Granite, bentonite, and starch were mixed with clinoptilolite zeolite to produce a modified zeolite. The modified zeolite was tested for its ability to absorb formaldehyde from air. The modified sample formaldehyde adsorption capacity was then compared with those of commercially available clinoptilolite, faujasite (Y), mordenite, and zeolite type A. Studies were focused on the relationships between the physical characteristics of the selected zeolites (crystal structure, surface porosity, pore volume, pore size) and their formaldehyde adsorption capacity. The removal of starch at high temperature (1100°C) and addition of bentonite during modified clinoptilolite zeolite (M-CLZ) preparation generated large pores and a higher pore distribution on the sample surface, which resulted in higher adsorption capacity. The formaldehyde adsorption capacities of M-CLZ, clinoptilolite, faujasite (Y), zeolite type A, and mordenite were determined to be 300.5, 194.5, 123.7, 106.7, and 70 mg per gram of zeolite, respectively. The M-CLZ, clinoptilolite, and faujasite (Y) crystals contained both mesoporous and microporous structures, which resulted in greater adsorption, while the zeolite type A crystal showed a layered structure and lower surface porosity, which was less advantageous for formaldehyde adsorption. Furthermore, zeolite regeneration using microwave heating was investigated focusing on formaldehyde removal by desorption from the zeolite samples. XRD, XRF, N₂ adsorption/desorption, and FE-SEM experiments were performed to characterize the surface structure and textural properties the zeolites selected in this study.