过硫酸钠缓释胶囊反应带修复苯胺污染地下水

针对有机污染地下水原位化学氧化修复中普遍存在的氧化剂过量使用、污染物反弹和二次污染问题，以苯胺（AN）为特征污染物，以活化过硫酸盐为氧化剂，采用硬脂酸为胶结剂，制备过硫酸钠（PS）和硫酸亚铁（FeSO₄）缓释胶囊，构建基于PS和FeSO₄缓释胶囊的可渗透反应屏障（PS-FeSO₄-PRB），考查了缓释胶囊组分、地下水流速对PRB中活性物质释放和AN去除的影响.结果表明，当缓释胶囊中活性物质/硬脂酸为1/2，地下水流速为0.1mL/min时，48h后PRB中PS和Fe²⁺累计释放率分别为43.18%和14.98%.当PRB中FeSO₄/PS为1/9时，AN累计去除率达到95.37%，TOC累计去除率为57.07%.采用砂柱模拟AN污染地下水，比较了直接注射PS和FeSO₄与PS-FeSO₄-PRB两种处理方式的修复性能，4d内两者的AN累计去除率分别为35.22%和69.74%，TOC累计去除率分别为15.83%与14.88%.PS-FeSO₄-PRB修复效果明显高于直接注射处理.GC/MS分析表明，处理后产生了对苯醌、偶氮苯以及长链烷烃等产物，导致AN矿化率不高.pH值和Eh连续记录结果表明，PS-FeSO₄-PRB处理能够保持反应体系氧化还原电位和酸碱性的相对稳定.相比直接注射氧化剂，基于PS和FeSO₄-缓释胶囊的PRB处理中地下水的急性毒性更低，二次污染风险更小.

Remediation of aniline contaminated groundwater by reaction zone with the sodium persulfate sustained release capsules reaction zone

In the in-situ chemical oxidation remediation of groundwater by organic contamination, there are common problems such as excessive use of oxidants, rebound of pollutants and secondary pollutions. Aniline (AN) was the characteristic pollutant, activated persulfate (PS) was used as the oxidant, and stearic acid was used as the cementing agent to prepare sodium and ferrous sulfate (FeSO₄) acting as a permeable reaction barrier (PS-FeSO₄-PRB). The effects of slow-release capsules components and groundwater flow rate on the release of active substances in PRB and the removal of AN were examined. The results showed that when the active substance/stearic acid in the slow-release capsule was 1/2 and the flow rate of groundwater was 0.1mL/min, the cumulative release rates of PS and Fe²⁺ in the PRB after 48h were 43.18% and 14.98% respectively. With a FeSO₄/PS ratio of 1/9 in PRB, the cumulative removal rate of AN and TOC was 95.37% and 57.07% respectively. A sand column was used to simulate the AN-contaminated groundwater and the remediation efficiencies of two different compared treatments : direct injection of PS and FeSO₄, and construction of PS-FeSO₄-PRB, within 4 days, the cumulative removal rates of AN were respectively 35.22% and 69.74%; the cumulative removal rates of TOC were 15.83% and 14.88% respectively. The remediation efficiency of PS-FeSO₄-PRB was significantly higher than that of direct injection treatment. GC/MS analysis showed that p-benzoquinone, azobenzene and long-chain alkanes were produced after treatment, resulting in low mineralization rate of AN. The continuous pH value and Eh records showed that the redox property and acid-base property of the reaction system of PS-FeSO₄-PRB treatment kept relatively stable. Compared with the direct injection of oxidizing agent, PRB treatment based on the slow-release PS and FeSO₄ capsules showed the lower acute toxicity and the lower secondary contamination risk in groundwater.