Novel amidoamine functionalized multi-walled carbon nanotubes for removal of mercury(II) ions from wastewater: Combined experimental and density functional theoretical approach

Amidoamine functionalized multi-walled carbon nanotubes (MWCNT-AA) have been prepared and characterized. Separation of mercury(II) ions from aqueous solution by solid-liquid extraction has been investigated using the synthesized material as an adsorbent. Batch adsorption studies as a function of pH, contact time, initial metal ion concentration, and temperature have been carried out. The best fit for the adsorption equilibrium data was observed with Redlich-Peterson isotherm model and the kinetics data showed superior fitting for pseudo second order model, signifying chemisorption. The adsorbent showed superior selectivity with high adsorption capacity towards mercury as compared to other metal ions present in industrial waste water containing mercury. The MWCNT-AA was successfully used for six adsorption-desorption cycles without significant loss of uptake using 0.05 M EDTA as desorbing agent. A small scale fixed bed column study was demonstrated to test the scale up application. DFT theoretical calculations establish the bi-dentate mode of complexation and correlate the experimental selectivity. (c) 2016 Elsevier B.V. All rights reserved.[Graphys]