The wastewater pollution of tanneries is of high concern. The investigation of technologies to minimize the consumption of chemicals in the leather production process can reduce the environmental burden. We focus on the reduction of ammonium salts in the leather production process. Salt-free deliming of animal hides with compressed carbon dioxide as deliming agent is performed for the first time in a technical scale 20-L drum. As a result, CO₂-deliming at 30 bar and 30 °C is two times faster than conventional deliming. In addition, the deliming efficiency is slightly improved. The initial calcium (Ca) content of the hides of 8 g/kg reaches the lowest value of 2 g/kg after a process time of 3 h. However, a process time of 60 min is sufficient to reach an elimination of 50 wt% of the initial lime. The resulting Ca-content of 4 g/kg after 60 min CO₂-deliming at 30 bar is comparable with the Ca-content of conventional delimed hide. We clarify that the ampholytic character of the collagen itself enables a buffering of the pH-value at pH-7. The stable pH-value supports the selection of specific bating enzymes that decompose non-collagen proteins. No buffering salts contaminate the wastewater. The high-pressure CO₂-deliming process has high potential to reduce wastewater emissions, save costs for chemicals, and process time in industrial beamhouse applications.

制革厂的废水污染备受关注。研究在皮革生产过程中尽量减少化学品消耗的技术可以减少环境负担。我们专注于减少皮革生产过程中的铵盐。首次在工业规模20L转鼓中以压缩二氧化碳为脱灰剂对动物皮进行无盐脱灰。因此，CO ₂- 在 30 bar 和 30 °C 下脱灰比传统脱灰快两倍。此外，脱灰效率略有提高。生皮的初始钙 (Ca) 含量为 8 克/千克，经过 3 小时的处理时间后达到最低值 2 克/千克。然而，60 分钟的处理时间足以消除 50%（重量）的初始石灰。在 30 bar 压力下进行 60 分钟 CO ₂脱灰后所得的 Ca 含量为 4 g/kg，与常规脱灰生皮的 Ca 含量相当。我们澄清，胶原蛋白本身的两性特性能够缓冲 pH-7 的 pH 值。稳定的 pH 值支持选择分解非胶原蛋白的特定软化酶。没有缓冲盐污染废水。高压 CO ₂-脱灰过程在减少废水排放、节省化学品成本和工业温室应用的处理时间方面具有巨大潜力。