Adsorption of methylene blue dye onto phosphoric acid-treated pomegranate peel adsorbent: Kinetic and thermodynamic studies

• Published in: Desalination and water treatment Vol. 318; p. 100406
• Main Authors: Waghmare, Charuta, Ghodmare, Sujesh, Ansari, Khalid, Alfaisal, Faisal M., Alam, Shamshad, Khan, Mohammad Amir, Ezaier, Yassine
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.04.2024
• Subjects: Chemical activation; Isotherms; Kinetics; Ortho-phosphoric acid; Pomegranate peel; Thermodynamics; Thermodynamics; Pomegranate peel; Chemical activation; Kinetics; Ortho-phosphoric acid; Isotherms
• ISSN: 1944-3986; 1944-3986
• DOI: 10.1016/j.dwt.2024.100406

The orthophosphoric acid-treated pomegranate peels (POPAC) performance was investigated through batch mode for Methylene Blue dye (MB) adsorption from an aqueous solution. Although chemical activation using various chemical agents has been explored by other research work, but novelty application of H3PO4 in a 1:1 wt percentage for activation exhibits unprecedented performance in enhancing the efficiency of MB dye removal. Dependent parameters were optimized, with pH of the sample, contact interval, initial MB concentration, and dose of adsorbent. Excellent removal efficiency (above 92 %) was observed at pH 8 with a dose of 0.25 g/100 mL for 120 min of contact duration. At the qmax value of 14.03 mg/g, the Langmuir isotherm demonstrated the MB dye monolayer adsorption onto POPAC, elucidating the adsorption mechanism with R2 = 0.9883. The kinetics of MB adsorption fit excellently through the pseudo-second-order model with R2 = 0.9997, and the model's estimated adsorption capacity agreed well with the results obtained from the experimental investigation. Thermodynamic parameters, including ΔGᵒ, ΔH°, and ΔS°, additionally demonstrated the spontaneous as well as endothermic adsorption nature of MB on the POPAC’s surface. Furthermore, regeneration studies using 0.1 M NaOH and 0.1 M HCl solutions show adequate MB dye elimination after three cycles. According to the research findings, pomegranate peel may be an inexpensive, environmentally acceptable, and operative biosorbent to eliminate MB dye from polluted aqueous matrices. [Display omitted] •Innovative use of phosphoric acid-treated pomegranate peel (POPAC) as an effective biosorbent to treat Methylene Blue dye.•FTIR and FE-SEM were employed to assess surface morphology and structure.•The experimental result revealed a high capacity for adsorption for methylene blue at 14.03 mg/g.