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| 椰壳生物炭同步吸附水中全氟辛酸和Hg（Ⅱ）的性能及机理 |
| Performance and mechanism of coconut shell biochar for simultaneous adsorption of perfluorooctanoic acid and Hg（Ⅱ）in water |
| Received:April 07, 2025 |
| DOI：10.13254/j.jare.2025.0296 |
| 中文关键词: 生物炭，全氟辛酸（PFOA），汞（Ⅱ），吸附机理，络合桥接作用 |
| 英文关键词: biochar, perfluorooctanoic acid, mercury（Ⅱ）, adsorption mechanism, complexation bridging interaction |
| 基金项目:天津市自然科学基金项目（23JCYBJC00450） |
| Author Name | Affiliation | E-mail | | Chen Zhen | School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China | | | Hu Ziying | School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China | | | Yue Junjie | School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China | yue_junjie@163.com | | Du Zhaolin | AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | duzhaolin@caas.cn |
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| 中文摘要: |
| 为探究椰壳生物炭（CSBC）同步吸附水体中全氟辛酸（PFOA）和 Hg（Ⅱ）的性能及机理，本研究开展了 PFOA与 Hg（Ⅱ）单组分及共吸附试验。单组分吸附实验重点考察了溶液初始pH的影响，并通过吸附动力学、等温吸附和吸附热力学分析了吸附行为。结果表明：PFOA和Hg（Ⅱ）吸附的适宜pH分别为5.0和7.0；PFOA吸附符合拟一级动力学和Sips等温吸附模型，以物理吸附为主，是自发放热过程；Hg（Ⅱ）的吸附则遵循拟二级动力学和Langmuir等温吸附模型，以化学吸附为主，是自发吸热过程。共吸附试验重点考察了溶液初始pH与PFOA-Hg（Ⅱ）浓度比的影响，结合FTIR、XPS等表征测试分析了CSBC对PFOA-Hg（Ⅱ）的共吸附机制。在PFOA-Hg（Ⅱ）体系中，pH 6.0为最佳初始条件，此时两种污染物的平衡吸附量均不低于单组分体系，且在不同PFOAHg（Ⅱ）浓度比下，PFOA和Hg（Ⅱ）的吸附量较单组分最高可分别提升48%和30%。机理分析表明：PFOA主要通过孔隙填充、疏水相互作用、静电相互作用及与 CSBC表面—OH/—COOH的氢键作用被吸附；Hg（Ⅱ）则与—OH/—COOH形成稳定络合物；吸附态的Hg（Ⅱ）/PFOA与溶液中的PFOA/Hg（Ⅱ）通过络合桥接作用促进协同吸附。本研究揭示的协同机制，为通过调控表面含氧官能团密度与构建疏水微区以优化改性CSBC性能，提供了明确的设计方向。 |
| 英文摘要: |
| To explore the simultaneous adsorption performance and mechanism of perfluorooctanoic acid（PFOA）and Hg（Ⅱ）on coconut shell biochar（CSBC）from water, this study conducted single-component adsorption experiments of PFOA and Hg（Ⅱ）and binary coadsorption experiments. The single-component adsorption experiment focused on investigating the effect of the initial solution pH, and analyzed the adsorption behavior through adsorption kinetics, isothermal adsorption, and thermodynamics. The results showed that the optimal pH for PFOA and Hg（Ⅱ）adsorption was 5.0 and 7.0, respectively. PFOA adsorption fitted pseudo-first-order kinetics and the Sips isotherm model, was mainly physical adsorption, and was a spontaneous exothermic process. Hg（Ⅱ）adsorption followed pseudo-second-order kinetics and the Langmuir isotherm model, was primarily chemical adsorption, and was a spontaneous endothermic process. In co-adsorption experiments, the effects of initial solution pH and the PFOA-Hg（Ⅱ）concentration ratio on adsorption were mainly investigated, and the co-adsorption mechanism of PFOA-Hg（Ⅱ）was analyzed by characterization tests such as FTIR and XPS. The results indicated that pH 6.0 was the optimal initial condition in the PFOA-Hg（Ⅱ）system, at which the equilibrium adsorption capacities of both pollutants were not less than those in the single-component systems. At different PFOA-Hg（Ⅱ）concentration ratios, the equilibrium adsorption capacities of PFOA and Hg（Ⅱ）increased by up to 48% and 30%, respectively, when compared to the single-component systems. Mechanism analysis revealed that：PFOA was primarily adsorbed through pore filling, hydrophobic interactions, electrostatic interactions, and hydrogen bonding with —OH/—COOH groups on the CSBC surface; Hg（Ⅱ）formed stable complexes with —OH/—COOH groups; adsorbed Hg（Ⅱ）/PFOA and dissolved PFOA/Hg（Ⅱ）promoted synergistic adsorption via complex bridging interactions. The synergistic mechanism revealed in this study provides a strategic direction for optimizing modified CSBC performance by precisely regulating the density of surface oxygen-containing functional groups and constructing hydrophobic microdomains. |
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