Chemical Problems; 2026; V. 24(4); p. 619-634
NANO-STRUCTURED VERMICULITE CLAY FOR HIGH-PERFORMANCE ADSORPTION OF MALACHITE GREEN DYE: STRUCTURAL CHARACTERIZATION AND REGENERATION POTENTIAL
1 Department of Chemistry, College of Sciences for Girls, University of Babylon, Hilla, Iraq
2 College of Pharmacy / Ahl Al Bayt University / Kerbala / Iraq
3 AL-Nisour University College, Department of Medical Laboratories Technology, Baghdad, Iraq
E-mail:
annenayad@gmail.com
Received Date: 2025-05-10
Accepted Date: 2025-07-27
Keywords:
Vermiculite, Clay, Dye, Malachite green, Nano, Removal, Regeneration
Notes:
Abstract: This study employed nanoclay as a low-cost, environmentally friendly adsorbent for the effective removal of malachite green (MG) dye from aqueous solutions. The nanoclay was characterized using XRD, FESEM, TEM, TGA, and FTIR. Structural and morphological analyses confirmed a porous, multilayered structure that was enhanced after adsorption. Batch experiments were conducted to evaluate the impact of key parameters, including dye concentration (10–100 mg/L), adsorbent dosage (0.02–0.15 g), contact time (5–60 min), temperature (10–40 °C), and pH (2–11). Adsorption equilibrium was reached within 60 minutes, and the highest removal efficiency (92.84%) was achieved under optimal conditions: 0.1 g of adsorbent, pH 7, 80 mg/L dye concentration, 60 minutes of contact time, and 30 °C. FTIR analysis confirmed the interaction of MG dye with hydroxyl and Si–O–Si functional groups through observed spectral shifts. FESEM and TEM images revealed increased surface porosity and dye–particle interaction. XRD analysis confirmed the crystalline nature of the nanoclay and minimal structural disruption after adsorption. Isotherm studies showed that the adsorption process followed the Freundlich model, indicating heterogeneous surface adsorption. Kinetic modelling revealed that the data fitted well with the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Thermodynamic parameters (∆G°, ∆H°, and ∆S°) indicated that the adsorption was spontaneous and exothermic. Regeneration tests over five cycles using ethanol and distilled water demonstrated that nanoclay retained over 90% of its initial efficiency, confirming its excellent reusability and structural stability. Overall, nanoclay proved to be a promising and sustainable adsorbent for treating dye-contaminated wastewater.