Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Chemosphere. 2018 Dec;212:533-539. doi: 10.1016/j.chemosphere.2018.08.107. Epub 2018 Aug 22.
Antibiotics as the severe contaminants of aqueous environments were received growing attention during the last decades. The current work is the first report on investigating the potency and efficiency of electrocoagulation process in the successful removal of metronidazole (MNZ) from pharmaceutical wastewater using response surface methodology based on central composite design. The applied method by optimizing the independent and combined effects of significant variables which affecting the EC process enhanced the removal efficiency of MNZ. Analysis of variance was applied to verify the significance of independent variables solely and their interactions. The best removal efficiency of 100% found under the optimal operating condition of initial MNZ concentration 21.6 mg L, pH 8.2, current density 6.0 mA cm, inter-electrode distance 3 cm, and reaction time of 14.6 min. Isotherm investigations revealed that the Langmuir model with the R of 0.994 best fitted to the obtained experimental equilibrium results. The fast adsorption of MNZ on the surface of Fe(OH) and [Fe(OH)] with the equilibrium time of 15 min confirmed that the kinetics of the electrocoagulation process follow the pseudo-second-order model (R = 0.962). The electrocoagulation process under the optimal operating condition revealed that the electrical energy consumption per each m of treated pharmaceutical wastewater, per each g of MNZ, removed, and per each kg of Fe electrode consumed, were found to be 0.516 kWh m, 0.0234 kWh g, and 0.0436 kWh kg, respectively.
抗生素作为水环境污染的严重污染物，在过去几十年中受到了越来越多的关注。本工作首次报道了采用基于中心复合设计的响应面法研究电凝聚工艺去除药物废水中甲硝唑（MNZ）的效能和效率。通过优化影响 EC 过程的显著变量的独立和联合效应的应用方法，提高了 MNZ 的去除效率。方差分析用于验证独立变量及其相互作用的显著性。在最佳操作条件下，初始 MNZ 浓度为 21.6mg/L、pH 值为 8.2、电流密度为 6.0mA/cm、电极间距为 3cm、反应时间为 14.6min 时，可获得 100%的最佳去除效率。等温线研究表明，与获得的实验平衡结果拟合最好的是朗缪尔模型（R 为 0.994）。MNZ 在 Fe(OH)和[Fe(OH)]表面的快速吸附，平衡时间为 15min，证实了电凝聚过程的动力学符合准二级模型（R=0.962）。在最佳操作条件下进行的电凝聚过程表明，处理每立方米药物废水、每克 MNZ 和每消耗千克 Fe 电极的电能分别为 0.516kWh/m、0.0234kWh/g 和 0.0436kWh/kg。
