Appraisal of the adsorption potential of novel modified gellan gum nanocomposite for the confiscation of methylene blue and malachite green

Abstract

In the present investigation a novel, environmentally affable and economical, modified gellan gum nanocomposite (MAA-g-GG/Ppy/MMT) was fabricated via free-radical polymerization for the liquid-phase mitigation of Methylene blue (MB) and Malachite green (MG) dyes. The innovation of this work is substantiated by the intentional combination of diverse materials, the strategic incorporation of polypyrrole for enhanced adsorption, and the thoughtful addition of MMT as a nanofiller to address mechanical strength and improve adsorption capacity. The physico-chemical facets of MAA-g-GG/Ppy/MMT and its interaction with the dye molecules were elucidated using FT-IR, SEM-EDX, BET, TEM, and XRD techniques. The optimum conditions for the sorption of MB and MG were deemed to be dosage (1.2 g/L for both dyes), contact time (50 min for both dyes), initial MG/MB concentration (MB = 40 mg/L & MG = 30 mg/L), and pH (MB = 10 & MG = 7). The Freundlich isotherm was identified as the most suitable model, as evidenced by the highest R2 value (∼0.999), indicating multilayer adsorption. The pseudo second-order model appraised the kinetic data. Thermodynamic findings revealed the adsorption process to be spontaneous, viable and exothermic which was ascertained by negative ∆H⸰ values (−22.8 kJ/mol for MB and −18.3 kJ/mol for MG). The substantial Langmuir adsorption capacity (Qm: MG =185.185; MB = 344.827) can be ascribed to the reason for strong interactions between MAA-g-GG/Ppy/MMT and dyes. The high reliability of MAA-g-GG/Ppy/MMT was determined by the regeneration studies that worked up to four cycles for both dyes. The real water (distilled water, tap water, and river water) samples spiked with MG/MB demonstrated a substantial uptake of dyes (>85 %) and the marginal influence of ionic strength on the adsorptive potential of MAA-g-GG/Ppy/MMT validated its efficacy for the decontamination of real effluents. The forces of attraction between the dyes and MAA-g-GG/Ppy/MMT included van der Waals, electrostatic forces of attraction, and π-π interaction. This green, economical, and viable MAA-g-GG/Ppy/MMT will prove to be an efficient adsorbent for the decontamination process of sequestration of dyes to achieve a sustainable environment.