Fe3O4/BC for Methylene Blue Removal from Water: Optimization, Thermodynamic, Isotherm, and Kinetic Studies
Sharf Ilahi Siddiqui, Naha Meslet Alsebaii, Azza A. Al‐Ghamdi, Reema H. Aldahiri, Elham A. Alzahrani, Sumbul Hafeez, Seungdae Oh, Saif Ali Chaudhry
Abstract
In this research, a nanoscale magnetic biosorbent was synthesized by incorporating magnetic nanoparticles (Fe3O4 NPs) into a natural carbon framework derived from black cumin (BC) seeds. The prepared Fe3O4/BC was utilized as a low-cost, eco-friendly, and reusable nanobiosorbent for the removal of organic (e.g., methylene blue (MB) dye) pollutants from synthetic solutions. The results indicated that Fe3O4/BC had extensive surface oxygenous functional groups with a high affinity for MB dye capture at different concentrations such as 10–60 mg L−1. The optimization results suggested the removal of ~99% of methylene blue from its initial concentration (i.e., 10 mg L−1) using 2.0 g L−1 of Fe3O4/BC at pH = 7, temperature = 27 °C, and contact time = 120 min, with equilibrium adsorption capacity = 5.0 mg g−1 and partition coefficient = ~57.0 L g−1. The equilibrium adsorption efficacy at the highest initial concentration (i.e., 60.0 mg L−1) was found to be 29.0 mg g−1. The adsorption isotherm was well explained by the Freundlich model for MB. The renderability of this magnetic bioadsorbent by acid treatments showed a ~66% decline in removal efficiency (%) (~99% to ~33%; ~5.0 to ~1.7 mg g−1) for MB after six repetitive cycles of adsorption and desorption. The current Fe3O4/BC gives a better partition coefficient than previously reported acid-washed BC seeds and other BC-seed-based nanobioadsorbents, Hence, a synthesized Fe3O4/BC nanobiosorbent demonstrates potential for use in treating water contaminated with organic pollutants.