Kinetic Studies on the Catalytic Degradation of Rhodamine B by Hydrogen Peroxide: Effect of Surfactant Coated and Non-Coated Iron (Iii) Oxide Nanoparticles

• Main Authors: Mohd Shaban Ansari, Kashif Raees, Moonis Ali Khan, M.Z.A. Rafiquee, Marta Otero
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Polymers
• Subjects: magnetite; co-precipitation method; Rhodamine B; sodium dodecyl sulfate; wastewater treatment
• Online Access: https://www.mdpi.com/2073-4360/12/10/2246
• ISSN: 2073-4360

Iron (III) oxide (Fe₃O₄) and sodium dodecyl sulfate (SDS) coated iron (III) oxide (SDS@Fe₃O₄) nanoparticles (NPs) were synthesized by the co-precipitation method for application in the catalytic degradation of Rhodamine B (RB) dye. The synthesized NPs were characterized using X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infra-red (FT-IR) spectroscopy techniques and tested in the removal of RB. A kinetic study on RB degradation by hydrogen peroxide (H₂O₂) was carried out and the influence of Fe₃O₄ and SDS@Fe₃O₄magnetic NPs on the degradation rate was assessed. The activity of magnetic NPs, viz. Fe₃O₄ and SDS@Fe₃O₄, in the degradation of RB was spectrophotometrically studied and found effective in the removal of RB dye from water. The rate of RB degradation was found linearly dependent upon H₂O₂ concentration and within 5.0 × 10⁻² to 4.0 × 10⁻¹ M H₂O₂, the observed pseudo-first-order kinetic rates (k_obs, s⁻¹) for the degradation of RB (10 mg L⁻¹) at pH 3 and temperature 25 ± 2 °C were between 0.4 and 1.7 × 10⁴ s⁻¹, while in presence of 0.1% <i>w</i>/<i>v</i> Fe₃O₄ or SDS@Fe₃O₄ NPs, k_obs were between 1.3 and 2.8 × 10⁴ s⁻¹ and between 2.6 and 4.8 × 10⁴ s⁻¹, respectively. Furthermore, in presence of Fe₃O₄or SDS@Fe₃O₄, k_obs increased with NPs dosage and showed a peaked pH behavior with a maximum at pH 3. The magnitude of thermodynamic parameters E_a and ΔH for RB degradation in presence of SDS@Fe₃O₄ were 15.63 kJ mol⁻¹ and 13.01 kJ mol⁻¹, respectively, lowest among the used catalysts, confirming its effectiveness during degradation. Furthermore, SDS in the presence of Fe₃O₄ NPs and H₂O₂ remarkably enhanced the rate of RB degradation.