The adsorption of Pb2+ by a compost obtained from the treatment of tobacco from smuggled cigarettes (SCT) and industrial sewage sludge (ISS) was investigated. The Pb2+ adsorption process was evaluated as function of different concentrations of adsorbent and adsorbate, pH variations, and contact time. Fourier transformed infrared spectroscopy (FTIR) and energy dispersive X-ray spectrometry (EDX) were adopted to obtain information regarding structural changes and a better understanding of the adsorption mechanism. The adsorbent maximum adsorption capacity for Pb2+, calculated using the Sips equation, was 21.454 mg/g with 3 g/L adsorbent at pH 5. The adsorption kinetics best adjustment was obtained using the pseudo-second-order model with a time of 240 min to reach the adsorption equilibrium. FTIR and EDX results suggest that Pb2+ might have bonded to phenolic, carboxylic, hydroxyl, and amine groups; they also show formation of organometallic complexes and cationic exchange between the compost and the solution. The study confirmed that the compost evaluated can be used as a potential adsorbent in environments contaminated with Pb2+.
Keywords: Adsorption; Compost; Isotherms; Pb2+ removal.