Caso do cobre num regossolo psamítico

Dissertação de mestrado em Engenharia SanitáriaDe forma a avaliar a potencial contaminação de águas subterrâneas, foram colhidas amostras de solo em área homogénea, não poluída, contígua a um aterro sanitário intermunicipal. Estas amostras foram submetidas a contaminação através de soluções com concentrações crescentes em cobre e para diferentes valores de pH, utilizando ensaios em descontínuo e realizados ensaios de percolação em contínuo. No estudo da retenção do metal no solo foram testados diferentes modelos de equilíbrio, verificando-se que a equação de Freundlich descreve satisfatoriamente a relação entre a quantidade de metal retida pelo solo e a concentração de metal na solução. A quantidade de metal retida mostrou ser directamente dependente do teor em metal na solução contaminante e do seu valor de pH. A extracção química sequencial após os ensaios em descontínuo, mostrou haver um aumento do metal em quase todas as fracções do solo, especialmente na fracção "óxidos e hidróxidos amorfos"

Electro-desalination of glazed tile panels - discussion of possibilities

info:eu-repo/semantics/publishedVersio

Electrodialytic hydrogen production and critical raw materials recovery from secondary resources

FCT/MCTES through grant UIDB/04085/2020. J. Almeida acknowledges Fundação para a Ciência e a Tecnologia and EcoCoRe Doctoral program for her PhD fellowship PD\BD\135170\2017.Electrodialytic technologies are defined as treatment processes that promote the removal/recovery of substances in a matrix, based on the application of low-level current intensities. Additionally, along these processes hydrogen is self-generated, allowing them to operationally produce clean energy. This energy carrier is produced due to electrolysis reactions occurring at the cathode end of the electrodialytic reactor, when using inert electrodes. Herein, hydrogen production during the electrodialytic treatment of sewage sludge and mining residues suspensions (coupled with effluent or sewage sludge), at 50 and 100 mA, was assessed. During the electrodialytic treatment of sewage sludge, hydrogen purity production achieved 33%. When effluent or sewage sludge were used as enhancements in mining residues suspensions, hydrogen purity reached 71% and 34%, respectively. Furthermore, a proton-exchange membrane fuel cell was connected to the cathode compartment of the electrodialytic reactor. The electrical energy generated from self-hydrogen produced at 100 mA achieved ≈1 V in all performed experiments. Simultaneously, critical raw materials extraction, namely phosphorus and tungsten, was evaluated. When the process was applied to mining residue suspensions combined with sewage sludge, the highest extraction ratio of phosphorus (71%) and tungsten (62%) was observed.publishersversionpublishe

Overview of mining residues incorporation in construction materials and barriers for full-scale application

This work has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 778045, as well as from Portuguese funds from FCT/MCTES through grant UID/AMB/04085/2019. J. Almeida acknowledges Fundação para a Ciência e a Tecnologia for her PhD fellowship 560 PD/BD/135170/2017.Resources efficiency regarding the decrease of residues generation and disposal are important steps towards a cleaner production in the construction and mining industry. Minning processes generate huge amounts of residues, and some deposits have accumulated them over hundreds of years, causing environmental and public health problems. However, mining residues can be recovered as secondary supplies for construction materials production due to its physical, chemical and microstructural properties. This study presents a critical review on sustainable strategies researched to introduce mining residues in the construction sector. The gaps and barriers of these strategies and final products are discussed, concerning a safe and sustainable inclusion of mine residues in construction materials productionauthorsversionpublishe

Environmental benefits and mechanical performance of cement mortars with tungsten mining residues incorporation

No. ERC2016-CoG 725034 UID/AMB/04085/2020 PD\BD\135170\2017. TSecondary mining resources have been largely applied for the development of alternative building products. Additionally, its reuse versatility increases the potential on the future circular economy generation. Herein, mining residues from Panasqueira mine were applied in the formulation of cement-based mortars, according to EN 196-1 standard.Mechanical performance of mortars was analysed after the replacement of the conventional binder (cement) by mining residues in 10, 25 and 50 % (v/v). As expected, compressive and flexural strength decrease when compared to the reference mortar (100 % cement) in all cases. This decrease was more significant in terms of compressive strength (between 27 % and 71 %), when compared to flexural strength results (between 18 % and 56 %). Furthermore, an environmental approach of secondary mining resources incorporation on mortars, regarding Portugal and Poland data, was carried out. The savings in terms of primary resources may promote to minimise energy impacts. When mining residues replace cement in 10 % is possible to save 0.3 or 1.9 Mt of cement production and 0.14 or 0.89 CO2 Mt emissions, in Portugal and Poland, respectively.publishersversionpublishe

Life Cycle Assessment of Electrodialytic Technologies to Recover Raw Materials from Mine Tailings

UIDB/04085/2020 PD/BD/135170/2017Currently, the development of new sustainable technologies to recover raw materials from secondary resources has shown a lack of available data on the processes and supplies involved, as well as their environmental impacts. The present research has conducted a life cycle assessment of electrodialytic (ED) technologies to improve critical raw materials recovery in the Portuguese mining industry. To critically appraise the activities from the mining sector and gather data on technical and environmental issues, three waste management scenarios were considered: (1) ED treatment with a deep eutectic solvent as an adjuvant; (2) ED treatment with simultaneous H2 recovery; and (3) ED treatment with sodium chloride as an enhancement. The data presented were based on global databases, technical reports from official sources, and peer-reviewed published experimental outcomes. The estimated results indicated that one of the constraints in applying ED technologies is energy consumption and thus the impacts are highly dependent on energy source choices. On the other hand, as a consequence of the H2 inherently produced by ED technologies, there is a direct potential for energy recovery. Therefore, considering an upscale approach of the ED reactor based on bench scale experimental results, the H2 could be reused in the ED facility or stored. Additionally, according to experimental data, 22% of the tungsten from the fine mine tailings could be recovered. Finally, the possibility to remove 63% of arsenic from mine tailings could decrease contamination risks while creating additional marketable co-products.publishersversionpublishe

Effect of mining residues treated with an electrodialytic technology on cement-based mortars

UIDB/04085/2020 PD/BD/135170/2017Mining residues have been accumulated for centuries due to excavation and mining processes, causing environmental degradation worldwide. Their application in cementitious products is a feasible alternative to waste disposal. Electrodialytic technologies can promote a safer reuse of mining residues in the construction sector, coupling economic advantages due to the possible removal of toxic elements and the recovery of critical raw materials. The application of treated mining residues in construction products, namely their effects on physico-mechanical properties, in comparison to raw residues and cement uses needs to be addressed. This work presents a study of cement-based mortars with the incorporation of mining residues treated with an electrodialytic process in comparison to raw mining residues. The replacement percentages studied were 0, 10, 25 and 50 % of the binder in volume. Tests were conducted to evaluate fresh and hardened properties of mortars considering physical, microstructural and mechanical performances. Results show the viability of applying mining residues after the electrodialytic treatment as mortars materials in rendering, plastering, joint repointing, bedding masonry or screed requirements, with improved thermal conductivity and eco-efficiency.proofpublishe

Electrochemical treatment of effluent for the removal of contaminants of emergent concern and culturable microorganisms

project CEMOWAS2 (SOE2/P5/F0505) UIDB/04085/2020 CEECIND/04210/2017The present work aims to study the electrochemical (EC) process applied for the removal of contaminants of emergent concern (CECs) from wastewater after secondary treatment and the effect of the process on the total culturable microorganisms. The EC experiments were performed in a cylindrical open reactor with 500 mL of effluent, and a fixed current density of 8 mA/cm² was applied through mixed metal oxide electrodes. The experiments were conducted in different sets. In the first round (Set 1), the effluent sample was spiked with three CECs (200 ppb each): Caffeine (CAF), carbamazepine (CBZ), and oxybenzone (OXY). For the best treatment period, 6 h, electrodegradation rates ranged from 41 ± 7% for CAF to 95 ± 6% for OXY, with an 87% removal of total culturable microorganisms. In the second round (Set 2), aiming to assess EC process efficiency in a more complex CEC mixture, the effluent was spiked with six more CECs (200 ppb each): Diclofenac (DCF), triclosan (TCS), bisphenol A (BPA), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and ibuprofen (IBU), giving a total of nine CECs. In this case, the EC process allowed decreasing the CEC content by 19-100% (below the limit of detection), depending on the effluent samples, and the culturable microorganisms by 99.98% after a 6 h treatment. By contributing to CEC degradation and microorganism removal, the EC process proved to be a viable remediation and disinfection technology for secondary effluent from wastewater treatment plants.publishersversionpublishe

Ultrasound-assisted electrodialytic separation of cobalt from tungsten carbide scrap powder

Funding Information: Fundação para a Ciência e a Tecnologia is also acknowledged for P. Guedes Contract established under Individual Call to Scientific Employment Stimulus (CEECIND/01969/2020). The US Strategic Environmental Research and Development Program (project ER19-1130); the Superfund Research Program of the National Institute of Environmental Health Sciences (NIEHS, National Institutes of Health) (NIH; grant number P42ES017198). João P. Veiga from CENIMAT/I3N at FCT NOVA is also acknowledged for the XRF analysis. This research is anchored at RESOLUTION LAB, an infrastructure at NOVA School of Science and Technology. Publisher Copyright: © 2024 The AuthorsRecycling of tungsten carbide-cobalt (WC–Co) will considerably grow in the future. Thus, efficient and greener methods for the recovery of the critical raw materials, Co and W, will be necessary. In this work, we evaluate the separation of Co from WC using an electrodialytic (ED) process alone and coupled with ultrasound-assisted extraction (UAE). The WC-Co powder was suspended in different leaching agents, and the effects of UAE amplitude (probe system), pulse periods, and treatment time were evaluated. The Co extraction was mainly dependent on the leaching agent when only UAE was applied, being more efficient under acidic pH. The ED process, alone and coupled to UAE, was then applied using a reactor with two compartments separated by a cation exchange membrane with nitric acid as anolyte; and the effect of DC intensity was tested for Co separation from WC. Between 24 % and 58 % of Co were solubilized when ED was applied alone, but these values increased up to 96 % through the combination with UAE. The ED process was also applied without the use of nitric acid, taking advantage of the acid generated through water electrolysis, aiming for a more environmentally friendly process. The best Co selective recovery was achieved when ED-UAE was used, reaching 99 % of Co solubilization and 90 % of the total Co electromigration to the cathode compartment, leaving behind the WC residue at the anode. The ED-UAE process presents as a greener process for Co separation from WC residues, with further tests needed to include W recovery.publishersversionpublishe