Competitive adsorption of dye species from aqueous solution onto melon husk in single and ternary dye systems

Abstract

Polluted water may contain more than one dye species. Consequently, the behavior of a particular dye in a water system may be affected by the presence of the others. In this study, the adsorption of methylene blue (MB) in single dye system (SDS) and in ternary dye system (TDS) comprising of MB, congo red and methyl orange onto formaldehyde-treated melon husk (FMH) was investigated as a function of pH, contact time and species concentrations. Surface studies of FMH were investigated by Fourier transform infrared and scanning electron microscopy. The dye species adsorption equilibria were rapidly attained after 60 (SDS) and 90 min (TDS) of contact times. The adsorption kinetics were analyzed using pseudo first-order, pseudo second-order and intraparticle diffusion models and the adsorption data were well described by the pseudo second-order model. The equilibrium adsorption data were interpreted in terms of the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Harkin-Jura and Halsey isotherm models and the goodness of fittings were inspected using linear regression analysis (R 2 ). Our results indicated that the Langmuir model was best fitted, suggesting monolayer adsorption. Thermodynamic study showed that the adsorptions in SDS and TDS on FMH are favourable. The change in entropy (DS°) and heat of adsorption (DH°) of dye species on FMH in TDS were estimated as 82.2 J/ mol K and 17.95 kJ/mol. respectively while in SDS, they were respectively -43.76 J/mol K and -21.84 kJ/mol. The sorption process in both systems was thermodynamically feasible with negative DG°values.

Crosslinked Egg White as Eco‐Friendly, Reusable, and Cost‐Effective Biosorbent for Rapid Removal of Indigo Carmine

“…Removal or disposal of dye is a crucial task for environmental aspects. The production of large amounts of dye results in requirement of low‐cost removal methods . The efficient removal methods with high energy requirements are not generally appropriate for industrial applications.…”

“…[4,5] The main drawback of high dye concentrations in effluents are low penetration of light to deeper parts of water resources. [5][6][7][8][9] The unfixed colorants and auxiliaries of textile industries are the main sources of dye effluents. [10] Removal or disposal of dye is a crucial task for environmental aspects.…”

“…The production of large amounts of dye results in requirement of low-cost removal methods. [9,11] The efficient removal methods with high energy requirements are not generally appropriate for industrial applications. The most wanted features of methods are (1) low cost, (2) easy operation, and (3) causing low secondary residues and sludge.…”

Removal of methyl violet dye by a low‐cost waste (Ajuga Pseudo‐Iva): Kinetic and equilibrium isotherm study

“…The results showed that increasing the dye's concentration from 10 to 100 mg · L −1 , lead to a decrease in removal efficiency from 97.51 to 79.76 % (Figure ). Such observations can be explained by the fact that the biosorbent has limited numbers of active sites, which become saturated above a certain concentration . It is observed that the removal efficiency increases by increasing the contact time (Figure ).…”

Adsorptive Removal of a Reactive Azo Dye Using Polyaniline-Intercalated Bentonite

“…Among these techniques, adsorption is attracting increasing interest due to its properties of simple operation, high performance, and low running cost [16][17]. Both natural and synthetic materials have been used as adsorbents to remove dyes from wastewater [18][19]. As natural clay, bentonite has been used widely as an adsorbent for much pollutant removal, including PPCPs, heavy metal, VOCs, etc.…”