Yimam, Abubeker (PhD)Tesfaye, Debela2018-07-272023-11-102018-07-272023-11-102016-07http://etd.aau.edu.et/handle/12345678/10210Industrial development has caused the release of various pollutants including heavy metals into the environment. These toxic compounds are extremely dangerous to living beings and the environment due to their non-biodegradability, severe toxicity, carcinogenicity, the ability to be accumulated in nature and the ability to contaminate groundwater and surface water. The aim of the present research was to provide an appropriate and cost-effective adsorbent to remove one of these heavy metals namely lead from waste water. The activated carbon was produced from the dried corn cob. Batch experiments were performed on synthetic samples at room temperature. The effect of pH, adsorbent dose, initial concentration, and contact time were studied, and the adsorption isotherms of heavy metals were determined. The optimum conditions for corn cobs activated carbon preparation were determined as impregnation ratio of 1.5, carbonization temperature of 450oC, activation time of 120min, and acid concentration 60% by weigh. The result of the characterization showed that the corn cob activated carbon has good properties as compared with other reference activated carbons. The maximum removal efficiency of heavy Pb2+ions by activated carbon adsorbent prepared from corn cobs was obtained optimum pH 5, optimum adsorbent dose of 3g, and the optimum contact time of 120 min; in these optimum conditions the removal efficiency was 96.8%. Greater adsorption amount of 10.7mg/g occurs at smaller adsorbent dose of 1g. The results were also confirmed that the adsorption process follows Langmuir isotherm model with a better sorption fit and supported for the monolayer adsorption of Pb+2ions on corn cobs activated carbon. The kinetic model of this study shows a pseudo-second order kinetic model with good correlation coefficient. Based on the results obtained, the activated carbon produced from corn cob has a good capability in removal of the lead ions from the aqueous solutions. Key words: corn cobs activated carbon; adsorption of lead (Pb2+); optimal conditions.enCorn cobs activated carbonAdsorption of lead (Pb2+); optimal conditionsThesis