Department of Chemistry, Banasthali Vidyapith, Banasthali, Rajasthan 304022, India.
Department of Chemistry, Banasthali Vidyapith, Banasthali, Rajasthan 304022, India; School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030, India.
J Environ Sci (China). 2020 Aug;94:52-63. doi: 10.1016/j.jes.2020.03.047. Epub 2020 Apr 18.
Local fluoride contamination and bacterial infections in potable water have dangerous effects on the human body and are today a global concern. In this study, we have synthesized a pH-responsive bifunctional biopolymer nanocomposite (HAZ) of humic acid with incorporating aluminum zirconium bimetallic oxide by deep freeze-drying method. Fast nucleation and interconnection of nanoparticles form a highly porous network because of sublimation of frozen HAZ. This duo nanocomposite has efficiently worked for fluoride removal and showed potent antibacterial activity against the Escherichia coli Gram-negative and Staphylococcus aureus Gram-positive bacteria. The X-ray photoelectron spectroscopy (XPS) analysis demonstrates that the hydroxyl groups act as a pivot in the ion exchange process of adsorption, each element of bimetallic oxide primarily takes part in the adsorption mechanism. The maximum adsorption capacity of the adsorbent was 180.62 mg/g at pH seven. Thermodynamic parameters like Gibbs free energy change (ΔG), entropy (ΔS), and enthalpy (ΔH) indicate that the process was endothermic, feasible, and taken place by a chemisorption mechanism. This is the first novel freeze-dried bifunctional biopolymer nanocomposite composed of humic acid natural polymer incorporated with Al-Zr metal oxide, and it exhibited three times higher adsorption efficacy with excellent antibacterial action at a concentration of 5 µg/mL of the nanocomposite.
饮用水中本地氟污染和细菌感染对人体有危险影响，是当前全球关注的问题。在这项研究中，我们通过深冷冻干燥法合成了一种具有 pH 响应功能的双功能生物聚合物纳米复合材料（HAZ），其组分为腐殖酸与掺铝锆双金属氧化物。由于 HAZ 的升华，纳米颗粒的快速成核和相互连接形成了高度多孔的网络。这种双纳米复合材料有效地去除了氟，并对革兰氏阴性大肠杆菌和革兰氏阳性金黄色葡萄球菌表现出了强大的抗菌活性。X 射线光电子能谱（XPS）分析表明，羟基作为吸附过程中离子交换的支点，双金属氧化物的每个元素主要参与吸附机制。吸附剂的最大吸附容量在 pH 为 7 时为 180.62 mg/g。热力学参数，如吉布斯自由能变化（ΔG）、熵（ΔS）和焓（ΔH）表明，该过程是吸热的、可行的，并且通过化学吸附机制发生。这是第一个由腐殖酸天然聚合物与 Al-Zr 金属氧化物组成的新型冻干双功能生物聚合物纳米复合材料，在浓度为 5 μg/mL 的纳米复合材料下，其吸附效果提高了三倍，且具有优异的抗菌作用。
