Equilibrium, kinetic, and thermodynamic studies of Basic Blue 9 dye sorption on agro-industrial lignocellulosic materials

Abstract

Abstract:© Versita Sp. z o.o. The sorptive potential of some lignocellulosic agro-industrial wastes (sunflower seed shells and corn cob) for Basic Blue 9 cationic dye removal from aqueous solutions was examined using the batch technique. The Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models were used in order to determine the quantitative parameters of sorption. The Langmuir isotherm model indicated a maximum sorption capacity for these materials in the range of 40-50 mg dye per g (25 o C), slightly higher for corn cob than for sunflower seed shells. The values of the thermodynamic parameters showed that the retention of cationic dye is a spontaneous and endothermic process. The application of pseudo-first order and pseudo-second order intraparticle diffusion models, and a BoydReichenberg model for kinetic data interpretation suggested that sorption of Basic Blue 9 dye onto the studied materials is a process where both surface sorption and intraparticle diffusion contributed to the rate-limiting step. These lignocellulosic wastes can be used with good efficiency for dye removal from aqueous effluents.

Enhanced sorption of methylene blue from aqueous solutions by semi-IPN composite cryogels with anionically modified potato starch entrapped in PAAm matrix

“…To evaluate the thermodynamic parameters, the relation between the Langmuir constant, K L [1,14,18,57,61], or the equilibrium constant of adsorption, K c [27,30,61], and the free energy of adsorption (DG o ) is considered in literature. In this work, the values of the equilibrium constant, K c , were first evaluated with Eq.…”

Valorization of food wastes (orange seeds) as adsorbent for dye retention from aqueous medium

“…The studied processes can be described as a chemical adsorption if the representation q vs. ln t must be linear and intersect the origin of the axes The Langmuir isotherm is based on the assumption that the maximum adsorption corresponds to a monolayer of solute molecules on the adsorbent surface, containing a finite number of energetically equivalent sites [19,37]. The values of Langmuir constants are summarized in Table 2.…”

“…q 0 -saturation capacity, mg/g; K L -binding (adsorption) energy, L/mg q 0 (mg/g) heterogeneity of the adsorbent surface and assumes that the adsorption process could be explained by an exponential distribution of active sites of the adsorbent [19,37]. The R 2 values higher than 0.9 indicate that the Freundlich model described the adsorption of the reactive dye onto orange seeds powder, and also the values of the Freundlich constant n (the measure of adsorption intensity) are greater than unit, suggesting a favorable adsorption process.…”

“…The equilibrium data were analyzed using three of the most known adsorption equilibrium models (Freundlich, Langmuir and Dubinin-Radushkevich- Fig. 3 and Table 2) [19,37].…”

“…A significant category of solid adsorbents is the lignocellulosic materials characterized by the most important characteristics: the easy availability at a low price and the non-pollutant character which implies the formation of nontoxic residues, highly hydrophilicity, fact that determines a rapid kinetics of the sorption process, high porosity, and good mechanical resistance and can be utilized in different shapes (particles of different sizes, fibers, filters, textures) [11]. Particularly useful in practice is the fact that these materials, could be used in native or modified forms [6,7,[11][12][13][14][15][16][17][18][19][20][21][22][23][24], applied in batch and/or fixed bed column techniques [6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] facilitate the study of a mono or binary dyes aqueous system [6][7][8][9][10][11][12][13][14][15]…”