MnFe2O4@HTC活化过硫酸盐体系除藻效能与机制

采用水热法和共沉淀法将MnFe₂O₄负载在水热炭（HTC）表面制备磁性MnFe₂O₄@HTC复合催化剂.采用SEM、XRD、BET、FTIR、XPS对催化剂进行表征，通过考察MnFe₂O₄/HTC负载比、过硫酸钠（PS）投加量、初始pH和不同化学体系对除藻效果的影响，探究无供氧条件下MnFe₂O₄@HTC活化PS体系除藻的效能.基于自由基屏蔽实验和XPS分析对MnFe₂O₄@HTC活化PS体系反应机制进行研究验证.结果表明，当初始藻浓度为1.4×10⁹个·L^-1（OD₆₈₀=0.14），催化剂投加量为0.2 g·L^-1，PS投加量为0.4 g·L^-1，pH为6时，降解30 min，该体系除藻率可达到99%.在该体系中，MnFe₂O₄@HTC材料可将藻细胞吸附在材料表面，通过Mn、Fe的价态循环和HTC的协同效应反应催化PS产生空穴、¹O₂、·O₂^-、SO₄^-·和·OH多种氧化物质，使藻细胞破裂死亡.

Performance and mechanism of MnFe2O4@HTC activated persulfate system for algae removal

A magnetic MnFe₂O₄@HTC composite catalyst was prepared by loading MnFe₂O₄ on the surface of the hydrothermal carbon (HTC) with hydrothermal-coprecipitation method. Through the Characterization by SEM, XRD, BET, FTIR and XPS, the effects of MnFe₂O₄/HTC load ratio, sodium persulfate (PS) dosage, initial pH and different chemical systems on algae removal performance of the catalyst were investigated, and the effects of MnFe₂O₄@HTC activated PS system on algae removal without oxygen were investigated. The reaction mechanism of MnFe₂O₄@HTC activated PS system was verified based on free radical quencing experiments and XPS analysis. The results indicated that when the initial algae concentration was 1.4×10⁹ cell·L^-1 (OD₆₈₀=0.14), the catalyst dosage was 0.2 g·L^-1, the PS dosage was 0.4 g·L^-1, and the pH was 6, the algae removal rate reached 99% after 30 minutes of reaction. In this system, MnFe₂O₄@HTC could adsorb algal cells on its surface, catalyze PS to produce holes, ¹O₂, ·O₂^-, SO₄^-· and ·OH by the valence cycle of Mn and Fe as well as the synergistic reaction of HTC, and then made algal cells to burst and die.