铬革屑和亚铁作还原剂制备铬-铁鞣剂

Preparation of Cr-Fe Tanning Agent Reduced by Chrome Shaves and Iron

用铬革屑和亚铁作还原剂,采用两步还原法制备铬-铁鞣剂,不仅可解决完全用革屑作还原剂制备铬鞣剂存在的问题,而且引入了无毒性具有鞣性的Fe3+,可进一步减少铬污染。通过考察铬铁配比、碱度对铬-铁鞣剂稳定性、鞣革性能的影响规律,改进合成方法、优化反应条件和蒙囿剂组合,合成出铬铁配比分别为1.5∶1、2∶1,一系列不同碱度的铬鞣剂,并通过大量试验建立了硫酸用量的理论计算公式。采用电位滴定、紫外-可见光谱分析等手段,考察了新型有机铬-铁鞣剂的稳定性和结构。

Chromium - rion（ Cr - Fe） tanning agent prepared by using chrome shavings in combination with Fe^2＋ as reducing agent would not only solve the problem of reducing the residual Cr（ Ⅵ ）, a crucial problem related to the reaction between shavings and Cr（ Ⅵ） ,but would also introduce nontoxic iron（ Ⅲ ） into the complexes to improve and sustain tanning properties, and thereby minimizing the potential of chromium pollution. By investigating the influence of Cr/Fe ratios, basicity on the storage stability and tanning properties of preparation, synthesis methods was selected and improved. It also became possible to optimize both the reaction parameters and mixture ratios of masking agent with Cr（ Ⅲ ）. A series of novel organic Cr - Fe tanning agents were prepared i） with the Cr/Fe ratios being 1.5： land 2： 1, ii） masked by tartrate and citrate and iii） adjusted to various basicities. For- mulae were also developed to calculate the demand quantity of sulfuric acid. The stability, and structure of each prepared tanning agent was investigated by potentiometric titration and ultraviolet -visible spectroscopy.