In the latest issue of clu-in.org I found several of them. It seems interest in this topic is revitalizing.
the first is not associated with surfactants I think
ADVANCED METHODOLOGIES FOR THE TREATMENT OF HYDROCARBON CONTAMINATED SLUDGES FROM SOIL WASHING PROCESSES
Fine products (silt-clay fractions) in sludge from soil washing plants following bulk soil treatment usually are highly contaminated. These fractions commonly are committed to landfill disposal or thermal destruction (in the case of organic contaminants). This paper presents the results of preliminary physical-chemical and bioremediation treatability tests carried out on a hydrocarbon-heavy sludge sample after bulk soil processing in a soil washing plant. To date, best results were obtained in two bioremediation processes tested at lab scale—landfarming and bioreactors—which decreased hydrocarbon levels by better than 50% in two months and one month, respectively. http://digital.csic.es/bitstream/10261/18607/1/S02_6.pdf
comment: reducing the very high contamination with spending time and money by only 50 % is really not worse the effort.
Proceedings of Symposium on Ultrasonic Electronics, Vol 30, p 147-148, 2009 [18-20 November 2009, Paper 1P4-31]
Mechanical mixing generally is a key process in conventional soil washing, sometimes accompanied by injection of anionic or non-ionic surfactants to enhance mass transfer of pollutants from soil to aqueous phase. Tests of the application of ultrasound to the washing process indicate a significant increase in removal efficiency. When the washing water or slurry was irradiated with ultrasound, cavitation events occurred, and sonochemical and sonophysical effects were induced. Sonophysical effects, such as micro jet and micro streaming, could enhance mass transfer of organic/inorganic pollutants from soil phase to aqueous phase. This paper describes the conduct and results of a study undertaken to compare an ultrasonic soil washing process with a conventional mechanical soil washing treatment to gain a better understanding of the mechanisms of each process. http://www.use-jp.org/USE2010/proceedings/USE09/pdf/1P4-31.pdf
Journal of Environmental Engineering, Vol 135 No 10, p 1015-1024, 2009
A bench-scale study was conducted to develop a two-stage remedial system consisting of surfactant washing followed by a Fenton-like oxidation process to remediate fuel-oil contaminated soils. The researchers also evaluated the effects of residual surfactant and soil organic matter (SOM) on the efficiency of Fenton-like oxidation; the effect of potassium dihydrogen phosphate (KH2PO4) addition on the stability of H2O2 and oxidation efficiency; and the possible oxidation products after the oxidation process. In the surfactant washing stage, a biodegradable surfactant, Simple Green (SG) at 50 g/L, was applied to flush fuel-oil contaminated soil having initial total petroleum hydrocarbons (TPHs) concentration of 50,000 mg/kg. Washing with 45 pore volumes (PVs) of SG followed by 25 PVs of deionized water achieved 90% TPH removal, dropping the soil TPH concentration from 50,000 to 4,950 mg/kg. In the Fenton-like oxidation stage at initial soil TPH concentration of ~4,950 mg/kg, TPH removal efficiency increased significantly with increased H2O2 concentrations. There was evidence that residual SG and SOM can compete with TPH for oxidants and thereby decrease oxidation efficiency; hence, an oxidation-sorption-desorption-oxidation scheme for soil TPH was observed in this experiment due to the initial sorption of TPH on SOM. Addition of 2.2 mM of KH2PO4 increased the stability and half-life of H2O2 but decreased TPH removal efficiency. The oxidation potential of the Fenton-like process was insufficient to oxidize fuel oil completely to nontoxic end products. The by-products observed after the oxidation process contained carboxyl groups with molecular weights similar to their parent compounds. Results indicate that the two-stage remedial system shows promise for future treatment of fuel-oil contaminated soil.
Ghazali, M., E. McBean, H. Shen, W. Anderson, and P.-A. Dastous.
Remediation Journal, Vol 20 No 4, p 119-132, 2010
A surfactant-aided soil washing technique was studied as an alternative method for remediation of DDT-contaminated clayey soil. The ex situ process used both nonionic and anionic surfactants. A mixture of 1% nonionic surfactant (Brij 35) and 1% anionic surfactant (SDBS) removed more than 50% of DDT from soil in a flow-through system, whereas individual surfactants or other combinations of the surfactants exhibited lower removal efficiency. The use of a mixing system improved the soil washing process. A combination of 2% Brij 35 and 0.1% SDBS was found to be optimum, removing 70 to 80% of DDT. Prewashing the soil with tap water decreased the adsorption of surfactants to soil particles by 30 to 40%, and postwashing recovered 90% of the surfactants.
BENCH SCALE TREATABILITY STUDIES OF CONTAMINATED SOIL USING SOIL WASHING TECHNIQUE
E-Journal of Chemistry, Vol 7 No 1, p 73-80, 2010
Surfactant washing is an ex situ process. The excavated contaminated soil can be heaped on plastic liners or other impermeable barriers and irrigated with washing solutions such as surfactant; alternatively, batch washing of the contaminated soil can be conducted in tanks or lined pits using continuous flows washing in countercurrent or normal modes. The authors applied soil washing using plain water enhanced with surfactants to a study of the remediation of soil contaminated with engine lubricant oil or a heavy metal. The engine oil was used at different percentages (by dry weight of the soil) to contaminate the soil artificially. The geotechnical properties of the soil underwent large modifications after mixing with the oil. Sorption experiments were conducted with cadmium metal in an aqueous medium at different initial concentrations of the metal and at varying pH values of the sorbing medium. For the remediation of contaminated soil matrices, a nonionic surfactant was used for the restoration of geotechnical properties of the soil samples contaminated with lubricant oil, while an anionic surfactant was employed to desorb cadmium from the contaminated soil matrix. The surfactant for soil contaminated with lubricant oil was able to restore properties up to 98% of those of virgin soil, while up to 54% cadmium was desorbed from the contaminated soil matrix in surfactant-aided desorption experiments. http://www.e-journals.in/PDF/V7N1/73-80.pdf
In my experience for mineral oil contaminated soil a mixture of anionic/nonionic works best, e.g. 3 parts Na Alkyl benzene sulfonate / 7 parts Synperonic 91/4
ELECTROKINETIC REMOVAL OF PETROLEUM HYDROCARBON FROM RESIDUAL CLAYEY SOIL FOLLOWING A WASHING PROCESS
Jeon, C.-S., J.-S. Yang, K.-J. Kim, and K. Baek.
CLEAN — Soil, Air, Water, Vol 38 No 2, Feb 2010
A study was conducted of total petroleum hydrocarbon (TPH) removal from residual clayey soil using an electrokinetic process following a washing procedure. Eight electrokinetic experiments were carried out to investigate the characteristics of TPH removal. When 0.1 M MgSO4 or 0.1 M NaOH was used as an electrolyte, the electric current increased rapidly within the first 100 or 200 h, respectively. A negatively charged soil surface resulted in a more negative zeta potential and greater electroosmotic flow toward the cathode. The accumulated electroosmotic flow was higher when using 0.1 M NaOH as the anolyte-purging solution than when using 0.1 M MgSO4. Although the energy consumption for the two purging solutions was similar, the efficiencies of TPH removal when 0.1 M MgSO4 and 0.1 M NaOH with surfactant were used were 0 and 39, respectively, because the electroosmotic flow rate increased with TPH removal efficiency. When 5 isopropyl alcohol was used as a circulation solution, the electric current increased, but the TPH removal was similar to that using water. In terms of energy consumption, the use of a surfactant-enhanced electrokinetic process with NaOH as electrolyte was effective in removing TPHs from low-permeability soil. http://onlinelibrary.wiley.com/doi/10.1002/clen.200900190/pdf
REMOVAL OF HIGH CONCENTRATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS FROM CONTAMINATED SOIL BY BIODIESEL
Jinbao Wu, Zongqiang Gong, Liyan Zheng, Yanli Yi, Jinghua Jin, Xiaojun Li and Peijun Li
Frontiers of Environmental Science & Engineering in China, [online prior to print publication] 2010
Solubilizing experiments were carried out to evaluate the ability of biodiesel to remove PAHs from highly contaminated manufactured gas plant (MGP) and PAH-spiked soils alongside applications of hydroxypropyl-beta-cyclodextrin (HPCD) and tween 80 as comparisons. Biodiesel displayed the highest solubilities for phenanthrene (420.7 mg/L), pyrene (541.0 mg/L), and benzo(a)pyrene (436.3 mg/L). These corresponded to several-fold increases relative to 10% HPCD and tween 80. Biodiesel showed a good efficiency for PAH removal from the spiked and MGP soils for both low- and high-molecular-weight PAHs at high concentrations. Biodiesel was a more effective agent for PAH removal from the spiked soils compared with HPCD and tween 80; it achieved over 77.9% removal of individual PAHs. Tween 80 also showed comparable capability with biodiesel for PAH solubilization at a concentration of 10% for the spiked soils. Biodiesel solubilized a wider range of PAHs than HPCD and tween 80 for the MPG soils. At PAH concentrations of 229.6 and 996.9 mg/kg, biodiesel removed >80% of total PAHs. The investigators observed a significant difference between PAH removals from the spiked and field MGP soils: PAH removals from the MGP soil by HPCD and tween 80 were much lower than those from the spiked soil. These results demonstrate the potential for utilizing biodiesel for remediation of highly PAH-contaminated soil.
comment: Though biodiesel worked best (I experienced the same), it works when used as 100 %. Clean-up of biodiesel for recycling proved difficult, with activated carbon it will be costly. For PAH extraction I would suggest a combination of about 1 part carboxymethyl cellulose / 9 Part Synperonic 91/4.
WASHING OF FIELD WEATHERED CRUDE OIL CONTAMINATED SOIL WITH AN ENVIRONMENTALLY COMPATIBLE SURFACTANT, ALKYL POLYGLUCOSIDE
Han, M., G. Ji, and J. Ni, Peking Univ., Beijing, China.
Chemosphere, Vol 76 No 5, p 579-86, 2009
Weathered crude oil-contaminated soils are much more difficult to remediate than those freshly contaminated. Although surfactant-enhanced ex situ soil washing can be used to remediate the weathered soils, surfactant toxicity is a major concern. A class of green surfactants, alkyl polyglucosides (APGs), was tested for washing field-weathered soils with relatively high oil concentration (123 mg/g dry soil) from an oilfield in China. APG1214, characterized with a longer alkyl chain, was more effective than APG0810 for removing crude oil. Addition of inorganic sodium salts to the APG1214 solution further improved crude oil removal efficiency. Washing parameters (temperature, washing time, agitation speed, and solution/soil ratio) were investigated, further optimized, and integrated with an orthogonal design. Under optimum conditions, removal efficiency reached 97%. GC/MS analysis showed that the proportion of small n-alkanes (C(16) to C(23)) in residual crude oil gradually increased, which helped to interpret the oil removal mechanism. Removal of large n-alkanes was achieved from the synergy between APG1214 and inorganic salts, which was the opposite of the effect when they were added separately. This study presents a promising technique for remediation of weathered crude oil-contaminated soils with ecologically compatible surfactant and provides guidelines for its practical application.
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