Hybrid magnetic CoFe₂O₄@γ-Fe₂O₃@CTAB nanocomposites as efficient and reusable adsorbents for Remazol Brilliant Blue R dye

ABSTRACT

The main goal of the present survey was to elaborate, characterize and evaluate the efficiency of ferrite-based nanoparticles modified with cetyltrimethylammonium bromide (CTAB) as potential magnetic nanoadsorbents to remove Remazol Brilliant Blue R (RBBR) from water. It is proposed an innovative nanomaterial architecture based on highly magnetic and chemically stable core@shell nanoparticles covered by an adsorptive surface layer of CTAB (CoFe₂O₄@γ-Fe₂O₃@CTAB). Samples of two different mean sizes (7.5 and 14.6 nm) were synthesized using a hydrothermal coprecipitation followed by surface treatment and functionalization. Batch tests were performed to evaluate the influence of contact time, temperature, pH, shaking rate, presence of interferents and mean size on the performance of the proposed nanomaterials. The kinetics of the adsorption process followed the pseudo-second-order model with an equilibrium time of 20 min. The adsorption capacity was estimated by the Langmuir isotherm model and was found to be 56.3 mg/g (smaller size) and 45.6 mg/g (larger size) at pH = 3 and a shaking rate of 400 rpm. The process was spontaneous, exothermic, and showed increased randomness. Sulphate ions negatively impacted the removal of RBBR. The best performance of the nanoadsorbent based on smaller mean sizes can be correlated to its larger surface area. Regeneration and readsorption tests showed that the nanoadsorbents retain more than 80% of their original removal capacity, therefore they can be effectively recycled and reused.

GRAPHICAL ABSTRACT

KEYWORDS:

• Magnetic nanoadsorbents
• dye removal
• adsorption
• water remediation
• magnetic separation

Acknowledgements

Authors gratefully acknowledge Prof. José Alves Dias (LabCat – Institute of Chemistry – University of Brasília, Brazil) for the BET experiments and analysis. The authors also thank Dr. Tatiane Oliveira dos Santos (LabMic – Federal University of Goiás, Brazil) for the TEM analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors con firm that the data supporting the findings of this study are available on request to the Corresponding author.

Additional information

Funding

This work was supported by the Brazilian agencies: the National Council for Scientific and Technological Development (CNPq) [grant number 400849/2016-0], and the Distrito Federal Research Foundation (FAP-DF) [grant numbers 0193.001194/2016, 0193.001569/2017 and 0193-00000229/2021-21].