化学氧化修复对农田土壤和菠菜中多环芳烃含量和组成的影响

Effects of chemical oxidation remediation on concentration and composition of PAHs in agricultural soils and spinach

采用盆栽实验,研究了过硫酸钠(Na2S2O8)和过氧化氢(H2O2)两种氧化剂分别与纳米Fe粉和硫酸亚铁(FeSO4)两种活化剂结合,以及加入腐殖酸(HA),对多环芳烃(PAHs)的去除,分析了对土壤和菠菜中溶剂可提取态PAHs以及土壤中不同结合态PAHs含量和组成的影响,并分析了波菜中PAHs的毒性当量浓度(BaPeq).结果表明,经过7周修复,对于土壤中溶剂可提取态PAHs,氧化剂剂量为0.2 g·kg-1时,H2O2的氧化效果优于Na2S2O8;活化剂剂量为0.448 g·kg-1时,纳米Fe粉的活化效果优于FeSO4;加入2 g·kg-1HA后PAHs含量有所降低,去除率升高.H2O2、纳米Fe粉和HA联合处理后土壤和菠菜中溶剂可提取态PAHs含量均最低,其在土壤中的去除率和菠菜中的减少率均最高,其中土壤中溶剂可提取态PAHs的去除率为36.8%,在菠菜地上部和地下部的减少率分别为45.3%、36.4%.土壤去除率和菠菜减少率中,2环和3环的PAHs高于4环、5环和6环.对于结合态PAHs,经过H2O2、纳米Fe粉和HA联合处理后土壤中不同结合态PAHs平均去除率最高,达44.5%.化学处理后,各处理对菠菜的生物量没有影响.H2O2、纳米Fe粉和HA联合处理后,菠菜地上部总BaPeq最低.

Two oxidants,sodium persulfate and hydrogen peroxide were used to remove polycyclic aromatic hydrocarbons(PAHs)in combination with two activators,ferrous sulfate and nanoparticles of zerovalent iron,in the agricultural soils and spinach with pot experiments.Humic acid(HA)was also added.PAHs bound to endogenetic soil humus in soils and the effects of chemical oxidation remediation on the concentration and composition of solvent extractable PAHs in soils and spinach were investigated.The toxic equivalent concentrations of benzo(a)pyrene(BaPeq)in spinach were analyzed.The results showed that,after 7 weeks,hydrogen peroxide was better than sodium persulfate to remove solvent extractable PAHs in soils when the oxidants in soils was 0.2 g·kg-1;and nanoparticles of zerovalent iron was better than ferrous sulfate when the activators in soils was 0.448 g·kg-1.PAH concentration decreased and removal percentage increased in the presence of 2 g·kg-1 HA.The combined treatment of hydrogen peroxide,nanoparticles of zerovalent iron and HA showed the lowest concentration of the solvent extractable PAHs both soils and spinach,and the highest PAHs removal percentage in soils and reduction percentage in spinach.The removal percentage of solvent extractable PAHs was 36.8%in soils,and the reduction percentage of spinach in shoots and roots reached up to 36.8%,45.3%and 36.4%,respectively.The relative removal percentage of 2-ring,3-ring PAHs in soils and the relative reduction percentage of 2-ring,3-ring PAHs in spinach were higher than that in 4-ring,5-ring,6-ring PAHs.The combined treatment of hydrogen peroxide,nanoparticles of zerovalent iron and HA showed the highest average removal percentage(44.5%)of PAHs bound to endogenetic soil humus.Chemical oxidation remediation did not have effect on the spinach biomass.The combined treatment of hydrogen peroxide,nanoparticles of zerovalent iron and HA showed the lowest toxic equivalent concentrations of BaPeq in spinach.