Survey of Chromium (VI) Removal By Using Oxidized Multi and Single Walled Carbon Nano Tubes from Aqueous Solution

The heavy metals are the most important pollutant that their concentration in environment is increasing with cities and industrials developing. One of this metals is chromium that in the trivalent and hexavalent oxidation state used in industries such as electroplating, glass, ceramic, tannery and leather. Hexavalent chromium has proven several health hazards such as a carcinogenicity. The aim of this study was survey the efficacy of oxidized multi walled and single walled carbon nano tubes in removal of hexavalent chromium from aqueous solution.This study was experimental which investigated the effect of initial chromium concentration,pH, adsorbent dose and reaction time on removal of chromium by oxidized multi and single walled carbon nano tubes. Oxidized carbon nano tubes were purchased from Research Institute of Petroleum Industry (R.I.P.I). The study performed on the synthetic samples contain 0.5,1 and 2 mg/l concentration of chromium(VI). The unknown concentration of hexavalent chromium detected by atomic absorption spectrophotometry. According to the results, adsorption capacities (qe) increased with increasing of initial Cr(VI) concentrations and reaction time and decreased with increasing adsorbent dose and increasing of pH. Maximum adsorption capacities of Hexavalent chromium by OSWCNTs and OMWCNT at 120 minutes, pH=3, initial Hexavalent chromium concentration 2mg/l and adsorbent dose 0.4g/l were obtained 3.94 and 3.74 mg/g respectively. Oxidized single walled Carbon Nano tubes(SWCNTs) is more efficient than oxidized multi walled carbon nano tubes (MWCNTs) in removal of hexavalent chromium from aqueous solutions