Advanced strategies for the removal of venlafaxine from aqueous environments: a critical review of adsorption and advanced oxidation pathways

Abstract

The persistence of venlafaxine (VEN), a widely prescribed antidepressant (1-[2-(dimethyl amino)-1-(4-methoxyphenyl)ethyl]cyclohexan-1-ol), in aquatic environments raises growing concerns due to its chemical stability, potential for bioaccumulation, and ecotoxicological effects. Conventional wastewater treatment technologies are largely ineffective in eliminating micropollutants, with removal efficiencies often below 30%. This review critically evaluates and compares adsorption-based and advanced oxidation process (AOP)-based methods for removing VEN from aqueous systems. Special focus is given to adsorption mechanisms, including hydrophobic, π–π, electrostatic, and hydrogen bonding interactions using biochar, activated carbon, and emerging nanomaterials. Simultaneously, state of the art AOPs, including Fenton-like, photocatalytic, and persulfate-based oxidation, are analyzed with emphasis on radical generation mechanisms, catalyst design, and operational optimization. Integrating heterogeneous catalysts such as metal oxide nanocomposites and graphene-based frameworks significantly enhances degradation kinetics, selectivity, and reusability under mild reaction conditions. Comparative analysis reveals that adsorption offers eco-friendly and cost-effective pre-treatment, AOPs enable complete mineralization, and are ideal for polishing steps in hybrid treatment systems. This review provides the first comprehensive comparison of adsorption and advanced oxidation pathways for the removal of venlafaxine (VEN), incorporating recent advances from 2022–2024. It critically evaluates mechanistic insights, efficiency trends, and sustainability aspects to establish future research directions for environmentally benign and efficient wastewater remediation.