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United States Department of Agriculture

Agricultural Research Service

Research Project: NEW AND EFFICIENT PROCESSES FOR MAKING QUALITY LEATHER Title: Modeling of salt diffusion in raw hide: an optimization of the curing process

Authors
item Hernandez, Eduard - VISITING SCIENTIST
item Marmer, William
item Kolomaznik, Karel - TOMAS BETA UNIVERSITY
item Dudley, Robert

Submitted to: American Leather Chemists Association Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 30, 2006
Publication Date: June 20, 2007
Citation: Hernandez, E., Marmer, W.N., Kolomaznik, K., Dudley, R.L. 2007. Modeling of salt diffusion in raw hide: an optimization of the curing process [abstract]. American Leather Chemists Association Meeting. p. 7.

Technical Abstract: The most common method of preserving raw hides is brine curing with sodium chloride. However, this process has three important disadvantages: first, the length of time that it takes, which is a minimum of 18 hours; second, the insufficient degree of curing reached in some hides due to an overload and possibly the low efficiency of the brine raceway; and finally, the environmental impact associated with the discharge of large quantities of electrolytes in the soaking step. Our long term goal is to address all three issues. Initially, we have carried out a study of the salt uptake and its diffusion mechanism in order to attempt a reduction in the curing time. A continuous reaction mathematical model of a closed one dimensional system that describes the diffusion of sodium chloride in the hide during the curing process was chosen in the search for the optimum brine curing conditions such as the optimum brine concentration and percent float. The effect of these two parameters on the values of effective diffusivity coefficients was reported. Moreover, the dependency of these coefficients with time was examined, showing an initial fast uptake zone followed by a slow and quite flat uptake zone. Brine diffusion into the hide was tracked by measurement of the electrolytic conductivity of the residual brine solution and moisture and ash content of the cured hide. In addition, a piece of hide was cured with a fluorescently labeled brine solution and analyzed by means of confocal laser scanning microscopy for direct visualization of the sodium location within the hide.

Last Modified: 4/23/2014
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