Abstract

Iron tanning is considered an alternative due to close similarity between the aqueous chemistry of Cr(III) and Fe(III). This arises primarily from the hydrolytic behaviour of Fe(III) complexes. An attempt has been made in the present study to improve the stability of Fe(III) complex by chelation with a suitable ligand in order to increase the shrinkage temperature of the leather. An Fe(III) based tanning system which involves a treatment with a fatty acid and a polycarboxylate has been standardized to produce leather with shrinkage temperature (Ts) >100°C. Scanning electron microscopy on the tanned leathers was used to study the structural characteristics of leathers produced. A comparative colour analysis was studied against standard chrome leather to reveal the dyeing and colour characteristics of the proposed tanning system. The excess neutral salt used in the developed process has the tendency to reduce the acidity of the metal ion, which produces iron-tanned leather with strength properties comparable to those of chrome-tanned leather.