Background

Industrial and medical wastewater treatment has been the focus of significant research and development in recent years. Especially untreated antibiotics commonly found within the wastewater generated by the hospitals or/and manufacturers have caused serious environmental concerns.

Methods

In this work, we proposed a heterogeneous graphene quantum dot (GQD)/ZnO composite as a photocatalyst for degrading antibiotics by using co-precipitation and thermal carbonization processes.

Significant findings

The introduction of N-GQDs efficiently facilitates the photocatalytic activity and reaction rate. Indeed, the N-functionalized GQDs, including pyrrolic/pyridinic N and graphitic N, can accelerate the charge transfer rate in the heterostructures. Optimizing the composition of GQD/ZnO catalyst, ultra-high removal ratio (∼100%) and significantly improved rate constant (i.e., 1.74 times higher compared to pristine ZnO) was achieved. In the binary catalyst, the presence of N-GQDs enhances the absorption in visible-light region and increases the photo-induced charge carrier, resulting in an elevated photocatalytic activity. This finding reveals that the GQD/ZnO composite structure demonstrated in this work can be employed as an in-expensive photocatalyst for degrading metronidazole (MNZ) in liquid phase under the UV-light irradiation.

中文翻译：

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用于光催化降解甲硝唑的高性能 ZnO/石墨烯量子点复合材料的合成与表征

背景

近年来，工业和医疗废水处理一直是重大研究和开发的重点。特别是在医院或/和制造商产生的废水中常见的未经处理的抗生素引起了严重的环境问题。

方法

在这项工作中，我们提出了一种异质石墨烯量子点 (GQD)/ZnO 复合材料作为光催化剂，通过共沉淀和热碳化过程降解抗生素。

重要发现

N-GQDs 的引入有效地促进了光催化活性和反应速率。事实上，N 功能化的 GQD，包括吡咯/吡啶 N 和石墨 N，可以加快异质结构中的电荷转移速率。优化了 GQD/ZnO 催化剂的组成，实现了超高去除率（~100%）和显着提高的速率常数（即与原始 ZnO 相比高 1.74 倍）。在二元催化剂中，N-GQDs 的存在增强了在可见光区域的吸收并增加了光生电荷载流子，从而提高了光催化活性。这一发现表明，这项工作中展示的 GQD/ZnO 复合结构可用作廉价的光催化剂，用于在紫外光照射下降解液相中的甲硝唑 (MNZ)。