Process effect, pollution analysis, and product quality comparison of wet-blue prepared from seawater vs. industrial water based on benchmarking method

Abstract： To reduce the freshwater intake in the leather-making industry, seawater was used instead of industrial water to prepare the wet-blue. Firstly, the main components and key indicators of the seawater after simple pre-treatment and the industrial water were compared and analyzed; then, using wet-salted bovine hide as raw material and industrial water as a benchmarking, the process effects of seawater of soaking, liming, deliming, softening, pickling, and chrome tanning, as well as the different pollutants content in the different discharged waste liquid, and the performances of resulted wet-blue were investigated. Furthermore, the properties of the obtained crust and finished leather were also investigated. The experimental results show that compared to conventional industrial water, the application of seawater in leather-making had better soaking and liming process effects; and except for the high content of chloride ions, the content of other pollutants in the waste liquids were relatively close; and the obtained wet-blue, crust, and finished leather also had better sensory performance and physical-mechanical properties. All these experimental results indicated that using seawater instead of industrial water to prepare the wet-blue was feasible, which provided a new approach to solving the problem of freshwater resource shortage in the leather-making industry.