Investigation of the performance and reaction mechanism of tetracycline degradation by LaMnO₃/GA composites activated PMS

Graphene aerogel (GA)-loaded LaMnO₃ perovskite-type oxides were prepared by sol-gel and hydrothermal methods and their catalytic performance for the degradation of tetracycline (TC) by peroxymonosulfate (PMS) was investigated. SEM, TEM, XPS, and Raman spectroscopy were employed to analyze the morphological structure, elemental composition, and chemical morphology. Characterization results showed the successful preparation of LaMnO₃ and LaMnO₃/GA crystalline phase heterojunction. The experimental results indicated that, when compared with the pure LaMnO₃ (58% degradation rate), the catalytic performance of the LaMnO₃/GA25 composites for the PMS activation for TC degradation improved to be more than 83%. This enhancement was mainly attributed to GA complexation, which promotes the charge transfer rate and increases the charge concentration at the reactive sites. The vital roles of •OH and SO₄•⁻ were certified by free radical trapping assays. In addition, the catalytic activity of the LaMnO₃/GA25/PMS system in complex aqueous (HA, ${{\text{H}}_{\text{2}}}\text{PO}_{\text{4}}^{{-}} $, $\text{SO}_{\text{4}}^{{2-}} $, Cl⁻, Urea, $\text{HCO}_{\text{3}}^{{-}} $) environments were also explored. This work demonstrated the feasibility of the LaMnO₃/GA25/PMS system for wastewater treatment and provided a novel way to make full use of manganese resources to solve the problem of environmental pollution.