Enhanced removal of anionic Methyl orange azo dye by an iron oxide (Fe3O4) loaded lotus leaf powder (LLP@Fe3O4) composite: Synthesis, characterization, kinetics, isotherms, and thermodynamic perspectives

• Published in: Inorganic chemistry communications 2023-05, Vol.151, p.110625, Article 110625
• Main Authors: Subbaiah Munagapati, Venkata, Wen, Hsin-Yu, Gollakota, Anjani R.K., Wen, Jet-Chau, Shu, Chi-Min, Andrew Lin, Kun-Yi, Yarramuthi, Vijaya, Wen, Jhy-Horng, Mallikarjuna Reddy, Guda, Zyryanov, Grigory V.
• Format: Article
• Language: English
• Subjects: Adsorption; Iron oxide; Lotus leaf powder; Magnetic separation; Methyl orange; Regeneration
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2023.110625

[Display omitted] •Novel magnetic LLP@Fe3O4 composite was successfully synthesized and characterized.•LLP@Fe3O4 composite possessed a high surface area and good magnetic separation.•The adsorption capacity for MO was 282.3 mg/g by LLP@Fe3O4 at 298 K.•Electrostatic interaction played an important role in the adsorption mechanism.•The removal rate of MO still reached 78.4% after five cycle regenerations. The goal of this work was to prepare a novel magnetic nanocomposite of Lotus leaf powder@iron oxide (LLP@Fe3O4) to remove Methyl Orange (MO) from a liquid medium. The co-precipitation approach was used to successfully synthesize the LLP@Fe3O4 composite, which was then characterized using FT-IR, XRD, pHPZC, SQUID-VSM, BJH/BET, and FE-SEM/EDX analysis. Batch tests were carried out to investigate the adsorption behaviour and mechanisms. The optimal MO removal efficiency of LLP@Fe3O4 reached up to 94.3% under the optimum reaction conditions (LLP@Fe3O4 dosage = 50 mg/30 mL, stirring speed = 200 rpm, contact period = 120 min, MO initial concentration = 20.8 mg/L, temperature = 298 K, and pH = 5.1). Adsorption isotherms and kinetics were analyzed using Temkin, Freundlich, Langmuir, Dubinin-Radushkevich (D-R), pseudo-second-order (PSO), intra-particle diffusion (IPD), pseudo-first-order (PFO), and Elovich models. Adsorption of MO on LLP@Fe3O4 is best matched to the Langmuir isotherm and PSO kinetic models. The data was analyzed utilizing four errors (SSE, ARE, RMSE, and χ2) and regression coefficient functions to estimate the best-fitting kinetic and isotherm models. The maximal monolayer adsorption uptake of MO was estimated to be 282.3 mg/g at 298 K. The thermodynamic variables, namely entropy (ΔSo = -98 J/mol K), enthalpy (ΔHo = -35.6 kJ/mol), and Gibbs free energy (ΔGo = -6.2808 kJ/mol at 298 K), indicated that the adsorption of MO onto LLP@Fe3O4 was spontaneous, exothermic, and feasible. The LLP@Fe3O4 composite may be regenerated and readily separated from the liquid medium without losing any weight. After regeneration, the LLP@Fe3O4 still has good adsorption efficiency for up to five cycles of adsorption and desorption. The experimental findings of this study output could be confirmed that LLP@Fe3O4 is a potential adsorbent to remove dyestuff from wastewater.