Zur Best?ndigkeit von Aluminiumchloridl?sungen mit tridekameren Kationen (Al 13 )

摘要

Background, aim, and scope The focus of popular interest on the subject of acid rain has been on the effects, which it has on aquatic ecosystems. Aluminium toxicity and the bioavailability depend on the species of aluminium present. The cationic aluminium species are important for the phytotoxocity and for the precipitation of aluminium containing precipitate. Materials and methods Speciation diagrams of aqueous aluminium chloride solutions with tridecameric cations (Al13) at room temperature as function of concentration (1·10–1–1·10–5 mol·l–1 Al) and aging time (9 month) have been obtained from a kinetic method; these Ferron method offers a simple and inexpensive alternative for identification and quantification of aluminium cations. Results The Al13-cation stability decrease with decreasing concentration and increasing aging time. Discussion Polynuclear aluminium species can be formed in nature by the dissolution of Al-containing minerals, as a consequence of surface water acidification, followed by neutralization process. The question of the occurrence of the tridecameric polycation (Al13) in natural soil solutions and stream waters is of considerable interest. Conclusions The results are important on the occurrence of the Al13 in natural waters, for the precipitation of aluminium species by acidification and for the aluminium phytotoxicity. Recommendations and perspectives This research suggests strongly that Al13 should be negligible in natural soil and surface waters. The toxicity of Al13 to plants and aquatic organism in natural conditions may be considered to be very?low.