腐殖酸对镰刀菌ZH-H2降解老化污染土壤4环芳烃效果的影响

Effects of humic acid on degradation of aged 4-ring polycyclic aromatic hydrocarbons contaminated soil by Fusarium sp.ZH-H2

以典型煤矿区老化污染土壤为修复对象,研究不同剂量腐殖酸对镰刀菌Fusarium sp.ZH-H2降解土壤4环多环芳烃(polycyclic aromatic hydrocarbons,PAHs)总量及各单体的降解效果,并进一步分析腐殖酸强化ZH-H2降解4环PAHs的动力学特征。结果表明:添加不同剂量腐殖酸后,ZH-H2对4环PAHs总量及各单体的去除率均显著提高,高低顺次为HF3(2.5g/kg)>HF1(0.5g/kg)≈HF2(0.1g/kg)>H。当腐殖酸添加量为2.5g/kg时,PAHs总量及各单体的去除率分别高达32.44%和35.06%,单体芘(pyrene,Pyr)降解最突出。在添加与不添加腐殖酸处理下,ZH-H2降解速率均在0-4d表现最快,总量降解速率高达43.70μg/(kg·d),随后降解速率呈现减弱趋势。与不添加腐殖酸处理相比,腐殖酸强化ZH-H2对Pyr的降解速率(提高了57.05%)。PAHs总量及其各单体降解速率均符合一级动力学方程,添加腐殖酸处理的相关系数和反应速率常数绝对值均显著高于不添加腐殖酸处理。与不添加腐殖酸处理相比,腐殖酸强化后的PAHs半衰期(55-69.3d)比自然衰减(96.3-177.7d)缩短了0.76-1.77倍,大幅提升了降解速率,缩短了降解时间。综上,添加2.5g/kg腐殖酸强化ZH-H2对4环PAHs的降解起到了良好的效果,降解时间也较快,为污染老化土壤原位修复提供了重要依据。

The aged contaminated soil in typical coal areas was taken as the remediation object to study the degradation effect of different dosages of humic acid on the total quantity of 4-ring polycyclic aromatic hydrocarbons(PAHs)in soil degraded by Fusarium sp.ZH-H2 and the degradation effect of each monomer,and to analyze the dynamic characteristics of degradation of 4-ring PAHs enhanced by humic acid.As a result,the removal rates of the total quantity of 4-ring PAHs and each monomer were significantly increased under ZH-H2 treatment after adding different dosages of humic acid,and increased efficiency ranged in order of HF3(2.5 g/kg)>HF1(0.5 g/kg)≈HF2(0.1 g/kg)>H.When added content of humic acid was 2.5 g/kg,the removal rates of the total PAHs and each monomer were as high as 32.44% and 35.06% respectively,and monomer Pyr was prominently degraded.Under the treatment with and without humic acid,the PAH degradation rate of ZH-H2 was the fastest in 0-4 d,with total degradation rate of 43.70μg/(kg·d),and then the degradation rate showed a weakening trend.Compared with the treatment without humic acid,the Pyr degradation rate of humic acid-enhanced ZH-H2 was up to 57.05%.The total quantity tidy of PAHs and the degradation rate of each monomer were in line with the first-order dynamic equation.The coefficient of correlation and absolute value of the reaction rate constant under the treatment with humic acid were significantly higher than those under the treatment without humic acid.Compared with the treatment without humic acid,the half-life(55-69.3 d)of 4-ring PAHs after humic acid enhancement was 0.76-1.77 times shorter than the natural attenuation(96.3-177.7 d),indicating that humic acid greatly promoted the degradation rate and shortened the degradation time.To sum up,adding 2.5 g/kg humic acid to Fusarium sp.ZH-H2 was effective on degradation of PAHs,and the degradation period was shortened.Our results provide technical improvement for in-situ remediation of contaminated aged soil.