Modulation of the Bifunctional CrVI to CrIII Photoreduction and Adsorption Capacity in ZrIV and TiIV Benchmark Metal-Organic Frameworks

The presence of hexavalent chromium water pollution is a growing global concern. Among the currently applied technologies to remove CrVI, its adsorption and photocatalytic reduction CrIII less mobile toxic forms are most appealing because their simplicity, reusability, low energy consumption. However, little attention has been paid bifunctional catalysts, that is, materials can reduce CrVI retain both trivalent species at same time. In this work, dual adsorption–reduction capacity two iconic photoactive water-stable zirconium titanium-based metal–organic frameworks (MOFs) investigated: UiO-66-NH2 MIL-125. bifunctionality MOFs depends on different parameters, such as particle size in MIL-125 or organic linker functionalization/defective positions UiO-66 type sorbents. For instance, defects shown be detrimental for photoreduction but beneficial retention phototransformed species. Both compounds able from 90 98% initial present acidic solutions well immobilize reduced species, demonstrating suitability environmental remediation. addition, it demonstrated carried out also continuous flux mode through diluted MOF/sand chromatographic column. obtained results open perspective assess sorption ability plethora MOF have capture purposes. parallel, work opens develop specific chemical encoding strategies within transfer other related remediation applications.