Xiao Chun, Li Su, Yi Fuhao, Zhang Bo, Chen Dan, Zhang Yang, Chen Hongxin, Huang Yueli
College of Environmental and Chemical Engineering, Zhaoqing University Zhaoqing 526061 China
RSC Adv. 2020 May 18;10(32):18704-18714. doi: 10.1039/d0ra03361h. eCollection 2020 May 14.
The Fenton reaction, as an important member of the advanced oxidation processes (AOPs), has gained extensive attention in recent years. However, the practical applications of the traditional Fenton process have been restricted by the poor degradation efficiency and the rigid pH range. In this study, we report a new strategy regarding the photo-Fenton oxidation of Rhodamine B (RhB) by kaolin-FeOOH (K-Fe) catalysts with the assistance of oxalic acid. It was found that the iron-oxalate complex was formed as oxalic acid was introduced into the K-Fe catalyst system by the chelation ability of oxalate. Benefiting from the high photosensitivity of the iron-oxalate complexes, the K-Fe/oxalic acid/HO/visible light system exhibited excellent catalytic activity towards the degradation of RhB under the optimized reaction conditions [(K-Fe) dosage = 1.0 g L, initial pH = 7.2, (oxalic acid) = 1.0 mM, (HO) = 0.5 mM], and its reaction rate constant for the degradation of RhB was 27.7 times greater than that of the K-Fe/HO/visible light system. More importantly, the K-Fe/oxalic acid/HO/visible system showed remarkable degradation efficiency over a wide pH range (3.3-10.8), which was superior to that of the traditional Fenton system. In addition, the degradation efficiency of RhB was found to remain at 94.7% after five cycles. This work is expected to provide an important approach for the application of the Fenton system.
芬顿反应作为高级氧化过程（AOPs）的重要成员，近年来受到了广泛关注。然而，传统芬顿工艺的实际应用受到降解效率低和pH范围狭窄的限制。在本研究中，我们报道了一种新策略，即在草酸的辅助下，用高岭土-FeOOH（K-Fe）催化剂对罗丹明B（RhB）进行光芬顿氧化。研究发现，由于草酸盐的螯合能力，当草酸引入K-Fe催化剂体系时会形成铁-草酸盐络合物。得益于铁-草酸盐络合物的高光敏性，在优化的反应条件下[（K-Fe）用量 = 1.0 g/L，初始pH = 7.2，（草酸） = 1.0 mM，（H₂O₂） = 0.5 mM]，K-Fe/草酸/H₂O₂/可见光体系对RhB的降解表现出优异的催化活性，其降解RhB的反应速率常数比K-Fe/H₂O₂/可见光体系高27.7倍。更重要的是，K-Fe/草酸/H₂O₂/可见光体系在较宽的pH范围（3.3 - 10.8）内表现出显著的降解效率，优于传统芬顿体系。此外，经过五个循环后，RhB的降解效率仍保持在94.7%。这项工作有望为芬顿体系的应用提供一种重要方法。
