Soil decontamination by supercritical extraction

Some of the existing techniques for soil decontamination are reviewed, giving particularemphasis to supercritical extraction (SCE), an environmental friendly technique whose applications to thetreatment of effluents and soil remediation are only emerging now. The experimental apparatus andanalytical technique used in our laboratory to study the extraction of atrazine from contaminated soil bySCE with carbon dioxide is described

Magnetic water treatment in a wastewater treatment plant: Part I - sorption and magnetic particles

[EN] The application of magnetic sorption to treat wastewaters is nowadays seen as a potential industrial method. In this work we apply magnetite particles to remediate real wastewater samples, with several contaminants competing for the same active sorption center at the same time. We also apply our studies at three different sampling points of a Wastewater Treatment Plant. In general terms, magnetite particles have shown a very good behaviour concerning the reduction of detergents and COD, while phosphates and total nitrogen, and the majority of heavy metals are high to moderately removed. The influence of the type of wastewater (i.e., sampling point) has also shown to be important especially for high concentration of contaminants

Development of pH-Sensitive magnetoliposomes containing shape anisotropic nanoparticles for potential application in combined cancer therapy

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) within the framework of the Strategic Funding of Research Units UIDB/04650/2020 (CF-UM-UP), UIDB/00319/2020 (ALGORITMI), UIDB/04077/2020 (MEtRICs), UIDB/04436/2020 (CMEMS) and UIDB/00511/2020 (LEPABE). FCT, POCI, FEDER and NORTE2020 are acknowledged for funding through research projects PTDC/QUI-QFI/28020/2017, EXPL/EMD-EMD/0650/2021, PTDC/EEI-EEE/2846/2021 and NORTE-01-0145-FEDER-000054. MINECO (Spain) is acknowledged for project MAT2016-76824-C3-2-R. B.D.C. and V.M.C. acknowledge FCT for PhD grants SFRH/BD/141936/2018 (B.D.C.) and UI/BD/151028/2021 (V.M.C.). R.O.R. thanks FCT for contract 2020.03975.CEECIND

Estudo da aplicação da extracção supercrítica à remoção de pesticidas de solos contaminados

Dissertação apresentada para obtenção do grau de Mestre em Engenharia do Ambiente,(área de especialização de Tratamento de Águas e Águas Residuais), na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Doutor Domingos Barbos

Application of Ultrasound-Assisted Supercritical Extraction to Soil Remediation

The coupling of ultrasound to supercritical extraction with carbon dioxide has been evaluated as a green remediation technique for soils contaminated with pesticides. The study used samples of soil spiked with atrazine, an organophosphate and contaminant of widespread use. The influence of the operating temperature and pressure on the extraction of atrazine was studied. The extraction of atrazine was enhanced with the use of ultrasound relative to the results obtained from conventional supercritical extraction. This study, operated in semi-continuous mode, demonstrates the possibility of increasing the yield of supercritical extraction by coupling with ultrasound instead of adding co-solvents, which is a greener alternative for removing contaminants such as pesticides from soil matrices. (c) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Cubic nanoparticles for magnetic hyperthermia: Process optimization and potential industrial implementation

© 2021 by the authors.Cubic nanoparticles are referred to as the best shaped particles for magnetic hyperthermia applications. In this work, the best set of values for obtaining optimized shape and size of magnetic particles (namely: reagents quantities and proportions, type of solvents, temperature, etc.) is determined. A full industrial implementation study is also performed, including production system design and technical and economic viability.This research was funded by: (a) Project MAT2016-76824-C3-2-R, “Diseño de Nanohilos Magneticos para su uso en Tecnologias Limpias”, MINECO, Spain. (b). Base Funding—UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE— Funded by national funds through the FCT/MCTES (PIDDAC); (c). Project PTDC/QUIQFI/ 28020/2017—POCI-01-0145-FEDER-028020—Funded by FEDER funds through COMPETE2020— Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES

Method to evaluate and prove-the-concept of magnetic separation and/or classification of particles

When designing new magnetic separators and/or classifiers or optimizing existing ones, it is usual to face several obstacles: the high cost of a proof of concept full laboratorial setup (including preliminary optimization procedures and/or feasibility demonstrations), time-consuming experiments, lack of flexibility of the assembled laboratorial apparatus, feed complexity, among others. In this work a method and corresponding methodology are proposed to apply in such cases, representing a low-cost, flexible and robust alternative to overcome the mentioned obstacles, from which working parameters of a laboratorial or even larger version of the device may be extrapolated. This represents a powerful tool when designing magnetic separators. In the proposed methodology by determining in one experiment the magnetic force required to separate/classify a particle in a certain point, it may be derived immediately the change in magnitude and shape of the magnetic force index (Bâ B) that must exist to separate other particles (with the same or different magnetic susceptibility) in another point, and it is possible to estimate, for example, the optimum, maximum or minimum value of other variables affecting the competing forces (e.g. radius of the particles, fluid density, rotation velocity), and also determine the critical limits of separation by extrapolating and obtaining the magnetic force required in those limits. It represents an open field allowing determining freely the values of the main variables. This methodology and associated method also allow repeating quickly and easily the experiments with different sets of geometrical design and positions. A case study was analyzed and tested for both processes: magnetic separation and magnetic classification, with good results, that allowed to conclude about the feasibility of the system for both processes, and to determine the best configuration geometry. The main objective of the present study was to demonstrate a cheap method and corresponding methodology that may be applied when designing magnetic separators and/or classifiers. Â(c) 2016 Elsevier B.V

Landfill leachate treatment by sorption in magnetic particles: preliminary study

Leachates are still an open issue in environmental protection. Many of the applied methods for their treatment present low efficiency and thus need to be used collectively. In practice reverse osmosis is mostly used, as it is the most effective option, regardless of its cost. Magnetic methods to treat effluents have been used for water and wastewater treatment by the use of magnetic particles together with magnetic separation for the removal of contaminants. However, large-scale applications are few or even non-existent when we deal with complex contaminated media such as landfill leachates, for which not even research studies at laboratorial scale with real samples have been done yet. In this work, we apply for the first time magnetic sorption for the treatment of leachates, and close the full cycle by studying the regeneration and re-use of the magnetic particles; we also study the influence of the concentration of magnetic particles, the use of several pre-treatment methodologies and the type of particle used in the process, in real landfill samples from the waste treatment plant of Salamanca (Spain), for the removal of COD, NO3-, NO2-, NH4+, Total-N, PO43-, SO42- and Cl-. Regeneration of the magnetic particles alter being used in the sorption stage is also studied, as well as their efficiency regarding their re-use. It is also determined the optimum number of batches for complete desorption and for regeneration of the particles, the effect of successive regeneration and re-use cycles, the use of two different regeneration methods, the efficiency of the desorption, the effect of the quantity of solvent and the influence of the time of sorption. Due to its innovative character and the complexity of the media, this work represents a first preliminary approach and, although some promising results have been obtained, further studies are required to completely understand and evaluate the proposed treatment process

Upscale Design, Process Development, and Economic Analysis of Industrial Plants for Nanomagnetic Particle Production for Environmental and Biomedical Use

Very few economical and process engineering studies have been made concerning the scale-up and implementation of nanomagnetic particle manufacturing into a full-scale plant, and determination of its viability. In this work we describe such a study for two types of industrial plants, one for manufacturing magnetic particles for applications in the environmental area, and the other for manufacturing nanomagnetic particles for applications in the biotechnology area; the two different applications are compared. The following methodology was followed: establish the manufacturing process for each application; determine the market demand of the product (magnetic nanoparticles) for both applications; determine the production capacity of each plant; engineer all the manufacturing process, determining all the process units and performing all the mass and energy balances for both plants; scale-up the main equipment; and determine the global economic impact and profitability. At the end both plants are found to be technologically and economically viable, the characteristics of the final products being, however, quite different, as well as the process engineering, economic analysis, and scale-up