Preparation and Characterization of Carbon Supported Nano-Nickel and its Sorption Behavior for Zinc from Aqueous Solutions

Abstract

Nickel deposited on carbon has been used as adsorbent to recover Zn (II) from aqueous system. The adsorbent was synthesized by depositing nickel nitrate on carbon under inert conditions and decomposing it to nickel by raising the temperature, washing and vacuum drying. Various techniques including XRD, FTIR, and SEM were employed for its characterization. FTIR showed that the nickel deposition enhanced the carbon functionalization due to presence of OH, C=O and C-O groups.Average crystallite size ofabout 9 nm was determined from XRD. Nickel deposition resulted in further division particles as indicated from the morphological study. Zn (II) was subjected to adsorptionon the synthesized adsorbent. It was observed that the rate of adsorption increased significantly on the nickel deposited carbon than the carbon alone. Morris-Weber, Lagergren and Reichenberg models were applied to find out the type and rate of adsorption employingfirst and second order rate equations.The adsorption data were applied toLangmuir, Freundlich and D-R isotherms and values of isotherm constants were calculated and were higher for Ni/C than carbon alone. The mean free energy of zinc sorption on carbon and Ni/C are 16.67 and 18.26 kJmol-1 which shows chemisorption. Thermodynamic studies were done to find out the effect of temperature on sorption. Positive values of ΔH and negative values of ΔG show endothermic and spontaneous type of sorption.

Nickel Coated Carbon Nanomaterial for the Removal of Heavy and Toxic Metals (Cd, Cu) from Water and Wastewater

“…From the XRD of nano nickel coated carbon ( Fig. 1) the crystallite size of the deposited nickel was determined as about 9 nm [7]. Various spectral changes have been observed for the nano nickel coated carbon; these being appearance of a broadband (free and hydrogen bonded OH groups) between 2900 and 3600 cm -1 , peaks around 1610 cm -1 (C=O group) and from 1180 to 1350 cm -1 (C-O of carboxylic group) respectively.…”

“…Creation of hydroxyl group peaks after the deposition of nickel creates functional groups which can attach more toxic metals thereby increasing adsorption. SEM micrographs have shown morphological changes (breaking down) undergone by the carbon due to chemical and heat treatment during nickel deposition [7]. Influence of pH.…”

“…Since the advancement of nanotechnology has taken over almost all the fields of science and engineering, therefore carbon based adsorbents in combination with nano technology have also gained importance. Nano nickel coated carbon has been prepared by our previously reported method and characterized by using Xray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), inductively coupled plasma-Atomic emission spectroscopy (ICP-AES) and scanning electron microscopy (SEM) [7]. This research has specially been designed to work out the possibility of using such an adsorbent which could not only adsorb copper and cadmium from the aquatic environment but also will not be deteriorated under rigorous conditions of pH and acid content.…”

“…12) furnish straight lines for both the sorbents; K c being the equilibrium constant and given as K c =F/(1-F) with F representing fraction of the sorbed ions. Increase of sorption with temperature may be attributed to acceleration of the steps including creation of more active sites and enhanced diffusion of the sorbate species [7]. The change in enthalpy ΔH for Cd(II) is 40.74±1.34 and for Cu(II) is 34.04±0.85 kJ .…”