Ethylthionocarbamates (ETC), which is the most widely used as collectors in the flotation of sulfide, is known to cause serious pollution to soil and groundwater. The potential biodegradation of ETC was evaluated by applying a mixed culture of iron-reducing bacteria (IRB) enriched from tailings dam sediments. The results showed that ETC can be degraded by IRB coupled to Fe(III) reduction, both of which can be increased in the presence of anthraquinone-2,6-disulfonate (AQDS). Moreover, Fe(III)-EDTA was found to be a more favorable terminal electron acceptor compared to α-Fe2O3, e.g., within 30 d, 72％ of ETC was degraded when α-Fe2O3+AQDS was applied, while it is 82.67％ when Fe(III)-EDTA+AQDS is added. The dynamic models indicated that the kETC degradation was decreased in the order of Fe(III)-EDTA+AQDS>α-Fe2O3+AQDS>Fe(III)-EDTA>α-Fe2O3, with the corresponding maximum biodegradation rates being 2.6, 2.45, 2.4 and 2.0 mg/(L·d), respectively, and positive parallel correlations could be observed between kFe(III) and kETC. These findings demonstrate that IRB has a good application prospect in flotation wastewater.%乙硫氨酯是一种广泛使用的硫化矿捕收剂,其大量使用给土壤和水体造成了严重的污染.本文研究了尾矿库底泥沉积物中的异化铁还原混合菌群对乙硫氨酯的降解能力.结果表明:异化铁还原混合菌群可以有效地降解乙硫氨酯,并耦联着铁的还原,蒽醌-2,6-二磺酸钠的加入可以有效提高乙硫氨酯的降解速率和铁的还原速率.相对赤铁矿而言,EDTA络合铁是更好的电子受体,例如,在异化铁还原混合菌群降解乙硫氨酯的过程中,加入赤铁矿和蒽醌-2,6-二磺酸钠时,30 d的乙硫氨酯的去除率为72％,而加入EDTA络合铁和蒽醌-2,6-二磺酸钠时,30 d的去除率为82.67％.在加入EDTA络合铁和蒽醌-2,6-二磺酸钠、赤铁矿和蒽醌-2,6-二磺酸钠、EDTA络合铁和赤铁矿条件下,乙硫氨酯的最大生物降解速率分别为2.6,2.45,2.4和2.0 mg/(L·d),铁的还原速率和乙硫氨酯的降解速率常数呈现很好的正相关性.研究表明异化铁还原菌在浮选废水处理方面具有良好的应用前景.
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