Abstract:

Metal cyanide complexes are highly stable and refractory environmental pollutants in nature, making them challenging to be removed through chemical oxidation. In the present study, potassium ferricyanide and potassium ferrocyanide we used as representative model substrates to investigate the biodegradation of iron complexes by a previously screened consortium capable of degrading metal-cyanide complexes. Our findings revealed an initial lag phase of approximately 8 hours for the growth of the degrading consortium in a system containing (45±2.5)mg/L Fe-cyanide complex, reaching a stationary phase after 36 hours. Under condition of 30℃ and 120r/min, the degradation efficiency reached 71.7%±1.2% within 5 days. It was found that the Fe-cyanide complexes could be served as a nitrogen source for the growth of degrading consortium and were degraded into formic acid, ammonium and ferric/ferrous ions. Furthermore, our results demonstrated that the degrading consortium effectively remediated simulated soils contaminated with (52.00±1.00)mg/kg of Fe-cyanide complexes, achieving a remediation efficiency of 64.3%±1.8% within 14 days by adding glucose at a C/N of 6∶1. This study would lay the groundwork for further developing an environmental-friendly technology of removing metal cyanide complexes.

Key words: metal cyanide complexes, biodegradation, soil remediation

摘要：

金属络合氰化物是自然界中性质非常稳定、难以衰减或分解的一类环境污染物，采用化学氧化法难以去除。本文以铁氰络合物（铁氰化钾、亚铁氰化钾）为典型模型底物，对前期筛选获得的金属络合氰化物降解菌群进一步开展铁氰络合物生物降解研究。结果表明，菌群在浓度为(45±2.5)mg/L铁氰络合物体系中，30℃、120r/min条件下，经过约8h生长延滞，36h后达到生长稳定期，对铁氰络合物的降解率第5天达到71.7%±1.2%。实验确认菌群能直接利用铁氰络合物作为氮源生长，铁氰络合物被降解转化为甲酸、铵和铁离子/亚铁离子。采用菌群对模拟受铁氰络合物(52.00±1.00)mg/kg污染的土壤进行生物修复获得了良好的效果，按照碳氮摩尔比为6∶1的比例添加葡萄糖进行生物刺激处理，受污染土壤第14天的生物修复效率可达到64.3%±1.8%。上述研究结果为进一步发展环境友好的金属络合氰化物处理技术提供了基础。

关键词: 金属络合氰化物, 生物降解, 土壤修复