Ageing in the inorganic nanoworld: Example of magnetite nanoparticles in aqueous medium

E. Tombácz, E. Illés, Andrea Majzik, Angéla Hajdú, Nóra Rideg, M. Szekeres

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Changes in the inherent solid phase and aqueous interfacial properties of magnetite nanoparticles in a Massart type magnetic fluid were investigated. Magnetite nanoparticles were synthesized, purified, dialyzed against 0.001 mol dm-3 HCl and then stored at 4 °C for 6 years. The solid phase transformation of magnetite to maghemite and formation of akageneite shell on the magnetic core, as well as a slight increase in particle size were proved, causing no change in the superparamagnetic features of nanoparticles after storage as long as 6 years. The aqueous interfacial properties, however, were altered in a strange way. Surprisingly, neither the surface charge density nor the particle charge in acidic region showed significant changes, except for a definite decrease in pHpzc and pHiep from pH ≈ 8 to ≈ 7. Coalescence of akageneite shell during recrystallization resulted in a significant decrease of the specific surface area of the aged sample, and probably contributed to its declining colloidal stability.

Original languageEnglish
Pages (from-to)503-515
Number of pages13
JournalCroatica Chemica Acta
Volume80
Issue number3-4
Publication statusPublished - 2007

Fingerprint

Magnetite Nanoparticles
Aging of materials
Ferrosoferric Oxide
Magnetic cores
Magnetic fluids
Surface charge
Charge density
Coalescence
Specific surface area
Phase transitions
Particle size
Nanoparticles

Keywords

  • Colloidal stability
  • Magnetic fluids
  • pH-dependence
  • Recrystallization
  • Solubility
  • Surface charging

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Ageing in the inorganic nanoworld : Example of magnetite nanoparticles in aqueous medium. / Tombácz, E.; Illés, E.; Majzik, Andrea; Hajdú, Angéla; Rideg, Nóra; Szekeres, M.

In: Croatica Chemica Acta, Vol. 80, No. 3-4, 2007, p. 503-515.

Research output: Contribution to journalArticle

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