嗜酸硫杆菌和黑曲霉对电镀污泥重金属浸出效果

Bioleaching of heavy metals derived from electroplating sludge by Acidithiobacillus sp. and Aspergillus niger

电镀污泥重金属浸出对电镀污泥资源化利用具有重要意义。为了降低处置成本,采用嗜酸硫杆菌与黑曲霉对电镀污泥重金属浸出效果进行了研究。结果表明,采用嗜酸性氧化硫硫杆菌和氧化亚铁硫杆菌混合菌种对含固率为3%的电镀污泥进行为期15 d(培养驯化后)的处理后,污泥中Ni、Cr与Cu的浸出率虽分别高达92.8%、85.0%和96.8%,但耗时久,无法大规模地实际应用。利用黑曲霉对电镀污泥进行为期6 d的处理,Ni、Cr和Cu的浸出率分别达到92.0%、74.4%和55.3%。若采用黑曲霉培养15 d后产生的生物有机酸和同pH的柠檬酸处理电镀污泥4 h后,两者对Ni、Cr和Cu的浸出率分别为:85.0%与94.2%、63.8%与73.7%、57.9%与99.6%。可见,利用黑曲霉发酵菌液浸出电镀污泥中重金属有一定的实际应用价值。

Extraction of heavy metals from electroplating sludge has important significance for safe disposal of electroplating sludge. In this study,the performance in bioleaching of Ni,Cr,and Cu-rich electroplating sludge using Acidithiobacillus sp. and Aspergillus niger was respectively investigated through flasks experiments. The results showed that for 3% sludge solids content after 15 days of bioleaching with Acidithiobacillus ferrooxidans LX5 and Acidithiobacillus thiooxidans TS6,as high as 92. 9% of Ni,85. 1% of Cr and 96. 8% of Cu could be leached from the tested sludge. On the other hand,for the bioleaching experiments using Aspergillus niger Y9,after 6 days of incubation 3. 3 g /L of citric acid,1. 2 g /L of oxalic acid,74. 8 g /L of gluconic acid were produced and,accordingly,92% of Ni,74. 4% of Cu and 55. 3% of Cr were leached from the tested sludge. In addition,approximately 85% of Ni,63. 8% of Cr and 57. 9% of Cu were leached from the tested sludge by the 15 days incubation solution of Aspergillus niger Y9 and,in contrast,94. 2% of Ni,73. 7% of Cr and 99. 6% of Cu were leached from the tested sludge by citric acid with the same pH mentioned above. These results demonstrate the potential of Aspergillus niger for the bioextraction of valuable metals from electroplating sludge.