Enhanced-solubilization and dissolution of multicomponent DNAPL from homogeneous porous media

Tick G. R., Slavic D. R., AKYOL N. H., Zhang Y.

JOURNAL OF CONTAMINANT HYDROLOGY, vol.247, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 247
  • Publication Date: 2022
  • Doi Number: 10.1016/j.jconhyd.2022.103967
  • Journal Name: JOURNAL OF CONTAMINANT HYDROLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, Compendex, EMBASE, Environment Index, Geobase, INSPEC, MEDLINE, Metadex, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Kocaeli University Affiliated: Yes

Abstract

The presence of multicomponent dense nonaqueous phase liquid (DNAPL) mixtures in porous media can significantly limit the effectiveness of groundwater remediation. A series of column transport and flushing experiments were conducted to quantify the impact of various enhanced flushing agents on dissolution and removal of a multicomponent DNAPL source within a macroscopically homogeneous porous medium. The columns were established with NAPL saturations consisting of an equal mole mixture of cis-1,2-dichloroethene, trichloroethene, and tetrachloroethene. The solubilization agents used included two complexing sugarshydroxypropyl13-cyclodextrin (HPCD and methyl-13-cyclodextrin (MCD); a surfactant sodium dodecyl sulfate (SDS); and a cosolvent ethanol (EtOH). The chemical flushing agents greatly reduced the time needed to remove each DNAPL component, compared to flushing with water alone. Initial DNAPL-component elution concentrations were successfully predicted using Raoult's Law for MCD, HPCD, and water flushing, indicating that ideal dissolution was initiated by the lower-power enhanced-solubilization agents. EtOH was most efficient at removing the contaminants in terms of normalized mass recovery but least efficient based on a mass-ratio and mole-ratio of contaminant to reagent analysis. SDS was most efficient for contaminant removal when analyzed based on mass contaminant to mass-reagent recovered and MCD was most effective based on a moles-contaminant to moles reagent recovered efficiency evaluation. However, in terms of mass flux reduction analysis (i.e. removal metric), SDS was least efficient for contaminant removal compared to all other enhanced-flushing agents tested, especially during the initial stages of DNAPL removal. Results from this study indicate that ideal dissolution was initiated during enhanced-solubilization and that several criteria should be used to evaluate the removal effectiveness of flushing agents for multi-component NAPL systems.