Effect of manganese dioxide (MnO₂) on tetracycline (TC) removal/degradation in zero-valent iron (ZVI) based permeable reactive barrier (PRB) system was investigated. To analyze the role of MnO₂, three different PRB columns packed with ZVI, ZVI and a layer of MnO₂, and MnO₂ were set up to investigate the removal effect and reaction mechanism of ZVI coupling with MnO₂ on TC removal, respectively. The results show that the removal efficiencies of three PRB columns are 65%, 85%, and 50%, respectively. MnO₂ could accelerate the transformation of Fe²⁺ into Fe³⁺ and combine with Fe³⁺ to degrade TC in different reaction sites in the ZVI-MnO₂ PRB system. Hydroxyl radicals (·OH) were produced in this process, which contributed to about 58.3% for the TC degradation. The UV–Vis spectrum demonstrated that A ring of TC was the main reaction site for interaction with Fe³⁺ and the BCD rings were crucial for interactions with MnO₂. On the basis of intermediates identified by LC-ESI-MS, the ring structure of TC was opened, and low-molecular-weight compounds were produced in ZVI-MnO₂ PRB system.

研究了二氧化锰（MnO ₂）对基于零价铁（ZVI）的渗透性反应性阻挡层（PRB）系统中四环素（TC）去除/降解的影响。为了分析MnO ₂的作用，建立了三种不同的PRB柱，分别装有ZVI，ZVI和一层MnO ₂和MnO ₂，以研究ZVI和MnO ₂偶联对TC去除的去除效果和反应机理。结果表明，三种PRB色谱柱的去除效率分别为65％，85％和50％。MnO ₂可以加速Fe ²⁺向Fe ³⁺的转化并与Fe ³⁺结合在ZVI-MnO ₂ PRB系统的不同反应部位降解TC 。在此过程中产生了羟基自由基（·OH），约占TC降解的58.3％。UV-Vis光谱表明，TC的A环是与Fe ³⁺相互作用的主要反应部位，而BCD环对于与MnO _2的相互作用至关重要。在LC-ESI-MS鉴定的中间体的基础上，TC的环结构被打开，并在ZVI-MnO ₂ PRB系统中产生了低分子量化合物。