Department of Environmental Health Engineering, Research Center for Health, Safety and Environment (RCHSE), Alborz University of Medical Sciences, Karaj, Iran.
Isra University, Faculty of Engineering, Department of Civil Engineering, Amman, Jordan.
Chemosphere. 2017 May;175:8-20. doi: 10.1016/j.chemosphere.2017.02.043. Epub 2017 Feb 9.
The synthesized MgO nanoparticles were used to coat the light-weight expanded clay aggregates (LECA) and as a metronidazole (MNZ) adsorbent. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transformed infrared (FTIR) techniques were employed to study the surface morphology and characteristics of the adsorbents. MgO/LECA clearly revealed the advantages of the nanocomposite particles, showing high specific surface area (76.12 m/g), significant adsorption sites and functional groups. Between pH 5 and 9, the MNZ sorption was not significantly affected. Kinetic studies revealed that the MNZ adsorption closely followed the Avrami model, with no dominant process controlling the sorption rate. The study of the effects of foreign ions revealed that the addition of carbonate raised the MNZ removal efficiency of LECA by 8% and the total removal of MNZ by MgO/LECA. Furthermore, nitrate and hardness only marginally influenced the MNZ removal efficiency and their effects can be ranked in the order of carbonate>nitrate>hardness. The isotherm adsorption of MNZ was best fitted with the Langmuir model enlighten the monolayer MNZ adsorption on the homogeneous LECA and MgO/LECA surfaces. The maximum adsorption capacity under optimum conditions was enhanced from 56.31 to 84.55 mg/g for LECA and MgO/LECA, respectively. These findings demonstrated that the MgO/LECA nanocomposite showed potential as an efficient adsorbent for MNZ removal.
合成的氧化镁纳米颗粒被用于包覆轻质膨胀粘土骨料（LECA），并作为甲硝唑（MNZ）的吸附剂。X 射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和傅里叶变换红外（FTIR）技术被用于研究吸附剂的表面形态和特性。MgO/LECA 明显显示了纳米复合材料颗粒的优势，表现出高比表面积（76.12 m/g）、大量的吸附位和功能基团。在 pH 值为 5 到 9 之间，MNZ 的吸附没有受到显著影响。动力学研究表明，MNZ 的吸附紧密遵循 Avrami 模型，没有主导过程控制吸附速率。对外离子影响的研究表明，碳酸根的加入将 LECA 对 MNZ 的去除效率提高了 8%，MgO/LECA 对 MNZ 的总去除率也提高了 8%。此外，硝酸盐和硬度对 MNZ 的去除效率只有轻微影响，其影响顺序为碳酸根>硝酸盐>硬度。MNZ 的等温吸附最符合 Langmuir 模型，说明 MNZ 在均匀的 LECA 和 MgO/LECA 表面上以单层形式吸附。在最佳条件下，LECA 和 MgO/LECA 的最大吸附容量分别从 56.31 增加到 84.55 mg/g。这些发现表明，MgO/LECA 纳米复合材料作为 MNZ 去除的有效吸附剂具有潜力。
