Formation conditions and stability of a toxic tridecameric Al polymer under a soil environment

Akira Etou, Shuqin Bai, Tomoyuki Saito, Hiroaki Noma, Yoshihiro Okaue, Takushi Yokoyama

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


It is important to study the formation conditions and the stability of the tridecameric Al polymer (Keggin-type Al13 polycation, [AlO4Al12(OH)24(H2O)12]7+, known as Al13) due to its strong toxicity to living organisms of a soil environment. In order to examine the pH range where toxic Al13 can exist in aqueous solution, 27Al NMR spectra for sample solutions containing Al3+ ions with various pH (pH 3.5-6.1) were measured. The results show that the peak due to Al13 (peak due to 4-coordinated Al around 63 ppm) appeared at pH 3.6-5.7 and the peak intensity was relatively high at pH 4.1-4.8, suggesting that Al13 can be formed at pH 3.6-5.7, while it can exist dominantly at pH 4.1-4.8. It was also found that Al13 can stably adsorb onto a chelate resin, Chelex 100, by weak electrostatic interaction. The Chelex 100, with iminodiacetate groups, served as a model compound for surfaces of microbes covered with carboxyl groups and for surfaces of soil particles covered with humic substances having many carboxyl groups. Additionally, decomposition of Al13 did not occur even after adsorption, and its pH stability range was wide compared to that in aqueous solution.

Original languageEnglish
Pages (from-to)606-609
Number of pages4
JournalJournal of Colloid And Interface Science
Issue number2
Publication statusPublished - Sept 15 2009

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


Dive into the research topics of 'Formation conditions and stability of a toxic tridecameric Al polymer under a soil environment'. Together they form a unique fingerprint.

Cite this