Chemical Engineering Journal 155 (2009) 627–636 Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej Application of carbon adsorbents prepared from the Brazilian pine-fruit-shell for the removal of Procion Red MX 3B from aqueous solution—Kinetic, equilibrium, and thermodynamic studies Tatiana Calvete a , Eder C. Lima a,∗ , Natali F. Cardoso a , Silvio L.P. Dias a , Flavio A. Pavan b a Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Gonc ¸ alves 9500, Postal Box 15003, ZIP 91501-970, Porto Alegre, RS, Brazil b Federal University of Pampa, UNIPAMPA, Bagé, RS, Brazil article info Article history: Received 8 April 2009 Received in revised form 20 August 2009 Accepted 22 August 2009 Keywords: Adsorption Brazilian pine-fruit-shell Activated carbon Procion Red MX 3B dye Simulated dyehouse effluent abstract Activated (AC-PW) and non-activated (C-PW) carbonaceous materials were prepared from the Brazilian pine-fruit-shell (Araucaria angustifolia) and tested as adsorbents for the removal of Procion Red MX 3B dye (PR-3B) from aqueous effluents. The activation process lead to increase in the specific surface area, average porous volume, and average porous diameter of the adsorbent AC-PW when compared to C-PW. The effects of shaking time, adsorbent dosage and pH on adsorption capacity were studied. PR-3B uptake was favorable at pHs ranging from 2.0 to 3.0 for C-PW and 2.0 to 7.0 for AC-PW. The contact time required to obtain the equilibrium using C-PW and AC-PW as adsorbents was 6 and 4 h at 298 K, respectively. The values of the function error (F error ) of fractionary-order kinetic model was at least 15 times lower than the values obtained with pseudo-first-order, pseudo-second order and Elovich kinetic models, indicating that this kinetic model was better fitted to the experimental results. For equilibrium data the F error values of the Sips isotherm model were at least 4.0 lower than the values of Langmuir, Freundlich, and Redlich- Peterson isotherm models using C-PW and AC-PW as adsorbents. The enthalpy and entropy of adsorption of PR-3B were obtained from adsorption experiments ranging from 298 to 323 K. Simulated dyehouse effluents were used to check the applicability of the proposed carbons for effluent treatment. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Industrial activity is responsible for generating large volumes of effluents containing hazardous species. Color is one of the most important hazardous species found in industrial effluents which needs to be treated, because the presence of dyes in water reduces light penetration, precluding the photosynthesis of aqueous flora [1,2]. Also, dyes can cause allergy, dermatitis, skin irritation and cancer in humans. There are reports that some dyes may cause mutagenicity in humans [3]. Colored waters are aesthetically objec- tionable for drinking and other purposes. Therefore, industrial effluents containing dyes need to be treated before being released into the environment. The most efficient procedure for the removal of synthetic dyes from industrial effluents is the adsorption procedure. This process transfers the dye species from the water effluent to a solid phase thereby keeping the effluent volume to a minimum [4–6]. Subse- quently, the adsorbent can be regenerated or stored in a dry place without direct contact with the environment [7–9]. ∗ Corresponding author. Tel.: +55 51 3308 7175; fax: +55 51 3308 7304. E-mail addresses: profederlima@gmail.com, eder.lima@ufrgs.br (E.C. Lima). Activated carbon is the most employed adsorbent for toxic specie removal from aqueous effluents because of well-developed pore structures and high internal surface area that lead to its excellent adsorption properties [10]. Besides these physical charac- teristics, the adsorption capacity is also dependent on the source of the organic material employed for the production of the activated carbon [11], as well as the experimental conditions employed in the activation processes [11]. Activated carbon can be prepared by a variety of chemical [12] and physical [13] activation methods and in some cases by a com- bination of both types of methods [14]. Chemical activation is the process where the carbon precursor material is firstly treated with aqueous solutions of dehydrating agents (i.e. H 3 PO 4 , ZnCl 2 ,H 2 SO 4 , KOH). Subsequently the carbon material is dried at 373–393 K to eliminate the water. In a subsequent step the chemically treated carbon material is heated between 673 and 1073 K under nitro- gen atmosphere [11,12]. Physical activation consists of a thermal treatment of previously carbonized material with suitable oxidiz- ing gases, such as air at temperatures in the 623–823 K range or 1073–1373 K using steam and/or carbon dioxide [11,13]. Although activated carbon is one of the best adsorbents for dye removal from aqueous solutions, the extensive use of high quality activated carbon for dye removal from industrial effluents is very 1385-8947/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.cej.2009.08.019