen transfer is quantified by the rate at which oxygen moves from a gas (often air) to a liquid, or from a liquid to a gas, in devices such as bioreactors or oxygenators. A common metric is the volumetric mass transfer coefficient kLa, with the transfer rate described by OTR = kLa (C* − C_L), where C* is the saturation concentration and C_L is the current dissolved oxygen. Factors include interfacial area, bubble size, agitation, aeration rate, temperature, and gas composition.

Applications span fermentation and wastewater treatment, aquaculture, and medical devices such as extracorporeal membrane oxygenation and hospital oxygenators. Challenges include maintaining sufficient oxygen supply while avoiding oxidative stress, handling viscous or complex fluids, and scaling mass transfer from lab to industrial scales.