Department of Environmental Science , Zhejiang University , Hangzhou , Zhejiang 310058 , China.
Zhejiang Provincial Key Laboratory of Organic Pollutant Process and Control , Zhejiang University , Hangzhou , Zhejiang 310058 , China.
Environ Sci Technol. 2018 Jun 19;52(12):7043-7053. doi: 10.1021/acs.est.8b01043. Epub 2018 Jun 5.
Fabrication of visible-light-responsive, macroscopic photo-Fenton catalysts is crucial for wastewater treatment. Here, we report a facile fabrication method for nano-FeO(OH)/reduced graphene oxide aerogels (FeO(OH)-rGA) equipped with a stable macrostructure and a high efficiency for catalytic degradation of phenolic organics. The structure of FeO(OH)/rGA was characterized by SEM, TEM, XPS, Raman analysis. The FeO(OH) is the main constituent of ferrihydrite, which dispersed in the graphene aerogel with a particle size of ∼3 nm can efficiently activate HO to generate abundant •OH. The excellent performance of the FeO(OH)/rGO aerogel was specifically exhibited by the outstanding catalyst activity, sustained mineralization and eminent reaction rate for phenolic organics. A synergy effect between FeO(OH) and graphene aerogel was observed, which came from the extensive electron transfer channels and active sites of the 3D graphene aerogel and the visible-light-activated FeO(OH) and HO consistently producing •OH. The FeO(OH)/rGA could be reused for 10 cycles without a reduction in the catalytic activity and had less iron leaching, which guarantees that the active ingredient remains in the gel. Moreover, the FeO(OH)/rGA induced photo-Fenton degradation of 4-chlorophenol under near neutral pH conditions because the tight connection of FeO(OH) with the rGO aerogel results in less iron leaching and prevents the generation of Fe(OH). The 4-chlorophenol was completely removed in 80 min with a 0.074 min rate constant in the FeO(OH)-rGA/HO photo-Fenton system under visible-light irradiation, and mineralization rate was up to 80% after 6 h. Oxidative •OH can continuously attack 4-chlorophenol, 2,4,6-trichlorophenol and bisphenol A without selectivity. These results lay a foundation for highly effective and durable photo-Fenton degradation of phenolic organics at near neutral pH and sufficient activation of HO for future applications.
可见光响应的宏观光芬顿催化剂的制备对于废水处理至关重要。在这里，我们报告了一种简便的制备方法，用于制备具有稳定宏观结构和高效催化降解酚类有机物的纳米 FeO(OH)/还原氧化石墨烯气凝胶（FeO(OH)-rGA）。通过 SEM、TEM、XPS、Raman 分析对 FeO(OH)/rGA 的结构进行了表征。FeO(OH)/rGA 的主要成分为水铁矿，其粒径约为 3nm，分散在石墨烯气凝胶中，可有效地将 HO 激活生成丰富的•OH。FeO(OH)/rGO 气凝胶表现出优异的性能，对酚类有机物具有出色的催化剂活性、持续的矿化和显著的反应速率。FeO(OH)和石墨烯气凝胶之间观察到协同效应，这源于 3D 石墨烯气凝胶广泛的电子转移通道和活性位点以及可见光激活的 FeO(OH)和 HO 持续产生•OH。FeO(OH)/rGA 可重复使用 10 次而不降低催化活性，且铁浸出较少，这保证了凝胶中的活性成分保持不变。此外，由于 FeO(OH)与 rGO 气凝胶紧密相连，铁浸出较少，生成的 Fe(OH)较少，因此在近中性 pH 条件下，FeO(OH)/rGA 可诱导 4-氯苯酚的光芬顿降解。在可见光照射下，FeO(OH)-rGA/HO 光芬顿体系中，4-氯苯酚在 80min 内完全去除，0.074min-1的速率常数较大，6h 后矿化率达到 80%。氧化性•OH 可以无选择性地连续攻击 4-氯苯酚、2,4,6-三氯苯酚和双酚 A。这些结果为在近中性 pH 下高效、持久地降解酚类有机物和充分激活 HO 奠定了基础，为未来的应用提供了依据。
