Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Chemosphere. 2020 Jan;238:124599. doi: 10.1016/j.chemosphere.2019.124599. Epub 2019 Aug 19.
In this study, an Fe(Ⅱ)/S(IV) system was designed for the degradation of chloramphenicol (CAP). The pseudo-first-order rate constants for CAP degradation under typical conditions with and without air purging were investigated. The greatly enhanced rate of 0.0099 min with air purging compared with 0.0006 min with no air purging indicated that aeration was significant to the degradation of CAP in Fe(Ⅱ)/S(Ⅳ) system. Radical scavenging experiments revealed that SO was the primary oxidant generated from the activation of S(IV) with Fe(II), accounting for around 70% of degradation under weak acidic and neutral conditions. Increasing Fe(II) and S(IV) doses promoted the degradation of CAP, whereas the overdose of them led to a decreased degradation rate by scavenging radicals. Owing to the participation of oxygen in the formation of ferric sulfite complex and SO, the increase of dissolved oxygen improved the removal efficiency of CAP. The removal efficiency of CAP was also found to be pH dependent, decreasing from acid condition (initial pH = 4) to basic condition (initial pH = 8). The presence of coexisting anions and water matrix was found inhibiting CAP degradation in Fe(Ⅱ)/S(Ⅳ) system. This work provides an understanding on the working mechanism and possible applications of Fe(Ⅱ)/S(Ⅳ) system in organic compound degradation in wastewater.
在本研究中，设计了一个 Fe(Ⅱ)/S(IV) 体系来降解氯霉素 (CAP)。在典型条件下，考察了有无曝气时 CAP 降解的准一级速率常数。与无曝气时的 0.0006 min相比，曝气时的 CAP 降解速率大大提高，达到了 0.0099 min，这表明曝气对 Fe(Ⅱ)/S(Ⅳ)体系中 CAP 的降解有重要作用。自由基清除实验表明，SO 是 S(IV)与 Fe(II)活化生成的主要氧化剂，在弱酸性和中性条件下，约占降解的 70%。增加 Fe(II)和 S(IV)的剂量可以促进 CAP 的降解，而过量的它们会通过清除自由基而导致降解速率降低。由于氧气参与了亚硫酸铁络合物和 SO 的形成，溶解氧的增加提高了 CAP 的去除效率。还发现 CAP 的去除效率也与 pH 值有关，从酸性条件（初始 pH=4）到碱性条件（初始 pH=8）下降。共存阴离子和水基质的存在被发现抑制了 Fe(Ⅱ)/S(Ⅳ)体系中 CAP 的降解。这项工作提供了对 Fe(Ⅱ)/S(Ⅳ)体系在废水有机化合物降解中的工作机制和可能应用的理解。
