Sodium silicate(Na2SiO3) was used to improve the elution of super heavy oil from weathered soil on an ultrasound-enhanced elution system by the solution containing 0―6000 mg/L surfactant Triton X-100.The removal extent of three markers[C 26―34 17α 25-norhopanes,C 26―28 triaromatic steroids(TAS),and C 27―29 methyl triaromatic steroids(MTAS)] was monitored.The average elution percentages of C 26―34 norhopanes,C 26―28 TAS,and C 27―29 MTAS by Triton X-100/Na2SiO3 solutions were increased by 11%―13%,9%―11% and 8%―13% with increasing Triton X-100 concentrations from 150 mg/L to 6000 mg/L.All the concentrations of Triton X-100 improved the elution of TAS homologs containing fewer carbon atoms,whereas high concentrations improved the elution of larger 17α 25-norhopane and MTAS species.Addition of Na2SiO3 produced a noticeable increase in elution,particularly for lower-weight species.Scanning electron microscope(SEM) images and energy spectroscopy data reveal that surfactant solution of 6000 mg/L Triton X-100 and 4000 mg/L Na2SiO3 produced the greatest improvement in the elution of super heavy oil aggregates encapsulating the soil surface and the emulsification of particle dispersions.That is to say mixed solutions of Triton X-100 and Na2SiO3 in combination with ultrasound are a potential means of removing super heavy oil from weathered soils.
