Formaldehyde adsorption in clinoptilolite zeolite modified with the addition of rich materials and desorption performance by microwave heating

Abstract

Granite, bentonite, and starch were mixed with clinoptilolite zeolite to produce a modified 3 zeolite. The modified zeolite was tested for its ability to absorb formaldehyde from air. The 4 formaldehyde adsorption capacity of the modified sample was then compared with those of 5 commercially available clinoptilolite, faujasite (Y), mordenite, and zeolite type A. Studies 6 focused on the relationships between the physical characteristics of the selected zeolites (crystal 7 structure, surface porosity, pore volume, pore size) and their formaldehyde adsorption capacity. 8 The removal of starch at high temperature (1100oC) and addition of bentonite during preparation 9 of modified clinoptilolite zeolite (M-CLZ) generated large pores and a higher distribution of 10 pores on the surface of this sample, which resulted in higher adsorption capacity. The 11 formaldehyde adsorption capacities of M-CLZ, clinoptilolite, faujasite (Y), zeolite type A, and 12 mordenite were determined to be 300.5 mg, 194.5 mg, 123.7 mg, 106.7 mg, and 70 mg per gram 13 of zeolite, respectively. The M-CLZ, clinoptilolite, and faujasite (Y) crystals contained both 14 mesoporous and microporous structures, which resulted in greater adsorption, while the zeolite 15 type A crystal showed a layer-layer structure and lower surface porosity, which was less 16 advantageous for formaldehyde adsorption. Furthermore, regeneration of zeolite using 17 microwave heating has been investigated focusing on the removal of formaldehyde by desorption 18 from zeolite samples. XRD, XRF, N2 adsorption/desorption, and FE-SEM experiments were 19 performed to characterize the surface structure and textural properties of selected zeolites in this 20 study.