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Adsorption of cadmium ions by cucumber peel in continuous mode
- Basu, M., Guha, A. K., Ray, L.
- International journal of environmental science and technology 2019 v.16 no.1 pp. 237-248
- adsorption, cadmium, cucumbers, glass, hydrochloric acid, ions, kinetics, models, pH, sorbents, wastewater
- The present work aims at employment of cucumber peel for adsorption of cadmium in packed-bed column reactor in an attempt to testify the efficiency of this sorbent for treating huge volume of wastewater needed for practical purpose. The study was performed with dried and powdered cucumber peel packed in a glass column reactor with influent metal solution being pumped in upflow mode using peristaltic pump at pH 5.0. Different design parameters of adsorption in continuous mode were evaluated, and experiments were performed at varied flow rates (15, 18 and 20 mL min⁻¹), bed heights (5.0, 6.5 and 8.0 cm) and influent concentrations (50 and 100 mg L⁻¹). Results illustrated delayed breakthrough, and higher percentage removal of cadmium were associated with lowest flow rate, highest bed height and lower influent concentration. Experimental outcome further revealed percentage removal of 78.03% at saturation with adsorption capacity of 107.76 mg g⁻¹ at 50 mg L⁻¹ influent concentration, 20 mL min⁻¹ flow rate and 8.0 cm bed height. Evaluation of experimental data with different kinetic models established pertinence of Thomas model and Yoon–Nelson model in defining adsorption pattern in continuous mode. Elution of adsorbed cadmium from packed bed was executed using 0.1 M HCl which efficiently recovered more than 94% of the loaded metal in three consecutive cycles. The work has conveniently established the prospect of cucumber peel as a cheap biological sorbent for treating large volume of cadmium contaminated water.