Revealing the performance of bio-MOFs for adsorption-based uremic toxin separation using molecular simulations

Abstract

Recently, adsorption-based separation methods have been used to remove uremic toxins from the blood of chronic kidney patients. Among the porous adsorbents, metal organic frameworks (MOFs) are recognized as potential materials due to their highly porous and tuneable structures. In this work, as a first time in the literature, we assess adsorption-based uremic toxin separation performance of 315 bio-compatible MOFs (bio-MOFs) by performing atomically-detailed simulations. We first identified hydrophobic bio-MOFs and then computed creatinine, urea, and water uptakes in these bio-MOFs by performing grand canonical Monte Carlo (GCMC) at 310 K and 1 bar. Results showed that several bio-MOFs outperform traditional adsorbents such as zeolites, activated carbons, zeolite-polymer composite nanofibers and polymers in terms of creatinine and urea uptakes. We also examined multi-component adsorption of uremic toxins in bio-MOFs at 310 K considering different bulk compositions of uremic toxins in water. The amount of adsorbed water in bio-MOFs slightly increased due to hydrogen bonds formed between the atoms of uremic toxins and water whereas the amount of adsorbed urea was significantly decreased due to competition between uremic toxins for the same adsorption sites. Overall, adenine-based bio-MOFs including bio-MOF-11 (YUVSUE), bio-MOF-12 (BEYSEF) and a dicyanamide based MOF, KEXDIB were found to be promising candidates for both urea/water and creatinine/water separations. Our results will be useful for the development of high-performance bio-MOF adsorbents for uremic toxin separation.