Remediation of hexachlorocyclohexanes by electrochemically activated persulfates

Abstract

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.

Effect of zero‐valent iron nanoparticles on the remediation of a clayish soil contaminated with γ‐hexachlorocyclohexane (lindane) in a bioelectrochemical slurry reactor

“…1,2,3,4,5,6‐hexachlorocyclohexane (HCH), also known as γ‐hexachlorocyclohexane ( γ‐ HCH) or lindane, is an organochlorine, highly toxic, persistent and bioaccumulative compound. [ 1 ] It has carcinogenic effects, [ 2,3 ] is neurotoxic, and is also known to be an endocrine disruptor. [ 4–6 ]…”

Polyetherimide Nanofibres as Sorbents for Organochlorinated Pesticides Determination

“…These compounds were selected: (a) as they belong to the group of persistent organochlorinated pesticides listed as POPs under the Stockholm Convention on persistent organic pollutants and have therefore priority attention, (b) as there is a need to perform detailed monitoring of the environmental contamination of HCH and ClB due to their former industrial production in the Czech Republic [20], and (c) as organochlorinated pesticides belong to widely studied groups of target analytes with SPME utilization [21][22][23][24][25]. HCH are always accompanied by ClB in groundwater, as ClB are products of HCH natural transformations [20]. Aside from characterization of PEI SPME analytical performance by GC-MS/MS system response, the prepared assemblies were characterized by thermogravimetry (TGA), differential scanning calorimetry, adsorption (BET isotherm), and scanning electron microscopy (SEM).…”

HCH-Contaminated Soils and Remediation Technologies

“…Due to the high refractoriness and adverse effects of HCHs on the ecosystem and human beings [3,15,16], several HCH isomers are considered persistent organic pollutants (POPs) by the Stockholm Convention [10] and classified as neurotoxic, carcinogen, and teratogen by the Environmental Protection Agency (EPA) and the World Health Organization (WHO) [17,18]. The structure and main chemical properties of HCH isomers are given in Table 1.…”