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The purpose of this study was to evaluate the relationship between motivation and meaningful learning for university students through m-learning. The implementation of m-learning in the learning process followed the ARCS model and was evaluated using the Instructional Materials Motivation Survey (IMMS). The Google Science Journal mobile application was used by the students in this study to determine the acceleration vector of a previously selected motor vehicle. The IMMS allowed us to measure the motivation of the kinematics and dynamics students from the Civil Engineering Department at Universidad Católica del Maule. The instrument's reliability was measured using Cronbach's α, giving an overall value of 0.89. The implementation of m-learning in university classrooms was positively valued by the majority of students surveyed, and it increased the percentage of students who achieved the expected learning objectives compared to previous versions of the course (without m-learning). Finally, this study provides a validated measurement model and solid scientific references, which aim to stimulate the use of m-learning. It has been shown that the implementation of m-learning favorably stimulates students, their interest in learning kinematics, and their confidence in themselves.
Luis A. Laurens Arredondo; Hugo Valdés Riquelme. M‐learning adapted to the ARCS model of motivation and applied to a kinematics course. Computer Applications in Engineering Education 2021, 1 .
AMA StyleLuis A. Laurens Arredondo, Hugo Valdés Riquelme. M‐learning adapted to the ARCS model of motivation and applied to a kinematics course. Computer Applications in Engineering Education. 2021; ():1.
Chicago/Turabian StyleLuis A. Laurens Arredondo; Hugo Valdés Riquelme. 2021. "M‐learning adapted to the ARCS model of motivation and applied to a kinematics course." Computer Applications in Engineering Education , no. : 1.
The aim of this work was to evaluate the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for treating rural domestic wastewater when strategies such as bed depth reduction and media change are used in combination with bottom saturation. Two treatment wetland systems were implemented: normal (VF-N), with a bed depth of 1.0 m, and modified (VF-M), with a bed depth of 0.5 m and a bottom layer of natural zeolite. Schoenoplectus californicus was used as experimental plant. These two treatment systems were operated at a hydraulic loading rate of 120 mm/d in two phases. Phase I did not use bottom saturation, while Phase II involved a bottom saturation of the zeolite layer of the VF-M system. The results show that bed depth reduction did not have a significant effect (p > 0.05) in terms of organic matter, solids, and ammonium removal. Conversely, it had a significant influence (p < 0.05) on phosphate as well as a negative effect on pathogen removal. This influence could be explained by initial media capacity for phosphorus removal and filtration importance in the case of pathogens. Partial saturation only had a positive influence on total nitrogen removal. The addition of a bottom layer of natural zeolite showed no positive effect on nutrient removal. The plant showed adaptation and positive development in both VF-N and VF-M. The water balance showed that water loss was not influenced by bed depth reduction. Therefore, according to the previous results, a combination of the proposal modifications to VSSF TWs can be introduced for treating rural domestic wastewater.
Ismael Vera-Puerto; Hugo Valdés; Christian Correa; Valeria Perez; Roberto Gomez; Erica Alarcon; Carlos Arias. Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands. International Journal of Environmental Research and Public Health 2021, 18, 4842 .
AMA StyleIsmael Vera-Puerto, Hugo Valdés, Christian Correa, Valeria Perez, Roberto Gomez, Erica Alarcon, Carlos Arias. Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands. International Journal of Environmental Research and Public Health. 2021; 18 (9):4842.
Chicago/Turabian StyleIsmael Vera-Puerto; Hugo Valdés; Christian Correa; Valeria Perez; Roberto Gomez; Erica Alarcon; Carlos Arias. 2021. "Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands." International Journal of Environmental Research and Public Health 18, no. 9: 4842.
The aim of this work was to study different desalination technologies as alternatives to conventional reverse osmosis (RO) through a systematic literature review. An expert panel evaluated thermal and membrane processes considering their possible implementation at a pilot plant scale (100 m3/d of purified water) starting from seawater at 20 °C with an average salinity of 34,000 ppm. The desalination plant would be located in the Atacama Region (Chile), where the high solar radiation level justifies an off-grid installation using photovoltaic panels. We classified the collected information about conventional and emerging technologies for seawater desalination, and then an expert panel evaluated these technologies considering five categories: (1) technical characteristics, (2) scale-up potential, (3) temperature effect, (4) electrical supply options, and (5) economic viability. Further, the potential inclusion of graphene oxide and aquaporin-based biomimetic membranes in the desalinization processes was analyzed. The comparative analysis lets us conclude that nanomembranes represent a technically and economically competitive alternative versus RO membranes. Therefore, a profitable desalination process should consider nanomembranes, use of an energy recovery system, and mixed energy supply (non-conventional renewable energy + electrical network). This document presents an up-to-date overview of the impact of emerging technologies on desalinated quality water, process costs, productivity, renewable energy use, and separation efficiency.
Aldo Saavedra; Hugo Valdés; Andrea Mahn; Orlando Acosta. Comparative Analysis of Conventional and Emerging Technologies for Seawater Desalination: Northern Chile as A Case Study. Membranes 2021, 11, 180 .
AMA StyleAldo Saavedra, Hugo Valdés, Andrea Mahn, Orlando Acosta. Comparative Analysis of Conventional and Emerging Technologies for Seawater Desalination: Northern Chile as A Case Study. Membranes. 2021; 11 (3):180.
Chicago/Turabian StyleAldo Saavedra; Hugo Valdés; Andrea Mahn; Orlando Acosta. 2021. "Comparative Analysis of Conventional and Emerging Technologies for Seawater Desalination: Northern Chile as A Case Study." Membranes 11, no. 3: 180.
A large part of the global brick manufacturing industry has evolved based on knowledge transmitted from generation to generation without developing a consistent scientific approach. The purpose of this article is to contribute to this approach by discussing the state-of-the-art and future trends of the design and construction of artisan brick kilns (ABK). The methodology proposed for this study is based on a systematic literature review whereby main question is: What research exists on brick kilns? Based on the results of this review, it is recommended that appropriate emerging technologies that should be incorporated to ABKs for either medium or small enterprises should be: mechanical fans, envelope thermal insulation, organic waste of uniform size as fuel, automatic control of process variables and computer simulations of phenomenological processes. This should be accompanied by technical training for the brick-makers and greater access to financing funds. The technologies reviewed throughout the paper will allow for a more thermally efficient design of kilns, which will emit less hazardous greenhouse gases and atmospheric pollutants.
Hugo Valdes; Juan Vilches; Gabriel Felmer; Mariela Hurtado; Juan Figueroa. Artisan Brick Kilns: State-of-the-Art and Future Trends. Sustainability 2020, 12, 7724 .
AMA StyleHugo Valdes, Juan Vilches, Gabriel Felmer, Mariela Hurtado, Juan Figueroa. Artisan Brick Kilns: State-of-the-Art and Future Trends. Sustainability. 2020; 12 (18):7724.
Chicago/Turabian StyleHugo Valdes; Juan Vilches; Gabriel Felmer; Mariela Hurtado; Juan Figueroa. 2020. "Artisan Brick Kilns: State-of-the-Art and Future Trends." Sustainability 12, no. 18: 7724.
The aim of this work was to determine the competencies that need to be included in engineering programs to develop water infrastructure based on Nature-Based Solutions (NBS) in the urban context, focused on its application in developing countries. Thus, the work was developed in three phases: i) a theoretical phase, ii) a validation phase and iii) a statistical analysis. For the theoretical phase, a literature review was conducted to determine a set of competencies for developing these type of projects. Next, in the validation phase, fifty participants were invited to complete a two-round Delphi questionnaire to rank the competencies detected in the literature review. The participants were classified according to their level of knowledge (skilled or expert) and place of work (countries with upper-middle-income or high-income). The results showed that twenty-one competencies were identified. In the validation phase, for the first Delphi round, the different groups studied (skilled vs expert; high-income vs upper-middle-income) did not agree about the most important competencies. However, after the second Delphi round, an agreement was achieved. Therefore, competencies related to water quality and process design for improving its quality were defined as “extremely important” competencies. In addition, the entire panel of experts also highlighted competencies related to legislation, circular economy, equipment, climate, and construction materials. Thus, for the first time, a set of competencies that needs to be included in educational programs for engineers with a special focus on developing water infrastructure based on NBS in the urban context of developing countries has been proposed in this work.
I. Vera-Puerto; H. Valdes; C. Correa; R. Agredano; G. Vidal; M. Belmonte; J. Olave; C. Arias. Proposal of competencies for engineering education to develop water infrastructure based on “Nature-Based Solutions” in the urban context. Journal of Cleaner Production 2020, 265, 121717 .
AMA StyleI. Vera-Puerto, H. Valdes, C. Correa, R. Agredano, G. Vidal, M. Belmonte, J. Olave, C. Arias. Proposal of competencies for engineering education to develop water infrastructure based on “Nature-Based Solutions” in the urban context. Journal of Cleaner Production. 2020; 265 ():121717.
Chicago/Turabian StyleI. Vera-Puerto; H. Valdes; C. Correa; R. Agredano; G. Vidal; M. Belmonte; J. Olave; C. Arias. 2020. "Proposal of competencies for engineering education to develop water infrastructure based on “Nature-Based Solutions” in the urban context." Journal of Cleaner Production 265, no. : 121717.
This study aims to evaluate the sorption characteristics of NH 4 + -N and PO 4 3 − -P onto the surface of natural zeolites coming from Chile and their potential application in the subsurface-flow treatment wetlands for wastewater treatment in rural areas. For this purpose, adsorption experiments onto the zeolite were developed in batch assays. The effects of the adsorbent quantity (20 g and 50 g) and particle size (0.2–1.0 mm; 1.5–3.0 mm, and 5.0–8.0 mm) were evaluated in terms of adsorption capacity at different NH4+-N and PO4−3-P concentrations. Then, the obtained laboratory results were adjusted to theoretical models: Saturation-growth-rate and Langmuir. The saturation adsorption of NH4+-N on the zeolite increases at the same time that the initial concentration increases for the same zeolite quantity; however, the saturation values were similar between the different zeolite sizes tested. For PO4−3-P, the adsorption did not have a direct relationship with the initial concentration nor zeolite quantity and better results were only achieved for zeolite sizes of 1.5–3.0 mm. Regarding the Langmuir model, sizes of 1.5–3.0 mm had the best adsorption characteristics, with the maximum adsorption capacity of up to 1.58 mg/g for NH4+-N and up to 0.08 mg/g for PO4−3-P. Therefore, a new material—a natural zeolite from the Maule Region of Chile—is described as a potential support medium for treatment wetlands.
Ismael Vera-Puerto; Matias Saravia; Jorge Olave; Carlos Arias; Erica Alarcon; Hugo Valdes. Potential Application of Chilean Natural Zeolite as a Support Medium in Treatment Wetlands for Removing Ammonium and Phosphate from Wastewater. Water 2020, 12, 1156 .
AMA StyleIsmael Vera-Puerto, Matias Saravia, Jorge Olave, Carlos Arias, Erica Alarcon, Hugo Valdes. Potential Application of Chilean Natural Zeolite as a Support Medium in Treatment Wetlands for Removing Ammonium and Phosphate from Wastewater. Water. 2020; 12 (4):1156.
Chicago/Turabian StyleIsmael Vera-Puerto; Matias Saravia; Jorge Olave; Carlos Arias; Erica Alarcon; Hugo Valdes. 2020. "Potential Application of Chilean Natural Zeolite as a Support Medium in Treatment Wetlands for Removing Ammonium and Phosphate from Wastewater." Water 12, no. 4: 1156.
In the context of the impact of urbanization on climate change, this work aims to evaluate the sensitivity of the thermal and radiative properties of building surfaces in urban areas to the urban heat island intensity, a local scale meteorological phenomenon. For this, variations of albedo values, emissivity, thermal conductivity and heat capacity of roofs, streets and walls were simulated through an urban scheme coupled with the BRAMS mesoscale atmospheric model for the metropolitan area of São Paulo, considering two main urban types. The simulations show that, in general, looking for cold surface situations, the change of building material can contribute to a reduction of up to 3 °C for São Paulo. In addition, the role of orientation and the typological characteristics of constructions should be taken into account. In this sense, it is expected that this work guides civil engineers and builders to search for new materials in order to reduce the effects of urbanization on the local climate.
Marcos Vinicius Bueno De Morais; Viviana Vanesa Urbina Guerrero; Edmilson Dias De Freitas; Edson R. Marciotto; Hugo Valdés; Christian Correa; Roberto Agredano; Ismael Vera-Puerto. Sensitivity of Radiative and Thermal Properties of Building Material in the Urban Atmosphere. Sustainability 2019, 11, 6865 .
AMA StyleMarcos Vinicius Bueno De Morais, Viviana Vanesa Urbina Guerrero, Edmilson Dias De Freitas, Edson R. Marciotto, Hugo Valdés, Christian Correa, Roberto Agredano, Ismael Vera-Puerto. Sensitivity of Radiative and Thermal Properties of Building Material in the Urban Atmosphere. Sustainability. 2019; 11 (23):6865.
Chicago/Turabian StyleMarcos Vinicius Bueno De Morais; Viviana Vanesa Urbina Guerrero; Edmilson Dias De Freitas; Edson R. Marciotto; Hugo Valdés; Christian Correa; Roberto Agredano; Ismael Vera-Puerto. 2019. "Sensitivity of Radiative and Thermal Properties of Building Material in the Urban Atmosphere." Sustainability 11, no. 23: 6865.
Nowadays, establishing clean energy sources is an undeniable need for all territories to reconcile energy and competitiveness objectives with those of security and sustainability. This article shows the main advantages of implementing clean energy sources in the long-term Chilean electrical network. The clean energy considered in this work is based on Renewable Energy (Conventional and Non-Conventional) with the backup of gas or nuclear. Thus, four scenarios are proposed and were simulated for the year 2050, the year assumed for the decommissioning of all coal plants in the country. These scenarios contemplate a high or low penetration of Renewable Energy. Additionally, a reference and realistic scenario for the year 2018 has also been considered to compare to the clean scenarios proposed. The results obtained coincide with the goals of reducing environmental impacts such as global warming emissions and fossil fuel dependence. However, the backup that was chosen for supporting the intermittence of renewable energy may have an important role in the main system considering the expected growth of energy demands in the near future.
Ivan Merino; Israel Herrera; Hugo Valdés. Environmental Assessment of Energy Scenarios for a Low-Carbon Electrical Network in Chile. Sustainability 2019, 11, 5066 .
AMA StyleIvan Merino, Israel Herrera, Hugo Valdés. Environmental Assessment of Energy Scenarios for a Low-Carbon Electrical Network in Chile. Sustainability. 2019; 11 (18):5066.
Chicago/Turabian StyleIvan Merino; Israel Herrera; Hugo Valdés. 2019. "Environmental Assessment of Energy Scenarios for a Low-Carbon Electrical Network in Chile." Sustainability 11, no. 18: 5066.
Avocado oil has generated growing interest among consumers due to its nutritional and technological characteristics, which is evidenced by an increase in the number of scientific articles that have been published on it. The purpose of the present research was to discuss the extraction methods, chemical composition, and various applications of avocado oil in the food and medicine industries. Our research was carried out through a systematic search in scientific databases. Even though there are no international regulations concerning the quality of avocado oil, some authors refer to the parameters used for olive oil, as stated by the Codex Alimentarius or the International Olive Oil Council. They indicate that the quality of avocado oil will depend on the quality and maturity of the fruit and the extraction technique in relation to temperature, solvents, and conservation. While the avocado fruit has been widely studied, there is a lack of knowledge about avocado oil and the potential health effects of consuming it. On the basis of the available data, avocado oil has established itself as an oil that has a very good nutritional value at low and high temperatures, with multiple technological applications that can be exploited for the benefit of its producers.
Marcos Flores; Carolina Saravia; Claudia E. Vergara; Felipe Avila; Hugo Valdés; Jaime Ortiz-Viedma. Avocado Oil: Characteristics, Properties, and Applications. Molecules 2019, 24, 2172 .
AMA StyleMarcos Flores, Carolina Saravia, Claudia E. Vergara, Felipe Avila, Hugo Valdés, Jaime Ortiz-Viedma. Avocado Oil: Characteristics, Properties, and Applications. Molecules. 2019; 24 (11):2172.
Chicago/Turabian StyleMarcos Flores; Carolina Saravia; Claudia E. Vergara; Felipe Avila; Hugo Valdés; Jaime Ortiz-Viedma. 2019. "Avocado Oil: Characteristics, Properties, and Applications." Molecules 24, no. 11: 2172.
The objective of this paper is to evaluate and to simulate the cogeneration process applied to an apartment building in the Polanco area (Mexico). Considering the building’s electric, thermal demand and consumption data, the cogeneration process model was simulated using Thermoflow© software (Thermoflow Inc., Jacksonville, FL, USA), in order to cover 1.1 MW of electric demand and to supply the thermal needs of hot water, heating, air conditioning and heating pool. As a result of analyzing various schemes of cogeneration, the most efficient scheme consists of the use of a gas turbine (Siemens model SGT-100-1S), achieving a cycle with efficiency of 84.4% and a heat rate of 14,901 kJ/kWh. The economic results of this evaluation show that it is possible to implement the cogeneration in the building with a natural gas price below US$0.014/kWh. The use of financing schemes makes the economic results more attractive. Furthermore, the percentage of the turbine load effect on the turbine load net power, cogeneration efficiency, chimney flue gas temperature, CO2 emission, net heat ratio, turbine fuel flow and after burner fuel flow was also studied.
Hugo Valdés; Gabriel Leon. Cogeneration Process Technical Viability for an Apartment Building: Case Study in Mexico. Processes 2019, 7, 93 .
AMA StyleHugo Valdés, Gabriel Leon. Cogeneration Process Technical Viability for an Apartment Building: Case Study in Mexico. Processes. 2019; 7 (2):93.
Chicago/Turabian StyleHugo Valdés; Gabriel Leon. 2019. "Cogeneration Process Technical Viability for an Apartment Building: Case Study in Mexico." Processes 7, no. 2: 93.
This research answers the following question: What is the fluid dynamic behavior of a supercritical fluid (SCF) inside a membrane module? At this time, there is very little or no reported information that can provide an answer to this question. The research studies related to the themes of supercritical CO2 (SC-CO2), hollow fiber membrane contactors (HFMCs), and numerical simulations have mainly reported on 2D simulations, but in this work, 3D profiles are presented. Simulations were performed based on the experimental results and other simulations, using the geometry of a commercial module. The results were mainly based on the different operating conditions and geometric dimensions. A mesh study was performed to ensure the mesh non-dependence of the results presented here. It was observed that the velocity profile developed at 10 mm from the wall of the supercritical CO2 entrance pipe. A profile equilibrium around the fiber close to the entrance of the module was achieved in the experimental hollow fiber membrane contactor when compared to the case of the commercial hollow fiber membrane contactor. The results of this research provided a visualization of the boundary layer, which did not cover the entire fiber length. Finally, the results of this paper are interesting for technical applications and contribute to our understanding of the hydrodynamics of SCFs.
Hugo Valdés; Kevin Unda; Aldo Saavedra. Numerical Simulation on Supercritical CO2 Fluid Dynamics in a Hollow Fiber Membrane Contactor. Computation 2019, 7, 8 .
AMA StyleHugo Valdés, Kevin Unda, Aldo Saavedra. Numerical Simulation on Supercritical CO2 Fluid Dynamics in a Hollow Fiber Membrane Contactor. Computation. 2019; 7 (1):8.
Chicago/Turabian StyleHugo Valdés; Kevin Unda; Aldo Saavedra. 2019. "Numerical Simulation on Supercritical CO2 Fluid Dynamics in a Hollow Fiber Membrane Contactor." Computation 7, no. 1: 8.
The purpose of this study has been to conduct an energy diagnosis research of the third level. An energy diagnosis is a tool aimed to seek improvements related to measures of energy efficiency and saving, and environmental conservation as well. These improvements would prove to be relevant for any kind of building. The diagnosis was carried out in 36 university buildings (Renewable Energy Institute—REI) through survey and census; that in order (to identify and) to characterize current patterns of energy consumption and demand, as well as for generating specific strategies towards energy efficiency and saving, for instance the identification of systemic indicators and corrective proposals, and non-financial investment. The results promote the achievement of grand energy efficiency. The task on energy conservation entails the supporting participation of each person who either studies or works in the entity, whereas some other activities require economic stimulus for being implemented. Annual per capita energy consumption in the REI is 40 kWh/person: that is greater than the country’s average consumption rate. The main energy consumption corresponds to Building 3.1 (49% of total energy consumption). This is due to its large concentration of laboratories specialized in renewable energy research and innovation.
Oscar González-Galvez; Miguel Morales; Carla Seefoó; David Morillón; Hugo Valdés. Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM. Buildings 2018, 8, 136 .
AMA StyleOscar González-Galvez, Miguel Morales, Carla Seefoó, David Morillón, Hugo Valdés. Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM. Buildings. 2018; 8 (10):136.
Chicago/Turabian StyleOscar González-Galvez; Miguel Morales; Carla Seefoó; David Morillón; Hugo Valdés. 2018. "Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM." Buildings 8, no. 10: 136.
The training of engineers in sustainable construction (SC) is becoming increasingly studied, since sustainable construction not only improves the quality of life of people, but also provides comprehensive solutions to the environmental problems we face today and thus takes care of the needs of future generations. This research is in line with the National Strategy for Sustainable Construction (NSSC) from the Chilean Government. One of the NSSC challenges is the training of engineers capable of adapting to the SC requirements. Although the competences in sustainability for the training of engineers has been discussed in other researchs, it has not been specifically in sustainable construction and it have not been grouped in a model that considers their degree of importance. The purpose of this article is to present a conceptual model can be used to design and evaluate engineering training programs in SC. The methodology to establish the skills and the proposed training model consists of three stages: Theoretical Phase, Methodological Phase and Validation Phase (surveys and interviews). 113 professionals who performed activities related to SC answered the survey. Interviews were conducted with five experts in training in different SC aspects. Three global skills are identified as: Sustainable Evaluation, Sustainable Construction Certification, and Sustainable Facility Management. In addition, the degree of importance of skills associated with these global skills was identified and assessed. There are five skills necessary for the future engineer, among them, two stand out: teamwork (collaborative) and ethics. Finally, the order of importance of the topics in SC is: energy, environment comfort, water, waste, and construction materials. A future investigation is recommended to apply the proposed conceptual model to current engineering training programs, both national and international.
Hugo Valdés; Christian Correa; Felipe Mellado. Proposed Model of Sustainable Construction Skills for Engineers in Chile. Sustainability 2018, 10, 3093 .
AMA StyleHugo Valdés, Christian Correa, Felipe Mellado. Proposed Model of Sustainable Construction Skills for Engineers in Chile. Sustainability. 2018; 10 (9):3093.
Chicago/Turabian StyleHugo Valdés; Christian Correa; Felipe Mellado. 2018. "Proposed Model of Sustainable Construction Skills for Engineers in Chile." Sustainability 10, no. 9: 3093.
An energy diagnosis is a tool used to seek the improvement of energy saving measures, environmental conservation and energy efficiency, making relevant its implementation in any kind of buildings. For this article, an energy diagnosis of third level was carried out in buildings of the Instituto de Energías Renovables (IER) from Universidad Nacional Autónoma de México (UNAM) through survey and census of the 36 buildings in the IER, in order to characterize current patterns of energy consumption and demand, and generating specific strategies towards savings and energy efficiency, such as indicators and corrective proposals within and non-financial investment.
Oscar González; Miguel Morales; Carla Seefoó; David Morillón; Hugo Valdés. Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM. 2018, 1 .
AMA StyleOscar González, Miguel Morales, Carla Seefoó, David Morillón, Hugo Valdés. Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM. . 2018; ():1.
Chicago/Turabian StyleOscar González; Miguel Morales; Carla Seefoó; David Morillón; Hugo Valdés. 2018. "Energy Diagnosis of University Buildings: Renewable Energy Institute from UNAM." , no. : 1.
The aim of this work is the experimental and theoretical characterization of the mass transfer in a membrane-based dense gas extraction of metal ions from aqueous solutions using a hollow fiber contactor. Extractions of Cu(II) were conducted in a single fiber membrane contactor operating under steady state conditions. Aqueous CuSO4 solutions were treated using a CO2 phase containing 1,1,1-trifluoro-2,4-pentanedione (TFA) or 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (HFA) at 40 °C and pressures ranged between 70 and 90 bar. Experiments show that the use of dense CO2 as extraction solvent of Cu(II) ions reaches extraction efficiencies valued up to 98.7%. Simultaneously, a mass transfer model was proposed correlating an effective rate function of the complex formation at the aqueous-CO2 interface. The highest extraction efficiencies were observed at higher pressures and lower pH values, which could confirm that a high content of protons is required to facilitate and stabilize the formation complex by means of keto-enol tautomerism. This work represents the first step in order to propose a novel intensified operation, which could be applied for high valued metals or hazardous materials.
Hugo Valdes; Rossana Sepúlveda; Julio Romero; Fernando Valenzuela; Jose Sanchez-Marcano. Near critical and supercritical fluid extraction of Cu(II) from aqueous solutions using a hollow fiber contactor. Chemical Engineering and Processing - Process Intensification 2013, 65, 58 -67.
AMA StyleHugo Valdes, Rossana Sepúlveda, Julio Romero, Fernando Valenzuela, Jose Sanchez-Marcano. Near critical and supercritical fluid extraction of Cu(II) from aqueous solutions using a hollow fiber contactor. Chemical Engineering and Processing - Process Intensification. 2013; 65 ():58-67.
Chicago/Turabian StyleHugo Valdes; Rossana Sepúlveda; Julio Romero; Fernando Valenzuela; Jose Sanchez-Marcano. 2013. "Near critical and supercritical fluid extraction of Cu(II) from aqueous solutions using a hollow fiber contactor." Chemical Engineering and Processing - Process Intensification 65, no. : 58-67.
This study aims to describe the mass transfer in a membrane-based solvent extraction system for the extraction of molybdenum(VI) from aqueous solutions, identifying chemical kinetics of the complex formation at the interface. The analyzed process is the membrane-based solvent extraction of molybdenum(VI) from aqueous solutions with n-hexane containing Alamine 336 as extraction phase using a hollow fiber contactor. This extraction process has been described through a resistances-in-series model, taking into account transport and thermodynamic relationships. In this work, the model has been used to identify an effective reaction rate expression and to describe the mass transfer by complex formation at the interface. The reaction rate expression has been estimated from experimental data obtained in a previous work [F. Valenzuela, H. Aravena, C. Basualto, J. Sapag, C. Tapia, Separation of Cu2+ and molybdenum(VI) from mine waters using two microporous extraction systems, Separation Science and Technology 35 (2000) 1409–1421]. The proposed calculation methodology can be used as a tool to scale-up when the information about chemical kinetics of complex formation is not available.
H. Valdés; J. Romero; J. Sanchez; S. Bocquet; G.M. Rios; F. Valenzuela. Characterization of chemical kinetics in membrane-based liquid–liquid extraction of molybdenum(VI) from aqueous solutions. Chemical Engineering Journal 2009, 151, 333 -341.
AMA StyleH. Valdés, J. Romero, J. Sanchez, S. Bocquet, G.M. Rios, F. Valenzuela. Characterization of chemical kinetics in membrane-based liquid–liquid extraction of molybdenum(VI) from aqueous solutions. Chemical Engineering Journal. 2009; 151 (1-3):333-341.
Chicago/Turabian StyleH. Valdés; J. Romero; J. Sanchez; S. Bocquet; G.M. Rios; F. Valenzuela. 2009. "Characterization of chemical kinetics in membrane-based liquid–liquid extraction of molybdenum(VI) from aqueous solutions." Chemical Engineering Journal 151, no. 1-3: 333-341.
Osmotic distillation (OD) or osmotic evaporation (OE) is a promising membrane process generally applied to concentrate solutions under isothermal conditions. In this work, this process was applied to concentrate commercial noni juice (Morinda citrifolia). Several nutraceutical properties have been reported for noni-derived products, mainly associated to the phenolic content of the fruit. The analyzed system is an osmotic distillation system where the solutions are circulated through a hollow fiber membrane contactor operating in transient configuration with circulation rates between 0.1 and 1.0 L min−1 and concentrated solutions of CaCl2 were used as extraction brine. At isothermal conditions (30 °C), transmembrane vapor water flux was experimentally determined from 0.090 up to 0.413 kg h−1 m−2. Noni juice was concentrated from 8 to 32 °Brix after 60 min of treatment. The content of phenolic compounds was preserved after this processing. Simulation algorithms based on phenomenological equations of heat and mass transfer were developed considering a resistances-in-series model to predict the performance of the process from theoretical information. The values of transmembrane water flux obtained by simulations showed deviations between 2.35 and 16.19% with the experimental ones for the operating conditions applied in this work.
H. Valdes; J. Romero; A. Saavedra; A. Plaza; V. Bubnovich. Concentration of noni juice by means of osmotic distillation. Journal of Membrane Science 2009, 330, 205 -213.
AMA StyleH. Valdes, J. Romero, A. Saavedra, A. Plaza, V. Bubnovich. Concentration of noni juice by means of osmotic distillation. Journal of Membrane Science. 2009; 330 (1-2):205-213.
Chicago/Turabian StyleH. Valdes; J. Romero; A. Saavedra; A. Plaza; V. Bubnovich. 2009. "Concentration of noni juice by means of osmotic distillation." Journal of Membrane Science 330, no. 1-2: 205-213.