• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.67-70
• /
• 2002

Remediation of groundwater contaminated with chlorinated organics, nitro aromatics, and heavy metals using zero valent iron (ZVI) filings has paid considerable attention in recent years. When the contaminants of high concentration leaked abundantly in subsurface environment, permeable reactive barrier technology using iron filing is taken a long time for the remediation of contaminated groundwater, The problem of contaminant shock is able to be solved using surfactant (hexadecyltrimethylammonium, HDTMA) modified bentonite (SMB) as immobilizing material. Therefore, the purpose of this research was to develop the combined remediation technology using conventional permeable reactive and immobilizing barrier for the enhanced decontamination of chlorinated compounds. Four column experiments were conducted to assess the performance of the mixed reactive materials with Ottawa sand, iron filing, and HDTMA-bentonite for trichloroethylene (TCE) removal under controlled groundwater flow conditions. TCE reduction rates with sand/iron filing/HDTMA-bentonite were highest among four column due to dechlorination of TCE by iron filing and sorption of TCE by SMB.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6B
• /
• pp.677-682
• /
• 2006

Dodecyldimethylethylammonium (DDDEA), a cationic surfactant, and aluminum metal ions were used with bentonite to synthesize to synthesize an improved organo bentonite. Among three different synthesis procedure for organo bentonites, aluminium-pillared bentonite showed the highest DDDEA sorption, which indicated that aluminium-pillared organo bentonite would exhibit the highest sorption capacity for organic contaminants. Aluminium pillared organo bentonite also showed a high sorption capability for phosphorus, while it did not exhibit strong sorption for nitrate. In the meantime, more desorption was observed with aluminium-pillared organo bentonite than ordinary organo bentonites.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.04a
• /
• pp.15-18
• /
• 2001

Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.

• Journal of Korean Society on Water Environment
• /
• v.23 no.6
• /
• pp.966-972
• /
• 2007

A novel organoclay has been developed with aluminium-pillared clay modified with an amphoteric surfactant, N-Dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DDAPS). This novel organoclay is expected to have phosphorus removal capacity as well as organic and inorganic contaminant removal capacity, due to aluminum inside the clay structure. It also exhibited less surfactant desorption than conventional cation surfactant-based organoclays. Phosphorus in water can be decreased from 0.2 mg/L to 0.0012 mg/L in 27 hours with this organoclay. Also, cadmium could removed from water using this proposed organo-clay. Experiments were performed under various pHs and amphoteric surfactants sorption capability was the highest at pH 5 when more of the amphoteric surfactant head group took on positive charges.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.4
• /
• pp.41-50
• /
• 2001

The use of clay has been the favored method of reducing or eliminating hazardous contaminants in the leachate from landfills. But, neither natural clays nor organoclays modified with surfactants are able to effectively sorb both heavy metals and organic contaminants. Therefore, the objective of this study is to determine the optimal amount of surfactant added on the clay mineral to effectively remove both of them. For this purpose, Na-Bentonite as the natural clay, and hexadecyltrimethylammonium (HDTMA) as the cationic surfactant were used, Chlorobenzene and lead ($Pb^{2-}$) were selected as representative contaminants. Experimental result showed that chlorobenzene sorption increased with increasing HDTMA to bentonite, ratios. On the contrary, the removal rate of lead decreased as the amount of HDTMA increased. The removal of chlorobenzene was influenced by the amount of HDTMA added to the bentonites rather than initial concentration of chlorobenzene, but the removal of lead was much more influenced by the initial concentration of lead. The adsorption of lead was not affected by chlorobenzene, and vice versa. The competitive sorption between the heavy metal and the organic contaminant was not present.