制革不同工段皮革碎料中铬的稳定性研究

Stability of Chromium in Leather Wastes from Different Workshop Sections in Tannery

研究选取单一浸提剂进行一步或多步提取、系列提取剂连续法对铬鞣、染整和涂饰工段后不同含铬皮革碎料进行了铬的浸出浓度分析和毒性评价。结果表明,皮革碎料中总铬浸出质量浓度随着工段延续依次降低,蓝湿革总铬浸出质量浓度最高为32.58 mg/L。染色革和涂饰革的总铬浸出质量浓度范围分别为11.16~16.51 mg/L和9.43~13.28 mg/L。采用1 mol/L柠檬酸钠对各样品进行72 h内一步浸提时,碎料中总铬浸出率亦随工段延续依次降低,其浸出率分别为81.9%、45.8%和38.1%。连续提取结果显示,总铬浸出质量浓度高于标准值的样品中碱溶态、酸溶态的铬含量均高于其他样品。扫描电子显微镜、能谱仪和红外光谱分析显示,有机酸盐处理后的染色皮革和涂饰皮革均保留了胶原的纤维束结构,这为含铬碎料无害化处置和再生利用效果评估提供了依据。

This work chose single leaching agent for one-step or multi-step leaching,and a series of leaching agents was used for continuous extraction method to analyze the leaching concentration and toxicity assessment of chromium from chromium tanned,dyed and finished leather scraps.Results showed that the total chromium leaching mass concentration in leather scraps decreased with the extension of the stage.The highest total chromium leaching mass concentration of wet blue leather was 32.58 mg/L.The total chromium leaching mass concentration ranges of the dyed and finished leather were 11.16-16.51 mg/L and 9.43-13.28 mg/L,respectively.Using 1 mol/L sodium citrate for one-step leaching of each sample within 72 h,the total chromium leaching rate in the crushed materials also decreased with the continuation of the process,with leaching rates of 81.9%,45.8%and 38.1%,respectively.The continuous extraction results showed that the alkali-soluble and acid-soluble chromium contents in samples with total chromium leaching mass concentration higher than the standard value were higher than other samples.Results of scanning electron microscopy,energy dispersive spectrometer and infrared spectroscopy indicated that both dyed and finished leather,treated with organic acid salts,retained the collagen fiber bundle structure,which provides a basis for the assessment of the effect of harmless disposal and recycling of chromium-containing shredded materials.