多环芳烃(PAHs)在不同腐殖酸组分中的赋存特征和氧化降解效果研究

Distribution characteristics and degradation effect of polycyclic aromatic hydrocarbons( PAHs) in different humus acid components

选取腐殖酸重要组分胡敏酸、富里酸、胡敏素为研究对象,研究了不同老化时间下多环芳烃(PAHs)在腐殖酸各组分中的赋存特征.同时,探究了过硫酸钠、高锰酸钾、芬顿试剂、过氧化氢4种氧化剂氧化PAHs过程中污染物在腐殖酸和上清液中的分布情况,确定胡敏酸、富里酸、胡敏素中PAHs的降解效率.实验结果表明,PAHs在胡敏素中存在吸附滞后现象,老化前期胡敏素对PAHs的吸附速率慢、吸附量少,但老化后期出现吸附量的反超,因此,胡敏素、胡敏酸和富里酸中PAHs的最终吸附量并没有明显差异.高环PAHs在3种腐殖酸组分中的吸附速率和最终吸附量远小于低、中环PAHs.过硫酸钠和高锰酸钾能够较好地去除胡敏酸、富里酸、胡敏素中的大部分PAHs,去除率均在95%左右,芬顿试剂对胡敏酸、富里酸和胡敏素中总PAHs的去除效果差别不大,去除率均在79.36%~88.05%之间;过氧化氢对胡敏酸和胡敏素中PAHs的去除率分别为82.82%和61.77%,而对富里酸中PAHs的去除效果最差,去除率仅为43.96%.过硫酸钠和高锰酸钾是氧化PAHs类有机污染土壤的最佳氧化剂,能够有效提高不同组分腐殖酸中PAHs的去除率.

In this study,we focused on the distribution characteristics of PAHs among humic acid,fulvic acid and humin at different aging time.Furthermore,sodium persulfate,potassium permanganate,Fenton and hydrogen peroxide were chosen as oxidants and the distribution and oxidative degradation efficiencies of PAHs in humus acid components and supernatant in the process of oxidation were explored. Results from batch experiments showed that the adsorption of humic had distinct hysteresis with a lower sorption rate and capacity at the early stage of aging. However,the sorption capacity became higher at later stage,so there were no significant differences among the three components. Compare to the low and medium rings PAHs,the high rings had a lower sorption rate and capacity. Sodium persulfate and potassium permanganate obtained better oxidation efficiencies of PAHs around95%,but the efficiencies of Fenton were in the range of 79.36% ～ 88.05%. The removal effects of humic acid and humin were 82. 82% and 61. 77%,respectively,while the removal of PAHs in fulvic acid was the lowest（ 43.96%）. In summary,sodium persulfate and potassium permanganate were both optimum for the remediation of PAHs contaminated site,which could improve the removal of PAHs in various components in humus acid.