(144f) Automation of Adsorption Differential Volumetric Apparatus (ADVA) for Kinetic Measurements

The Adsorption Differential Volumetric Apparatus (ADVA) is a unique system that allows highly accurate measurements of very fast gas adsorption kinetics. The technique is based on the use of two symmetrical branches (namely, sample and reference side) connected by a differential pressure transducer. The gas transport kinetics are determined by monitoring the pressure signal as the gas expands from the dosing and the uptake volume of the sample side. The system is specifically designed for kinetic measurements featuring very small volumes, high acquisition rates and a small range differential pressure transducer (+/– 35 mbar) and allows to measure reliably fast adsorbing systems with just few mg of sample. In a previous publication [1], we have demonstrated the use of the technique to determine the diffusion of N₂ and Ar on a single pellet and fragments of 4A zeolite.

In the present work, we present a collaboration between Air Liquide, The University of Edinburgh and Konrad Technologies, to develop the first, fully automated ADVA for adsorption kinetics. The current system allows the user to plan a wide variety of sequential adsorption and desorption steps at any pressure level up to the limit of the pressure transducer. The logics developed for the automated ADVA include the dosing of the target amount of gas, the acquisition of all pressures and temperatures as well as the automatic determination of the final adsorption equilibrium. An essential feature of the automated system is a protection protocol implemented to prevent any damage to the differential pressure transducer. Additional safety features protect the vacuum pump.

We will demonstrate the modes of operation and validate the newly upgraded ADVA with a sequence of experiments on reference commercial adsorbents.

1. Wang, E. Mangano, S. Brandani, F. Brandani, P. Pullumbi. A novel adsorption differential volumetric apparatus to measure mass transfer in nanoporous materials. Separation and Purification Technology (283), 2022.