Mechanism and isotherm modeling of effective adsorption of malachite green as endocrine disruptive dye using Acid Functionalized Maize Cob (AFMC)

Abstract

Cationic Malachite green has been identified as a candidate for the endocrine disruptive compound found in the environment. In this study, the mechanism and isotherm modeling of effective adsorption of cationic malachite green dye onto acid-functionalized maize cob (AFMC) was investigated by batch technique. The operational parameters such as initial concentration (100–600 mg/L); contact time (10–120 min) and pH (3–10) influenced the removal efficiency and quantity adsorbed. A maximum of 99.3% removal efficiency was obtained at optimum conditions. AFMC physicochemical properties (surface area 1329 m2/g and particle size 300 μm < Ф < 250 μm) enhanced its efficiency. Based on R2 > 0.97 and consistently low values of adsorption statistical error functions (ASEF), equilibrium data were best fitted to Freundlich isotherm. Kinetic data were best described by a pseudo-second-order model with consistent R2 > 0.98 and validated by ASEF. The mechanism of the process was better described by intraparticle diffusion. Evidence of the adsorption process was confirmed by the change in morphology via Scanning Electron Microscopy (SEM) and surface chemistry by Fourier Transform infrared (FTIR). The performance of AFMC enlisted it as a sustainable and promising low-cost adsorbent from agro-residue for treatment of endocrine disruptive dye polluted water.

Performance of Dye Removal from Single and Binary Component Systems by Adsorption on Composite Hydrogel Beads Derived from Fruits Wastes Entrapped in Natural Polymeric Matrix

“…Our conclusions are comparable with those of other studies conducted for the removal of dyes by adsorption on different materials. Similar findings were published by Ali et al [ 88 ], who explored the adsorption of indigo carmin and Congo Red dyes on calcinated layered double hydroxides, and by Ojediran et al [ 89 ], who inspected the retention of malachite green on acid functionalized maize cob and pointed out that the adsorption does not obey the Langmuir model. Abramian and El-Rassy focused on the adsorption of Orange II dye on a porous titania aerogel [ 79 ] and revealed that the Freundlich isotherm is suitable for describing the process.…”

Molecularly Imprinted Polymeric Sorbent for Targeted Dispersive Solid-Phase Microextraction of Fipronil from Milk Samples

“…Studies have shown that the determination of the best isotherm model does not depend only on the R 2 value, and to determine the best isotherm model, coupled with a higher R 2 value, there must be closeness between the data of q e cal and q e exp . 36 In the fitted models, the q e values are 43.25 and 60 for Freundlich and Langmuir isotherms, respectively. These results indicate the best fitting of the Freundlich isotherm, which not only has both linear and nonlinear model values close to 1 but also the q e value is close to the calculated value.…”

“…On the other hand, the nonlinear fitting models have R 2 values of 0.99 and 0.98 for Langmuir and Freundlich isotherms, respectively. Studies have shown that the determination of the best isotherm model does not depend only on the R 2 value, and to determine the best isotherm model, coupled with a higher R 2 value, there must be closeness between the data of q e cal and q e exp . In the fitted models, the q e values are 43.25 and 60 for Freundlich and Langmuir isotherms, respectively.…”

Characteristics of the Properties of Absodan Plus Sorbent and Its Ability to Remove Phosphates and Chromates from Aqueous Solutions

“…The worst fit shows the Halsey isotherm, for which the value of R 2 is <0.1 and the value of χ 2 /DoF is 520 (phosphates ions) and 4320 (chromates ions). The Halsey model is used for multilayer adsorption on the heterogeneous surface [ 76 ], which does not occur with the adsorption performed.…”