Use and comparison of the non-ionic surfactants Poloxamer 407 and Nonidet P40 with HP-b-CD cyclodextrin, for the enhanced electroremediation of real contaminated sediments from PAHs John N. Hahladakis a,⇑ , Wolfgang Calmano b,⇑ , Evangelos Gidarakos a,⇑ a Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100, Greece b Department of Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Eissendorfer Str. 40, D-21073 Hamburg, Germany article info Article history: Received 21 December 2012 Received in revised form 10 April 2013 Accepted 12 April 2013 Available online 20 April 2013 Keywords: Electroremediation PAHs Surfactants Sediments Heavy metals abstract Real contaminated sediments often come with the simultaneous existence of heavy metals and PAHs requiring, thereby, appropriate choice of flushing agents when subjected to electroremediation. The application and efficiency evaluation of the innovative non-ionic surfactants octylphenoxypolyethoxy- ethanol (Nonidet P40) and 2-methyloxirane (Poloxamer 407), in comparison with the already known Tween 80 and HPCD cyclodextrin, were examined during enhanced electrokinetic remediation of surficial sediments, mainly from PAHs. Heavy metal removal was also assessed. The results indicated a removal efficacy for SUM PAHs of approximately 48% and 43% with the use of Nonidet P40 and Poloxamer 407 respectively, which was far better than the ones taken from both the cyclodextrin and Tween 80. Further- more, removal percentages for individual PAHs, e.g. fluorene and chrysene, reached almost 83% or 92%, respectively. As far as heavy metals are concerned, unenhanced treatment was the only one demonstrat- ing a removal efficacy in all metals examined, however, giving ‘‘poor to medium’’ percentages (5% for Zn to 43% for Cr). On the other hand, the enhanced runs exhibited sufficient removal only in some of the metals examined, e.g. Zn and As, indicating that although surfactants favor the removal of PAHs are not suitable for all heavy metals. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction The anthropogenic derived industrial activities that have been constantly increasing over the last decades have created an alarm- ing situation in the aquatic ecosystem that can no longer be ig- nored. Heavy metals as well as volatile and semi-volatile organic substances such as benzene, toluene and Polycyclic Aromatic Hydrocarbons (PAHs) are common contaminants found in both the water column and sediments, as a result of careless disposal or accidental release of toxic and hazardous chemicals [1–4]. On the one hand, heavy metals, being persistent, bioaccumula- tive, non-degradable and toxic can become a constant source of pollution to both the environment and human health. More specif- ically, heavy metals in aquatic environments can interact with or- ganic or particulate matter resulting in deposition upon sediments which, in their turn, release them again in the water column through various processes and finally reach humans through food chain [5–10]. On the other hand, PAHs can enter marine environment through various ways such as industrial discharge, oil spills or urban run- offs. Being hydrophobic, carcinogenic and of low solubility, they can be associated with both organic and inorganic particles, accumulated, consequently, to high concentrations in sediments, arising, thereby, an equal or even greater concern for benthic organisms and sediment dwelling fauna [11–15]. Taking into con- sideration all the aforementioned facts, it is quite undisputable that sediments, dredged or surficial, represent the most important recipient of both heavy metals and PAHs [16]. The remediation of sediment contaminated sites, therefore, is of great significance and over the years many studies have reported multiple ways of achieving it such as solidification, stabilization and washing. How- ever, these techniques have not been proved suitable, especially for fine grained and low permeable soils or sediments [17,18]. Electrokinetic remediation (EK) involves the application of low direct current electrical potential between electrodes, within a confined contaminated area. The movement of the dissolved ionic species, present in the pore fluid, towards opposite electrodes is considered to be a major transport mechanism for ionic metals and micelles. This phenomenon is characterized by the term elec- tromigration. Moreover, the transport of H + and OH  generated by the electrolysis reactions is also attributed to electromigration. 1383-5866/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.seppur.2013.04.018 ⇑ Corresponding authors. Tel.: +30 2821037789/7832; fax: +30 2821037850. E-mail addresses: john_chach@yahoo.gr (J.N. Hahladakis), gidarako@mred.tuc.gr (E. Gidarakos). Separation and Purification Technology 113 (2013) 104–113 Contents lists available at SciVerse ScienceDirect Separation and Purification Technology journal homepage: www.elsevier.com/locate/seppur