%0 Journal Article
%T Valorization of Agroindustrial Wastes as Biosorbent for the Removal of Textile Dyes from Aqueous Solutions
%A Elsa Contreras
%A Luisa Sep¨²lveda
%A Carolyn Palma
%J International Journal of Chemical Engineering
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/679352
%X The goal is to determinate the technical feasibility of using agroindustrial wastes for adsorption of dyes. The pHpzc of Brewer¡¯s spent grains and Orange peel is 5.3 and 3.5, respectively. The equilibrium isotherms of Basic Blue 41, Reactiive Black 5, and Acid Black 1 were carried out without pHs control which ranging between 4 and 5.5. The equilibrium concentrations for both adsorbents were fitted by the Freundlich and Langmuir models. The maximum adsorption capacity measured for Basic Blue 41, Reactive Black 5, and Acid Black 1 was 32.4, 22.3, and 19.8£¿mg g£¿1 for Brewer¡¯s spent grains; and 157, 62.6, and 45.5 for orange peel, respectively. The kinetic of process was fitted by the model of pseudo-second order. The constant rate for orange peel decreased to extend the initial concentration of dye increased, obtaining 4.08 * 10£¿3£¿0.6 * 10£¿3 (Basic Blue 41), 2.98 * 10£¿3£¿0.36 * 10£¿3 (Acid Black 1), and 3.40 * 10£¿3£¿0.46 * 10£¿3£¿g£¿mg£¿1£¿min£¿1 (Reactive Black 5). The best removal efficiency was obtained in orange peel with values started from 63% to 20%. Consequently, according the results obtained there are two positive effects, the reuse of agricultural wastes and its use as low-cost adsorbent of the dyes. 1. Introduction The discharges of industrial wastewater containing dyes cause serious environmental problems, because their chemical structure gives them a persistent and recalcitrant nature. The released dye in water streams represents a risk of ecotoxicity and a potential danger of bioaccumulation. The transport of these contaminants through the food chain could even affect the human health. In the last two decades, the elimination of dyes from industrial textile waste waters has been one of the major challenges for researchers. Adsorption has received special attention as a treatment for colorized wastewater because it produces an effluent of better quality and comparatively can become more effective and less expensive than conventional treatments. Granular-activated carbon has been designated by the Environmental Protection Agency (EPA) of USA as the best available technology (BAT) for organic chemicals removal. In fact, activated carbon adsorption is an effective treatment for removing varied organic contaminants and, particularly, textile dyes of different ionic nature [1, 2]. However, the high volume of effluents generated in the textile wet process involves a high cost for regeneration of the activated carbon [3, 4]. On the other hand, as a consequence of industrial development, enormous quantities of agroindustrial wastes are generated annually
%U http://www.hindawi.com/journals/ijce/2012/679352/