With ever-increasing attention toward the removal of pharmaceuticals and personal care products (PPCPs), it is highly essential to study promising approaches for this purpose. We introduced a novel Z-scheme SNO-ACO photocatalyst developed via hydrothermal precipitation for degrading tetracycline (TC-HCl) under visible light. SNO-ACO-9% achieved 93% TC-HCl removal in 30 min, with a high pseudo-first-order kinetic rate (0.064 min^-1), 3.5 times faster than SNO, demonstrating exceptional efficiency and potential in environmental remediation, especially for antibiotic pollution. The photocatalyst’s mechanisms involve enhanced light absorption and charge separation, which was facilitated through the addition of a strong oxidative photocatalyst, Ag₂CO₃, in a comparatively low amount in ratio to the parent reductive photocatalyst, SnNb₂O₆, without using a third agent as a charge mediator. Electron spin resonance (ESR) and scavenging experiments verified the formation of different reactive oxygen species and the Z-scheme heterojunction mechanism. This study will provide insight into using a more efficient system with heightened overall photodegradation activity in emerging contaminant removal.

Metal-organic frameworks (MOF) are a class of crystalline, porous materials possessing well-defined channels that have widespread applications across the sustainable landscape. Analogous to zeolites, these materials are well-suited for adsorption processes targeting environmental contaminants. Herein, a zirconium MOF, UiO-66, was functionalized with ferrocene for the selective removal of oxyanion contaminants, specifically NO₃^-, SO₄^2-, and PO₄^3-. Electrochemical oxidation of the embedded ferrocene pendants induces preferential adsorption of these oxyanions, even in the presence of Cl^- in a 10-fold excess. Anion selectivity strongly favoring PO₄^3- (S_oxy/comp = 3.80) was observed following an adsorption trend of PO₄^3- > SO₄^2- > NO₃^- > (10-fold)Cl^- in multi-ion solution mixtures. The underlying mechanisms responsible for ion selectivity were elucidated by performing ex situ X-ray photoelectron spectroscopy (XPS) on the heterogeneous electrode surface postadsorption and by calculating the electronic structure of various adsorption configurations. It was eventually shown that oxyanion selectivity stemmed from strong ion association with a positively charged pore interior due to the spatial distribution of charge by oxygen constituents. While ferrocenium provided the impetus for ion migration-diffusion, it was the formation of stable complexes with zirconium nodes that ultimately contributed to selective adsorption of oxyanions.