Investigation on the Removal of Chromium (III) from Tannery Wastewater by Cement Kiln Dust

Abstract

Tannery effluent is characterized not only by heavy loads an organic sludge but also with toxic heavy metals especially chromium ions. Chromium is considered an important source of contamination due to large volume of exhaust liquid discharged. An effort has been made in the present study to evaluate the potential of Cement Kiln Dust (CKD) for the elimination of trivalent chromium from the tannery effluents wastewaters by adsorption technique. The effects of various pararneters such as adsorbent dosage, initial concentration of Cr(111), agitation rate, contact time and solution pH on the adsorption efficiency were studied during batch experiment at room temperature. The results indicate to that, the removal was effective at low Cr(111) concentrations and low pH value, and the optimum conditions for chromium tanning removal operation wastewater investigated were 60 minutes and 1200 rpm as a contact time and agitation rate respectively, and pH value equals to 0.5 at the temperature 25±2*C. And adsorbent dose 16 g/L was sufficient for the high removal of Cr(111) from wastewater for two both batches which is reach up to 95.11 and 93.72% respectively for both different batches that which is studied. The experimental data obtained during the study fitted well with the Langmuir and Freundlich isotherms. The maximum adsorption capacity of CKD was found to be 303 mg/g. The results obtained from this study show that, the CKD can be used as low cost adsorbent for completely removal of trivalent chromium from tanning wastewater.