Race, Marco (2016) Chemical washing of contaminated soils and photocatalytic treatments of spent soil washing effluent. [Tesi di dottorato]

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Tipologia del documento:	Tesi di dottorato
Lingua:	English
Titolo:	Chemical washing of contaminated soils and photocatalytic treatments of spent soil washing effluent
Autori:	Autore Email Race, Marco marco.race@unina.it
Data:	30 Marzo 2016
Numero di pagine:	88
Istituzione:	Università degli Studi di Napoli Federico II
Dipartimento:	Ingegneria Civile, Edile e Ambientale
Scuola di dottorato:	Scienze della terra
Dottorato:	Analisi dei sistemi ambientali
Ciclo di dottorato:	28
Coordinatore del Corso di dottorato:	nome email Fedi, Maurizio maurizio.fedi@unina.it
Tutor:	nome email Fabbricino, Massimiliano [non definito] Andreozzi, Roberto [non definito] Marotta, Raffaele [non definito] Pirozzi, Francesco [non definito]
Data:	30 Marzo 2016
Numero di pagine:	88
Parole chiave:	soil washing, EDDS, heavy metals extraction, soil contamination,intra-particle diffusion,solar photocatalysis, soil washing effluents, Ecotoxicity assessment
Settori scientifico-disciplinari del MIUR:	Area 08 - Ingegneria civile e Architettura > ICAR/03 - Ingegneria sanitaria-ambientale
Depositato il:	03 Mag 2016 07:50
Ultima modifica:	31 Ott 2016 09:10
URI:	http://www.fedoa.unina.it/id/eprint/10826

Abstract

This dissertation has been addressed to study the reclamation of heavy metal contaminated soils by soil washing, and to investigate the feasibility of photocatalytic processes for the treatment of the spent soil washing solution (SSWS). Indeed, the collected SSWS, containing the extracted metals and chelating agents, represents one of the main drawbacks of the washing technique, as it has to be submitted to further treatments for a complete detoxification before being discharged into the environment. The soil washing using EDDS as chelating agent has been demonstrated to be an efficient soil remediation technique to remove Cu and Zn from real polluted soils. Only Cu and Zn present as exchangeable and reducible fractions have been extracted by EDDS. The intra-particle diffusion was the main rate controlling step in the extraction of heavy metals from the solid matrix. Different contributions have been found by applying the Weber and Morris intra-particle diffusion model due to the different roles of superficial and intra-particle diffusive processes. The diffusion coefficients of the Cu/EDDS and Zn/EDDS complexes in real contaminated soils have been estimated using simplified diffusive models. The simultaneous removal of EDDS and metals (Cu, Fe and Zn) from both synthetic solutions and real contaminated soil washing mixtures at neutral pH has been investigated to assess the possibility of applying TiO2 based photocatalytic processes for the treatment of SSWS and identify the sequence of photocatalytic processes required to optimally decontaminate the liquid wastes. The photocatalytic tests have demonstrated that the sequence of treatment constituted by two steps, TiO2-photocatalysis with oxygen followed by TiO2-sacrificial photocatalysis, is required to completely detoxify the SSWS. In particular, the results show that Fe and Zn are mainly removed by precipitation as insoluble hydroxides during the first step whereas the second step is necessary to reduce cupric ions to zero-valent Cu, which precipitates from the solution.

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