Sodium and potassium ferrocyanide derived Prussian blue pigment
Abstract
Purpose
This study aims to synthesize Prussian blue {FeIII4[FeII(CN)6]3} pigment by reacting ferric chloride with different ferrocyanides through the same procedure. The influence of the ferrocyanide used on resulting pigment properties is studied.
Design/methodology/approach
Prussian blue is commonly synthesized by direct or indirect methods, through iron salt and ferrocyanide/ferricyanide reactions. In this study, the direct, single-step process was pursued by dropwise addition of the ferrocyanide into ferric chloride (both as aqueous solutions). Two batches – (K-PB) and (Na-PB) – were prepared by using potassium ferrocyanide and sodium ferrocyanide, respectively. The development of pigment was confirmed by an identification test and characterized by spectroscopic techniques. Pigment properties were determined, and light fastness was observed for acrylic emulsion films incorporating dispersed pigment.
Findings
The two pigments differed mainly in elemental detection owing to the dissimilar ferrocyanide being used; IR spectroscopy where only (Na-PB) showed peaks indicating water molecules; and bleeding tendency where (K-PB) was water soluble whereas (Na-PB) was not. The pigment exhibited remarkable blue colour and good bleeding resistance in several solvents and showed no fading in 24 h of light exposure though oil absorption values were high.
Originality/value
This article is a comparative study of Prussian blue pigment properties obtained using different ferrocyanides. The dissimilarity in the extent of water solubility will influence potential applications as a colourant in paints and inks. K-PB would be advantageous in aqueous formulations to confer a blue colour without any dispersing aid but unfavourable in systems where other coats are water-based due to their bleeding tendency.
Keywords
Acknowledgements
Funding. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.
Declaration of competing interest. The authors declare that there is no conflict of interest.
Citation
Sanghvi, M.R., Chugh, K.W. and Mhaske, S.T. (2024), "Sodium and potassium ferrocyanide derived Prussian blue pigment", Pigment & Resin Technology, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/PRT-10-2023-0087
Publisher
:Emerald Publishing Limited
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