Synthesis of CdS/CoFe2O4 nanocomposites by a novel thermal decomposition approach and their use as magnetically separable adsorbent for the removal of toxic dyes
| Main Authors: | Dimpal Tomar, P. Jeevanandam |
|---|---|
| Format: | Article Journal |
| Terbitan: |
, 2021
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| Online Access: |
https://zenodo.org/record/5373709 |
Daftar Isi:
- Introduction: Adsorbents which are magnetic are very useful in the adsorption process due to their easy and rapid magnetic separation after adsorption (1). In order to achieve this goal, combination of metal ferrite nanoparticles and metal sulfide nanoparticles in a nanocomposite has been proposed in the present study. CoFe2O4 nanoparticles are promising due to their high magneto-crystalline anisotropy, higher coercivity and moderate saturation magnetization compared to other metal ferrite nanoparticles (2). Cadmium sulfide which is a semiconductor (band gap = 2.45 eV) is a valuable candidate for many applications. The reported synthetic methods for the synthesis of CdS/CoFe2O4 nanocomposites often require stringent reaction conditions. In order to overcome these limitations, a simple thermal decomposition approach has been proposed in the present study. After characterization, the adsorption efficiency of CdS/CoFe2O4 nanocomposites towards the adsorption of rhodamine B (RhB) from an aqueous solution has been tested. Methods: CoFe2O4 nanoparticles (CFG-220°C (500)) were first synthesized via glycolate route followed by calcination (3). For the synthesis of nanocomposites, cadmium acetate and thiourea were added to 10 mL diphenyl ether in a 50 mL round bottom flask followed by refluxing in air at 220 ̊C for 90 min in the presence of CoFe2O4 nanoparticles. Cadmium acetate to thiourea molar ratio was varied as 0.1:0.1, 0.25:0.25 and 0.50:0.50 for the synthesis of nanocomposites CdS/CF (0.10), CdS/CF (0.25) and CdS/CF (0.50), respectively. Results & Discussion: Powder XRD results indicate the presence of CdS and CoFe2O4 phases in the nanocomposites. The intensity of XRD peaks due to CdS increases and that due to CoFe2O4 decreases in the nanocomposites as the concentration of precursors (cadmium acetate and thiourea) is increased. EDX results indicate the presence of Cd, S, Co, Fe in the nanocomposites with uniform distribution. TEM image of pure CoFe2O4 nanoparticles suggests that the sample consists of nanoparticles with mean particle size of 20.3 ± 5.1 nm. In CdS, CdS/CF(0.25) and CdS/CF(0.50) agglomerated nanoparticles with mean particle size of 11.2 ± 1.2 nm, 13.0 ± 2.9 nm and 14.3 ± 3.5 nm, respectively are observed. SAED patterns of the nanocomposites, CdS and CoFe2O4 nanoparticles indicate their polycrystalline nature. The CdS/CoFe2O4 nanocomposites are soft ferrimagnetic and they exhibit lower Ms and Mr compared to pure CoFe2O4 nanoparticles. The nanocomposites show higher adsorption efficiency with higher pseudo second order rate constant and equilibrium adsorption capacity compared to CdS and CoFe2O4 nanoparticles. Conclusions: CdS/CoFe2O4 nanocomposites were synthesized via a novel thermal decomposition method. XRD, EDX SAED, and TEM results confirm the presence of CdS and CoFe2O4 nanoparticles in the nanocomposites. The nanocomposites are soft ferrimagnetic and they are promising magnetically separable adsorbent for the adsorption of RhB from an aqueous solution. Keywords: Nanocomposites, Thermal decomposition method, Magnetically separable adsorbent References 1. Jarrah, A, Farhadi, S. Preparation and Characterization of Novel Polyoxometalate/CoFe2O4/Metal–Organic Framework Magnetic Core–Shell Nanocomposites for the Rapid Removal of Organic Dyes from Water. RSC Adv. 2020;10:39881–39893. https://doi.org/10.1039/d0ra04603e. 2. Ansari H, Miralinaghi M, Azizinezhad F. CoFe2O4/Chitosan Magnetic Nanocomposite: Synthesis, Characterization and Application for Adsorption of Acidic Yellow Dye from Aqueous Solutions. Cellul. Chem. Technol. 2019;53:191–204. https://doi.org/10.35812/cellulosechemtechnol.2019.53.20. 3. Tomar D, Jeevanandam P. Synthesis of Cobalt Ferrite Nanoparticles with Different Morphologies via Thermal Decomposition Approach and Studies on Their Magnetic Properties. J. Alloys Compd. 2020;843. Article ID.155815. https://doi.org/10.1016/j.jallcom.2020.155815.