Modeling of cobalt and lead adsorption by Ficus benghalenesis L. in a fixed bed column

Heavy metals presence in waste water is detrimental to human and animal health. Treatment of such contaminated waters emanating from various process industries is needed to make the reuse of water possible. Adsorption is a useful technique available for treatment of such waste waters. Several studies with different adsorbents have been reported in the literature but their relevance is limited to small quantities of waste waters as those studies were conducted in batch mode. Continuous contacting is the only viable option to augment the treatment capacity and this calls for further study to understand the impact of relevant parameters on continuous adsorption. In the present article, treatment of cobalt and lead laden waste water with Ficus benghalenesis leaf powder as the adsorbent is studied in a laboratory scale fixed bed column. Effect of operating parameters such as inlet flow rate (1-2 mL/min), bed height (2-4 cm), and feed metal ion concentration (20-100 mg/L) on the breakthrough curve is reported. The highest uptake capacities realized are 11.09 mg/g for cobalt and 12.27 mg/g for lead, when a 20-mg/L metal solution is admitted at 1.0 mL/min in to a 2-cm long bed of the adsorbent. Experimental data collected are tested to three empirical models: Thomas, Adams-Bohart, and Yoon-Nelson models and parametric values of the three models evaluated. Experimental results confirmed the suitability of the sorbent for Co(II) and Pb(II) ion adsorption with adsorptive nature being favorable, efficient, and environment friendly.