In-situ groundwater remediation by selective colloid mobilization
First Claim
1. A method of aqueous solution remediation by selectively mobilizing metal oxides in colloidal form having a net-positive surface charge in the aqueous solution which comprises metal oxide colloids and phyllosilicate clays, comprising the steps of:
- (a) adding a cationic surfactant to the aqueous solution, thereby shielding said metal oxide colloids from at least a portion of the negatively charged sites associated with said phyllosilicate clays present in the aqueous solution, resulting in a stable suspension of the metal oxides in the aqueous solution;
(b) flocculating the resulting suspension, resulting in a sediment of metal oxides and a supernatant liquid; and
(c) separating the resulting sediment from the supernatant liquid, resulting in the removal of the sediment and the remediation of the aqueous solution.
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Abstract
An in-situ groundwater remediation pump and treat technique effective for reclamation of aquifers that have been contaminated with a mixed, metal-containing waste, which promotes selective mobilization of metal oxide colloids with a cationic surfactant, preferably a quaternary alkylammonium surfactant, without significantly reducing formation permeability that often accompanies large-scale colloid dispersion, thus increasing the efficiency of the remediation effort by enhancing the capture of strongly sorbing contaminants associated with the oxide phases. The resulting suspension can be separated from the bulk solution with controlled pH adjustments to destabilize the oxide colloids, and a clear supernatant which results that can be recycled through the injection well without further waste treatment.
52 Citations
21 Claims
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1. A method of aqueous solution remediation by selectively mobilizing metal oxides in colloidal form having a net-positive surface charge in the aqueous solution which comprises metal oxide colloids and phyllosilicate clays, comprising the steps of:
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(a) adding a cationic surfactant to the aqueous solution, thereby shielding said metal oxide colloids from at least a portion of the negatively charged sites associated with said phyllosilicate clays present in the aqueous solution, resulting in a stable suspension of the metal oxides in the aqueous solution; (b) flocculating the resulting suspension, resulting in a sediment of metal oxides and a supernatant liquid; and (c) separating the resulting sediment from the supernatant liquid, resulting in the removal of the sediment and the remediation of the aqueous solution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for in-situ remediation of groundwater by selectively mobilizing metal oxides in colloidal form having a net positive surface charge in the groundwater which comprises the metal oxide colloids and phyllosilicate clays, comprising the steps of:
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(a) injecting a cationic surfactant to the groundwater; (b) capturing groundwater containing the cationic surfactant; (c) flocculating the captured groundwater to settle colloids, resulting in a precipitate of metal oxides and a supernatant liquid; and (d) returning the now remediated supernatant liquid to the groundwater. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification