Experimental and DFT study of Cu(II) removed by Na-montmorillonite

Abstract

The experimental and theoretical studies on the adsorption of Cu(II) on the surface of Na-montmorillonite (Na-Mt) were reported. Effects of batch adsorption experimental parameters were studied. Density functional theory (DFT) and molecular dynamics (MD) simulations were used to study the adsorption of Cu(II) on montmorillonite(001) surface. The adsorption reached equilibrium within 80 min and the adsorption capacity was 35.230 mg · g–1 at 25 °C. The adsorption data of Cu(II) were consistent with pseudo-second-order kinetic and Langmuir isotherm models. The activation energy (Ea) was 37.08 kJ · mol–1, which implied the nature of physical adsorption. The thermodynamic experiment illustrated that the adsorption was a spontaneous endothermic behavior. The influence of coexisting cations on the adsorption capacity of Cu(II) was Mg(II) > Co(II) > Ca(II) > Na(I). The simulation results demonstrated that there were no significant differences in the adsorption energy of Cu(II) at the four adsorption sites on the montmorillonite(001) surface. Cu(II) had more electron transfer than Na(I). The diffusion coefficient of Cu(II) in the aqueous solution system containing montmorillonite was 0.850 × 10–10 m2 · s–1. A considerable amount of Cu(II) ions were adsorbed at a distance of 0.257 and 2.25 Å from the montmorillonite(001) surface. The simulation results provided strong supporting evidence for experimental conclusions.

A Unique Modified Eggshell Method as a Model to Reduce and Remove Copper(II) from Aqueous Solutions for Water Treatment

“…Here, two main factors have been examined pH, and contact time at a specific temperature with five different concentrations from 100-500 ppm. While pH was determined between [2][3][4][5][6][7][8][9][10] .…”

“…4 The presence of copper in water resources and the environment due to industrial activities such as copper and gold mining, electronic factories, and wire electric factories 5 . The concentration levels of copper in drinking water due to WHO should not exceed 0.2 ppm, while high concentration than 6 ppm can cause serious illnesses like vomiting, abdominal cramps, skin irritation, nausea and anemia, while excess Cu(II) can accumulate in the kidneys, liver, brain and other human organs it causes health problems 6,7 .…”