DETERMINATION OF ACETALDEHYDE ADSORPTION ON SYNTHETIC ZEOLITES AND CHARACTERIZATION OF SAMPLES BY FTIR METHOD

Acetaldehyde is one of the most common carcinogenic organic compounds (pollutants) that can be found in the air in urban and industrial areas, as well as in indoor spaces. Generally, the most efficient method for removing pollutants from the air is adsorption with suitable adsorbents. To choose a suitable adsorbent, it is necessary to know its characteristics, the most significant of which is the adsorption capacity, i.e., the maximum amount of adsorbed substance per gram of adsorbent under given conditions. Nowadays, there is still a search for an adequate method that would provide an answer to how much and which organic substances are adsorbed on adsorbents. This paper presents the possibility of applying the FTIR analysis method for the identification and detection of adsorbed acetaldehyde on different types of zeolites. Adsorption of acetaldehyde from the gaseous phase was performed on ZSM zeolite (ZEOflair 100, ZEOflair 110), NaA zeolite (ZEOflair 1000), and the Na-form of mordenite (ZEOflair 800). Initial concentrations of acetaldehyde in the air ranged from 0.071 mol/m³ to 1.239 mol/m³, and the adsorption was carried out at atmospheric pressure, T=25 °C, and relative humidity (rH) 65%. On the FTIR spectra of the examined samples after adsorption, peaks were observed at a wavelength of 1700 cm⁻¹, which are characteristic of the carbonyl group of acetaldehyde. It was observed that the peak areas were proportional to the amounts of adsorbed acetaldehyde, which were very small and ranged from 0.107 mmol/g to 2.98 mmol/g of zeolite. Results indicate that FTIR is a rapid, non-destructive method suitable for qualitative and semi-quantitative analysis of low-level acetaldehyde adsorption, especially in the absence of co-adsorbed water.