Remoción De Colorantes Azo Con Alginato: Relación Entre Estructura De Colorante Y Eficiencia De Remoción

Lozano-Álvarez, Juan Antonio; Marañón-Ruiz, Virginia F.; Jáuregui-Rincón, Juan; Medina-Ramírez, Iliana E.; Salinas-Gutiérrez, Rogelio; Frausto-Reyes, Claudio

doi:10.20937/rica.2019.35.01.16

“…(3) The adsorption energy does not depend on the surface covered by adsorbate molecules The Pec-Ca-DR80 system does not satisfy the above assumptions. For example, [37] reported that the attachment of the first dye molecule to the adsorbent promoted the formation of aggregates on the adsorbent surface. This is attributed to aromatic rings and other functional groups of the dye molecules, which generate molecular planarity and lead to the formation of H-type aggregates [38,39].…”

Section: Resultsmentioning

confidence: 99%

A Stochastic Model for Adsorption Kinetics

Rodríguez-Narciso

¹

,

Lozano-Álvarez

²

,

Salinas-Gutiérrez

³

et al. 2021

Adsorption Science & Technology

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A novel stochastic model is proposed to characterize the adsorption kinetics of pollutants including dyes (direct red 80 and direct blue 1), fluoride ions, and cadmium ions removed by calcium pectinate (Pec-Ca), aluminum xanthanate (Xant-Al), and reed leaves, respectively. The model is based on a transformation over time following the Ornstein–Uhlenbeck stochastic process, which explicitly includes the uncertainty involved in the adsorption process. The model includes stochastic versions of the pseudo-first-order (PFO), pseudo-second-order (PSO), and pseudo- n -order (PNO) models. It also allows the estimation of the adsorption parameters, including the maximum removal capacity ( q e ), the adsorption rate constant ( k n ), the reaction pseudoorder ( n ), and the variability σ 2 . The model fitted produced R 2 values similar to those of the nonstochastic versions of the PFO, PSO, and PNO models; however, the obtained values for each parameter indicate that the stochastic model better reproduces the experimental data. The q e values of the Pec-Ca-dye, Xant-Al-fluoride, and reed leaf-Cd+2 systems ranged from 2.0 to 9.7, 0.41 to 1.9, and 0.04 and 0.29 mg/g, respectively, whereas the values of k n ranged from 0.051 to 0.286, 0.743 to 75.73, and 0.756 to 8.861 (mg/g)1-n/min, respectively. These results suggest a variability in the parameters q e and k n inherent to the natures of the adsorbate and adsorbent. The obtained n values ranged from 1.13 to 2.02 for the Pec-Ca-dye system, 1.0–3.5 for the Xant-Al-fluoride system, and 1.8–3.8 for the reed leaf-Cd+2 system. These ranges indicate the flexibility of the stochastic model to obtain fractional n values, resulting in high R 2 values. The variability in each system was evaluated based on σ 2 . The developed model is the first to describe pollutant removal kinetics based on a stochastic differential equation.

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“…However, the presence of hydrogen bonds between DB and chitosan chains, due to the partial deprotonation of amino groups, cannot be excluded, indicating that the driving force of the adsorption process was not only attributable to electrostatic interactions but also to hydrogen bonds and hydrophobic interactions. To infer more information, the IR spectrum of DB was collected [see Figure (a)], and the detailed description is reported in the Supporting Information. Unfortunately, the typical bands of DB were not detected in the chitosan blended films [Figure (b,c)], and this behavior could be ascribed to two factors.…”

Section: Resultsmentioning

confidence: 99%

A comprehensive investigation of dye–chitosan blended films for green chemistry applications

Rizzi

¹

,

Longo

²

,

Placido

³

et al. 2017

J of Applied Polymer Sci

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In this paper, the ability of chitosan film to remove dyestuff from wastewater was evaluated for environmental applications, using three commercial direct azo dyes. Two chitosan films were adopted: the standard one prepared following a well‐known procedure to form it, and a novel one, with a weakly acidic character. Moreover, to improve the adsorption process, the hydrophobic character of the films was investigated. The pH of the dye solutions was also changed, showing an excellent ability in dye removal at pH 12. The films were characterized by means of spectroscopic and morphologic methods to better understand the nature of interactions between dyes and chitosan chains. Swelling ratio measurements were also performed. All analyses suggest that all dyes showed a strong affinity to chitosan polymer chains, with the presence of extended hydrogen bonds and Van der Waals forces perturbing the chitosan network. Interestingly, very good results were obtained in recycling experiments related to the dyeing capacities of chitosan blended films in the presence of textiles. An ecofriendly application is thus presented in this paper. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45945.

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“…The Zimm-Bragg model has been applied and reported as an adsorption model by our group [32]. In this work, the theoretical parameters of the Zimm-Bragg model, K u and U (nucleation and cooperativity parameters, respectively), were obtained by using the nonlinear regression method in the experimental isotherms.…”

Section: Methodsmentioning

confidence: 99%

Application of the Zimm-Bragg Model to the Removal of Azo Dyes with Pectin

Lozano-Álvarez

¹

,

Jáuregui-Rincón

²

,

Medina-Ramírez

³

et al. 2021

Adsorption Science & Technology

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0

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In this work, the ability of pectin (Pec) to remove direct red 80 (DR80), Congo red (CR), methyl orange (MO), and methyl red (MR) was studied. The removal percentages under adequate pH and ionic strength conditions were as follows: DR80 (99.5%), CR (99.8%), MO (88.6%), and MR (68%), showing that this methodology is efficient to remove azo dyes. The proposed method included the addition of native Pec to the dye aqueous solution and the formation of a gel that occurred when a calcium salt solution was added. This gel retains the molecules adsorbed onto the molecular surface of Pec through hydrogen bonds and electrostatic and hydrophobic interactions. To our knowledge, it is the first time that the Zimm-Bragg model is used to describe the removal of azo dyes with native Pec. This model includes two parameters: K u (nucleation constant), which is related to the tendency exerted by a dye molecule attached to the Pec to bind to other molecules present in the aqueous phase, and U (cooperativity parameter), which determines the aggregation capacity of the dye molecules already attached to the Pec. This model fits the experimental isotherms very well, suggesting that Pec binds single molecules and dye aggregates. The obtained results in the values of K u ranged from 922 mol/kg (MR) to 1,157,462 mol/kg (CR), and U varied from 2.51 (MR) to 169.19 (MO). These results suggest that the use of Pec is a viable option to remove azo dyes from aqueous effluents and that the Zimm-Bragg model fits adequately the isotherms of dyes that have a high tendency to form aggregates.

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Remoción De Colorantes Azo Con Alginato: Relación Entre Estructura De Colorante Y Eficiencia De Remoción

Cited by 6 publications

References 45 publications

A Stochastic Model for Adsorption Kinetics

A Stochastic Model for Adsorption Kinetics

A comprehensive investigation of dye–chitosan blended films for green chemistry applications

Application of the Zimm-Bragg Model to the Removal of Azo Dyes with Pectin

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