Remediation of hexachlorocyclohexanes by electrochemically activated persulfates.
Hexachlorocyclohexane (HCH) isomers represent a family of formerly widely utilized pesticides that are persistent, capable of undergoing long-range transport and tend to bioaccumulate in human and animal tissue. Their widespread global utilization coupled with a propensity to adversely impact human health and the environment translates into an urgent need to develop feasible methodologies by which to treat HCH-impacted groundwater and soil. The present study was conducted to evaluate the efficacy of two persulfate-based oxidants: peroxydisulfate (S2O8 (2-), PDS) and peroxymonosulfate (HSO5 (-), PMS) activated by electrochemical processes (EC) to treat HCH-impacted environmental media. This research demonstrated that the optimal experimental conditions (oxidant dose and electrical current) were 2 mM PDS and 20 mA for an aqueous solution of 4 μM of summed HCHs (ΣHCH). GC/MS full scan analysis revealed the presence of 2,4,6-trichlorophenol as the only detectable intermediate formed during electro-activated PDS treatment of ΣHCH. The investigated method was tested on leachate from a known HCHs-impacted site in Hajek, Czech Republic which contained 106 μg/l of ΣHCH and 129 μg/l of chlorobenzenes. Results from batch treatment showed positive results for electro-activated PDS but only negligible effectiveness for electro-activated PMS. In addition to explaining the efficacy of the electro-activated PDS, this research also explored the basis for the differing reactivities of these two persulfates.
Centre for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic. stanislaw.waclawek@tul.cz.
Stanisław
S
Wacławek
Centre for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.
Vojtech
V
Antoš
Centre for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.
Pavel
P
Hrabák
Centre for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.
Miroslav
M
Černík
Geosyntec Consultants Inc., 7 Graphics Drive, Suite 106, Ewing, NJ, USA.
Daniel
D
Elliott
D002733:Chlorophenols / Q000737:chemistry; D018153:Czech Republic; D004563:Electrochemistry; D052918:Environmental Restoration and Remediation; D060587:Groundwater; D001556:Hexachlorocyclohexane / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010545:Peroxides / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*
D002733:Chlorophenols; D007306:Insecticides; D016877:Oxidants; D010545:Peroxides; D012989:Soil Pollutants; D013431:Sulfates; C038288:peroxymonosulfate; D001556:Hexachlorocyclohexane; C024564:2,4,6-trichlorophenol
Chemical oxidation; Chlorobenzenes; HCH; Hexachlorocyclohexanes; Lindane; Peroxydisulfate; Peroxymonosulfate