过硫酸钠对我国典型土壤中多环芳烃氧化降解效果的影响

过硫酸钠是污染土壤化学氧化修复技术中应用较为广泛的氧化剂.为研究过硫酸钠对不同土壤中PAHs（polycyclic aromatic hydrocarbons，多环芳烃）的修复效果，以我国多种典型土壤（黑土、潮土、黄土、紫色土、褐土、砖红壤）为试验样本，以萘、菲、蒽、芘、苯并a]芘5种PAHs为目标污染物，分析活化过硫酸钠对人为老化的降解率；此外，通过对氧化前后土壤pH、w（有机碳）等土壤性质变化的比较和分析，探讨氧化修复过程对土壤性质的影响.结果表明:当活化过硫酸钠用量为0.8 mmol/g、温度为25℃时，PAHs污染土壤中萘、菲、蒽、芘、苯并a]芘的降解率最高，分别为87.82%、79.68%、87.93%、83.40%、94.31%.随着温度的升高，PAHs降解率逐渐升高，当温度达到25℃时，PAHs的降解率（85.69%）达到最高，随后随着温度的继续升高，总PAHs的降解率没有明显增加；随着pH的升高，PAHs的降解率逐渐升高，当pH达到6~7时，PAHs降解率维持在一个较高水平；随后随着pH的继续升高，总PAHs的降解率逐渐降低.随着温度以及pH的变化，5种PAHs的降解率与总PAHs的降解率变化趋势一致. w（有机碳）越低，PAHs环数越高，PAHs降解率越高；高环（5~6环）、中环（4环）、低环（2~3环）PAHs降解率与总PAHs降解率变化趋势一致.此外，过硫酸钠氧化修复后土壤结构遭到一定程度的破坏，土壤的pH、w（有机碳）和土壤肥力会有不同程度的下降，对土壤的再次利用有较大影响.研究显示，过硫酸钠可有效氧化降解不同性质土壤中PAHs，在氧化修复PAHs污染土壤方面具有较好的应用前景. 

Oxidative Degradation Effect of Sodium Persulfate on Polycyclic Aromatic Hydrocarbons in Typical Chinese Soils

Sodium persulfate has been widely used as an oxidant in the oxidation remediation of contaminated soils. To study the oxidative degradation effect of sodium persulfate in different kinds of soils, various soils, including black soil, fluvo-aquic soil, yellow soil, purple soil, cinnamon soil, and humid-thermo ferralitic were used in this work. The soils were artificially contaminated by polycyclic aromatic hydrocarbons (PAHs), such as naphthalene (NAP), phenanthrene (PHE), anthracene (ANT), pyrene (PYR) and benzoa]pyrene (BaP). The remediation efficiency of artificially aging PAHs contaminated soils oxidized by activated sodium persulfate was studied under optimum experimental conditions. The comprehensive assessment of remediation efficiency was assessed by comparing and analyzing the soils' properties, including pH and organic carbon content. The results showed that the oxidation degradation rate of NAP, PHE, ANT, PYR and BaP got their top levels as 87.82%, 79.68%, 87.93%, 83.40% and 94.31%, respectively. The degradation rate of PAHs increased with the rising temperature or pH. When the temperature reached 25 ℃, the degradation rate of PAHs got the highest level (85.69%). The degradation rate of PAHs had no significant rise after 25 ℃. The degradation rate of PAHs was maintained at a high level when pH was 6-7. When pH set to more than 7, the degradation rate of PAHs decreased. The individual and total PAHs performance the same trend when the temperature or pH changing. The PAHs contaminated soil with low organic carbon content had high oxidation degradation efficiency. The high rings PAHs (5-6 carbon rings), the middle rings PAHs (4 carbon rings), the low rings PAHs (2-3 carbon rings)and the total PAHs shared the same degradation trend, but the PAHs with more rings showed higher degradation efficiency. Otherwise, soil properties were damaged to some extent after being oxidized by sodium persulfate. For example, the soil pH lowered slightly and the organic carbon content and the fertility of soil declined sharply, which might affect the reuse of the remediated soils. This work indicates the fantastic potential of sodium persulfate applied as oxidant in contaminated soil remediation.