The influence of chloride ions on the formation of iron(III) oxyhydroxide

Reconciling kinetic and equilibrium observations of iron(III) solubility in aqueous solutions with a polymer-based model

“…Even when this is accounted for, effects of other common constituents of natural waters are usually not. For example, chloride, nitrate, sulphate, silicate and phosphate anions can participate in the Fe(III) precipitation process (Dousma et al, 1978(Dousma et al, , 1979Rose et al, 1996Rose et al, , 1997aSchwertmann et al, 1999;Doelsch et al, 2003), a fact that may also contribute to the sub-optimal fit of solubility models to data.…”

Effect of base addition rate on the preparation of partially neutralized ferric chloride solutions

“…The pH evolution of hydrolyzed Fe(III) solutions was studied by numerous researchers [2,6,7,9,[11][12][13][14][15][16] and was observed to decrease with time. Tang and Stumm [2] indicated that an induction period was observed for B = 0.2-0.5 before pH decrease (relaxation).…”

“…Many researchers have used turbidity (light scattering) or light absorption to observe the change of aging PICl solutions [6,7,[9][10][11]. Fresh FeCl 3 is yellowish orange with a turbidity of 4-7 NTU.…”

“…The partially neutralized Fe(III) solutions are not in equilibrium and are subject to changes upon aging. The changes observed upon aging of the solution include an increase in particle sizes as characterized by electron microscopy [6][7][8], light absorption [6,7,9,10], and light scattering [6,11] and a decrease in pH [2,6,7,9,[11][12][13][14][15][16]. Spiro et al [17] have isolated some sort of Fe(III) polycation containing 900 iron atoms which has a molecular weight of ∼2.4 × 10 5 and a size of ∼7 nm.…”

“…A special vessel has been designed and used by a number of researchers to accomplish rapid homogeneous mixing [6,7,9,12,13]. A majority of authors have worked on a fixed base addition rate, typically less than 10 µl/s [1,2,[6][7][8][9][10][11][12][13][14][15][16]21].…”