三维Fe/Mn双金属有机框架的制备及吸附-活化过硫酸盐去除四环素的性能

Preparation of 3D Fe, Mn-MOF and Its Performance for Tetracycline Removal by Adsorption and Activating Persulfate

  • 摘要: 基于过硫酸盐的高级氧化工艺在去除水体中抗生素类污染物方面展现出巨大应用潜力, 其中催化剂对抗生素的吸附过程是实现高效催化降解的关键环节。本研究在室温条件下, 通过简单搅拌Fe/Mn金属盐与1, 4-苯二甲酸(1, 4-BDC)的混合反应液, 制备出三维(3D)结构的Fe/Mn双金属有机框架(Fe, Mn-MOF)材料, 并将其用于吸附与活化过硫酸盐(PS)以去除四环素(TC)。结果表明, Fe/Mn摩尔比为1∶0.1的3D Fe, Mn0.1-MOF对TC的吸附与催化性能最优, 该材料具备丰富的孔隙结构与充足的活性位点, 其比表面积可达202.01 m2·g-1, 为高效吸附和催化降解TC提供了结构支撑。在298 K条件下, 3D Fe, Mn0.1-MOF对初始浓度为45 mg·L-1的TC最大吸附容量可达243 mg·g-1; 当体系中添加PS后, 该材料可在45 min内将TC去除率提升至80%, 充分体现其优异的吸附与催化协同性能。此外, 3D Fe, Mn0.1-MOF在天然污染水体中的吸附与催化性能也得到了有效验证。经过3次循环使用后, 3D Fe, Mn0.1-MOF/PS体系对TC的去除率仍维持在≥64%水平, 表明该材料具有良好的循环稳定性和实际应用潜力。通过吸附动力学与吸附等温线模型分析可知, 催化剂对TC的吸附过程符合拟一级动力学模型, 且以物理吸附为主, 同时该吸附反应为自发的吸热反应。自由基淬灭实验结果表明, TC的降解主要依赖于硫酸盐自由基(SO4·-)、羟基自由基(·OH)、单线态氧(1O2)和超氧阴离子(O2·-)4种自由基介导的反应途径。本研究不仅深化了对MOF/PS体系吸附-催化协同作用机理的认知, 还为MOF材料在TC污染水体修复领域的实际应用提供了坚实的理论支撑与实践参考。

     

    Abstract: Persulfate-based advanced oxidation processes (PS-AOPs) hold significant promise for antibiotic remediation in wastewater, wherein the adsorption capacity of catalyst plays a pivotal role in facilitating subsequent catalytic degradation. In this study, a three-dimensional (3D) Fe/Mn bimetallic framework (Fe, Mn-MOF) was synthesized via a facile room-temperature stirring method using Fe/Mn salt and 1, 4-phthalic acid (1, 4-BDC) as precursors. The as-prepared material was employed for simultaneous adsorption and PS activation toward tetracycline (TC) removal from aqueous solutions. Optimal adsorption and catalytic performance were achieved at an Fe/Mn molar ratio of 1∶0.1 (designated Fe, Mn-MOF0.1), which exhibited an abundant void structure with a specific surface area of 202.01 m2·g-1 and numerous accessible active sites. The maximum adsorption capacity of 3D Fe, Mn0.1-MOF for TC reached 293 mg·g-1 at 298 K with an initial TC concentration of 45 mg·L-1. In the integrated Fe, Mn-MOF0.1/PS system, 80% removal efficiency was achieved within 45 min. The material also demonstrated efficacy in treating naturally contaminated water matrices. Moreover, the Fe, Mn-MOF0.1/PS system retained ≥64% TC removal efficiency after three consecutive cycles, indicating satisfactory operational stability. Adsorption kinetics and isotherm analyses reveal that TC uptake followed a pseudo-first-order kinetic model and corresponded to a spontaneous, endothermic process governed by monolayer surface adsorption. Quenching experiments elucidated the dominant role of radical species, including sulfate radicals (SO4·-), hydroxyl radicals (·OH), singlet oxygen (1O2), and superoxide anions (O2·-), in TC degradation. This work provides mechanistic insights into the coupled adsorption-catalytic function of MOF-based materials in PS systems, establishing a theoretical foundation for their application in antibiotic-contaminated water remediation.

     

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