MIL-125-NH2 functionalized chitin scaffold as dual sorbent and photocatalyst filter for degradation of trimethoprim

Abstract

A porous, photocatalytically active, and water-stable composite filter has been developed based on MIL-125-NH2, a Titanium-based Metal-Organic Framework (MOF) and chitin polymeric scaffold. In order to tune the structure and functional properties of the CH/MOF composites, the loading degree of the MOF within the polymer was systematically varied. The composite material optimal performance was achieved with a 10% wt/wt loading of MIL-125-NH2 into the chitin scaffold. This composite material was able to capture and photodegrade Trimethoprim (TMP) under acid and alkaline conditions with outstanding efficiency (82% within 180 min), as well as in waters collected from different geographical locations nearby Buenos Aires that were spiked with TMP. Furthermore, the chemical stability of MIL-125-NH2 is significantly improved when incorporated into the chitin scaffold, maintaining its structural integrity even after four cycles of reactivation and reusability. The study outlines the experimental procedures for synthesizing MIL-125-NH2, preparing chitin hydrogel and nanostructured composites, and details on the adsorption and photocatalysis experiments. The practical application of our approach can be further expanded to prevent degradation during gas or liquid adsorption processes of hydrolytically unstable MOFs.