Tailoring ZIF-8 surface chemistry via amine modification for efficient p-Cresol adsorption

To effectively remove p-Cresol from blood, adsorbents with high adsorption efficiency need to be designed and developed. Due to their unique textual properties, wide surface area, and chemical stability, metal-organic frameworks (MOFs) have attracted attention as promising materials for a variety of applications. However, their potential in adsorption processes, especially for removing uremic toxins like p-Cresol, remains underexplored. Zeolitic imidazolate frameworks-8 (ZIF-8) and its amine-functionalized derivative (A-ZIF-8) were synthesized in this study to evaluate their performance as p-Cresol adsorbents in aqueous solutions. To confirm the structural properties and successful amine modification of A-ZIF-8, various characterization techniques were used, such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Brunauer-Emmett-Teller (BET) analysis. The results revealed that A-ZIF-8 exhibited enhanced crystallinity, surface area, and pore volume compared to pristine ZIF-8. Zeta potential measurements showed a shift from − 3.47 mV for ZIF-8 to + 35 mV for A-ZIF-8, significantly improving its adsorption capacity of the negatively charged p-Cresol. Experimental Adsorption studies demonstrated that A-ZIF-8 achieved the maximum experimental adsorption of p-Cresol at 432 mg g⁻¹, substantially outperforming ZIF-8, which achieved 289 mg g⁻¹. Thermogravimetric analysis and adsorption-desorption isotherms further indicated enhanced thermal stability and microporosity in A-ZIF-8. These findings underscore the effectiveness of amine modification in enhancing the adsorption capabilities of ZIF-8, positioning A-ZIF-8 as a superior candidate for uremic toxin removal, particularly in p-Cresol adsorption.