In the last years, dye wastewater pollution became a major problem due to its toxicity and environmental restrictions. Indigo carmine is an indigoid dye that is largely used, and it is known by its toxicity and stability. In this work, we synthesized a magnetite/reduced graphene oxide (Fe₃O₄/RGO) composite with approximately 90%wt of Fe₃O₄ and used in the indigo carmine dye photo-Fenton discoloration (accompanied by UV–Vis spectrometry analysis). By using scanning electron microscopy (SEM), X-ray diffractometry (XRD), Laser Raman Spectroscopy (LRS), Magnetization Curves (VSM), and X-ray photoelectron spectroscopy (XPS) analyses it was observed that Fe₃O₄ particles of ~ 21 nm were successfully anchored on reduced graphene sheets. Zeta potential showed that the Fe₃O₄/RGO composite has a less negative electrostatic behavior in ultrapure water (− 46.9 mV) than the bare RGO (− 77.7 mV), promoting the attraction of indigo carmine molecule. Magnetic studies proved the ferromagnetic character of the composite with a saturation magnetization of 43 emu/g, thus promoting the easy separation from the reaction medium. In the first 5 min of reaction with the composite, the solution was completely discolored. The composite was recovered, and its reuse also showed total discoloration in the first 30 min of reaction. After first indigo carmine discoloration cycle, XPS results showed that Fe³⁺/Fe²⁺ atomic ratio was maintained, which can explain the total discoloration in the second cycle.

近年来，由于其毒性和环境限制，染料废水污染成为一个主要问题。靛蓝胭脂红是一种广泛使用的靛类染料，以其毒性和稳定性而著称。在这项工作中，我们合成了具有约90％wt的Fe ₃ O ₄的磁铁矿/还原氧化石墨烯（Fe ₃ O ₄ / RGO）复合材料，并用于靛蓝胭脂红染料的光芬顿褪色（通过UV-Vis光谱分析） ）。通过使用扫描电子显微镜（SEM），X射线衍射（XRD），激光拉曼光谱（LRS），磁化曲线（VSM）和X射线光电子光谱（XPS）分析，观察到Fe ₃ O ₄〜21 nm的粒子成功地锚定在还原的石墨烯片上。Zeta电位表明，Fe ₃ O ₄ / RGO复合材料在超纯水中的负静电行为（− 46.9 mV）比裸露的RGO（− 77.7 mV）小，促进了靛蓝胭脂红分子的吸引。磁性研究证明了饱和磁化强度为43 emu / g的复合材料的铁磁特性，从而促进了与反应介质的轻松分离。与复合材料反应的前5分钟，溶液完全变色。回收了复合材料，并且其再利用在反应的前30分钟内也显示出完全变色。在第一个靛蓝胭脂红变色循环后，XPS结果显示Fe ³⁺ / Fe ²⁺ 保持了原子比，这可以解释第二个循环中的总变色。