Calcined eggshells as a new biosorbent to remove basic dye from aqueous solutions: Thermodynamics, kinetics, isotherms and error analysis Rachid Slimani a , Imane El Ouahabi a , Ferid Abidi b , Mohammadine El Haddad a,c, *, Abdelmajid Regti c , My Rachid Laamari c , Saı ¨d El Antri a , Saı¨d Lazar a a Laboratoire de Biochimie, Environnement & Agroalimentaire URAC 36, Universite´ Hassan II Mohammedia-Casablanca, BP 146, 20650 Mohammedia, Morocco b Laboratoire d’Inge´nierie des Prote´ines & des Mole´cules Bioactives, Institut National des Sciences Applique´es et Technologie, Universite´ de Carthage, BP 676, 1080 Tunis Cedex, Tunisia c Equipe de Chimie Analytique & Environnement, Faculte´ Poly-Disciplinaire, Universite´ Cadi Ayyad, BP 4162, 46000 Safi, Morocco 1. Introduction Dyes and pigments represent one of the problematic groups; they are emitted into wastewaters from various industrial branches, mainly from the dye manufacturing and textile finishing and also from food coloring, cosmetics, paper and carpet industries [1,2]. Wastewater streams from the textile dyeing operation contain unused dyes (about 8–20% of the total pollution load due to incomplete exhaustion of the dye) and auxiliary chemicals along with large amounts of water [3]. The presence of dyes in water reduces light penetration and has a derogatory effect on photosynthesis. There are many structural varieties, such as acidic, basic, disperse, azo, diazo, anthraquinone based and metal complex dyes [4]. Cationic dyes, commonly known as basic dyes, are widely used in acrylic, nylon, silk, and wool dyeing [5]. Due to the complex chemical structure of these dyes, they are resistant to breakdown by chemical, physical and biological treatments. Furthermore, any degradation by physical, chemical or biological treatments may produce small amount of toxic and carcinogenic products [5,6]. The conventional methods for treating dye- containing wastewaters are coagulation and flocculation, reverse osmosis, electroflotation, membrane filtration, irradiation and ozonation and active carbon adsorption [7–9]. The most popular of these technologies is activated carbon adsorption and widely used but it is expensive. Recently, numerous approaches have been studied for the development of cheaper and effective adsorbents. Many non-conventional low-cost adsorbents, including natural materials, biosorbents, and waste materials from industry and agriculture, have been proposed by several workers. These materials could be used as sorbents for the removal of dyes from Journal of the Taiwan Institute of Chemical Engineers xxx (2013) xxx–xxx A R T I C L E I N F O Article history: Received 13 June 2013 Received in revised form 7 September 2013 Accepted 20 October 2013 Available online xxx Keywords: Removal dye Calcined eggshells Biosorption Kinetics Isotherms Error analysis A B S T R A C T The biosorption of basic yellow 28 dye onto calcined eggshells as a new and potential biosorbent have been studied. Batch biosorption studies were conducted to evaluate the effect of various parameters such as contact time, temperature, initial dye concentration, biosorbent dose and ionic strength on the removal of BY 28. From thermodynamic studies, it was seen that the biosorption was spontaneous and exothermic. Biosorption kinetics data were tested using pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the biosorption followed a pseudo-second-order reaction. Maximum of biosorption capacity was attained 28.87 mg/g. Thermodynamic studies reveals that the biosorption of dye was occurred as exothermic in nature (DH = 4.3185 kJ/mol), spontaneous and reflects the decreased randomness at the solid/solution interface during the biosorption (DS = 0.135 j/ mol K). The experimental isotherm data were analyzed using the Freundlich, Tempkin, Toth, Dubinin- Radushkevich, Sips or Koble-Corrigan and Generalized isotherms equations using regression analysis linear and non-linear, showed that the Freundlich isotherm best-fits the equilibrium data for adsorptive removal of basic yellow 28 by calcined eggshells. A detailed error analysis has been undertaken to investigate the effect of using different error criteria for the determination of the isotherm parameters which describe the biosorption process. ß 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. * Corresponding author at: Equipe de Chimie Analytique et Environnement, Faculte´ Poly Disciplinaire, Universite´ Cadi Ayyad, BP 4162, 46000, Safi, Morocco. Tel.: +212 524 669 357; fax: +212 524 669 516. E-mail address: elhaddad71@gmail.com (M. El Haddad). G Model JTICE-776; No. of Pages 10 Please cite this article in press as: Slimani R, et al. Calcined eggshells as a new biosorbent to remove basic dye from aqueous solutions: Thermodynamics, kinetics, isotherms and error analysis. J Taiwan Inst Chem Eng (2013), http://dx.doi.org/10.1016/j.jtice.2013.10.009 Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers jou r nal h o mep age: w ww.els evier .co m/lo c ate/jtic e 1876-1070/$ – see front matter ß 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jtice.2013.10.009