Removal of Cd (II) and Pb (II) Ions from Aqueous Solutions Using Raw and Modified Activated Carbon

Abstract

: The main objective of this study is to investigate the feasibility of using raw and modified activated carbon with ammonia for the maximum removal of Pb 2+ and Cd 2+ ions from aqueous solutions and polluted water samples at optimized process parameters such as initial metal concentration, adsorbent dose, contact time and solution pH. The treatment of a commercial granular activated carbon by ammonia was performed to increase the power of the heavy metal ions removal from aqueous samples. In this work, the adsorption of these ions on raw and modified activated carbon was studied using the batch equilibrium technique, and the equilibrium adsorption data was described by Langmuir isotherm models. In the current work, Pb 2+ and Cd 2+ ions were adsorbed out of aqueous solutions using raw and modified activated carbon as an adsorbent. Investigations have been done into the effects of solution pH, contact time, initial metal ion concentrations, and adsorbent dosage on removal efficiency. The pH studies demonstrated that Pb 2+ and Cd 2+ ion removal efficiency is pH-dependent, increasing with increasing pH value, peaking at pH 6.5, and then remaining nearly constant. Due to an increase in the number of adsorption sites, an increase in adsorbent mass causes an increase in Pb 2+ and Cd 2+ adsorption. According to the data, activated carbon has removal efficiency (96.0 - 98.0%) for removing Pb 2+ and Cd 2+ ions from aqueous solutions in the initial metal concentration range of 10 to 50 mg/l. The experimental data suited the Langmuir and Freundlich adsorption isotherms well, and their constants were assessed. The effectiveness of Pb 2+ ions removal by adsorption (starting Pb 2+ concentration ranging from 1 - 10 mg/l) is shown by the treatment results of various polluted water samples to be between (81.5 - 86.7%), between (91 - 98%), utilizing raw Activated carbon (R-AC) and modified activated carbon with ammonia (A-AC), respectively. the results for cadmium ions reveal that the effectiveness of Cd 2+ ions removal by adsorption (starting Cd 2+ concentration ranging from 1 to 10 mg/l) is ranged from (74.3 to 83.7%), and from (97.6 to 98.4%) when the raw activated carbon (R-AC) and modified activated carbon with ammonia (A-AC) are used, respectively.