Study on adsorption performance of zinc-based metal-organic framework for trimethylamine

Rich in proteins and other active substances, seafoods have been widely used in the food and cosmetic industries. How to remove fishy substances such as trimethylamine from seafoods with high selectivity is a challenge for the current seafood processing. In this paper, zeolite imidazole framework-8 (ZIF-8), zeolites socony mobil-5 (ZSM-5) and activated alumina were characterized by powder X-ray diffraction and scanning electron microscopy, and their adsorption performance for the typical fishy substance (Trimethylamine) was also investigated. Adsorption kinetics tests show that the adsorption saturation of the three adsorbents reached at about 600 min in a 200 mg·L⁻¹ trimethylamine solution. The adsorption isotherms of the three adsorbents at 25 ℃ were tested and their adsorption capacities for trimethylamine followed a descending order of ZIF-8 (517.1 mg·g⁻¹) > activated alumina (401.8 mg·g ⁻¹) > ZSM-5 (390.3 mg·g ⁻¹). Under the same conditions, the adsorption uptake of trimethylamine on ZIF-8 was 3.2 times higher than that on activated carbon, exceeding those of most materials in the same period. Fourier transform infrared spectroscopy tests and Zeta potential tests show that the adsorption interactions between ZIF-8 and trimethylamine were dominated by C-H···π interaction, C-H···N interaction and electrostati force.