Dept. of Civil, Chemical, Environmental and Materials Engineering - DICAM, University of Bologna, Italy.
School of Biomedical Sciences, Faculty of Life and Health Sciences, University of Ulster, Coleraine, BT52 1SA, UK.
N Biotechnol. 2018 Jul 25;43:13-22. doi: 10.1016/j.nbt.2017.12.007. Epub 2017 Dec 28.
Washing is a rapid and effective treatment to remediate contaminated sands impacted by oil spills, although synthetic additives used to increase extraction efficiency may cause additional pollution issues due to their intrinsic toxicity and very often low biodegradability. In this study, different biogenic mobilizing agents (soybean lecithins, cyclodextrins, cholic acids, plant-derived cleaners, rhamnolipids and sophorolipids) were tested in the washing of beach sands artificially contaminated with the Intermediate Fuel Oil IFO-180. Among these, a de-oiled soybean lecithin (SL-1), hydroxypropyl-β-cyclodextrins (HPB-CD) and sophorolipids (SR) achieved hydrocarbon removals close to those attained with the synthetic surfactant Triton™ X-100 (TX) in preliminary washing tests carried out at constant mixing rate, water/sand ratio and IFO-180 contamination level using agents concentrations close to their critical micelle concentration (0.1% and 1% w/v for microbial and non-microbial agents, respectively). The effects of agent concentration, water/sand ratio, mixing rate and IFO-180 contamination on hydrocarbons removal were modelled using face-centred central composite design and ANOVA. Optimal washing parameters for sand contamination levels in the range 0.5-20 g/kg were identified with response surface methodology. While HPB-CD and SR performed equally to TX only at low sand contaminations, SL-1 attained hydrocarbon removal higher or equal to that of TX at any IFO-180 contamination and at lower application rates. SL-1 also outperformed TX when minimizing the water/sand ratio, i.e., the volume of water used. Considering its lower toxicity, higher biodegradability and higher hydrocarbon removal efficiencies, SL-1 is an effective and environmentally sustainable alternative to synthetic surfactants in washing treatments for marine fuel-contaminated sands.
洗涤是一种快速有效的处理方法，可修复受溢油污染的沙滩，尽管为提高提取效率而使用的合成添加剂可能会因其固有毒性和通常较低的生物降解性而引起其他污染问题。在这项研究中，不同的生物衍生的增溶剂（大豆卵磷脂、环糊精、胆酸、植物衍生清洁剂、鼠李糖脂和槐糖脂）被测试用于洗涤人工污染的海滩砂，污染物质为中间燃料油 IFO-180。在这些增溶剂中，一种脱油大豆卵磷脂（SL-1）、羟丙基-β-环糊精（HPB-CD）和槐糖脂（SR）在初步洗涤试验中，在恒定的混合速率、水/砂比和 IFO-180 污染水平下，使用接近其临界胶束浓度（0.1%和 1%w/v，分别用于微生物和非微生物增溶剂）的浓度，实现了接近使用合成表面活性剂 Triton™ X-100（TX）的烃类去除率。使用中心复合设计和方差分析对增溶剂浓度、水/砂比、混合速率和 IFO-180 污染对烃类去除的影响进行了建模。使用响应面法确定了沙污染水平在 0.5-20g/kg 范围内的最佳洗涤参数。虽然 HPB-CD 和 SR 仅在低砂污染时与 TX 表现相当，但 SL-1 在任何 IFO-180 污染和较低的应用率下，都能达到或超过 TX 的烃类去除率。当最小化水/砂比，即所用的水量时，SL-1 也优于 TX。考虑到其较低的毒性、较高的生物降解性和较高的烃类去除效率，SL-1 是一种有效的、环境可持续的替代合成表面活性剂的方法，可用于洗涤受海洋燃料污染的沙滩。
