钛网表面Fe_(3)O_(4)/FeS_(2)膜层制备及其类芬顿降解苯酚研究

Synthesis of Fe_(3)O_(4)/FeS_(2) coating on Ti mesh and its Fenton-like degradation of phenol

为了拓宽类芬顿催化剂的pH适用范围、改善其有机污染物降解性能并解决其分离回收难的问题,本文采用易于大规模制备的电沉积法在钛网表面沉积了Fe_(3)O_(4)/FeS_(2)固定化膜层。通过XRD、SEM及XPS等表征手段研究了所合成催化剂的相组成、形貌及表面元素价态。结果显示,所合成的材料主要由Fe_(3)O_(4)与FeS_(2)物相组成,且膜层表面呈现由纳米片间相互交联形成的多孔网状结构。类芬顿降解苯酚性能表明,在0.20 mol/L硫源含量下所得膜层于pH 6.0、H_(2)O_(2)含量6 mmol/L、苯酚初始质量浓度35 mg/L、反应温度30℃的条件下降解60 min,可将98%的苯酚去除。因而,Fe_(3)O_(4)/FeS_(2)固定化膜层催化剂表现出优异的类芬顿催化活性。分析发现:材料较大的比表面积可增强传质,同时提供更多的活性位点参与苯酚降解;而催化剂表面键合的S_(2)^(2-)可促进Fe^(3+)/Fe^(2+)以及Fe^(3+)/Fe^(2+)的氧化还原循环,同时,以硫酸根形式存在的硫物种可为类芬顿反应提供合适的酸性微环境,从而提高羟基自由基的产生速率及产生量,最终显著改善该催化剂在近中性条件下的催化活性。

To widen the working pH range of Fenton-like catalyst,improve the degradation performance of organic pollutant and meanwhile tackle its recycling difficulty,Fe_(3)O_(4)/FeS_(2)immobilized coating on Ti mesh was synthesized by electrodeposition technique,which is simple and easy for large-scale synthesis.Phase composition,morphology and surface elemental valence of the as-prepared catalysts were characterized by XRD,SEM and XPS analysis.The results showed that phase composition of the sample was mainly comprised of Fe3O4 and FeS_(2).The microstructure was the porous structure formed by nanosheet interconnection.Fenton-like degradation of phenol by as-prepared catalysts revealed that Fe_(3)O_(4)/FeS_(2)on Ti mesh with 0.20 mol/L sulfur source can degrade 98%35 mg/L phenol with 6 mmol/L H_(2)O_(2)at 30℃within 60 min,thus exhibiting excellent Fention-like degradation of phenol performance.Further studies revealed that Fe_(3)O_(4)/FeS_(2)with larger specific surface area can enhance mass transfer and meanwhile provide plentiful active sites for phenol degradation.In addition,the sulfur species on sample surface can promote the redox cycle of Fe^(3+)/Fe^(2+).Moreover,the sulfate species can supply a suitable acidic environment for Fenton-like reaction,contributing to the increase of hydroxyl radical production rate and output.Finally,the catalytic activity of Fe_(3)O_(4)/FeS_(2)under near-neutral pH can be improved.