In Situ Chemical Oxidation of Contaminated Soil and Groundwater Using Persulfate: A Review

Advanced oxidation processes (AOPs) were first proposed in the 1980s for drinking water treatment and later were widely studied for treatment of different wastewaters. During the AOP treatment of wastewater, hydroxyl radicals (OH·) or sulfate radicals (SO 4 ·− ) are generated in sufficient quantity to remove refractory organic matters, traceable organic contaminants, or certain inorganic pollutants, or to increase wastewater biodegradability as a pre-treatment prior to an ensuing biological treatment. In this paper, we review the fundamental mechanisms of radical generation in different AOPs and select landfill leachate and biologically treated municipal wastewater as model wastewaters to discuss wastewater treatment with different AOPs. Generally, the treatment efficiencies rely heavily upon the selected AOP type, physical and chemical properties of target pollutants, and operating conditions. It would be noted that other mechanisms, besides hydroxyl radical or sulfate radical-based oxidation, may occur during the AOP treatment and contribute to the reduction of target pollutants. Particularly, we summarize recent advances in the AOP treatment of landfill leachate, as well as advanced oxidation of effluent organic matters (EfOM) in biologically treated secondary effluent (BTSE) for water reuse.

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“…In a thermally activated persulfate method, the temperature applied broadly ranges within 35 and 130°C [15]. As seen in Eqs.…”

Section: Other Aopsmentioning

confidence: 99%

“…Elevated pH can also activate persulfate, but the relevant mechanisms are still unclear [15]. In a thermally activated persulfate method, the temperature applied broadly ranges within 35 and 130°C [15].…”

Section: Other Aopsmentioning

confidence: 99%

Advanced Oxidation Processes (AOPs) in Wastewater Treatment

2015

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“…15−18 In the application of S 2 O 8 2− for in situ chemical oxidation, the low reactivity of S 2 O 8 2− under low temperature or the natural minerals conditions ensured the S 2 O 8 2− reaching the contaminated zone. 9,19 However, in order to employ the S 2 O 8 2− in the wastewater treatment, acceleration of the S 2 O 8 2− activation was desired. It has been exhibited that 4-chloro-3-methylphenol was abated within 3−59 s in pressurized hot water and in supercritical water with the S 2 O 8 2− addition activated by high temperature.…”

Section: ■ Introductionmentioning

confidence: 99%

Enhanced Photoelectrocatalytic Decomplexation of Cu–EDTA and Cu Recovery by Persulfate Activated by UV and Cathodic Reduction

Zeng

Liu

Chai

et al. 2016

Environ. Sci. Technol.

139

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In order to enhance Cu−EDTA decomplexation and copper cathodic recovery via the photoelectrocatalytic (PEC) process, S 2 O 8 2− was introduced into the PEC system with a TiO 2 /Ti photoanode. At a current density of 0.2 mA/cm 2 and initial solution pH of 3.0, the decomplexation ratio of Cu complexes was increased from 47.5% in the PEC process to 98.4% with 5 mM S 2 O 8 2− addition into the PEC process (PEC/S 2 O 8 2− ). Correspondently, recovery percentage of Cu was increased to 98.3% from 47.4% within 60 min. It was observed that nearly no copper recovery occurred within the initial reaction period of 10 min. Combined with the analysis of ESR and electrochemical LSV curves, it was concluded that activation of S 2 O 8 2− into SO 4 ·− radicals by cathodic reduction occurred, which was prior to the reduction of liberated Cu 2+ ions. UV irradiation of S 2 O 8 2− also led to the production of SO 4 ·− . The generated SO 4 ·− radicals enhanced the oxidation of Cu−EDTA. After the consumption of S 2 O 8 2− , the Cu recovery via cathodic reduction proceeded quickly. Acidification induced by the transformation of SO 4 ·− to OH· favored the copper cathodic recovery. The combined PEC/S 2 O 8 2− process was also efficient for the TOC removal from a real electroplating wastewater with the Cu recovery efficiency higher than 80%.

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“…Finally, heat-activated PSF was tested as sulfate and hydroxyl radical generator. SO 4 •-and OH • are one of the strongest known oxidants used for in situ chemical oxidation in the remediation of soil and groundwater [20].…”

Section: Introductionmentioning

confidence: 99%

Chemical Degradation of PCDD/F in Contaminated Sediment

Hrabák

Homolková

Černík

2016

Ecological Chemistry and Engineering S

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Due to the extreme toxicity of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), the remediation of PCDD/F aquifer source zones is greatly needed; however, it is very difficult due to their persistence and recalcitrance. The potential degradability of PCDD/F bound to a real matrix was studied in five systems: iron in a high oxidation state (ferrate), zero-valent iron nanoparticles (nZVI), palladium nanopowder (Pd), a combination of nZVI and Pd, and persulfate (PSF). The results were expressed by comparing the total toxicity of treated and untreated samples. This was done by weighting the concentrations of congeners (determined using a standardized GC/HRMS technique) by their defined toxicity equivalent factors (TEF). The results indicated that only PSF was able to significantly degrade PCDD/F. Toxicity in the system decreased by 65% after PSF treatment. Thus, we conclude that PSF may be a potential solution for in-situ remediation of soil and groundwater at PCDD/F contaminated sites.

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In Situ Chemical Oxidation of Contaminated Soil and Groundwater Using Persulfate: A Review

Cited by 1,016 publications

References 47 publications

Advanced Oxidation Processes (AOPs) in Wastewater Treatment

Advanced Oxidation Processes (AOPs) in Wastewater Treatment

Enhanced Photoelectrocatalytic Decomplexation of Cu–EDTA and Cu Recovery by Persulfate Activated by UV and Cathodic Reduction

Chemical Degradation of PCDD/F in Contaminated Sediment

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