Removal of azo dyes in aqueous solutions using magnetized and chemically modified chitosan beads

Muedas-Taipe, Golfer; Mejía, Ily Marilú Maza; Santillan, Fátima A.; Velásquez, Carlos J.; Asencios, Yvan J.O.

doi:10.1016/j.matchemphys.2020.123595

Cited by 18 publications

(5 citation statements)

References 46 publications

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“…Various technologies, including adsorption, flocculation, membrane separation, chemical oxidation, and photocatalytic degradation, among others, have been used to treat colored wastewater (Bilińska et al, 2019;Chen et al, 2020;Xia et al, 2020); among which adsorption is considered to be economically efficient and very favorable (Awasthi & Datta, 2019;Naushad et al, 2019), mainly for industrial treatments in fixed bed columns (Alardhi et al, 2020;Charola et al, 2018). For the elimination of colorants in solution different types of adsorbent materials have been studied, with good adsorption properties, which include the activated carbon (Castellar-Ortega et al, 2020;Daoud et al, 2019;Patra et al, 2020), carbon nanotubes (Dutta et al, 2018;Elsagh et al, 2017;Saxena et al, 2020); biomass (Cheruiyot et al, 2019;da Silva & Pietrobelli, 2019;Jia et al, 2017), clays (Bentahar et al, 2019;Jawad & Abdulhameed, 2020;Thirumoorthy & Krishna, 2020), chitosan (da Silva et al, 2020Lipatova et al, 2018;Muedas-Taipe et al, 2020), bentonite (Khalilzadeh Shirazi et al, 2020;Saeed et al, 2020;Santos et al, 2020), zeolites (Abdelrahman, 2018;Humelnicu et al, 2017;Rashid et al, 2020) and diatomites (Mohamed et al, 2019;Sriram et al, 2020;Xia et al, 2020) among others.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of diatomaceous earth in the removal of crystal violet dye in solution

Cely-Bautista

Arrieta

Colpas

et al. 2022

JART

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In this research, the adsorption capacity of diatomaceous earth in the removal of the crystal violet dye (CV) in aqueous solution was evaluated. The experimental methodology began with the determination of the texture properties by adsorption-desorption isotherms with N2 a 77 K, the identification of functional groups by Fourier transform infrared spectrophotometry (FTIR), morphology by scanning electron microscopy (SEM) and, the pH of the isoelectric point by the point of zero charge (PZC). A categorical multifactorial design was developed with factors such as the initial concentration of the dye (300-1000 mg/dm3), the temperature (30, 35 and 40ºC) and the initial pH of the solution (5, 6, 7 and 8). The maximum adsorption capacity was of 96.1 mg/g up 30ºC and pH 8, satisfactorily fitting the experimental data to the Langmuir isotherm model with R2 = 0.99, suggesting a monolayer adsorption mechanism on a homogeneous surface. In conclusion, diatomaceous earth can be considered as an efficient adsorbent in the removal of CV in aqueous solution.

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Section: Introductionmentioning

confidence: 99%

Evaluation of diatomaceous earth in the removal of crystal violet dye in solution

Cely-Bautista

Arrieta

Colpas

et al. 2022

JART

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“…The experimental maximum absorption wavelengths are reported in Table 2. Buffer solutions were employed to fix pH in an acetone/water-mixed solvent [51,52]. The two bands detected in the titration experiment (around 490 nm and around nm) can be ascribed to the formation of the deprotonated form from the protonated By plotting absorption intensity vs. pH, the intercept between the first band maxima gests a pKa = 8.55, coinciding with the calculated pKa value of 8.5 (see Section 2.2).…”

Section: Ph Colorimetric Responsementioning

confidence: 61%

Experimental and Theoretical Insights into a Novel Lightfast Thiophene Azo Dye

Diana,

Sessa,

Concilio

et al. 2023

Crystals

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Thiophene ring-enhancing electron delocalization imparts unique properties to azoic chromophore tools. The novel TA-OH dye contains a push–pull π-electron system, including a thiophene-azo scaffold with a hydroxyl group at the ortho position to the azo bridge. The hydroxyl group is expected to lock the azo bridge in its trans conformation, concurring with the photostability and fastness of the dye. The single crystal analysis identified the molecule’s primary conjugation plane, and the theoretical analysis provided electronic pattern insights. The absorption behavior and the trans-to-cis conversion were examined from both experimental and theoretical perspectives. The effect of solvent polarity and the role of pH on the photophysical properties were explored. The solvent polarity strongly affects the absorbance spectrum of TA-OH, therefore potentially making NLO active. Additionally, TA-OH exhibited pH responsiveness akin to classic dichromatic pH indicators, with a noticeable color shift from red to blue observed as pH transitioned from neutral to alkaline. Absorbance titration experiments, along with experimental/theoretical determination of pKa, defined the pH sensing ability.

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“…e adsorption behavior of the chitosan gel microbeads results in a saturated curve, which ts the Langmuir isotherm model of monolayer adsorption, yielding a q max value of 1.84 g-dye/g-adsorbent (Figure 4(b)) with an adsorption equilibrium (K) of 143 L/g. e obtained q max was one of the highest values reported for dye adsorption in similar chitosan gel adsorbent systems (Jóźwiak et al, 2017;Muedas-Taipe et al, 2020;Jamali and Akbari, 2021). e value of the maximum adsorption capacity provided insight into a 1 : 1 stoichiometric ratio of interaction between the protonated amino groups (-NH 3…”

Section: E Ect Of Ph On Dye Adsorptionmentioning

confidence: 80%

Biodegradable Crosslinked Chitosan Gel Microbeads with Controlled Size, Prepared by Membrane Emulsification-External Gelation and Their Application as Reusable Adsorption Materials

Kalidason

Saito

Nanbu

et al. 2022

J. Chem. Eng. Japan

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Gel microbeads composed of chitosan biopolymers were synthesized via membrane emulsi cation, as novel adsorbents for the adsorption of anionic azo dye (Acid Orange 7 (AO7)) and protein (bovine serum albumin (BSA)). The synthesis route involved the production of size-controlled water-in-oil emulsion droplets containing the chitosan solution using a porous, hydrophobic polytetra uoroethylene membrane. The resulting size-controlled emulsion droplets were successfully converted into stable gel microbeads via external gelation, followed by chemical crosslinking using ethylene glycol diglycidyl ether (EGDE). Scanning electron microscopy results revealed the size of the gel microbeads having a diameter ranging from 15 to 20 µm, which was comparable to the size of the emulsion droplets. The e ect of the crosslinking reaction between the prepared gel microbeads with EGDE was con rmed via Fourier transform infrared spectroscopy. The batch adsorption studies employed the Langmuir adsorption model with maximum adsorption capacities at pH values of 5 and 6 for AO7 dye (q max 1.84 g/g) and BSA (q max 0.87 g/g), respectively, with electrostatic interaction being the dominant mechanism of adsorption for both the azo dye and protein. The prepared crosslinked chitosan gel microbeads in this study exhibited excellent recyclability up to 30 times without a decline in their adsorptive capacities, a shelf life of >100 d, and a fair susceptibility toward enzymatic biodegradation, making them some of the most e ective and versatile green adsorbents for wastewater treatment.

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Removal of azo dyes in aqueous solutions using magnetized and chemically modified chitosan beads

Cited by 18 publications

References 46 publications

Evaluation of diatomaceous earth in the removal of crystal violet dye in solution

Evaluation of diatomaceous earth in the removal of crystal violet dye in solution

Experimental and Theoretical Insights into a Novel Lightfast Thiophene Azo Dye

Biodegradable Crosslinked Chitosan Gel Microbeads with Controlled Size, Prepared by Membrane Emulsification-External Gelation and Their Application as Reusable Adsorption Materials

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