Molecular electron density and nitrate-phosphate sorption efficiency of zeolite-A: Physico-chemical and DFT analyses

Abstract

Design of nitrate and phosphate carrying molecular scaffolds is significant in various sectors of applied interest. Motivated towards this interesting field, herein a combined experimental-DFT study of zeolite-A is reported. The sorption efficiency of this complex framework towards nitrate and phosphate ion has been analyzed. The implications of surface modification, change in pH and temperature upon the property of ion adsorption/absorption have been discussed. An increasing trend in sorption is observed up to pH~7 and up to temperature ~ 40 °C. In addition to experimental measures theoretical calculations have also been added to discuss the optimal frame work of the zeolite using Stuttgart-Dresden basis set and WB97XD as functional. Molecular simulations involving spectroscopic and electrostatic potential determination have been computed after optimization. A combined experimental and theoretical thermodynamic study has also been the active part of the study. From the study it may be established that the experimental results are in good agreement with the DFT based speculations.