Facile mercury detection and removal from aqueous media involving ligand impregnated conjugate nanomaterials

Abstract

The conjugate nanomaterial (CNM) was prepared by sulfur donor containing organic ligand onto the silica substrate for simultaneous mercury (Hg(II)) ions detection and removal from water samples through a batch technique. The potential and feasibility of the CNM as Hg(II) ions selective materials were evaluated in terms sensitivity, selectivity both in the detection and removal operations. In detection, the absorbance spectra increment was linear with the Hg(II) ions concentration in low concentration area, and the detection limit of the CNM was 0.26μg/L. In addition, the colorimetric changes were extremely specific for Hg(II) ions, and no significant color change was evident in case of other competing metal ions in the sample matrix. In removal, the optimization of experimental conditions, including effect of pH, equilibrium time, initial Hg(II) ion concentration was examined. Due to the strong interaction between Hg(II) ions and sulfur atoms of the active surface, the CNM exhibited high adsorption capacity and excellent selectivity during Hg(II) adsorption. The experimental results showed that the solution pH had a major impact for Hg(II) adsorption by the CNM. The experimental data were well fitted with the linear form of Langmuir model the maximum adsorption capacity of Hg(II) ions was 164.22mg/g. The Hg(II) loaded CNM could be successfully desorbed with 0.20M HCl solution, and the adsorption capacities were not decreased sharply even after six cycles showing the practical significance in remediation of Hg(II) contaminated wastewater. In addition, the present approach has the advantages of sensitivity, selectivity, rapidity, simplicity, and low cost for Hg(II) detection and removal, and the newly developed assay might open a new assay avenue for Hg(II) ions contaminated water treatment.