Characterization of partially neutralized ferric chloride solutions

• Published in: Journal of colloid and interface science Vol. 56; no. 2; pp. 284 - 297
• Main Authors: Murphy, P.J, Posner, A.M, Quirk, J.P
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.1976
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(76)90254-X

In all the ferric choride solutions the initial polycations were discrete spheres 1.5-3 nm (diameter). The subsequent aging processes depended on the ferric concentration and total ionic strength. In the 0.1 M solution (OH/Fe > 1.0) the spheres formed short rods of 2–5 spheres with widths of 2 nm. With aging, the spheres coalesced and the rods increased in both length and thickness to give rods ∼20 × 3 nm. These formed raft-like arrays and were identified as βFeOOH. The same process was found in the 0.26 M solutions and the 0.1 and 0.02 M solutions, both 1 M in chloride. The rate of formation of the rafts was much more rapid and they became large enough to settle out on standing. The 0.0165 M solution also formed spheres and rods composed of spheres. These rods remained 2 nm wide over the aging period and formed side-by-side pairs. It was these “pairs” that eventually formed into rafts of βFeOOH.