Premium
Mononuclear and Polynuclear Aluminum Speciation through Differential Kinetic Reactions with Ferron
Author(s) -
Jardine P. M.,
Zelazny L. W.
Publication year - 1986
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1986.03615995005000040013x
Subject(s) - chemistry , absorbance , monomer , kinetics , inorganic chemistry , polymer , chromatography , organic chemistry , physics , quantum mechanics
Abstract The kinetic reaction of ferron (8‐hydroxy‐7‐iodo‐5‐quinoline‐sulfonic acid) with partially neutralized Al solutions of varying basicity and age were investigated with the intent of separating mononuclear and polynuclear Al. Ferron solutions buffered with varying quantities of NaOAc, NH 2 OH·HCl, and acetic acid suggested that reduction of ferron by NH 2 OH·HCl may be essential before monotonically increasing absorbance vs. time functions occur for Al reactions with ferron. When ferron is buffered with appropriate quantities of NaOAc and NH 2 OH·HCl it must be aged for ⋍5 d at room temperature until reduction has slowed. This solution remains stable for ⋍25 d and exhibits consistent kinetic reactions with Al during this time period. A large portion of ferron interactions with partially neutralized Al of varying basicity and age were described by a binary species first‐order rate function, which provided the rates of monomer and small polymer reactions with ferron as well as the mole fraction of monomeric species present ( f a ). Modelfitted f a are based on the differential kinetic reactions of ferron with Al, thus arbitrary separation times for determining mononuclear and polynuclear Al are avoided. Rate parameters established for mononuclear Al solutions using a single species first‐order equation compared well with those determined for mononuclear Al from partially neutralized solutions using the binary species model. Ferron reactions at longer times were related to the decomposition of large Al polymers, which were welldescribed by pseudo first‐order kinetics.