Department of Applied Chemistry, Faculty of Science, University of Maragheh, Maragheh, Iran.
Department of Applied Chemistry, Faculty of Science, University of Maragheh, Maragheh, Iran.
Ecotoxicol Environ Saf. 2018 Jul 15;155:1-8. doi: 10.1016/j.ecoenv.2018.02.043. Epub 2018 Feb 24.
The aim of this work was to design a low cost adsorbent for efficient and selective removal of glyphosate from water at neutral pH conditions. For this purpose, zeolite 4A, a locally abundant and cheap mineral material, was ion-exchanged with Cu to produce Cu-zeolite 4A. The FTIR results revealed that the modification has no important effect on chemical structure of zeolite 4A. After modification, highly crystalline zeolite 4A was converted to amorphous Cu-zeolite 4A according to XRD studies. The SEM images showed spherical-like particles with porous surfaces for Cu-zeolite 4A compared to cubic particles with smooth surfaces for zeolite 4A. Adsorption equilibrium data were well fitted with non-linear forms of Langmuir, Freundlich and Temkin isotherms. The maximum adsorption capacity for Cu-zeolite 4A was calculated to be 112.7 mg g based on the Langmuir model. The adsorption of glyphosate by the modified adsorbent had fast kinetics fitted both pseudo-first-order and pseudo-second-order models. A mechanism based on chemical adsorption was proposed for the removal process. The modified adsorbent had a good selectivity to glyphosate over natural waters common cations and anions. It also showed desired regeneration ability as an important feature for practical uses. The potential use of the developed material as antibacterial agent for water disinfection filters was also investigated by MIC method. Relatively strong antibacterial activity was observed for Cu-zeolite 4A against Gram-positive and Gram-negative model bacteria while zeolite 4A had no antibacterial properties. No release of Cu to aqueous solutions was detected as unique feature of the developed material.
本工作旨在设计一种低成本吸附剂，以在中性 pH 条件下从水中高效、选择性地去除草甘膦。为此，沸石 4A，一种本地丰富且廉价的矿物材料，与 Cu 进行离子交换以制备 Cu-沸石 4A。FTIR 结果表明，修饰对沸石 4A 的化学结构没有重要影响。修饰后，XRD 研究表明，高结晶度的沸石 4A 转化为无定形的 Cu-沸石 4A。SEM 图像显示，与沸石 4A 具有光滑表面的立方颗粒相比，Cu-沸石 4A 具有多孔表面的球形颗粒。吸附平衡数据与 Langmuir、Freundlich 和 Temkin 等温线的非线性形式拟合良好。根据 Langmuir 模型，Cu-沸石 4A 的最大吸附容量计算为 112.7mg/g。吸附动力学符合准一级和准二级模型，表明草甘膦的吸附具有快速动力学。提出了一种基于化学吸附的去除机制。改性吸附剂对天然水中常见阳离子和阴离子对草甘膦具有良好的选择性。它还表现出良好的再生能力，这是实际应用的一个重要特征。还通过 MIC 方法研究了开发材料作为水消毒过滤器的抗菌剂的潜在用途。与沸石 4A 相比，Cu-沸石 4A 对革兰氏阳性和革兰氏阴性模型细菌表现出相对较强的抗菌活性，而沸石 4A 没有抗菌性能。作为开发材料的独特特征，未检测到 Cu 向水溶液中的释放。
