Effective Cd 2+ removal from water using novel micro-mesoporous activated carbons obtained from tobacco: CCD approach, optimization, kinetic, and isotherm studies

• Published in: Journal of environmental health science and engineering Vol. 19; no. 2; p. 1851
• Main Authors: Manfrin, Jéssica, Gonçalves Junior, Affonso Celso, Schwantes, Daniel, Zimmermann, Juliano, Conradi Junior, Elio
• Format: Journal Article
• Language: English
• Published: England 01.12.2021
• Subjects: Alternative adsorbents; Cadmium removal; CCD approach; Cigarettes; Nicotiana tabacum; Advanced water treatment
• ISSN: 2052-336X; 2052-336X

This research aimed to develop activated carbons from tobacco by double (thermal-physical) and triple activations (thermal-chemical-physical) for high-efficiency removal of Cd . The adsorbents were characterized by their chemical composition, point of zero charge (pH ), SEM, FT-IR, BET, and BJH. The subsequent adsorption studies were conducted: optimal conditions (CCD on adsorbent dose pH of Cd solution), kinetics, equilibrium, thermodynamics, and desorption studies. The activated carbons have irregular and heterogeneous morphology, surface functional groups COO-, C-O, C-O-C, C=O and O-H, pH of 11.11 and 10.86, and enhanced SSA (especially for CT NaOH + CO  = 103.40 g m ). The optimal conditions for Cd adsorption occur using 4.0 g L , pH from 3.0 to 7.0, with most of the Cd adsorbed in the first 10-20 min. The goodness of the fit found for pseudo-first order, pseudo-second order, intraparticle diffusion, Langmuir, Freundlich, Dubinin-Radushkevich, Sips, and Temkin suggest the occurrence of Cd chemisorption and physisorption in mono and multilayers. The values of ∆G° < 0 kJ mol indicate that the observed phenomena are energetically favorable and spontaneous; the values of ∆H° < 0 and the effective desorption rates (58.52% and 44.64%) suggest that the adsorption of Cd is ruled mainly (but not only) by physical interactions. Our excellent results on Cd removal allow us to state that tobacco use as a raw material for adsorbent development is a renewable and eco-friendly technique, allowing the production of highly effective activated carbons and providing an adequate destination for this waste. The online version contains supplementary material available at 10.1007/s40201-021-00740-8.