Publicação

Electro-based technologies for contaminants removal from soil and effluent targeting further reuses

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Resumo:	Soil and water resources are interconnected, and their protection is essential to Human life. Emerging organic contaminants (EOC) are a large group of unregulated compounds, which presence in both soils and effluents is a matter of major concern with unknown consequences. Thus, in order to reduce environmental and human associated risks, there is a need to develop viable techniques for the removal of these contaminants. In this Ph.D. dissertation, cost-effective key solutions based on electro-technologies were designed and studied for soil and effluent remediation, which are the downstream and upstream sources of the contamination. Soil remediation was focused on EOC and contamination legacy that is more resistant to natural attenuation (arsenic and petroleum hydrocarbons). The effluent treatment was focused on EOC removals and also the possibility to promote phosphorus recovery/reuse, a critical raw material essential to life. The electrokinetic contaminants removal from soil was developed aiming its valorization either in agriculture or as a secondary raw material. Soil treatment was highly dependent on both soil and contaminants properties. More aggressive electro-treatment conditions were designed ex-situ using 1-to 3-compartment electrodialytic reactors with soil stirring. For all the cases, the electric current enhanced contaminants removal. Up to 80% of arsenic was removed from soil in a 2-compartment cell, whereas remediation experiments of EOC achieved at least a 44% removal (mobilized and/or degraded) for three tested set-ups. An in-situ treatment with different electrical current strategies aiming at less soil disturbance was also developed for more sensitive scenarios like agricultural soil and arctic environment. The removal of hydrocarbons in artic soil was challenged by a more recalcitrant contamination, whereas EOC remediation in agricultural soil was enhanced up to a 37% by the electric current. The electro-technologies developed for effluent treatment were designed to promote a safer irrigation and/or environmental discharge. For either the reuse or the removal of phosphorus, together with EOC removal, a reactor with an anion exchange membrane with polarization switch showed to be the best approach developed (up to 15% P recovery and 57-72% of EOC removal). A one-compartment reactor with a sequence of more than two circular-shaped metal mixed oxide coated titanium mesh electrodes, alternated in polarity, was the best approach for EOC removal (up to 90% in 2 hours). This treatment does not require the addition of reagents and represents low energetic costs, making it more environmentally friendly. The technologies based on electrokinetic treatment showed to have a high potential for a wide array of applications, although the selection of the suitable treatment setup should be done case-by-case.
Autores principais:	Ferreira, Ana Rita Lourinho
Assunto:	Electrokinetic electrodialytic contaminants of emergent concern cell design
Ano:	2018
País:	Portugal
Tipo de documento:	tese de doutoramento
Tipo de acesso:	acesso aberto
Instituição associada:	Universidade Nova de Lisboa
Idioma:	inglês
Origem:	Repositório Institucional da UNL