Abstract

This research aimed to transform tobacco originating from smuggled cigarettes into activated carbons, and their application in the remediation of contaminated water by cadmium and lead. For this, a triple activation was performed (thermal – chemical H3PO4 – physical CO2), resulting in the studied activated carbon (CT H3PO4 + CO2). The carbon was characterized by its chemical composition, pHPZC, SEM, FT-IR, BET, and BJH. The influence of the pH of Cd2+ and Pb2+ solutions, and the influence of the adsorbent dose were studied. Isotherms were constructed by linear and nonlinear models of Langmuir, Freundlich, Sips, Dubinin-Radushkevich, and Temkin. CT H3PO4 + CO2 activated carbon has on its surface carbonates, hydroxyls, carboxylic, and carbonic acids. The triple activation caused changes on pHPZC (from 5.40 to 9.59). The SEM reveal a carbon surface full of irregular and heterogeneous structures, spongy aspect, with an estimated SSA increase of 395x and pore volume of 37x. The produced activated carbon has applicability over a wide pH range (3.00–7.00), with an ideal dose of the activated carbon estimated at 4 g L−1 for greater efficiency in removing Cd2+ and Pb2+. The linear and nonlinear models reveal that metal adsorption is predominantly physical and multi-layered, with a possible reuse in new sorption cycles.

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