腐殖质/铁氧化物协同促进2,4-D微生物厌氧降解

摘要

构建“铁/腐殖质还原菌(Comamonas koreensis,CY01)、腐殖质模式物、铁氧化物、2,4-D”厌氧反应体系,研究2,4-D转化效率与转化途径,探讨2,4-D转化促进机制.结果表明,CY01对2,4-D的直接脱氯效果微弱,蒽醌-2,6-二磺酸钠(AQDS)与针铁矿(α-FeOOH)的加入可有效促进2,4-D厌氧转化,25 d时降解率提高2倍,达33.3％. CY01/AQDS/α-FeOOH/2,4-D体系中,AQDS、Fe(Ⅲ)及2,4-D微生物还原3种过程同时存在,AQDS和Fe(Ⅲ)充当电子穿梭体,加速胞内电子向胞外2,4-D的转移,协同促进2,4-D还原脱氯.本研究可为难降解有机氯农药污染土壤的修复研究提供借鉴.%The biotransformation of 2,4-D was studied in an anaerobic system of Fe(Ⅲ)/humus-reducing bacteria (Comamonas koreensis, CY01)/humus analog/iron oxide/2,4-D. The results showed that the CY01 biotic system alone exhibited low 2,4-D dechlorination rate, and the rate was significantly accelerated by the presence of iron oxide (α-FeOOH) and humus analog (sodium anthraquinone-2,6-disulphonate, AQDS). On the 25th day, 2,4-D biodegradation efficiency increased two times to 33.3% in the CY01/AQDS/α-FeOOH treatment than in CY01 biotic treatment. Fe(Ⅲ)/AQDS reduction and 2,4-D biodegradation by strain CY01 occurred simultaneously. AQDS and α-FeOOH could severed as the electron shuttles between the strain CY01 and 2,4-D to facilitate 2,4-D reductive dechlorination. The study would be helpful for exploring in-situ remediation strategies of organic chlorine pesticides-contaminating sites in iron oxide or humus-rich environments.