过硫酸盐氧化与水泥固化稳定化协同修复苯胺污染土壤

为了快速高效地处理突发性事故造成的苯胺污染土壤,在水泥固化稳定化苯胺污染土壤时加入过硫酸盐和活性炭,评估固化稳定化产物中苯胺的浸出特征和降解机理. 结果表明:①过硫酸盐的加入可以快速有效地去除污染土壤中高浓度(10 g/kg)的苯胺,当反应时间为10 min、过硫酸盐添加量为1.0 eq(即过硫酸盐与土壤中苯胺的摩尔浓度比为1.0)时,处理后土壤中苯胺残留量为1 345 mg/kg；过硫酸盐添加量为2.0 eq时,苯胺残留量为43 mg/kg,反应时间对苯胺的去除效率影响不大,碱性条件有利于苯胺的降解. ②过硫酸盐-活性炭-水泥复合固化稳定化剂可以有效固化稳定化高浓度苯胺污染土壤,过硫酸盐的加入可以有效氧化土壤中的苯胺,是浸出液中ρ(苯胺)降低的主要因素；活性炭的加入可以进一步吸附残留的苯胺及降解产物,使浸出液中ρ(TOC)大幅降低；水泥水化产生的强碱性和温度升高有助于过硫酸盐对苯胺的氧化降解. ③苯胺氧化降解产物分析发现,偶氮苯、苯酚和联苯胺是苯胺的主要降解产物. 

Oxidation of Aniline in Cement-Based Solidified/Stabilized Contaminated Soil Using Persulfate

To quickly and effectively treat aniline-contaminated soil after sudden accidents, the effectiveness of cement was studied with the addition of persulfate and activated carbon for solidification/stabilization of aniline-contaminated soil. The leachability and removal mechanisms of aniline in solidified/stabilized materials were evaluated. Aniline in soil (10 g/kg) can be quickly and effectively removed with the addition of persulfate. When the soils were treated for 10 min, ρ(aniline) was 1345 mg/kg after adding persulfate at 1.0 equivalent (1.0 eq) of aniline in soil, while it was 43 mg/kg with the addition of persulfate at 2.0 eq. Treatment time had little effect on the removal of aniline. Alkaline environment facilitated the degradation of aniline. Highly aniline-contaminated soil could be effectively solidified/stabilized by the mixtures of persulfate, activated carbon and cement. The reduction of aniline in leachates was mainly due to the addition of persulfate, while the reduction of TOC and intermediates of aniline were mainly due to the addition of activated carbon, the alkaline environment and the rise of temperature produced by hydration of cement facilitating the oxidation of aniline during the process of solidification/stabilization. Azobenzene, phenol and benzidine have been identified as the major intermediates of aniline oxidation by persulfate.