Optimizing adsorption and photocatalysis for tetracycline and sulfamethoxazole removal: the role of Ag+ and NH4+ in Bi-MOF derivatives

Abstract

This study focuses on the synthesis, characterization, and evaluation of the photocatalytic efficiency of bismuth-based metal–organic frameworks (Bi-MOFs) and their derivatives, specifically Ag⁺/Bi-MOF and NH₄⁺/Ag⁺/Bi-MOF, in the degradation of tetracycline (TC) and sulfamethoxazole (SMX) under visible light irradiation. Bi-MOFs are promising photocatalysts due to their large surface area, tunable porosity, and unique electronic properties that are favorable for visible light absorption. In this study, Bi-MOFs were synthesized using a solvothermal method, with the incorporation of silver (Ag⁺) and ammonium (NH₄⁺) ions to enhance their photocatalytic performance. The photocatalytic activity of Bi-MOF, Ag/Bi-MOF, and NH₄⁺/Ag⁺/Bi-MOF was evaluated by measuring the degradation rates of TC and SMX in aqueous solutions under visible light. The experiments demonstrated that Bi-MOFs effectively degraded both antibiotics, with the Ag/Bi-MOF derivative showing superior performance due to improved charge separation and light absorption. NH₄⁺/Ag⁺/Bi-MOF also exhibited significant photocatalytic activity, influenced by the presence of ammonium ions, which altered the surface chemistry of the catalyst and affected the adsorption and degradation processes. Reusability tests confirmed that these photocatalysts maintained high degradation efficiency over multiple cycles, highlighting their potential for practical environmental applications. This research provides a sustainable and effective solution for the removal of persistent organic pollutants such as TC and SMX.