Removal of Copper (II) from Wastewater Using Modified Carbon Nanotubes

Abstract

In the present work, carbon nanotubes were prepared by Chemical VaporDeposition (CVD) method, acetylene gas was used as a carbon source. In CVDsystem, a catalytic growth of CNTs is carried out by decomposition of acetylene(C2H2 ) at a temperature of 750 0C for one hour ,argon is used as an oxidationprotection gas. The carbon nanotubes produced are purified to remove impuritiessuch as metal catalyst and then functionalized by treating with HNO3. ScanningElectron Microscopy (SEM), FT-IR spectra and BET for Surface Area measurementtechnique were used for characterization of CNTs. CNTs with about 30 nm indiameter and with length of several microns were obtained. The effects of initialconcentration of metal (ppm), pH, carbon nanotube (CNT) dosage (mg) and contacttime (min) on the adsorption of Cu+2 ion were studied.The results show that the pH of aqueous solution is one of the major parametersthat control the adsorption of ion at the solid-water interfaces. Maximum removalpercentage of Cu+2 species is achieved at pH 8, CNT dosage of 50 mg/L and initialconcentration of 50 mg/L and it is 98.39%. The constants of Langmuir andFreundlich models are obtained from fitting the adsorption equilibrium data. Thecorrelation coefficients of Langmuir and Freundlich models are 0.75 and 1,respectively, indicating that the Freundlich model is more appropriate to describe theadsorption characteristics of Cu+2 onto CNTs.