Review of Adsorption Studies for Contaminant Removal from Wastewater Using Molecular Simulation

Abstract

In recent years, simulation studies have emerged as valuable tools for understanding processes. In particular, molecular dynamic simulations hold great significance when it comes to the adsorption process. However, comprehensive studies on molecular simulations of adsorption processes using different adsorbents are scarcely available for wastewater treatment covering different contaminants and pollutants. Hence, in this review, we organized the available information on various aspects of the adsorption phenomenon that were realized using molecular simulations for a broad range of potentially effective adsorbents applied in the removal of contaminants from wastewater. This review was compiled for adsorbents under five major categories: (1) carbon-based, (2) oxides and hydroxides, (3) zeolites, (4) metal–organic frameworks and (5) clay. From the review, it was found that simulation studies help us understand various parameters such as binding energy, Gibbs free energy, electrostatic field, ultrasound waves and binding ability for adsorption. Moreover, from the review of recent simulation studies, the effect of ultrasound waves and the electrostatic field was elucidated, which promoted the adsorption capacity. This review can assist in the screening of classified adsorbents for wastewater treatment using a fast and cheap approach while helping us understand the adsorption process from an atomistic perspective.

Screening of Metal Oxides and Hydroxides for Arsenic Removal from Water Using Molecular Dynamics Simulations

“…The software used to carry out the molecular simulation investigation in the present work was BIOVIA Materials Studio (MS) version 8.0. 20 It was used to carry out an atomistic simulation where interactions were represented by empirical potential functions to integrate the standard equations of motion as positions of each atom were recorded. 20,41 The molecular simulation methodology of this study is described in two sections.…”

“…20 It was used to carry out an atomistic simulation where interactions were represented by empirical potential functions to integrate the standard equations of motion as positions of each atom were recorded. 20,41 The molecular simulation methodology of this study is described in two sections. The specifications of the MD simulation are listed in Table 1.…”

“…Several arsenic removal methods have been utilized, including coagulation, adsorption, ion exchange, and membrane separation. , Adsorption is thought to be the most appropriate and effective approach for removing toxins from water and wastewater due to its high effectiveness and low cost. , In this context, adsorption processes do not contribute to unwanted byproducts and have been found to be superior to other wastewater treatment methods in terms of ease of design and operation. Adsorbents of several kinds, such as zeolites, oxides, hydroxides, carbon-based materials, metal–organic frameworks, and clay, have been developed for the adsorption process . Each adsorbent tends to remove pollutants from water and wastewater and has potential advantages.…”

“…These advantages of adsorption have encouraged many researchers to employ it to remove arsenic from drinking water. , In addition, adsorption is considered more adaptable than ion exchange, easier to run and safer to handle than the contaminated sludge produced by coagulation/precipitation, and cheaper than membrane separation . Metal oxides/hydroxides, zeolites, and other adsorbents are commonly used in adsorption . Among these adsorbents, metal oxides and hydroxides can eliminate arsenic more effectively, since surface functional groups, typical oxygen-containing groups, assist in its removal .…”

“…The MD simulation allows for the microscopical study of the adsorption process within a sufficient time frame, budget, and space. Molecular modeling is currently regarded as a successful research method for elucidating the adsorption process. , MD simulations can produce effective techniques to simulate structures and elucidate the adsorption phenomenon at a molecular level by applying appropriate computational computations. , Moreover, recently, molecular simulations have evolved as a prominent technology for the screening of materials in industrial applications. It has been performed to circumvent the limitations of experimental apparatus and materials .…”