土壤修复：腐植酸作为天然表面活性剂在严重污染土壤淋洗中的应用

修复位于意大利北部的原ACNA化工厂（在Savona附近）周围的严重污染地是意大利政府的当务之急。当前工作目的是寻找创新、环保的技术来修复ACNA污染的土壤。取自ACNA化工厂的两种不同质地、不同数量、不同有机污染物类型的土样（土壤A和土壤B），分别用水、两种合成表面活性剂——十二烷基硫酸钠（SDS）和非离子表面活性剂Triton X-100（TX100）以及一种天然表面活性剂溶液——处在临界胶束浓度（CMC）的腐植酸（HA）进行土壤淋洗后，比较它们的去除率。土壤淋洗前后均采用了超声波萃取法和索氏萃取法对污染物进行提取。土壤A富含多环芳烃（PAH），而土壤B含有大量的噻吩。在分析细质地土壤B时，超声波萃取法更为有效；而对于粗质地土壤A来说，索氏萃取法也同样有效。水不能彻底清除两种土壤中的污染物，而所有有机表面活性剂则都表现出相似的去除率（高达90％）。由于天然腐植酸溶液与合成表面活性剂相比具有增强微生物活性的功能，这样有利于淋洗土壤中污染物的进一步自然降解。因此，对于严重污染土壤的淋洗来说，HA应该是一个更好的选择。

Soil Remediation: Humic Acids as Natural Surfactants in the Washings of Highly Contaminated Soils

The remediation of the highly contaminated site around the former chemical plant of ACNA(near Savona) in Northern Italy is a top priority in Italy. The aim of the present work was to contribute in fi nding innovative and environmental-friendly technology to remediate soils from the ACNA contaminated site. Two soils sampled from the ACNA site(A and B), differing in texture and amount and type of organic contaminants, were subjected to soil wash-ings by comparing the removal effi ciency of water, two synthetic surfactants, sodium dodecylsulphate(SDS) and Triton X-100(TX100), and a solution of a natural surfactant, a humic acid(HA) at its critical micelle concentration(CMC). The extraction of pollutants by sonication and soxhlet was conducted before and after the soil washings. Soil A was richer inpolycyclic aromatic hydrocarbons, whereas soil B had a larger content of thiophenes. Sonication resulted more analyti-cally eff icient in the f ine-textured soil B. The coarse-textured soil A was extracted with a general equal eff iciency also by soxhlet. Clean-up by water was unable to exhaustively remove contaminants from the two soils, whereas all the organic surfactants revealed similar effi ciencies(up to 90%) in the removal of the contaminants from the soils. Hence, the use of solutions of natural HAs appears as a better choice for soil washings of highly polluted soils due to their additional ca-pacity to promote microbial activity, in contrast to synthetic surfactants, for a further natural attenuation in washed soils.