生物质炭结构调控及其负载Co_0.5Mn_0.5Fe₂O₄催化降解环丙沙星性能

Structural Modulation of Biomass Charcoal and Its Performance in Catalytic Degradation of Ciprofloxacin with Co_0.5Mn_0.5Fe₂O₄ Loading

摘要: 为提升生物质炭载体的性能，利用碱改性工艺对纤维素生物质炭(CLB)进行改性，进而制备复合催化剂催化过硫酸盐氧化分解水中的抗生素。在碱改性实验中，NaOH与纤维素质量比分别为1:1、1:2、2:1。当m (NaOH):m (纤维素) = 1:1时，CLB表面形成粗糙多级孔结构，其比表面积虽未显著提升，但其对环丙沙星(CIP)的吸附容量提升120%。通过水热法制备MCCLB@Co_0.5Mn_0.5Fe₂O₄复合催化剂，并对其结构和磁性进行了系统表征。结果显示，Co_0.5Mn_0.5Fe₂O₄纳米颗粒均匀负载在MCCLB表面上。样品比磁化强度为39.76 emu·g⁻¹，可通过外磁场高效磁分离。过硫酸盐催化降解试验表明，对CIP的60 min降解率达94.8%，循环5次后降解效率稳定于77.2%，且磁回收率提升至79.5%。共存阴离子试验表明：Cl⁻对体系抑制效应显著。自由基淬灭实验表明，体系以硫酸根自由基($\cdot S{O}_4^{-}$ )为主要自由基，辅以单线态氧(¹O₂)非自由基路径，后者通过选择性氧化CIP哌嗪环实现分子定向裂解。

Abstract: In order to enhance the performance of biomass charcoal carriers, cellulosic biomass charcoal (CLB) was modified using an alkali modification process, which in turn led to the preparation of a composite catalyst to catalyse the oxidative decomposition of antibiotics in water by persulfate. In the alkali modification experiments, the mass ratios of NaOH to cellulose were 1:1, 1:2, and 2:1, respectively. When m(NaOH):m(cellulose) = 1:1, the surface of CLB formed a rough multilevel pore structure, and its adsorption capacity for ciprofloxacin (CIP) was enhanced by 120%, although its specific surface area was not significantly increased. MCCLB@Co_0.5Mn_0.5Fe₂O₄ composite catalyst was prepared by hydrothermal method and systematically characterized for its structure and magnetic properties. The results showed that Co_0.5Mn_0.5Fe₂O₄ nanoparticles were uniformly loaded on the MCCLB surface. The specific magnetisation intensity of the sample was 39.76 emu∙g⁻¹, which could be separated efficiently magnetically by an external magnetic field. The catalysed degradation test of persulfate showed that the degradation rate of CIP reached 94.8% at 60 min, and the degradation efficiency was stable at 77.2% after 5 cycles, and the magnetic recovery was enhanced to 79.5%. The coexisting anion test showed that Cl-had a significant inhibitory effect on the system. The free radical quenching experiments showed that the system was based on sulfate radical ($\cdot S{O}_4^{-}$ ) as the main radical, supplemented by a single linear oxygen (¹O₂) non-radical pathway, and the latter achieved molecularly oriented cleavage by selectively oxidising the CIP piperazine ring.