Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils

Ultrasonic soil washing processes using organic solvents were investigated for the development of novel remediation technologies for persistent organic pollutants (POPs)- contaminated soils. Aluminum foil erosion was first tested to understand sonophysical activity in water, methanol (polar) and n-h...

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Autores principales:	Dukyoung Lee, Younggyu Son
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Polychlorinated biphenyls Cavitation Soil washing Methanol n-Hexane Chemistry QD1-999 Acoustics. Sound QC221-246
Acceso en línea:	https://doaj.org/article/79c0328144fb438eb5c91d0c8ac5cb82
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spelling	oai:doaj.org-article:79c0328144fb438eb5c91d0c8ac5cb822021-12-02T04:59:52ZUltrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils1350-417710.1016/j.ultsonch.2021.105825https://doaj.org/article/79c0328144fb438eb5c91d0c8ac5cb822021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S1350417721003679https://doaj.org/toc/1350-4177Ultrasonic soil washing processes using organic solvents were investigated for the development of novel remediation technologies for persistent organic pollutants (POPs)- contaminated soils. Aluminum foil erosion was first tested to understand sonophysical activity in water, methanol (polar) and n-hexane (nonpolar) in a 28 kHz double-bath-type sonoreactor. Significant sonophysical damage on the aluminum foil was observed at the antinodes for all solvents, and the order of degree of sonophysical damage was as follows: water > methanol > n-hexane. Subsequently, conventional (mechanical mixing only) and ultrasonic soil washing (mechanical mixing and ultrasound) techniques were compared for the removal of polychlorinated biphenyls (PCBs) from soil. Two types of contaminated soils, fresh (Soil A, C0 = 2.5 mg/kg) and weathered (Soil B, C0 = 0.5 mg/kg), were used and the applied soil-to-liquid (S:L) ratio was 1:5 and 1:10 for methanol and n-hexane, respectively. The polar solvent significantly increased washing efficiencies compared to the nonpolar solvent, despite the nonpolar nature of the PCBs. Washing efficiency was significantly enhanced in ultrasonic soil washing compared to conventional washing, owing to macro- and micro-scale sonophysical actions. The highest washing efficiencies of 90% for Soil A and 70% for Soil B were observed in the ultrasonic washing processes using methanol. Additionally, a single operation of the ultrasonic washing process was superior to two sequential processes with conventional mixing in terms of washing efficiency, consumption of washing agents, treatment of washing leachate, and operation time. Finally, the removal of PCBs in an organic solvent (methanol) was investigated in photolytic and sonolytic processes for the post-treatment of soil washing leachate. A photolysis efficiency of 80% was obtained within 60 min of UV exposure for intensities of 1.0, 2.0, and 4.0 W/cm2. The primary mechanism of PCBs degradation is photolytic dechlorination. In contrast, no degradation was detected in the sonolytic process, as the excess organic solvent acted as a strong radical scavenger.Dukyoung LeeYounggyu SonElsevierarticlePolychlorinated biphenylsCavitationSoil washingMethanoln-HexaneChemistryQD1-999Acoustics. SoundQC221-246ENUltrasonics Sonochemistry, Vol 80, Iss , Pp 105825- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Polychlorinated biphenyls Cavitation Soil washing Methanol n-Hexane Chemistry QD1-999 Acoustics. Sound QC221-246
spellingShingle	Polychlorinated biphenyls Cavitation Soil washing Methanol n-Hexane Chemistry QD1-999 Acoustics. Sound QC221-246 Dukyoung Lee Younggyu Son Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
description	Ultrasonic soil washing processes using organic solvents were investigated for the development of novel remediation technologies for persistent organic pollutants (POPs)- contaminated soils. Aluminum foil erosion was first tested to understand sonophysical activity in water, methanol (polar) and n-hexane (nonpolar) in a 28 kHz double-bath-type sonoreactor. Significant sonophysical damage on the aluminum foil was observed at the antinodes for all solvents, and the order of degree of sonophysical damage was as follows: water > methanol > n-hexane. Subsequently, conventional (mechanical mixing only) and ultrasonic soil washing (mechanical mixing and ultrasound) techniques were compared for the removal of polychlorinated biphenyls (PCBs) from soil. Two types of contaminated soils, fresh (Soil A, C0 = 2.5 mg/kg) and weathered (Soil B, C0 = 0.5 mg/kg), were used and the applied soil-to-liquid (S:L) ratio was 1:5 and 1:10 for methanol and n-hexane, respectively. The polar solvent significantly increased washing efficiencies compared to the nonpolar solvent, despite the nonpolar nature of the PCBs. Washing efficiency was significantly enhanced in ultrasonic soil washing compared to conventional washing, owing to macro- and micro-scale sonophysical actions. The highest washing efficiencies of 90% for Soil A and 70% for Soil B were observed in the ultrasonic washing processes using methanol. Additionally, a single operation of the ultrasonic washing process was superior to two sequential processes with conventional mixing in terms of washing efficiency, consumption of washing agents, treatment of washing leachate, and operation time. Finally, the removal of PCBs in an organic solvent (methanol) was investigated in photolytic and sonolytic processes for the post-treatment of soil washing leachate. A photolysis efficiency of 80% was obtained within 60 min of UV exposure for intensities of 1.0, 2.0, and 4.0 W/cm2. The primary mechanism of PCBs degradation is photolytic dechlorination. In contrast, no degradation was detected in the sonolytic process, as the excess organic solvent acted as a strong radical scavenger.
format	article
author	Dukyoung Lee Younggyu Son
author_facet	Dukyoung Lee Younggyu Son
author_sort	Dukyoung Lee
title	Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
title_short	Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
title_full	Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
title_fullStr	Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
title_full_unstemmed	Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils
title_sort	ultrasound-assisted soil washing processes using organic solvents for the remediation of pcbs-contaminated soils
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/79c0328144fb438eb5c91d0c8ac5cb82
work_keys_str_mv	AT dukyounglee ultrasoundassistedsoilwashingprocessesusingorganicsolventsfortheremediationofpcbscontaminatedsoils AT younggyuson ultrasoundassistedsoilwashingprocessesusingorganicsolventsfortheremediationofpcbscontaminatedsoils
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Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils

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