Hydrothermal synthesis of magnetic-biochar nanocomposite derived from avocado peel and its performance as an adsorbent for the removal of methylene blue from wastewater

E. Prabakaran, K. Pillay, H. Brink

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

In this work hydrothermally prepared magnetic iron oxide coated biochar nanocomposite (Fe3O4-BC), from raw avocado peel (raw AVP) and ferric chloride hexahydrate, effectively adsorbed aqueous methylene blue (MB) dye. Successful Fe3O4-BC formation was confirmed by TEM, FT-IR, XRD, and SEM. BET analyses measured a higher surface area (25.98 m2/g vs. 18.89 m2/g) and smaller-pore diameter (8.25 nm vs. 13.01 nm) for Fe3O4-BC compared to raw AVP. The Tempkin and Langmuir isotherm models successfully modeled the Fe3O4-BCMB adsorption equilibrium data, indicating uniform adsorption binding energy and homogeneous single layer adsorption. The maximum Langmuir adsorption capacity qmax = 62.1 mg/g for MB compared well with previously reported values for low cost carbonaceous adsorbents. The temporal experimental data was best represented by the pseudo-second order and two-phase pseudo-first-order kinetic models suggesting that chemisorption dominated. Thermal studies indicated spontaneous endothermic adsorption (ΔG < 0, ΔH > 0). Fe3O4-BCshowed remarkable stability and reusability during four consecutive adsorption–desorption cycles. Compared to literature, Fe3O4-BC adsorption was markedly faster requiring between 1 and 3 orders of magnitude less time to reach equilibrium. Consequently, a significantly lower treatment time would be required industrially which, coupled with magnetic separation, reusability, and relatively high adsorption capacity of the adsorbent, highlights the unprecedented industrial potential of Fe3O4-BC nanocomposite as an adsorbent for the treatment of MB polluted waters.

Original languageEnglish
Article number100123
JournalMaterials Today Sustainability
Volume18
DOIs
Publication statusPublished - Jun 2022

Keywords

  • Adsorption
  • FeO-BC nanocomposite
  • Isotherm models
  • Kinetic models
  • Methylene blue
  • Thermodynamic studies

ASJC Scopus subject areas

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

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