Kinetic studies on the catalytic degradation of rhodamine B by hydrogen peroxide: effect of surfactant coated and non-coated iron (III) oxide nanoparticles
This article belongs to the Special Issue Current Trends and Perspectives in the Application of Polymeric Materials for Wastewater Treatment[EN] 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@Fe3O4 magnetic 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 (kobs, 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% w/v Fe3O4 or SDS@Fe3O4 NPs, kobs 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 Fe3O4 or
SDS@Fe3O4, kobs increased with NPs dosage and showed a peaked pH behavior with a maximum at
pH 3. The magnitude of thermodynamic parameters Ea 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 degradationSIMarta Otero is thankful to the Portuguese “Fundação para a Ciência e a Tecnologia” (FCT) for the Investigator Program (IF/00314/2015). We would also like to thank FCT/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) for the financial support to CESAM (UIDP/50017/2020+UIDB/50017/2020) through national fund
