Porovolyymi

Porovolyymi (from Finnish poro- meaning pore and volyymi meaning volume) refers to the total volume of empty space, or pores, within a porous material. It is commonly expressed as pore volume PV or as porosity φ = PV / Vbulk, the latter being a dimensionless fraction.

Porovolyymi is a fundamental parameter affecting fluid transport, storage, and chemical accessibility. Materials with higher pore volume can hold more liquid and provide larger pathways for diffusion. Pore volume is related to, but not identical with, skeletal volume—the solid portion of the material.

Measurement methods include mercury intrusion porosimetry, gas adsorption (such as nitrogen at liquid nitrogen temperature) to estimate pore volume and surface area, helium pycnometry for skeletal volume, and X-ray computed tomography for 3D pore structure. Pores are often categorized by size: micropores (<2 nm), mesopores (2–50 nm), and macropores (>50 nm).

Applications span geology and hydrogeology (sandstones, coal seams), catalysis and chemical engineering (zeolites, activated carbons), energy storage (porous electrodes and batteries), and construction materials. Porovolyymi influences permeability, capillary behavior, sorption capacity, and transport kinetics.

In Finnish scientific literature, porovolyymi is a standard term alongside porosity and pore-size distribution, used to discuss the pore structure of diverse materials.