Quantum Chemistry Investigation of Adsorption Phenomena and Chemical Reactions of Importance in Environmental Engineering

Abstract

Chemical phenomena that occur in environmental engineering processes usually need to be addressed from different perspectives. The present document contains computational chemistry simulations to describe several reactions. Density Functional Theory calculations explore the adsorption kinetics of nitrilotris(methylenephosphonic acid) (NTMP) with ferric hydroxide minerals and the different chemical products of the reactions. The adsorption and desorption reactions with ferric hydroxide are important because NTMP ends up in the environment and interacts with soil and aquifer minerals, and it also can be recovered using ferric hydroxide adsorbents. Quantum chemistry calculations for catalyzed and uncatalyzed water dissociation rates as a function of electric field are explored. It has been difficult to measure the electric field-enhanced water splitting because it has not been possible to accurately describe the bipolar membrane’s interface. Furthermore, the catalytic activity of different oxygenated functional groups sites of graphene oxide is described as a function of the pKa and the electric field intensity. Graphene oxide has been proposed as water splitting catalyst. Finally, several degradation pathways are presented for guanidinium-based polymers and quaternary amine-based anion exchange. Polymers such as poly(sulfone) are commonly used in exchange membranes, and newly developed poly(phenyl) polymers have been proposed as alkaline stable membrane backbones. The guanidinium cation is assumed to be more stable than commonly used trimethylammonium due to its resonant structure.