Abstract

This study aimed to transform tobacco from illegal cigarettes into high-efficiency and low-cost adsorbents, and test them in the remediation of lead-contaminated water resources. Biochar and activated carbon were produced by thermal activation technique (originated material CT Biochar) and by thermal, chemical and physical activation techniques (originated material CT ZnCl2+ CO2). Firstly, the materials were characterized by chemical analysis (pHPZC, SEM, FT-IR, BET and BJH). After this, they were submitted to adsorption tests, and to studies aiming the reuse of the adsorbents. The tobacco adsorbents have a surface with tubular structure and spongy aspects, surface functional groups such as alkane, aldehyde, hydroxyl, carboxylic acid, carbonate, alcohol and ether. CT Biochar has a surface area of 83.60 m(2) g(-1) and CT ZnCl2 + CO2 of 46.97 m(2) g(-1). The optimal Pb2+ adsorption conditions are: solution at pH 5.0, adsorbent dose of 4 g L-1, and time to reach equilibrium of 45 min (CT Biochar) and 10 min (CT ZnCl2 + CO2). The best adjustments were found for pseudo-second order and Langmuir. It was observed that adsorption of Pb2+ occurs in monolayer, and it is predominantly chemical. Estimates regarding costs showed that the production of CT ZnCl2 + CO2 is 0.412 US$ Kg(-1), and for CT Biochar is 0.243 US$ Kg(-1). Finally, this study provides support for future studies using activated carbons and biochar in remediation of different contaminants, including the use of the adsorbents in larger scales of application, such as wastewater treatment plants.