EFFECT OF CHEMICAL MODIFICATION OF HYDROXYAPATITE/ZEOLITE COMPOSITE ON MALODORS ADSORPTION BEHAVIOR

Abstract

Hydroxyapatite (HAp)/zeolite composite (HZc) was prepared by a simple immersion method, and it was then modified with Cu²⁺ and 3-aminoplopyltriethoxysilane (APES) to produce a novel adsorbent for unpleasant odors such as NH₃, H₂S and CH₃CHO gases. The obtained materials were characterized by SEM-EDS, XRD, FT-IR, TG-DTA and ninhydrin reaction test. Nano-sized order HAp was observed distributed on zeolite for HZc, and modification of HZc with Cu²⁺ and APES maintained the original framework structure of HZc. Introduced amount of Cu²⁺ and APES after the modification was 3.6 mol% and 12.6 mg·g^-1, respectively. The adsorption ability evaluated via a gas bag-detection tube method showed that Cu²⁺-modified HZc increased NH₃ and H₂S adsorption ability, and APES-modified HZc enhanced CH₃CHO adsorption ability in comparison to unmodified one, respectively. Sequential modification of HZc with Cu²⁺ and APES also maintained H₂S and NH₃ adsorption ability, but decreased CH₃CHO adsorption ability. This suggests that adsorption sites for CH₃CHO were impeded in case of formation of Cu-N coordinate bond derived from direct interaction between Cu²⁺ and amino groups of APES. Therefore, use of HZc individually modified with Cu²⁺ and APES is recommended to capture multiple unpleasant odors.