Determination of Chromium in Contaminated Water Samples Using Chemically Modified Nanoadsorbent: A Computational and Experimental Study

In the reported work, a solid phase extraction method for speciation of chromium species in contaminated industrial and river water samples has been studied by using both experimental and computational methods. Multiwalled carbon nanotubes (MWCNTs) functionalized with tris(2-aminoethyl)amine (TREN) was used as a solid phase extractant for the hyphenated preconcentration of chromium species. The characterization of the immobilized MWCNTs was done by FTIR and SEM analysis. This hyphenated system significantly improves the overall analytical performance by reducing sample consumption and sampling time. The computational results supported the experimental findings. The negative adsorption energy (-2.71 eV) suggested that the interaction process between chromium and modified nanoadsorbent is spontaneous. The system showed a limit of detection of 0.07 mu g L-1 at optimized condition with an RSD value of 1.2 %. Adsorption capacity was measured using Lagergren's equation which showed that adsorption kinetics follows pseudo second-order. The suggested method was applied to contaminated real water samples by performing spike recovery tests. The validation of the reported system was done by analysing NIST Standard Reference Material Trace Elements in Natural Water 1640a.