Muna Sarhan Sando,Ahlam M. Farhan,Lee D. Wilson,Ali H. Jawad
Herein, a biocomposite of crosslinked chitosan polyethylene glycol diglycidyl ether (CS-PEDGE), montmorillonite (MMT), and food-grade algae (FGA) was successfully prepared by a hydrothermal technique. The resulting absorbent (CS-PEDGE/FGA/MMT) was assessed for its adsorption property with methyl violet 2B (MV 2B) a toxic cationic dye. The physicochemical properties of CS-EDGE/FGA/MMT were assessed via various analytical techniques, including BET, Elemental analysis, pHpzc, and spectroscopy (FTIR, XRD, SEM-EDX). The influence of three adsorption variables, namely adsorbent dose (A: 0.02–0.1 g/100 mL), solution pH (B: 4–10), and contact time (C: 10–420 min) on the rate of MV 2B dye removal was examined using the Box-Behnken design (RSM-BBD). The findings from the equilibrium isotherm and kinetic analyses suggest that the MV 2B dye adsorption onto the biocomposite surface follow the Freundlich model and pseudo-second-order kinetic models. The biocomposite adsorbent exhibits a maximum dye adsorption capacity (qmax) of 94.2 mg/g. The proposed MV 2B dye adsorption mechanism involves hydrogen bonding, n-π stacking, and electrostatic forces. This research demonstrates the unique structure and outstanding adsorption properties of CS-EDGE/FGA/MMT, which offers a viable solution for removal of detrimental MV 2B dyes from aqueous media.
A quaternary composite adsorbent of chitosan-polyvinyl alcohol/food grade algae/ montmorillonite clay (CS-PVA/FGA/MMT) was synthesized by hydrothermal process to be a promising adsorbent for the removal of cationic methyl violet 2B dye (MV 2B). The adsorption working variables including CS-PVA/FGA/MMT dosage (A: 0.02–0.1 g/100 mL), pH of the dye solution (B: 4–10) and contact duration (C: 20–480 min) were optimized using response surface methodology with Box-Behnken design (RSM-BBD). The optimal conditions of the adsorption key parameters were confirmed by desirability function test and identified to be CS-PVA/FGA/MMT dosage of 0.099 g/100 mL and solution pH of 8. The equilibrium adsorption studies revealed that the adsorption of MV 2B dye on CS-PVA/FGA/MMT surface follows the Langmuir isotherm model and the pseudo-second-order kinetic model. The highest adsorption capacity of CS-PVA/FGA/MMT towards MV 2B was determined to be 105.7 mg/g at 25 ⁰C based on the Langmuir isotherm model parameters. The suggested mechanism of MV 2B adsorption by CS-PVA/FGA/MMT can be assigned to the various possible interactions such as electrostatic forces, n-π stacking, and H-bonding. This study shows that the synthesized CS-PVA/FGA/MMT material possesses a unique structure and preferable adsorption capabilities towards cationic dye. Therefore, it offers a practical solution for removing harmful cationic dyes from contaminated wastewater.
Heren, chitosan (CH), algae (AL), and montmorillonite clay K10 (MK10) were used in the hydrothermal synthesis of a new Schiff-base system of glutaraldehyde-crosslinked chitosan-based biocomposite (CH-AL-MK10/GL) for the removal of a model cationic dye [MV (2B)] from aqueous environments. Various analytical methods were employed to evaluate the characteristics of the synthesized biocomposite (e.g., BET surface analysis method, elemental analysis, FTIR, SEM–EDX, XRD, and point of zero charge). The key adsorption parameters (CH-AL-MK10/GL dose, pH, and time) were optimized using the BBD model and the optimum adsorption (%) value of 86.4% was achieved at the following operating conditions: CH-AL-MK10/GL dose: 0.99 g/100 mL, pH: 8.3, time: 418 min and a quadratic model was generated for predicting the dye removal values based on the adsorption conditions. The adsorption equilibrium data revealed great compatibility with the pseudo-second order kinetic model and Langmuir and Freundlich isotherm models, achieving a maximum adsorption capacity of 98.3 mg/g at 25 °C. Hence, the adsorption of MV (2B) by CH-AL-MK10/GL was through chemisorption in an initially monolayered fashion which then proceeds to a multilayered model after the surface layer reaches a saturated state. The results of all the characterization methods as well as the adsorption equilibrium studies were utilized to determine the possible interactions between the CH-AL-MK10/GL surface and MV (2B) dye molecules and the electrostatic forces, hydrogen bonding, Yoshida hydrogen bonding and n- π stacking interactions were concluded to be responsible for the adsorption process.
In this study, a cross-linked chitosan tripolyphosphate (CS-TPP) was modified by food-grade algae (FGA) and montmorillonite clay (MMT) with assistance of hydrothermal process to produce a biocomposite adsorbent (CS-TPP/FGA/MMT). The effectiveness of CS-TPP/FGA/MMT was evaluated towards removal of toxic cationic dye (methyl violet 2B (MV 2B)) from aqueous environment. The key factors affecting adsorption, namely (A) CS-TPP/FGA/MMT dosage (0.02–0.1 g/100 mL); (B) pH (4–10); and (C) time (10–60 min) were optimized using the Box-Behnken design (BBD). The desirability function test confirmed the desirable conditions of the adsorption key parameters and identified as CS-PVA/FGA/MMT dosage of 0.09 g/100 mL solution pH of 7.7 and time 59 min. The adsorption kinetic and isotherm were well explained by pseudo-second-order (PSO) and Langmuir isotherm model respectively. The maximum adsorption capacity ( q max ) of CS-TPP/FGA/MMT for removing MV 2B was determined to be 165.9 mg/g at 25C°. The proposed MV 2B adsorption mechanism by CS-TPP/FGA/MMT can be assigned to electrostatic forces, n-π stacking, and H bonding. The findings of this study suggest that CS-TPP/FGA/MMT can effectively be applied for removal of toxic organic cationic dyes from aqueous solution.
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