Central Laboratory for Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), El Qanater El Khayria, Egypt.
Int J Nanomedicine. 2020 Sep 28;15:7117-7141. doi: 10.2147/IJN.S265739. eCollection 2020.
Metronidazole (MNZ) is an antibiotic form that is considered as a dangerous environmental pollutant due to its widespread use as growth promoters in livestock and aquaculture operations along with its therapeutic application for humans.
The objective of this work was to conduct a comparative study between the efficiency of the adsorption and photocatalytic degradation of MNZ in an aqueous solution by using magnesium oxide nanoparticles (MgO NP) under different effects, as well as evaluate the performance, reusability and cost study.
Several instruments such as XRD, EDX, SEM, and TEM were used to characterize the chemical composition and morphological properties of the synthesized MgO NP, while the GC-MS analysis was used to monitor the degradation pathway of MNZ particles within 180 min. The simple photo-batch reactor was used to investigate the degradation of MNZ under the effect of UV radiation, initial concentration of MNZ, pH, catalyst loading, inorganic salts addition, time, and temperature.
The degradation efficiency is mainly divided into two steps: 35.7% for maximum adsorption and 57.5% for photodegradation. Adsorption isotherm models confirmed that the process nature is chemisorption and appropriate Langmuir model, as well as to be a nonspontaneous and endothermic reaction according to the thermodynamic study. Adsorption constant during dark condition is smaller than typical adsorption equilibrium constant derived from the Langmuir-Hinshelwood kinetic model through photodegradation of MNZ that follows pseudo-first-order kinetics. Toxicity rates were reduced considerably after the photodegradation process to 88.21%, 79.84%, and 67.32% and 57.45%, 51.98%, and 43.87% by heamolytic and brine shrimp assays, respectively, for initial MNZ concentrations (20, 60, and 100 mg/L).
We significantly recommend using MgO NP as a promising catalyst in the photodegradation applications for other organic pollutants in visible light.
甲硝唑（MNZ）是一种抗生素形式，由于其在畜牧业和水产养殖中的广泛用作生长促进剂以及在人类中的治疗应用，被认为是一种危险的环境污染物。
本工作的目的是在不同影响下，通过使用氧化镁纳米粒子（MgO NP）比较研究在水溶液中 MNZ 的吸附和光催化降解的效率，并评估其性能、可重复使用性和成本研究。
使用 XRD、EDX、SEM 和 TEM 等多种仪器对合成的 MgO NP 的化学组成和形态特性进行了表征，而 GC-MS 分析则用于监测 180 分钟内 MNZ 颗粒的降解途径。简单的光批式反应器用于研究在 UV 辐射、MNZ 的初始浓度、pH 值、催化剂负载、无机盐添加、时间和温度的影响下 MNZ 的降解。
降解效率主要分为两个步骤：最大吸附率为 35.7%，光降解率为 57.5%。吸附等温线模型证实，该过程的性质为化学吸附，适宜的 Langmuir 模型，以及根据热力学研究，是一个非自发和吸热反应。在黑暗条件下的吸附常数小于从 MNZ 光降解的 Langmuir-Hinshelwood 动力学模型推导出来的典型吸附平衡常数，该模型遵循准一级动力学。光降解后，毒性率大大降低，对于初始 MNZ 浓度（20、60 和 100mg/L），溶血和盐水虾试验的毒性率分别降低到 88.21%、79.84%和 67.32%和 57.45%、51.98%和 43.87%。
我们强烈推荐使用 MgO NP 作为一种有前途的催化剂，用于可见光下其他有机污染物的光降解应用。
