Investigation on the release kinetics of chrome from finished chrome tanned leather

Content: Chrome tanning is the commonest tanning agent in leather manufacture, and the discard of chrome tanned leather goods inevitably leads to chrome discharge that might have potential environmental risks. In this study, the kinetic behaviors of the release of chrome and organics were investigated by ICP-OES and TOC analyzers respectively. Deionized water was used as medium, and leaching tests were proceed at solid liquid ratio 1:20 as well as rotational speed 60 r/min to simulate the release of chrome tanned leather under natural conditions. The effect of temperature on the behavior kinetics was further explored. The results showed that the release of chrome and organics could be well fitted by the second-order kinetic equation, and the rate constant for the release process indicated the release of organics was faster than chrome. Then Tenax model was used to illustrate the release kinetics experiments of chrome to obtain the three release compartments (fast, slow and very slow). The results could provide the theoretical parameters for the assessment of risks of chrome-tanned leather. Take-Away: The second-order kinetic equation could describe the release of chrome and organics from chrome tanned leather under natural environment. The activation energy of the release of chrome and organics from leather could be obtained. The fast, slow and very slow compartments of chrome release could be obtained