Study on the enhancement of colloidal stable poly(sodium 4‐styrene sulfonate) coated magnetite nanoparticles and regeneration capability for rapid magnetophoretic removal of organic dye

• Published in: Journal of chemical technology and biotechnology (1986) 2020-12, Vol.95 (12), p.3093-3104
• Main Authors: Chong, Wai Hong, Ng, Qi Hwa, Lim, Jit Kang, Yeap, Swee Pin, Low, Siew Chun
• Format: Article
• Language: English
• Subjects: Adsorption; Aqueous solutions; Chemical pollution; Clustering; Coating; Coatings; Colloids; Color removal; Diameters; Dispersions; Dyes; environmental remediation; Light scattering; Magnetite; Methylene blue; Nanoparticles; pH effects; Photon correlation spectroscopy; Physiochemistry; Pollutants; Polyelectrolytes; Reaction kinetics; recovery; Regeneration; Sodium; Sorbents; Stability analysis; Styrene; Styrenes; Sulfonates; transmission electron microscope (TEM); Transmission electron microscopy; waste‐water; Water pollution; water treatment and waste minimization
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.6485

BACKGROUND A good colloidal stability of magnetite nanoparticles (MNPs) dispersion is of utmost importance for its environmentally related applications. In the present work, a water‐soluble anionic polyelectrolyte, poly(sodium 4‐styrene sulfonate) (PSS), was used to stabilize dispersions of MNPs in a pH‐dependent aqueous medium. RESULTS An excellent methylene blue (MB) dye removal efficiency at equilibrium of up to 94% has been observed by the colloidally stabilized nano‐magnetites. Dynamic light scattering and electrophoretic analysis showed that the PSS‐coated MNPs exhibited better colloidal stability, with an almost constant hydrodynamic diameter of ~150 nm and insignificant clustering behavior throughout the measuring time scale of 5 h. Transmission electron microscopy evidenced the success coating of PSS onto MNPs. In terms of its chemical resistance, the PSS‐coated MNPs were able to tolerate a wide pH range from 2 to 10. This work depicts a simple physiochemical coating method to stabilize dispersions of nano‐magnetites, which promoted a better MB adsorption capacity of PSS‐coated MNPs at 14.9 mg g–1 than the naked MNPs at 10.38 mg g–1. The adsorption process follows Langmuir isotherm and pseudo‐second‐order reaction kinetics with both correlations R2 > 0.99. PSS‐coated MNPs demonstrated outstanding regeneration capacity for four batch adsorption cycles with an almost consistent MB removal efficiency higher than 85%. CONCLUSION This in‐house developed nano‐sorbent has potential in economical applications with a less budgeted adsorbent replacement (at least 4 cycles of regeneration) for low‐cost separation of pollutants, such as MB from polluted water. © 2020 Society of Chemical Industry