腐殖酸强化六氯苯还原脱氯的作用规律

摘要

为探索厌氧条件下腐殖酸(HA)对六氯苯(HCB)降解的影响,构建厌氧发酵体系,设置ρ(HA)分别为0 mg/L(HA0)、40mg/L(HA40)、120 mg/L(HA120)、160 mg/L(HA160)及200 mg/L(HA200)的5个处理,并利用总有机碳分析仪(TOC)和气相色谱-电子捕获检测器(GC-ECD)对体系中ρ(HA)及ρ(HCB)的动态变化进行测定.结果表明,发酵系统运行96 h后,HA0、HA40、HA120、HA160、HA200处理中HCB降解率分别为10.4％、15.9％、20.7％、23.4％和22.1％,说明厌氧发酵系统中,HA可以促进HCB的降解,但是随着ρ(HA)的增加,消耗单位HA对HCB脱氯的强化效果逐渐降低.分析ρ(HA)变化规律发现,添加HA的四组发酵系统运行96 h后HA降解率分别为29.05％、17.27％、10.98％和8.68％,说明在HCB发生还原脱氯的过程中,HA自身也会发生降解,并且随着ρ(HA)的增加,体系中HA相对消耗量逐渐减少.利用Origin 8.0软件对体系中ρ(HA)与ρ(HCB)变化进行非线性拟合,二者具有正相关性,并且整个发酵过程中,0 ～24 h内HA对HCB降解效率影响作用明显大于24～ 96 h.研究显示,在厌氧条件下,HA能快速有效促进HCB的还原脱氯.%In order to explore the impacts of humic acid (HA) on the degradation of hexachlorobenzene (HCB) in anaerobic environment,five anaerobic fermentation systems of HA concentration 0 mg/L (HA0),40 mg/L (HA40),120 mg/L (HA120),160 mg/L (HA160) and 200 mg/L (HA200) were constructed,and a total organic carbon analyzer (TOC) and a gas chromatography-electron captur e detector (GC-ECD) were used to measure the concentrations of HA and HCB.The results showed that the degradation rates of HCB in the HA0,HA40,HA120,HA160 and HA200 systems were 10.4％,15.9％,20.7％,23.4％ and 22.1％ respectively after 96 h fermentation.HA could promote the degradation of HCB under anaerobic fermentation conditions,and with the increase of HA,the dechlorination efficiency gradually decreased by HA unit content.The variation range of HA concentration showed that the degradation rate of HA in four fermentation systems with added humic acids were 29.05％,17.27％,10.98％ and 8.68％ respectively after 96 h reaction.In the dechlorination process of HCB,HA would be degraded correspondingly.Meanwhile,the relative consumption of HA was gradually reduced with the increase of HA content in the system.Origin 8.0 software was used to make nonlinear fitting about the concentration of HA and HCB.The result suggested that the concentration of HA and HCB was positively correlated,and the effects of the HCB degradation by HA within 0-24 h reaction process was significantly better than 24-96 h.HCB could quickly and effectively be reduced by humic acid under anaerobic conditions.