Tecnológico Nacional de México/Instituto Tecnológico de Toluca, Av. Tecnológico s/n, Colonia Agrícola Bellavista, 52149 Metepec, Estado de México, Mexico.
Facultad de Geografía, Universidad Autónoma del Estado de México, Cerro de Coatepec s/n, Ciudad Universitaria, 50110.Toluca, Estado de México, Mexico.
Biomolecules. 2020 Jan 18;10(1):156. doi: 10.3390/biom10010156.
The fluoride content in groundwater varies depending on geological configuration. Fluoride problems tend to occur in places where these minerals are most abundant in rocks. The objective of the present work was to synthesize four biopolymers based on chitosan-polyvinyl alcohol (Ch-PVA) cross-linked with sodium tripolyphosphate pentabasic (TPP) and ethylene glycol diglycidyl ether (EGDE) and determine their ability to remove fluoride from water. The characterization of the Ch-PVA beads was performed by way of Scanning Electron Microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The percentage of humidity and the point of zero charge were determined. The Ch-PVA beads showed a surface area of 63.87 m g, a pore size of 7.6 nm, a point of zero charge of 7.4, and 98.6% humidity. The kinetic adsorption study was adjusted to the pseudo-second-order model and the adsorption equilibrium data were adjusted to the Freundlich adsorption isotherm, showing a maximum fluoride adsorption capacity of 12.64 mg.g at pH 7 and 30 °C, for the beads of Ch-PVA-NaOH-TPP. According to the thermodynamic parameters: -∆G, +∆H and -∆S, fluoride adsorption is spontaneous, endothermic in nature and there is no random energy change in the solid/liquid interface during the adsorption process.
地下水中的氟含量取决于地质构造。氟问题往往发生在这些矿物质在岩石中最丰富的地方。本工作的目的是合成四种基于壳聚糖-聚乙烯醇（Ch-PVA）的生物聚合物，其与三聚磷酸钠五钠（TPP）和乙二醇二缩水甘油醚（EGDE）交联，并确定它们从水中去除氟化物的能力。Ch-PVA 珠的表征是通过扫描电子显微镜（SEM）和傅里叶变换红外光谱（FTIR）进行的。测定了湿度百分率和零电荷点。Ch-PVA 珠的比表面积为 63.87 m²/g，孔径为 7.6nm，零电荷点为 7.4，湿度为 98.6%。吸附动力学研究调整为拟二级模型，吸附平衡数据调整为 Freundlich 吸附等温线，在 pH7 和 30°C 下，NaOH-TPP 交联的 Ch-PVA 珠对氟的最大吸附容量为 12.64mg/g。根据热力学参数：-∆G、+∆H 和-∆S，氟吸附是自发的，本质上是吸热的，并且在吸附过程中固体/液体界面没有随机能量变化。
