Evaluación de la adsorción de especies de arsénico en medio acuoso usando nanopartículas de magnetita, mediante simulaciones AB-Initio en el marco DFT orientada a la creación de filtros de agua.

Abstract

The objective of this study is to evaluate the adsorption of arsenic species in aqueous medium using magnetite nanoparticles (NPs), through ab-initio simulations within the framework of functional density theory (DFT) oriented to the creation of water filters. The VASP software was used to generate numerical simulations of a magnetite nanoparticle following three steps. The first allows determining the exchange functionalities in DFT and the dimensions of the cells to generate reliable simulations. Three environments are proposed whose energetic difference (adsorption energy) determines the adsorption of As atoms. The second stage corresponds to optimizing the adsorption of arsenic in magnetite. The dynamics dictates that there will be an adsorption energy minimization point that would represent the maximum adsorption capacity. A fit based on Taylor polynomials provides the maximum adsorption value of As through optimization processes using one-variable calculation. Finally, the third phase made it possible to determine the optimal cross-sectional area of said filter, as well as its width from a differential approach. As a case study, the Rasayacu, Toacaso –Ecuador flow was considered. The PBE functional and a 24.08361A magnetite cell were used without magnetization. As a result, in aqueous medium, magnetite has the ability to adsorb 5 atoms of As species. A filter (cellulose -magnetite NPs) of cylindrical geometry of area 216,423 mm^2 was proposed; and 2 differential equations that measure the infinitesimal adsorption of a given cross-sectional area (dAd(x))/dx=-µ and (dAd(x))/dx=-µAd(x). The solution to these equations describes the adsorption of As by an infinitesimal crosssectional area of the filter as a function of its width (x) with 1.08Gr and 1.513Gr (Gr cellulose towel thickness) respectively for each solution. It is recommended to perform experimental measurements to verify the data presented in this work.