臭氧降解低浓度四溴双酚A及生物毒性控制

Degradation of low concentration tetrabromobisphenol A and toxicity controlling by ozone

为考察臭氧氧化技术对水中低质量浓度四溴双酚A的降解和毒性控制效能,利用臭氧反应装置研究不同pH和臭氧投加量条件下四溴双酚A(质量浓度为0.15mg/L)的降解效果,考察反应过程中水样的急、慢性毒性和遗传毒性的变化规律及控制效果,分析毒性变化内在原因,并提出可能性降解机理.结果表明,当溶液pH为7.0、臭氧投加量为0.12mg/L,四溴双酚A可被完全降解.反应初期,水样的急、慢性毒性迅速升高,原因主要是产生了毒性更高的有机中间产物;随着反应的进行,有毒中间产物被深度降解,急、慢性毒性均得到有效控制,且随着臭氧投加量的增加毒性控制得更快、更显著.当臭氧投加量为0.12mg/L时,急性毒性在反应20min时即可被完全控制,慢性毒性在反应60min也被控制至0.76TU,反应后水样的急、慢性毒性均满足排放标准.反应过程中水样的致突变比均小于2.0,不具有基因水平的遗传毒性.降解机理分析表明,臭氧降解四溴双酚A主要包括脱溴、β位断裂、加成、去羟基化、甲基化等反应过程.

Aiming at investigating the degradation of low concentration tetrabromobisphenol A(TBBPA)in water and toxicity controlling by ozone oxidizing technology,the degradation of TBBPA(concentration:0.15 mg/L)was carried out by ozone reactor under different values of pH and different dosages of ozone.The variation and controlling of the acute,chronic toxicity,and genotoxicity of the samples during the reaction were investigated,the internal reasons of toxicity were analyzed,and the possible degradation mechanism was proposed.Results show that TBBPA could be completely degraded when pH is 7.0 and ozone dosage is 0.12 mg/L.At the beginning of the reaction,the acute and chronic toxicity increased rapidly,and it was mainly because of the production of more toxic organic intermediates.As the reaction proceeded,the toxic intermediates were further degraded,and both of the acute and chronic toxicities were effectively controlled and the toxicity was controlled more quickly and significantly with the increase of ozone dosage.When the dosage of ozone was 0.12 mg/L,the acute toxicity could be completely controlled within 20 min of reaction,and the chronic toxicity could be controlled to be 0.76 TU within 60 min.After the reaction,the acute and chronic toxicities of the water samples could meet the emission standard.During the reaction,the mutagenic ratios of the samples were all smaller than 2.0,which had no genotoxicity at the genetic level.The analysis of mechanism showed that the degradation of TBBPA by ozonation mainly included the reaction process of debromination,the beta scission,addition,dehydroxylation,methylation,and so on.