Mercury adsorption on functionalized carbon nanotubes
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Date
2016
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Abstract
Heavy metal contaminations possess serious threat to life and livelihood of people around the globe. Studies aimed to employ carbon based nanomaterials to decontaminate water from heavy metal ions of mercury. For this thiol functionalized carbon nanotubes (CNTs) were synthesized by first oxidizing the tubes and then reacting them further with thionyl chloride in a sequence. Then the successful functionalization of the CNTs was confirmed using Fourier Transform Infra-red (FT-IR) spectroscopy, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Effect of different parameters like adsorbent dosage, contact time, pH and temperature on different adsorbents capacity to remove Hg(II) ions from solution was studied and a comparative data was collected. The thiol functionalized CNTs showed better adsorptions for Hg(II) ions as compared to carboxylic functionalized CNTs. Values of ∆Ho and ∆So were also calculated and found to be positive, indicates that adsorption of mercury ions on CNTs surface was an endothermic process. Then the maximum adsorption capacity was investigated for all the adsorbents using equilibrium isotherms, such as Langmuir and freundlich, the maximum adsorption capacity of SWCNTs-SH for Hg (II) ion removal was achieved at 111.12 mg/g and for MWCNT-SH it was 83.34 mg/g by fitting with Langmuir isotherm model.
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Physics, carbon nanotubes, Mathematics, Thermodynamic parameters, Mercury adsorption, Adsorption isotherms