sorptionstester

A sorptionstester is a laboratory instrument designed to measure sorption properties of solid materials by monitoring the uptake and release of a sorbate, such as a gas or liquid. It is used to determine how much sorbate a material can absorb (sorption capacity), how quickly uptake occurs (kinetics), and how the amount sorbed varies with pressure, concentration, or humidity (sorption isotherms).

Many sorption testers operate on gravimetric, volumetric, or microbalance principles. Gravimetric systems track mass changes during exposure; volumetric systems measure pressure changes in a known gas or vapor volume; microbalance systems detect minute mass changes with high sensitivity. Some configurations include calorimetric modules to measure the heat evolved or absorbed during sorption.

Typical components include a sealed sample chamber, a controllable source of the sorbate, a balance or sensor, temperature and humidity/pressure control, a degassing or preconditioning port, and software to control experiments and analyze data.

Outputs from a sorption tester include adsorption and desorption isotherms, uptake curves, rate constants, and diffusion parameters. Data are often analyzed with models such as Langmuir, BET, or diffusion-based approaches; hysteresis between adsorption and desorption is commonly observed and provides information about pore structure.

Applications span polymer science and coatings to assess barrier properties; porous materials such as activated carbons, zeolites, and metal-organic frameworks; soils and environmental samples to study contaminant sorption; and packaging or construction materials to predict moisture transport.

Operation considerations include sample drying or degassing preconditioning, maintaining controlled temperature and environmental conditions, and regular calibration. Standards and guidelines from ISO or ASTM frameworks are commonly referenced, though specific methods vary by instrument and vendor.