Universitat Rovira i Virgili - Chemical Engineering scenario leads to an ... nano-structures (such as particles, fibers ... As presented in the international conference “TOWARDS

Department of Physical and Inorganic Chemistry - URV - 0 -

Universitat Rovira i Virgili

Department of Chemical Engineering (http://www.etseq.urv.es/9deq/en)

Department of Physical and Inorganic Chemistry (http://www.urv.cat/dquimfi/ficma/en)

Project Proposals for the

NEU-URV Student Exchange Program

May-June 2016

Total positions offered: 20

Department of Chemical Engineering - URV - 1 -

Project #1

Title: An electrifying jet set

Supervisors: Dr. Joan Rosell-Llompart & Dr. Jordi Grifoll

Contact: [email protected]

Research Group: DEW Lab – Droplets, intErfaces, and floWs (www.etseq.urv.cat/dew)

Description:

We study the formation of nanofibers and nanodroplets that form when a strong electrical field is applied to a liquid drop (i.e. liquid-gas interface). The basic fluid-dynamic phenomenon is illustrated in Figure 1. A liquid is supplied through a capillary tube (shown on left) from left to right. The tube is held at a high electrical potential relative to its surroundings (at a few kilovolts, typically). The electrical stresses pull the liquid into a conical shape, from whose apex a liquid micro-jet is emitted. The jet width is microscopic (Figure 2), and either breaks up into droplets (when using a “normal” liquid), or stretches to form a long continuous fiber (when the liquid is “gooey”, usually a polymeric solution). The first scenario leads to an electrostatically charged spray, called “electrospray” (Figure 3), the second to the formation of nanofibers, or “electrospinning” (Figure 4). We are interested in the development of electrospray and electrospinning processes and systems. The applications of these systems are numerous. By collaboration with specialized teams, we apply these methods to build novel micro- and nano-structures (such as particles, fibers, coatings, films) for use in optics, catalysis, energy, etc.

The main goal of this activity will be to engage the student in the research of DEW’s PhD students and faculty. A main current aim is to engineer multiplexed systems, in which electrostatic interference between nozzles is prevented, and to develop fundamental understanding of such systems. This involves a combination of experimental, theoretical, and computer modeling approaches. Our web site contains further information.

Join us for an electrifying experience!

Fig.1. Electrospray emitter. A conical liquid meniscus (Taylor cone) forms on a 0.3 mm diameter tube; a micro-jet (invisible) breaks up forming a spray (right) which fans out.

Fig. 2. Close up view of the microjet formed at the Taylor cone apex.

Fig. 3. Electrospray plume generated from an electrified capillary tube (shown at top).

Fig. 4. Electrospinning in action, showing a fiber undergoing characteristic whipping motion.

Positions: 1


Project #2a,b

Title: Self-assembling polymers for novel proton transport membranes

Supervisors: Dr. Marta Giamberini


Research Group: METEOR (http://www.urv.cat/recerca_innovacio/en_meteor.html)

Description:

In the last 40 years, there has been a growing interest toward the "hydrogen economy", that is a system where hydrogen is in charge of energy delivery and acts as an energy carrier (like electricity) and not as a primary energy source (like coal or oil)1. This could be a possible solution to the huge energy problems caused by the disappearance of fossil fuels. On the other hand, hydrogen needs to be produced by an energy consuming method, stored and finally used as fuel in a fuel cell to deliver electric energy when needed.

As far as hydrogen production is concerned, the idea of using solar energy to perform water splitting, according to the reaction:

2H2O → 2H2 + O2

is currently under development2. The energy required for this reaction can be supplied by sunlight, but requires the use of a dye-sensitized solar cell, as water does not absorb the electromagnetic radiation emitted by the sun to promote water splitting in a kinetically facile way. This process can be combined with the reduction of carbon dioxide to carbohydrates, and is generally referred to as "artificial photosynthesis". As presented in the international conference “TOWARDS GLOBAL ARTIFICIAL PHOTOSYNTHESIS. Energy, Nanochemistry & Governance”, the artificial photosynthesis project has the category of a global research project comparing or even overtaking the Human Genoma project. The two red-ox half-reactions involved in water splitting must take place in two different compartments so that hydrogen and oxygen gases can be stored in different containers. For this reason, a water-splitting device has to include in a single cell the following components: a light harvesting device, a water-oxidation catalyst, a proton-reduction catalyst and a proton-exchange membrane (PEM). The separation of the anodic and cathodic compartments through a PEM is crucial in order to separate efficiently H2 and O2 as well as to prevent short-circuiting of the cell. Moreover, in such a device the PEM should be capable of resisting quite severe conditions of pH and red-ox potentials.

Fuel cells are a kind of electrochemical device that converts chemical energy directly into electrical energy. They can be divided into five major categories: alkaline, phosphoric acid, solid oxide, molten carbonate and proton exchange membrane. Proton exchange membrane fuel cells (PEMFC) work at relatively low temperature (about 80 ºC), have high power density, can vary their output quickly to meet shifts in power demand and are suitable for automobile applications. In PEMFCs the electrolyte is constituted by a polymer membrane, able to conduct protons, which is sandwiched between two electrodes. They, in turn, contain Pt-based catalysts that allow the oxidation and reduction reactions to take place. Among PEMFCs, we can find hydrogen fuel cells and direct methanol fuel cells (DMFC).

In DMFCs, the fuel is directly methanol; this entails several advantages over fuel cell systems based on hydrogen and compressed natural gas3, as methanol can be simply transported and applied under room temperature and atmospheric pressure by pumping from existing gasoline infrastructures without an external compressor or refrigeration equipment. This makes the volume of DMFCs as small as possible.

Furthermore, methanol has the highest hydrogen-to-carbon ratio among alcohols, thus giving the highest energy generation and the least carbon dioxide emissions; in addition, methanol is miscible with water: as a consequence, DMFCs can be fueled with different concentrations of a methanol aqueous solution. Besides, methanol can be obtained through biomass and is more environmentally


friendly than gasoline since it breaks down quickly in the environment. The ideal membrane to be used in a DMFC should resist to relatively high temperatures, transport protons efficiently, be an insulator to electrons, act as barrier between the anode and cathode, possess good mechanical strength and be inexpensive.

The membranes currently used as PEM are far away to be considered optima with regard to their performance; therefore, the development of new proton exchange membranes is a topic of permanent interest. In this project we tackle this problem by preparing membranes based on self-assembling columnar side-chain liquid-crystalline polymers which lead to the formation of biomimetic ionic channels. These channels contain basic atoms (oxygen or nitrogen) to interact with protons thus allowing their transport across the membrane.

N.A. Kelly, T.L. Gibson, M. Cai, J.A. Spearot, D.B. Ouwerkerk, International Journal of Hydrogen Energy, 35, 892-899 (2010).

T.L. Gibson, N.A. Kelly, International Journal of Hydrogen Energy, 35, 900-911 (2010).

K. Kordesch, G. Simader, Fuel Cells and their Applications, Weinheim, Germany (ISBN 3-527-28579-2), p. 2-8 (1996).

Positions: 2

A. The first one deals with the synthesis and characterization of columnar side-chain liquid-crystalline polymers. This internship is addressed to strongly motivated students with an Organic Chemistry background. We offer the possibility of working with the classical methodology of the organic chemistry synthesis, as well as with techniques such as 1H and 13C NMR, Fourier-transform infra-red spectroscopy (FTIR), polarized optical microscopy (POM), differential scanning calorimetry (DSC), and small and wide-angle X-ray diffraction (XRD).

B. The second one is focused on the preparation and assessment of PEMs based on columnar side-chain liquid-crystalline polymers. In this case, the internship is addresses to strongly motivated students with Applied Chemistry or Chemical Engineering background. The student will have the possibility to work with membrane preparation techniques, microscopic techniques (environmental and conventional scanning electron microscopy -E-SEM, SEM, atomic force microscopy-AFM) and contact angle measurements, as well as with XRD and POM; moreover, permeability tests and electrical characterizations (impedance tests, current-voltage curves, MEA tests) will be eventually performed.


Project #3

Title Transformation of biomass into D-lactic acid using microwave and microbial fermentation reactors

Supervisors: Dr. Francesc Medina & Dr. Magda Constantí

Contact: [email protected] / [email protected]

Research Group: Heterogeneous Catalysis Group, CATHETER (http://www.etseq.urv.es/catalisi/) and Bioengineering & Bioelectrochemistry Group, BBG (http://www.etseq.urv.es/BBG/)

Description:

Nowadays the main industrial use of lignocellulose is direct combustion. Its usage as feedstock for value added compounds has a great potential for replacing petrochemical resources in industry. The chemical structure of lignocellulose obstructs its cleavage into profitable products. Lignocellulose is made of lignin, hemicellulose and cellulose. Its proportion depends on the concrete biomass source, nonetheless cellulose use to be the most abundant one. Thus, finding a successful process to hydrolyse cellulose would lead to a satisfactory usage of biomass as a feedstock to any industrial process. Enzymatic hydrolysis of cellulose is the most common treatment found on bibliography. However, in this work, a new process of hydrolysing cellulose and taking benefit of it is followed to replace the expensive enzymatic process. Sulfuric acid is tested on dilute acid pre-treatment of cellulose assisted by microwave reactor, and characterized with TOC (total organic carbon), HPLC (high performance liquid chromatography) and XRD (X-ray diffraction). Then the hydrolysed carbohydrates are used in fermentative processes, verifying their aptness for microbial feedstock. Lactic acid bacteria (LAB) are used in order to obtain optically pure lactic acid; extremely appreciate starting product for polylactic acid (PLA) production, a highly consumed bioplastic. Microwave pretreatment converted 80 % of cellulose, then bacterial fermentation by Lactobacillus delbrueckii delbrueckii produces D-lactic acid 97% optically pure. The growing demand of PLA together with the capability of explode cellulose potential, places this work as a potential industrial application.

The student will work on the fractionation and characterization of lignocellulose and/or cellulose materials for their application in microbiological processes.

Positions: 1


Project #4a,b

Title: Fuel cells/artificial photosynthesis research

Supervisors: Dr. Ricard Garcia-Valls


Research Group: METEOR-group

Description:

The student will assist the PhD students already at METEOR in the existing funded project for the application of membranes in energy systems. He or she will learn about the preparation of the membranes, their characterization, and its inclusion in membrane electrode assemblies (MEA). The MEA’s will be included within real fuel cells and tested for the generation of electricity. On the other hand, the student would also take part of the production and characterization of CO2 adsorbing membranes mimicking tree leaves. As possible last step, the student would contribute to the construction of real demo units based on our membrane technology.

Positions: 2


Project #5a,b

Title: Encapsulation of bioactive compounds using dynamic membranes

Supervisors: Dr. C. Güell; Dr. M. Ferrando; Dr. S. de Lamo

Contact: [email protected]; [email protected]; [email protected]

Research Group: Food Innovation & Engineering (FoodIE)

Description:

Description: Food industry is increasingly interested in producing healthy foods with good sensory properties. One of the most common trends is to enrich the food products using bioactive compounds or probiotics. Encapsulation technology enables to protect the bioactive compounds, providing the industry with the ingredients required to optimize food formulations and to meet market needs. Production of emulsions and solid microcapsules have evolved as main strategies to encapsulate. Membrane Emulsification (ME), in which droplets are formed (direct ME) or broke up (premix ME) by means of a porous medium, has some advantages compared to conventional homogenizers, that is, lower energy requirements and production of emulsions with a narrow droplet size distribution. ME drawbacks encompass low productivity and membrane fouling, especially during ME of food applications.

The project will focus on applying a new type of porous system in premix ME: dynamic membranes. Dynamic membranes are packed bed systems of silica microbeads that enable: i) to design the porous system for a particular emulsion formulation, improving the process efficiency and productivity, and ii) to re-use the porous material, which improves the process sustainability compared to conventional ME. Emulsification with dynamic membranes is an interesting alternative to reduce process costs and promote industrial application. The target compounds to encapsulate are examples of the ones typically used by the food industry: phenolic extracts, as example of bioactive compounds, and lactic bacteria as example of probiotics. These compounds will be encapsulated in double emulsions and solid microcapsules using protein polysaccharide complexes as stabilizers of the oil-water interphase. The project will study the impact of process parameters (flux, pressure, height of the bed, size of the silica microbeads, among others) in the encapsulation efficiency of the compounds.

Positions: 2


Project #6

Title: Recovery of ionic liquids from aqueous solutions

Supervisors: Dr. Josep Font & Dr. Christophe Bengoa


Research Group: Chemical Reaction Engineering & Process Intensification Group (CREPI) (http://webgrec.urv.es/webpages/personal/ang/000004_jose.font.urv.cat.html)

Description:

The global continuous growth of energy demand poses urgent problem due to the fossil fuels' depletion, as they currently represent about 75% of all energy consumed worldwide [1]. One of the most promising renewable fuels proposed as an alternative is biodiesel that can be directly used with current engine and refuelling technology. However, the competitive potential of biodiesel is currently limited by the price of the common lipid feedstocks, which constitutes 70–85% of the overall biodiesel production cost, thus strongly influencing the final price of this biofuel and raising the concerns of food shortage versus fuel crisis.

In turn, municipal sewage sludge from wastewater treatment plants (WWTPs) is gaining more attention nowadays as a lipid feedstock for the production of biodiesel as the dry sludge can contain up to 30 wt.% of lipids. In fact, sewage sludge is a waste that needs specific treatment before disposal and represents a major cost in the WWTP operation. The main challenge to be faced by biodiesel production from waste sludge is an efficient lipid extraction from water, as water can account for up to 95-98 wt.%, so dewatering and drying constitute more than 50% of total biodiesel production cost.

Our research group has developed and new efficient route for lipid recovery using water soluble ionic liquids avoiding the costly sludge dewatering. In this alternative, water is eliminated in a final stage, after extraction and decantation of the lipid fraction. This final step could be conducted through a combination of membrane processes; however, the critical factor is the ionic liquid concentration from a diluted aqueous stream applying nanofiltration (NF), which should be able to reject the ionic liquid and permeate the excess water content. This project aims at characterising (flux, recovery, rejection, fouling) the NF performance of an ionic liquid-water system in a broad range of operation (feed flowrate, transmembrane pressure) conditions.

References

Olkiewicz M., Caporgno M.P., Fortuny A., Stüber F., Fabregat A., Font J., Bengoa C. (2014). Direct liquid–liquid extraction of lipid from municipal sewage sludge for biodiesel production. Fuel Processing Technology 128: 331-338.

Olkiewicz M., Caporgno M., Plechkova N.V., Legrand J., Pruvost J., Lepine O., Bengoa C. (2014). Extraction of Lipid form Microalgae Biomass using Phosphonium based Ionic Liquid: Comparison Study with Standard Methods. Alg’n’ Chem 2014, 31 March - 3 April 2014, Montpellier (France).

Siddiquee M.N., Rohani S. (2011). Lipid extraction and biodiesel production from municipal sewage sludges: A review. Renewable and Sustainable Energy Reviews 15: 1067-1072.

Kim Y.-H., Choi Y.-K., Park J., Lee S., Yang Y.-H., Kim H.J., Park T.-J., Kim Y.-H., Lee S.H. (2012). Ionic liquid-mediated extraction of lipids from algal biomass. Bioresource Technology 109: 312–315.

Fernández J.F., Bartel R., Bottin-Weber U., Stolte S., Thöming J. (2011). Recovery of Ionic Liquids from Wastewater by Nanofiltration. Journal of Membrane Science & Technology, S:4.

Positions: 1


Project #7

Title: Toxicity of heavy metal mixtures: effects on freshwater microalgae growth and modelling

Supervisors: Dr Gemma Giménez Papiol & Dr Vikas Kumar


Research Group: TecnATox (http://www.tecnatox.cat/) and Environmental Analysis and Management Group (AGA) (http://www.etseq.urv.es/aga/Equipo/equipo.php)

Description:

Several environmental regulations rely on ecotoxicological data for the assessment and management of chemical contaminants. Ecotoxicology, as defined by René Truhaut in 19771, is a branch of the toxicology that studies the toxic effects of contaminants, both natural and synthetic, on the animal (human being included), vegetal and microbiological compartments of an ecosystem. It has, from its very origins, the aim of an holistic approach in the study of a toxic effect on the ecosystem, and has gained a fundamental role in the assessment and management of environmental risks. In aquatic ecotoxicology, the three compartments typically belong to three basic trophic levels: microalgae (at the bottom of the trophic chain), zooplankton (the intermediate link) and fish (top trophic level). There are several toxicological tests, developed and standardized in laboratory conditions, based on model species of each level, and considered fast tests. These tests are more developed and standardized in the field of freshwater ecotoxicology, for instance: tests based on fish larval development (usually the model species Danio rerio or Pimephales promelas) that last about 7 days; tests based on the spawning success and larval survival of freshwater zooplankton (Daphnia sp.) that last 8 days; and tests based on the growth of microalgae cultures (Raphidocelis subcapitata, Chlorella vulgaris, etc.), that last 4 days. Depending on the concentration of the compound and the exposure time, the tests are able to assess chronic or acute toxicity2,3. Regarding acute toxicity tests, OECD has been revising its protocols4, and based on results showing a higher sensitivity of microalgae and zooplankton5,6 and the European requirement of reducing the use of animals in laboratory assays, the revised version states that fish-based tests will only be performed at one concentration of toxic compound, the lowest one bringing EC50 with microalgae or zooplankton; consequently, it is expected that zooplankton- and microalgae-based tests reliability and importance will increase in the future.

The term “microalgae” groups a wide variety of unicellular organisms: they belong to different and much separated phyla (i.e. cyanobacteria are prokaryotes, dinoflagellates and diatoms are eukaryotes, etc.), they have different life strategies (colony forming or unicellular; symbionts or free living organisms, etc.) and metabolisms (some are able to fixate nitrogen, others accumulate metals, etc.)… The differences are almost unlimited. But, technically, we can take advantage of their similarities: it is relatively easy to keep them in laboratory conditions and several microalgae species/strains can be purchased from microalgae collections worldwide, their growth rate is fast compared to other model organisms, it is possible to miniaturize the tests7 (increasing the number of replicates, reducing the sample/compound required per test and the generation of waste, etc.), etc...

There are many standardized protocols based on the growth inhibition of a microalgae culture published by OECD in 1984. The sensitivity to a toxic compound is microalgae species-dependent8; additionally, the combined toxicity of mixtures of compounds can be different than each compound’s toxicity by its own due to interactions9. On the other hand, there are publicly available databases with microalgae species sensitivity to specific substances and compounds whose data are generally obtained in standardized growth inhibition conditions (for instance, the United States Environmental Protection Agency Ecotox Database; http://cfpub.epa.gov/ecotox).

The specific aims of the project will be:


(1) to develop growth inhibition assays under suboptimal conditions,

(2) to gather information about the toxicity of heavy metals mixtures on freshwater microalgae in laboratory conditions,

(3) to validate the assays performance with natural samples with known mixtures of contaminants,

(4) to model the toxicity of heavy metal mixtures on freshwater microalgae.

References

1] Truhaut R. 1977. Ecotoxicology: objectives, principles and perspectives. Ecotoxicology and Environmental Safety 1, 151 – 173.

2] Lewis PA, Klemm DJ, Lazorchak JM, Norberg-King TJ, Peltier WH, Heber MA (Eds.). 1994. Short-term methods for estimating the chronic toxicity of effluents and receiving waters to freshwater organisms. Third Edition.

3] Organisation for Economic Co-operation and Development (OECD) Guideline for Testing of Chemicals. 1984. Algal growth inhibition test.

4] Organisation for Economic Co-operation and Development (OECD) Guideline for testing of chemicals. 2008. Draft revised guideline 203: fish, acute toxicity test.

5] Weyer A, Sokull-Klüttgen B, Baraibair-Fentanes J, Vollmer A. 2000. Acute toxicity data: A comprehensive comparison of results from fish, Daphnia and algae tests with new substances notified in the European Union. Environmental Toxicology and Chemistry 19, 1931–1933.

6] Jeram S, Riego Sintes JM, Halder M, Baraibar Fentanes J, Sokull-Klüttgen B, Hutchinson TH. 2005. A strategy to reduce the use of fish in acute ecotoxicity testing of new chemical substances notified in the European Union. Regulatory Toxicology and Pharmacology 42, 218–224.

7] Blaise CR. 1986. Micromethod for acute aquatic toxicity assessment using the green alga Selenastrum capricornutum. Toxicity Assessment: An International Quarterly 1, 377 – 385.

8] Giménez Papiol G, Roig N, Sierra J, Schuhmacher M. Effects of arsenic compounds on freshwater microalgae from different phyla under suboptimal conditions. SETAC Europe 25th Annual Meeting, Barcelona, Spain, 3 – 7 May 2015.

9] Giménez Papiol G, Bouloux M, Roig N, Sierra J, Schuhmacher M. Mixtures of contaminants and complex samples: basic challenges for microalgae-based ecotoxicological tests”. MESAEP 18th International Symposium on Environmental Pollution and its Impacts on Life in the Mediterranean Region, Crete, Greece, 26 – 30 September 2015.

Number of positions: 1


Project #8a,b

Title: Understanding complex systems using big data

Supervisors: Dr. Roger Guimerà Manrique & Dr. Marta Sales-Pardo


Research Group: Science and Engineering of Emerging Systems, SEES:lab (http://seeslab.info)

Description:

Technological advances during the last fifteen years have boosted our capacity to generate and store data in many areas of science and business. Indeed, 90% of the world’s stored data has been generated in the last two years, and the availability of such large quantities of data (for example time-resolved geo-location of mobile devices or usage data of social networks) is changing the way we think about crisis response, social mobilization, marketing, and intelligence.

Big data is a particularly relevant opportunity for the study of complex systems such as cells, ecosystems or economies. In complex systems, non-linear interactions among the many components that comprise the system give rise to macroscopic behaviors that cannot be explained by looking at individual components alone. Traditionally, the analysis of complex systems was constrained by the limited information available from the different components (and layers of components) comprising the system (for example, metabolites and proteins in cells, species in ecosystems, and people and institutions in economies). The availability of unprecedented highly detailed data on these systems opens the door to significantly advance our understanding of their behavior, and of how this behavior evolves in time. With large amounts of data we now have the possibility to uncover correlations and patterns that will enable us to build predictive models of these systems.

The goal of our research is to contribute, from the perspective of statistical mechanics, new tools and methods for the analysis and modeling of large-scale datasets.

This project will involve computational work, thus students selecting this project should have an interest in programming.

Positions: 2


Project #9

Title: Signal amplification in lateral flow biosensors using a novel HRP-DNA binding protein conjugate

Supervisors: Dr. Lluis Masip Vernis


Research Group: Bioengineering & Bioelectrochemistry Group, Interfibio (http://www.etseq.urv.es/nbg/Interfibio/)

Description:

The field of biosensors has been growing continuously over the last few decades, both commercially and scientifically. The availability of biosensors that fulfil the ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment free and deliverable to end-users) characteristics of diagnostics for developing countries as indicated by the World Health Organization can be particularly advantageous, since early diagnosis can change dramatically the development of a disease (Parolo & Merkoçi 2013). Paper-based biosensors can be one of the answers to this demand, since they exhibit many of the ASSURED characteristics. Their major drawback, especially in the case of optical detection (naked-eye) paper-based devices, is their lower sensitivity. For this reason over the last years research has focused on improving this feature with the final aim of expanding their use, by following several strategies like sample preconcentration, optimization of the design and geometries of the paper devices, chemical patterning to control fluid flow and increase of the signal at the test zone by using nanoparticles and enzymes in various bioconjugate formats (Cheung et al. 2015, Quesada-González & Merkoçi 2015).

Our group has recently developed a novel HRP bioconjugate that has been successfully used for signal amplification in a colorimetric Human papillomavirus (HPV) DNA sensor (Aktas et al. 2015). The HRP-scCro conjugate is used in tandem with a hybrid ssDNA-dsDNA detection probe that contains multiple specific DNA binding sites for the DNA binding protein component of the HRP conjugate. The signal increases with the number of DNA binding sites present on the detection probe, leading to higher signal amplification. With this project we intend to explore the possibility of using this HRP-DNA binding protein conjugate in lateral flow optical (naked-eye) DNA biosensors in order to improve their sensitivity. The student will work together with a PhD student of the group in order to assist in the evaluation of different approaches to achieve this objective: membrane geometry, test and control zone elements, assay buffer solution, substrate for the enzyme conjugate, and concentrations of all the components.

Aktas G.B., Skouridou V., Masip L. (2015) Biosens. Bioelectron. 74: 1005-1010.

Cheung S.F., Cheng S.K.L., Kamei D.T. (2015). JALA 20: 316-333.

Parolo C., Merkoçi A. (2013). Chem. Soc. Rev. 42: 450-457.

Quesada-González D., Merkoçi A. (2015). Biosens. Bioelectron. 73: 47-63.



Project #10

Title: Direct liquid-liquid extraction of lipid from primary and secondary sludge

Supervisors: Christophe Bengoa


Research Group: Chemical Reaction Engineering & Process Intensification Group (CREPI)

Description:

Liquid-liquid direct extraction of lipids. The primary sludge essentially consists of organic matter originated from raw wastewater, which is a combination of floating grease and solids (the highest lipid fraction). For this reason, direct liquid-liquid extraction can be easily performed. The objective of this activity will be the optimisation of a process previously developed in the group. The lab scale pilot plant, batch mixer–settler reactor with mechanical stirring, will be scaled-up to work with volumes of at least 5 L (more if possible). In this process, acidification of primary sludge will be necessary in order to increase the lipid extraction capacity by the conversion of insoluble soaps present in the primary sludge into FFAs that are soluble in the extracting solvent, thus increasing the lipid yield as well as the amount of saponifiable lipid, thereby the biodiesel yield. Interaction between the two phases should be improved by optimising the contact into the reactor. The influence of the contact time and the sedimentation time as well as the speed of mechanical agitation during extraction phase and decantation will be evaluated. Besides hexane, other organic solvents will be tested. The number of extraction steps should be also explored. Great importance will be given to the decantation step that is typically the bottleneck of the process and will have a dramatic impact on the extraction process and in the size of the commercial units once scaled. Finally, the influence of the temperature will be also checked to improve contact and mass transfer rate and decrease time of contact.



Project #11

Title: Cellulose recovery from primary sludge

Supervisors: Christophe Bengoa


Research Group: Chemical Reaction Engineering & Process Intensification Group (CREPI)

Description:

The vast amount of cellulose contained in wastewater mainly comes from the toilet paper. Cellulose can be efficiently recovered by extraction with ionic liquids and then reused in paper industry. This technique allows recovering up to 80% of low -lignin cellulose, with both organic and inorganic material. Lignin cellulose will then be repeatedly cleaned and its quality monitored by FTIR. Operation conditions must be optimised in order to improve the recovery of cellulose and decrease the amount of ionic liquid used.



Project #12

Title: Modelling of a refrigeration system with thermal energy storage with fluctuation in cooling demand and electricity cost

Supervisors: Dr. Dieter Boer & Dr. Laureano Jiménez Esteller


Research Group: SUSCAPE

Description:

Energy availability is considered one of the most important global problems and with the increase of

population and industrialization, the demand on energy and the associated environmental impact

grows significantly. The energy efficiency of all related processes should be improved, as even

marginal percentages will have a significant impact in absolute values reducing the energy

consumption.

In refrigeration systems many strategies can be applied. The integration of thermal energy storage

(TES) and a scheduling of the operation according the variation of electricity cost are promising

options. This becomes especially important in future energy systems with fluctuation of the prices

according to the production from renewable intermittent sources.

This work focusses on the modelling of a refrigeration system with TES in an environment with

variations in demand and electricity price. The model should enable the sizing of the refrigeration

cycles, the TES capacity and the selection of an adequate operation mode.

The specific objectives of the project are:

1. Review of the use and modelling of thermal energy storage (TES) in refrigeration applications.

2. Design of a refrigeration system based on a case study of an industry.

3. Establish a mathematical model which enables us to describe the system in transient

operation.

4. Evaluation and optimization of the economic cost and the energy consumption



PROJECT #13

Title: Development of new photonic biosensors

Supervisors: Dr. Jaume Massons


Research Group: FiCMA-FiCNA (http://www.urv.cat/dquimfi/ficma/en/)

Description:

The proposed research project aims at the study and the final development of a microfluidic device for the efficient on-chip integration of probes for optically sensing physical parameters

Background and State of the Art:

Micro-fluidics is the science of designing, manufacturing and using devices and processes that deal with volumes of fluids on the order of nL, having dimensions ranging from mm to a few micrometers. Although most current effort in micro-fluidics concerns devices with applications in chemistry, biology, and medicine, there are also applications in the physical sciences, energy generation and display technology, for control systems and heat management. Examples of bioassays and biological procedures that have been miniaturized into a chip format include DNA sequencing, polymerase chain reaction (PCR), electrophoresis, DNA separation, enzymatic assays, immunoassays, cell counting, cell sorting, and cell culture. Miniaturized versions of bioassays offer many advantages, including small requirements for solvents, reagents, and cells (critical for valuable samples and for high-throughput screening), short reaction times, portability, low cost, low consumption of power, versatility in design, and potential for parallel operation and for integration with other miniaturized devices.

The T-sensor is a recently developed microfluidic chemical measurement device that exploits the low Reynolds number flow conditions in microfabricated channels. The interdiffusion and resulting chemical interaction of components from two or more input fluid streams can be monitored optically, allowing measurement of analyte concentrations on a continuous basis. Parallel laminar flow of two or more liquid streams in microchannels has been studied extensively over the past decade for use in microfluidic and biomedical applications such as controlling flow paths, patterning of surfaces, diffusional sensors, flow cytometry on a chip, and impedance spectroscopy. In many of these devices, one or multiple streams focus another stream by influencing its fluidic path.

Positions: 1


PROJECT #14

Title: Pr:KGd(PO3)4 nanoparticles as a new scintillator material

Supervisors: Dr. Rosa M. Solé



Description:

Overview:

The proposed research project aims to study the synthesis of Pr:KGd(PO3)4 nanoparticles which can be used as a new scintillator material.


Type III KGd(PO3)4 (KGdP) is a noncentrosymmetric monoclinic crystal with interesting nonlinear optical properties [1]. The presence of Gd facilitates the doping with rare earth elements [2,3]. Among them, due to its energy levels, Pr has gain interest for scintillator materials. KGdP has also a wide transparency window from 180 nm to 4 [2] which cover the main absorption and the emitting wavelengths of Pr.

Project Contribution and Methodology:

The successful candidate will incorporate to the Physics and Crystallography of Materials and Nanomaterials (FiCMA-FiCNA) groups with high experience in the growth of single crystals, epitaxial layers and nanoparticles of materials with nolinear optical properties and laser materials. During the project, the synthesis of Pr:KGdP nanoparticles using the modified Pechini method will be investigated [4]. X-ray powder diffraction technique will be used to identify the phase obtained, TGA-DTA will be used to study the phase transitions and melting temperatures and microscopy techniques will be used for morphological characterization. A preliminary optical characterization of the crystals obtained to check their utility as scintillators will be carried out.

The project offers the opportunity to gain experience in the synthesis of nanocrystals, X-ray and thermal analysis, microscopy techniques and optical characterization.

Positions: 1

References:

1. Parreu, I, Ph D Thesis, “Crystal growth and characterization of ytterbium or neodymium doped type III-KGd(PO3)4. .A new bifunctional nonlinear and laser crystal”, University Rovira i Virgili, Tarragona, Spain (2006).

2. Parreu, I.; Carvajal, J. J.; Solans, X.; Díaz, F.; Aguiló, M. “Crystal structure and optical characterization of pure and Nd-substituted Type III KGd(PO3)4”, Chem. Mater. 2006, 18(1), 221.

3. Parreu, I; Solé, R.; Massons, J.; Díaz, F. and Aguiló, M. “Crystal growth and characterization of Type III Ytterbium-doped KGd(PO3)4: A new nonlinear laser host”, Chem. Mater. 2007, 19, 2868.

4. Galceran, M., Ph D Thesis, “Synthesis and characterization of optical nanocrystals and nanostructures. An approachto transparent laser nanoceramics”, University Rovira i Virgili, Tarragona, Spain (2010).


PROJECT #15

Title: Synthesis of Ln3+:M2O2S/TiO2 (M= Y, Gd and Lu) composite for photocatalytic applications

Supervisors: M. C. Pujol



Overview:

The aim of the proposed research project is to explore the use of lanthanide doped oxysulfide material as enhancing agent for photo-catalytic applications based on TiO2 catalysts.


TiO2 semiconductor compound is a very attractive and well-known photo-catalyst [1], it can be applied in such as water and gas treatment, decomposition of organic contaminants and water photo-splitting into H2 and O2 [2]. TiO2 is a wide band gap material, with Eg= 3.2 eV (388 nm). One of the strategies reported in the literature to enhance his photo-catalytic activity is to increase his capacity of light absorption [3,4] by the use of lanthanides ions as doping ions. Another strategy, it is the use of dielectric materials, which convert the Near Infrared light (NIR) in visible or UV (Upconversion processes, UC). By this, this light can be more efficiently used by the TiO2 compound. Qin et al. in 2010 and 2013 firstly demonstrated NIR-driven photo-catalysis of TiO2 by combining it with (Yb,Tm):YF3 or (Yb, Tm): NaYF4 [5,6].High efficient UC dielectric host are for lanthanide ions, are usually based on fluoride materials, due to their low phonon values. Oxysulfide materials (M2O2S) have been proved to be also very competitive UC materials, and in some cases, their Quantum yield efficiency can be higher than the one in fluoride host. [7]. Their synthesis can be performed through a simple route by the ethanol-assisted solution method (EASC) [8]. It is expected to be able to use this method for depositing a lanthanide doped oxysulfide shell on TiO2 core particles to obtain a core shell composite structure, to test how the UC in these hosts can improve their photo-catalytic properties.


The successful candidate will join a research team formed by the FiCMA-FiCNA research groups. FiCMA-FiCNA has a large experience in spectroscopy of lanthanide ions in dielectric hosts; and also in the synthesis of nanocrystals and core shell composites by modified sol-gel methods. During the present multidisciplinary project, it will be developed for first time the synthesis of the described core-shell composites; using commercial TiO2 micro-particles or synthesising them also via a Sol gel route

1 A.L. Linsebigler, G.Lu, and J.T. Yates. Photocatalysis on TiO Surfaces: Principles, Mechanisms, and Selected Results. Chem. Rev. 1995, 95, 735-758. 2 Fujishima, X.T. Zhang, Titanium dioxide photocatalysis: present situationand future approaches, C. R. Chim. 9 (2006) 750–760; M.R. Hoffmann, S.T. Martin, W. Choi, W.B. Detlef, Environmental applicationsof semiconductor photocatalysis, Chem. Rev. 95 (1995) 69–96; A. Zaleska, A. Hänel, M. Nischk, Photocatalytic air purification, Recent Patents Eng. 4 (2010) 200–216. 3 D. Tz. Dimitrov, M. M. Milanova, R. P. Kralshevska, Lanthanide oxide doped titania photocatalysts for degradation of organic pollutants under UV and visible light illumination, Bulgarian Chemical Communications, 43, 489-501, 2011. 4 J. Reszczy´nska, T. Grzyb, J.W. Sobczak, W. Lisowskic, M. Gazda, B. Ohtanie, A. Zalesk, Lanthanide co-doped TiO2: The effect of metal type and amount on surface properties and photocatalytic activity, Applied Surface Science 307 (2014) 333–345. 5 W. Qin, D. Zhang, D. Zhao, L. Wang and K. Zheng, Near-infrared photocatalysis based on YF3: Yb3+,Tm3+/TiO2 core/shell nanoparticles Chem. Commun., 2010, 46, 2304–2306. 6 Tang, Y. N., Di, W. H., Zhai, X. S., Yang, R. Y. & Qin, W. P. NIR-Responsive Photocatalytic Activity and Mechanism of NaYF4(Yb,Tm)@TiO2 Core-Shell Nanoparticles. ACS Catal. 3, 405–412 (2013). 7 M. Pokhrel, G. A. Kumar and D. K. Sardar, Highly efficient NIR to NIR and VIS upconversion in Er3+ and Yb3+ doped in M2O2S (M= Gd, La, Y) Mater. Chem. A, 2013, 1,11595. 8 Maria Méndez Málaga, SYNTHESIS AND CHARACTERIZATION OF DOWN-SHIFTING LN3+ DOPED LANTHANUM-BASED NANOPARTICLES FOR PHOTOVOLTAIC APPLICATIONS, PhD. Thesis in Departament de Química Física i Inorgànica Engineering of Materials and Micro/Nanosystems (EMaS),Tarragona,2013.


[9]. Structural and morphological characterization techniques, such as X-ray powder diffraction, micro-raman and electron microscopies will be used to optimise the synthesis procedure. The spectroscopic characterization of the composites will be performed via optical absorption, emission and excitation measurements, and a very significant measurement of the quantum efficiency in the UC of the samples. Finally, some photocatalytic activities will be tested by evaluating the decomposition of NOx in a flow type reactor under irradiation of different wavelengths of LEDs and NIR laser. The set-up and experiments should be developed in collaboration with another group with large expertise in Catalytic processes.This project is multidisciplinary covering basic material science and new technologies developing, in the field of material science, chemistry, physics and optics.

Positions: 1

9 M. Galceran, M. C. Pujol, C. Mendez , A. Garcia, P. Moreno, L. Roso, M. Aguiló, F. Díaz, Synthesis of monoclinic KGd(WO4)2 nanocrystals by two preparation methods, J Nanopart Res (2009) 11, 717–724.


PROJECT #16

Title: Lanthanide doped Gadolinium sesquioxide nanoparticles for thermometry in the second biological window

Supervisors: J. J. Carvajal and M. C. Pujol

Contact: [email protected], [email protected]


Overview:

The aim of the proposed research project is to explore the use of lanthanide doped sesquioxide nanocrystals as nanothermometers in the second biological window for biomedical applications.


Fluorescent nanothermometry in the second “near tissue –transparent” infrared window (SWIR II, 1-1.4 m) is promising due to: low absorbance of the biological tissue, minimal auto-fluorescence of the tissue, and great reduction of the scattering losses of the biological tissues in this wavelength range [i]. The reduction of the scattering effect, beneficed by the long wavelength of the emitted SWIR photons, maximizes the possible penetration depth [ii]. On the other hand, lanthanides doped nanoparticles have been already tested for bio probes, using the fluorescence coming from the electronic transitions of the lanthanides elements [iii].

So, recently some researchers have now focused the attention also in the lanthanides elements but in this case in the electronic transitions located in the SWIR II region. Some works to be highlighted are: Hemmer et al. [iv], which have used Y2O3 and Gd2O3 nanocrystals codoped by (Er, Yb) and (Ho, Yb) as NIR-NIR biolabels; using the 1.5 m emission of Erbium sensitized by Ytterbium, and the Holmium emission at 1.2 m microns sensitized with Yb, and Rocha et al. in which nighly doped Neodymium LaF3 nanocrystals were acting simultaneously as nanoheaters and fluorescents nanothermometers.[v]

In this framework, it is pretended to explode the lanthanide emission in the SWIR II, using the also the Neodymium emissions, 4F3/2 4I11/2 (around 1.1 m) and

4F3/2 4I13/2 (around 1.3 m) by direct excitation to the Nd3+ ion, and also by sensitivization via codoping with Yb3+. The host selected will be the crystalline cubic Gd2O3 sesquioxide, due to its chemical and thermal stability; the easiness to dope with lanthanide ions and also, due to the presence of Gd3+, which allows future applications based on its magnetic response.


The successful candidate will join a research team formed by the FiCMA-FiCNA research groups. FiCMA-FiCNA has a large experience in the spectroscopy of lanthanide ions in dielectric hosts; and also in the synthesis of nanocrystals by modified sol-gel methods.

During the present project, it will be developed the synthesis of lanthanide doped sesquioxide nanocrystals by the modified Pechini method [vi]. Depending of the results, an alternative methodology could be also used [vii]. Structural and morphological characterization techniques, such as X-ray powder diffraction, micro-raman and electron microscopies will be used to optimise the synthesis procedure. The spectroscopic characterization of the nanocrystals will be performed via optical absorption and emission measurements.Finally, it will be performed the evaluation of the thermal sensitivity. After these steps and evaluation of the results, maybe next steps of coating of the nanoparticles with Silanes or/and THEOS, will be considered.

Positions: 1


[i] Rocha et al. Small 10, 1141 (2014) [ii] Welsher et al. PNAS, 108, 8943 (2011) [iii] Jaque et al. Nanoscale, 4, 4301 (2012) [iv] Hemmer et al. Nanoscale, 5, 11339 (2013) [v] Rocha et al. Appl. Phys. Lett. 104, 053703 (2014) [vi] Galceran et al. J. Lumin.130,1437 (2010) [vii] Gai et al. CrystEngComm, 13, 5480 (2011)

Documents

Universitat Rovira i Virgili - Chemical Engineering scenario leads to an ... nano-structures (such as particles, fibers ... As presented in the international conference “TOWARDS