Influence of Process Variables on the Adsorption of Methylene Blue from Aqueous Solution Using Iron-Modified Zeolite A

• Esther M. GANA

  Author

This study presents the synthesis and characterization of iron-modified zeolite-A derived from Nigerian kaolin for methylene blue adsorption. Zeolite-A was synthesized via hydrothermal alkaline activation of metakaolin, followed by iron functionalization using FeCl₃·6H₂O. Materials were characterized by XRD, FTIR, SEM, XRF, and BET. XRD confirmed phase-pure zeolite-A with an LTA framework (peaks at 7.14°, 24.06° 2θ) and crystallite size of 20.74 nm. After iron incorporation, the framework remained intact while new iron-related reflections appeared at 44.8° and 65.20°, with crystallite size reducing to 9.06 nm. FTIR verified the aluminosilicate framework with peaks at 3724.94 and 3471–3466 cm⁻¹ (Si-O-T vibrations), with additional Fe-O bands after modification. SEM showed typical cubic morphology preserved but with surface texturing after iron loading. BET of Fe-modified zeolite A gave a surface area of 380.350 m² g⁻¹ with Type IV isotherms (hierarchical micro-mesoporosity), versus 515.22 m² g⁻¹ for pristine zeolite A. XRF confirmed iron incorporation: Fe₂O₃ increased from 2.26 to 9.83 wt.%, and Si/Al ratio rose from 1.36 to 1.89 due to Na⁺ exchange and partial dealumination. Batch adsorption of MB using the iron modified zeolite A under optimum  dosage, initial concentration, contact time of  0.6 g, 6mg/L and 90 min resulted to 99.6% methylene blue removal, outperforming unmodified zeolite-A (98.3). The preserved zeolite A framework, enhanced adsorption potential, and hierarchical porosity positions the iron-modified zeolite-A as a promising adsorbent for MB removal from dye contaminated wastewater.

• FJET_21_63_63

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