Enhanced venlafaxine degradation in amorphous FeS2 under redox-dynamic aqueous environments: Critical role of citrate in electron utilization for boosted hydroxyl radical generation
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引用次数: 0
Abstract
Pharmaceuticals and organic acids ubiquitously coexist in urban riverine environments, yet the transformation mechanisms of antidepressants like venlafaxine (VNF) in iron sulfide-rich sediments under redox-dynamic conditions remain poorly resolved. This study comprehensively analyzed adsorption/desorption dynamics and reactive oxygen species (ROS)-mediated oxidative degradation of VNF in amorphous iron sulfide (FeS2(am)), emphasizing the role of citric acid (CA) in modifying these interactions. Our results revealed that VNF was stably adsorbed onto FeS2(am) under anoxic conditions with no observable degradation. Conversely, exposure to O2 triggered rapid desorption of VNF (93.58%) and its partial degradation (16.96%) mediated by hydroxyl radicals (•OH). Remarkably, CA amendment significantly promoted VNF degradation under oxic conditions, achieving 97.36% degradation and increasing the observed rate constant (kobs) 17.4-fold (from 6.38×10−4 to 1.11×10−2 min−1). Mechanistically, CA optimized electron utilization efficiency in FeS2(am) through three synergistic pathways: (i) generation of carbon-centered radicals that amplified secondary •OH production via Fenton-like chain reactions; (ii) acceleration of Fe2+ regeneration through enhanced electron transfer from sulfur intermediates (e.g., S2−, S0) to Fe3+; and (iii) elevation of H2O2 into •OH conversion efficiency from 57.20% to 83.20%. Electrochemical analyses corroborated that CA enabled a more efficient four-electron O2 reduction pathway, thereby enhancing electron utilization for rapid •OH generation. Density functional theory calculations combined with LC-Orbitrap-HRMS analyses identified nine distinct VNF degradation pathways. Additionally, ECOSAR results indicated a significant reduction in ecotoxicity of the transformation products compared to the parent compound. Collectively, these findings pave the way for developing ligand-enhanced in situ remediation strategies for antidepressant contaminants in redox-dynamic sediments.
期刊介绍:
Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include:
•Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management;
•Urban hydrology including sewer systems, stormwater management, and green infrastructure;
•Drinking water treatment and distribution;
•Potable and non-potable water reuse;
•Sanitation, public health, and risk assessment;
•Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions;
•Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment;
•Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution;
•Environmental restoration, linked to surface water, groundwater and groundwater remediation;
•Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts;
•Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle;
•Socio-economic, policy, and regulations studies.