Renewable Energy Global Innovations features: Lactic acid production from recycled paper sludge: Process intensification by running fed-batch into a membrane-recycle bioreactor

Significance Statement

Lactic acid has many industrial applications. It acts as a precursor of polylactic acid that is promptly broadening in the market as a suitable substitute of petrochemical-based plastics. Polylactic acid is a biodegradable and biocompatible polymer. During combination of homopolymers poly-l-lactic acid and poly-d-lactic acid, high optical purity is used by which regular structures are formed in the crystalline phase. The ratio of poly-l-lactic acid and poly-d-lactic revamps the properties and disintegratability of polylatctic acid.

However D-lactic acid is non-edible and can be toxic. Hence there arose challenges in producing optically pure lactic acid using economical renewable resources. Large amounts of waste is produced by European paper industry of which seventy percent of recycled paper production. So it is indispensable to identify economical and environmentally sustainable application to avoid harmful deposition in landfills. Portuguese researchers proposed an approach to improve the production of lactic acid using recycled paper sludge as an attractive alternative raw material.

The selective production of L(+)-lactic acid from recycled paper sludge by simultaneous saccharification and fermentation had already been implemented under a pulsed fed-batch mode using lactobacillus rhamnosus. Many studies have made clear that lactic acid promotes an important inhibitor effect both on cell growth and on lactic acid production. On preferring a fed-batch strategy, a high lactic acid concentration is achieved significantly limiting the conversion.

Various approaches had been suggested to avoid product inhibition on lactic acid fermentation, but product removal is the most effective approach. Susana Oliveira Marques and her colleagues proposed membrane separation processes, which have many advantages in terms of energy efficiency, separation capacity, etc. and also possesses increased capacity, yield by operating at high cell densities and avoiding product inhibition.

The authors’ objective is to intensify simultaneous saccharification and fermentation (SSF) implementation into a membrane-recycle bioreactor in which the substrate was fed to the fermentor and the reaction mixture is continuously recycled through an external filtration unit. Thereby, maintaining a stream with constant product concentration while extending operation the product is removed as soon as it was formed.

To get consistent product concentrations, high dry matter contents should be used for running simultaneous saccharification and fermentation processes. However, on handling high solids loadings, the operational feasibility of membrane bioreactors is doubtful as they disintegrated membranes functionality due to increased cake layer formation and membrane fouling. Simultaneous saccharification and fermentation processes not only grow microbial cells, but also deals with residual lignocellulosic solid material providing a very high content of suspended solids.

According to the authors, it was very important to adequately select the module configuration and process conditions, so as to decrease the concentration polarization phenomena. Instead of using high flow velocities and lower transmembrane pressures, dynamic membrane filtration configuration should be adopted to promote higher membrane shear rate.

Henceforth the team of author’s study proposed flat sheet filtration module will be allowed by promoting the feed stream pass along the surface at a high cross flow velocity, and thus operating as a dynamic cross-flow filtration system. Porous asymmetric polymeric membranes with an ultrafiltration process would be implemented. Polysulphone and polyether sulphone membranes, exhibiting very good chemical and thermal stability could  be utilized for micro and ultrafiltration.

Thereby authors suggested the best approach to run the simultaneous saccharification and fermentation process for the lactic acid production from recycled paper sludge into the in house membrane recycle bioreactor (MRB) based on the product inhibition along with the limitations imposed by the high solids concentrations. It would improve other simultaneous saccharification and fermentation processes dealing with high-solids concentrations, also using cost-effective lignocellulosic feedstock biorefineries. For instance, the fermentation that produces butanol, an advanced biofuel platform, is also strongly affected by end-product inhibition, and thus this bioprocess might also be enhanced by applying the authors’ proposed strategy. In terms of alternative feedstocks for bio-production of lactic acid, the combination of recycled paper sludge with a lignocellulosic material exhibiting lower ash content, such as brewer’s spent grains, might be important by reducing the gathering of unreacted inert to elimination.

The attractiveness of the innovative system proposed by these authors thus lies in the application of membrane assisted technology, under a MRB configuration, to a SSF process dealing with high suspended solids loadings, which might improve several biorefinery processes.

Journal Reference

S. Marques¹, C.T. Matos^1,4, F.M. Gírio¹, J.C. Roseiro¹, J.A.L. Santos^2,3, Lactic acid production from recycled paper sludge: Process intensification by running fed-batch into a membrane-recycle bioreactor, Biochemical Engineering Journal, Volume 120, April 2017, Pages 63–72

Show Affiliations

1. Laboratório Nacional de Energia e Geologia, I.P. (LNEG), Unidade de Bioenergia, Estrada do Paço do Lumiar 22, 1649-038 Lisboa, Portugal.
2. Departamento de Bioengenharia, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
3. IBB, Institute for Bioengineering and Biosciences, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
4. Current address: European Commission, Joint Research Centre (JRC), Institute for Environment and Sustainability (IES), Sustainability Assessment Unit, Via Fermi, 21021, Ispra, VA, Italy

 

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Renewable Energy Global Innovations features: Assessment on the Research Trend of Low-Carbon Energy Technology Investment: A Bibliometric Analysis

Significance Statement

As a result of high carbon emission which leads to global warming, there exists a persistent desire to create an alternative route for energy supply from renewable sources. The fusion of low-carbon energy technologies, which is a form of renewable energy to the developing world would not only reduce emission of carbon particles but also satisfy energy demand.

Despite the use of bibliometric analytical method of study and evaluation of previous research with focus on low-carbon technology investment, there exists a need for more detailed bibliometric strategy to provide an encompassing knowledge in this field.

Dr. Zhifu Mi and colleagues conducted a comprehensive bibliometric analysis from obtainable literatures in order to find the research status and trend in line with that of the low-carbon energy technology investment, coupled with measurements of comprehension strength between countries, followed by a frequency analysis of keywords to discover research hot topics as a base for future assessment and lastly, provision of relevant ideas needed for the future development and investment of low-carbon energy technology. The paper is now published in the journal, Applied Energy.

The authors made use of databases of Science Citation Index Expanded from 1981 to date and that of Social Sciences Citation Index dating back to 2002. They also considered some characteristic terms such as general statistics, number of countries’ publications, journal and subject distributions, authors and institution statistics, academic collaboration, article citation and comprehensive strength in the field of low-carbon energy technology investment among countries from 2121 publications.

Following the trends of top 10 productive countries, two stages were observed from the year 1985 to 2013; the first stage with stable development from 1985 to 2014 with research growth rate of 13.15%, and the second, with rapid development from 2005 to 2013 with research growth rate of 29.06%. This shows that the low-carbon energy technology investment has reached the rapid development stage.

The USA had the highest number of publications, followed by European countries of Germany and UK, and the fourth was China. Highest number of publications was observed in developed countries compared to the developing ones, but a decrease in disparity as years go by was also envisaged.

Energy Policy had the highest number of total publications, followed by Renewable Energy and Energy. However, the highest citations per publications were found in the journals of Biomass Bioenergy followed by International Journal of Hydrogen Energy and Solar Energy. They also found Energy Fuel journal followed by the journals of Environmental Sciences Ecology and Engineering to have the highest number of subjects related to the low-carbon energy technology investment.

The national comprehensive strength of the USA, in the field of the low-carbon technology was the highest followed by the UK. European countries dominated the top 15 productive countries with inclusion of developing countries of China and Turkey.

When the authors analysed the frequency of keywords, “renewable energy” was discovered to be the mostly used. “Carbon capture and storage” was observed to be an emerging keyword with an upward trend, followed by the frequently used “electricity”. Research hotspots with keywords such as “policy”, “real option theory” and “uncertainty” are also developing rapidly.

This study was able to provide a broad bibliometric method which analyzed the investment in low-carbon energy technology for future assessments.

About The Author

Dr. Zhifu Mi is a Senior Research Associate in the School of International Development, University of East Anglia (UEA) and Senior Research Fellow in the Tyndall Centre for Climate Change Research. He is a Managing Guest Editor of Journal of Cleaner Production (IF=4.959). His research is focused on climate change mitigation, energy policy, and climate change economic theories and modelling. He has authored over 20 articles in peer-reviewed journals.

He was invited to write a review article entitled Integrated Assessment Models (IAMs) for Climate Change in Oxford Bibliographies which invites top scholars and researchers in the field to contribute. He has served as an Author for Chapter 37 on International Policies and Actions to Tackle Climate Change in the Third National Assessment Report on Climate Change which is known as Chinese “IPCC Assessment Report”.

Journal Reference

H. Yu^1,2,3,4, Y.M. Wei^1,2,3, B.J. Tang^1,2,3, Z. Mi^1,5, S.Y. Pan^1,2,3, Assessment on the Research Trend of Low-Carbon Energy Technology Investment: A Bibliometric Analysis, Applied Energy 184 (2016) 960–970.

Show Affiliations

1. Center for Energy and Environmental Policy Research, Beijing Institute of Technology, Beijing 100081, China
2. School of Management and Economics, Beijing Institute of Technology, Beijing 100081, China
3. Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081, China
4. Visitor of Energy Policy Research Group, University of Cambridge, Cambridge CB2 1AG, UK
5. School of International Development, University of East Anglia, Norwich NR4 7TJ, UK

 

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Renewable Energy Global Innovations features: Scale Up the Collection Area of Luminescent Solar Concentrators Towards Metre-Length Flexible Waveguiding Photovoltaics

Significance Statement

Luminescent solar concentrators are largely dependent on concentration factor. The derived concentration factor values from previous research are always less than one; hence, various methods have been implemented in view of increasing the value of the concentration factor. The methods which rely on the application of large area luminescent solar collectors have also failed in producing solar factors greater than one. The cylindrical geometry of luminescent solar concentrators which offers greater potential compared with that of the planar geometry have also not almost been extensively studied before.

A new study led by professors Luís D. Carlos and Rute Ferreira from University of Aveiro in Portugal provided a new method for the fabrication of long-length fibre wave guiding luminescent solar concentrators with the use of an optical fibre manufacturing facility to obtain cylindrical large-area luminescent solar concentrators based on bulk-coated and hollow-core plastic optical fibres. The work was published in the journal, Progress in Photovoltaics: Research and Applications.

The authors fabricated in semi-industrial fibre manufacturing facility a length of approximately 2.5m bulk plastic optical fibres with di-ureasil, doped with either rhodamine 6G (RhdG) or Eu(tta)₃.2H₂O, coupled with another fabrication of PMMA-based hollow-core plastic optical fibres with di-ureasil [d-U(600)] or tripodal tri-ureasil [t-U(5000)] and doped with rhodamine or Eu(tta)₃.2H₂O. They further provided optical characterization of the surface and edges of the fibre waveguiding luminescent solar concentrators.

The authors showed similarities using emission spectra of fibre waveguiding luminescent solar concentrators collected at the fiber surface for the hollow-core and bulk-coated plastic optical fibres. Observations of the excitation spectrum at the optical active centers show a large ocerlap with that of AM1.5G within the region available for DS conversion. Also the luminescent solar concentrators with tripod tri-ureasil have high values of absolute emission quantum yield above 0.85.

A small value of refractive index contrast in the Eu(tta)₃.2H₂O -based fibre waveguiding luminescent solar concentrators resulted to a trapping efficiency of approximately 73% compared with that of the rhodamine-based which has a larger trapping efficiency of approximately 80%. The refractive index contrast was due to the difference between refractive index values of the PMMA and hybrid layer.

However, absorption losses were predominant in hollow-core geometry despite their higher trapping efficiency. After some further considerations, it was said that light propagation of the fibre waveguiding luminescent solar concentrators also depends on the absorption spectra of the hybrid and PMMA layers.

Low values of PMMA attenuation coefficient values for both Eu(tta)₃.2H₂O- and rhodamine-based fibre waveguiding luminescent solar concentrators indicated that light propagation may occur in total length of bulk-coated fibre waveguiding luminescent solar concentrators while light is expected to travel at a shorter length for hollow-core fibre waveguiding luminescent solar concentrators due to hybrids’ attenuation.

This study was able to achieve a high optical conversion efficiency of 72.4% and a concentration factor of 12.3 for the hollow-core fibre waveguiding luminescent solar concentrators. Maximum optical conversion efficiency and concentration factor for bulk-coated fibre waveguiding luminescent solar concentrators were 0.6% and 6.5 respectively.

The increased conversion efficiency and high value of concentration factor compared with previous reported ones verifies the approach used by the authors in developing lightweight and flexible high-performance waveguiding photovoltaics.

About The Author

Luís António Dias Carlos got his Ph.D. in physics from the University of Évora, Portugal, in 1995 working on photoluminescence of polymer electrolytes incorporating lanthanide salts. Currently, he is Full Professor in the Department of Physics at the University of Aveiro and vice-director of the CICECO-Aveiro Institute of Materials (Portugal). He is member of the Lisbon Academy of Sciences and of the Brazilian Academy of Sciences.

His current research interests include luminescent nanothermometers, luminescent solar concentrators, organic-inorganic hybrids for green photonics (solid-state lighting and integrated optics), and luminescent/magnetic nanoparticles, as new probes for multimodal imaging. He has published around 390 papers and 6 international patents, which have received ca. 12000 citations (Hirsch’ index h of 55), and co-guest editor of a RSC book on Nanoscale Thermometry (Nanoscience & Nanotechnology series) and special issues of the Journal of Sol-Gel Science and Technology (2010) and of the Journal of Luminescence (2015).

He is editor of Physica B – Condensed Matter, associate editor of the Journal of Luminescence and member of the editorial board of the Journal of Coordination Chemistry, Journal of Sol-Gel Science and Technology and Journal of Rare Earths.

About The Author

Maria Rute de Amorim e Sá Ferreira André (born 1974) got her Ph.D. in Physics from the University of Aveiro, Portugal in 2002 and the Agregação in Physics in 2012, from University of Aveiro. Currently, she is an Associate Professor at Department of Physics (University of Aveiro), coordinates the research Line Information and Communication technology’’ of CICECO – Aveiro Institute of materials.

She has published around 290 papers, which have received ca. 7200 citations (Hirsch’ index h of 43). Her scientific interests include optoelectronic properties of hybrid materials and semiconducting nanoparticles for lighting, integrated optics and energy conversion.

Reference

Correia, S.F.H.^1,2, Lima, P.P.¹, Pecoraro, E.³, Ribeiro, S.J.L.³, André, P.S.⁴, Ferreira, R.A.S.¹, Carlos, L.D.¹ Scale Up the Collection Area of Luminescent Solar Concentrators Towards Metre-Length Flexible Waveguiding Photovoltaics, Progress in Photovoltaics: Research and Applications 24 (2016) 1178-1193.

Show Affiliations

1. Department of Physics and CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
2. Instituto de Telecomunicações, University of Aveiro, Aveiro, Portugal
3. UNESP – Institute of Chemistry, São Paulo State University, Araraquara-SP, Brazil
4. Department of Electric and Computer Engineering and Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal

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Renewable Energy Global Innovations features: A Dynamic Programming Approach for Modeling Low-Carbon Fuel Technology Adoption Considering Learning-by-doing effect

Significance Statement

Most governments around the world are trying to reduce the dependency on petroleum fuels and mitigate greenhouse gas emissions from the transportation sector, by implementing various policies and regulations including adoption of low-carbon fuel technologies in current transportation fuel portfolios. To replace petroleum-based fuel consumption in transportation, an advanced biofuels such as cellulosic biofuels was introduced.

Dr. Yuche Chen and colleagues proposed an economical way of using cellulosic biofuels by establishing an analytical framework to investigate the least-cost cellulosic biofuel technology adoption while considering the learning by doing modeling effect. The research work is now published in Applied Energy.

Cellulosic biofuels are fuels produced from non-edible cellulosic biomass, such as woody crops, or agricultural residues, they have the advantages of producing low-carbon emissions based on lifecycle assessment and of not competing with food crops for land use. There is need for government guidance to ensure enough cellulosic biofuel is produced to develop the technology and to achieve the aim of low-carbon fuel in transportation. To economically promote cellulosic biofuels, the government should know the appropriate timing and approach. However, knowing the appropriate time to promote cellulosic biofuels can be challenging.

The authors introduced dynamic programming and learning by doing modeling approaches to tackle the issue of appropriate timing. The proposed framework was applied in a case study to explore the most economical pathway for California to develop a solid cellulosic biofuel industry under its low carbon fuel standard.

They observed that petroleum-based fuels gasoline and diesel, have 60% higher prices compared with those of sugarcane, ethanol and biodiesel. The biodiesel production significantly increase and remains at a 20% blend rate in the diesel fuels category for all modeling years. The team pointed out that high market penetration of zero Emission Vehicles and plug-in hybrid electric vehicle can lead to a lower production of cellulosic ethanol. The research team also found that learning capabilities in cellulosic biofuels have a significant impact on the overall fuel pathway and adoption of cellulosic biofuels.

This was the first study of its kind to use both dynamic Programming and learning by doing modeling approaches to study transportation energy problems. Their results confirmed that reducing the transportation greenhouse gas emissions requires an approach and the cellulosic biofuel plays a vital role.

About The Author

Dr. Yuche Chen is a senior research scientist at United States National Renewable Energy Laboratory (NREL), United States Department of Energy’s only national lab dedicated to renewable energy research. He actively involves in research development and implementation activities in both vehicle systems analysis and infrastructure analysis. His research addresses transitions to a sustainable transportation system with focuses on alternative fuels, as well as advanced vehicle technologies such as connected and automated vehicles.

Before joining NREL, Chen was a research scientist at Texas A&M Transportation Institute within Texas A&M University System and served as the academic lead for Environmental and Emissions Research Facility. He has also worked for The International Council on Clean Transportation, International Institute for Applied Systems Analysis (IIASA), California Air Resource Board, Lawrence Berkeley National Laboratory, and National Transportation Research Center at Oak Ridge National Laboratory. He has a Ph.D. degree in Civil and Environmental Engineering from University of California, Davis; a Master’s degree in Statistics and a Master’s degree in Agricultural & Resource Economics both from University of California, Davis, a Master’s degree in Management Science and Engineering from Zhejiang University, China; and a bachelor’s degree in Transportation Engineering from Central South University, China.

Reference

Yuche Chen¹, Yunteng Zhang², Yueyue Fan², Kejia Hu³, Jianyou Zhao⁴, A Dynamic Programming Approach for Modeling Low-Carbon Fuel Technology Adoption Considering Learning-by-doing effect, Applied Energy 185 (2017) 825–835.

Show Affiliations

¹ College of Transportation Engineering & The Key Laboratory of Road and Traffic Engineering of the Ministry of Education, Tongji University, Shanghai, China.

² University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA.

³ Kellogg School of Management, Northwestern University, Evanston, IL 60208, USA.

⁴ School of Automobile, Chang’an University, Xi’an 710064, China.

 

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Renewable Energy Global Innovations features: A Longitudinal Quantitative-Qualitative Systems Approach to the Study of Transitions toward a Low Carbon Society

Significance Statement

To address the challenges of climate change, the dissemination of carbon neutral technologies will be required with the accompanying formation of new socio-technical systems. It is only through association with human agency, social structures and organization that technology attains its functionality. A socio-technical system is defined as a cluster of elements that includes technology, regulation, user practices and markets, cultural meaning, infrastructure, maintenance networks, and supply networks. It is for this reason that a comprehensive understanding of the interrelationship between technological systems and social systems is imperative if the intended technological change is to be a part of the solution to the problem of climate change. The process of technical change must be considered in its institutional and social context. Simon Robertson from University of New South Wales in Australia proposed a systems approach for an integrated quantitative and qualitative analysis of low carbon transition pathways. The paper is now published in peer-reviewed, Journal of Cleaner Production.

The socio-technical approach, according to the author, is well-equipped to examine the co-evolution of the social and technical aspects of the system under consideration with regard to ‘who’ and ‘how’ parameters of the transition. Notwithstanding the requirement for the contextualisation of technology, socio-technical studies concerned with low carbon pathways have a propensity to describe, qualitatively, transitions that are essentially concerned with quantitative objectives, such as emissions reduction target fulfillment. Due to this inability to consider quantitative elements within the qualitative analysis, the author argues that the established socio-technical approach is found to be deficient to the extent that only general assertions can be made as to the mitigation potential of the proposed green technologies. Such a deficiency results in the ‘what’ parameter remaining generic rather than specific. He postulates that this poses a significant limitation to the resolution quality of low carbon transition policy recommendations given the critical importance for quantity certainty when developing greenhouse gas mitigation policies.

In order to address this deficiency, the author expounds an interdisciplinary approach that integrated the quantitative tool of Life Cycle Assessment and the qualitative Socio-technical Scenario tool. The integrated quantitative-qualitative methodology, with its what-who-how disposition, affords a higher degree of resolution to the proposed transition policy recommendations. Ultimately, the integrated methodology provides greater quantity certainty in respect to the development of appropriate low carbon transition pathways and the suite of policy instruments to be employed. In addition to the suite of transition policy recommendations, the integrated methodology provides an order of implementation. This capacity of the integrated methodology improves the probability of sustaining the inertia of the transition via a process of sequencing the transition policies in order to concert the effects of each policy measure. This innovative, integrated quantitative-qualitative methodology is highly applicable to both government and industry concerned with strategic transition management.

About The Author

Simon Robertson’s principal research focus is the development of original, innovative, interdisciplinary approaches for the study of sustainability transition pathways. Awarded a Bachelor of Technology, a Master of Environmental Management (recipient of the Orica-Harding University Prize, University of New South Wales), and a Doctorate in Environmental Policy and Management, he applied his significant interdisciplinary knowledge to successfully develop an integrated quantitative and qualitative tool for the analysis of sustainability transition pathways. Simon’s interdisciplinary tool was a world first to cross-pollinate the distinct disciplinary inquiries of environmental engineering (i.e., Life Cycle Assessment) and sustainability transition theory (i.e., Multi-Level Perspective). In addition to the development of interdisciplinary approaches for the study of sustainability transitions, his research also focuses on the efficacy of ‘green’ technologies through process-based life cycle assessment.

Simon’s research interests span all aspects of sustainability across multiple disciplines. With diverse expertise in environmental engineering, the sociology of science and technology, and in political ecology, his research continues to engage with multi-faceted, complex issues from transitioning towards low-carbon societies to the socio-environmental nexus of natural
resource management.

Journal Reference

Simon Robertson, A Longitudinal Quantitative Qualitative Systems Approach to the Study of Transitions toward a Low Carbon Society, Journal of Cleaner Production 128 (2016) 221-233.

Faculty of Science/Faculty of Arts and Social Science, The University of New South Wales, Kensington, New South Wales 2052, Australia.

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Renewable Energy Global Innovations features: Micromorphological changes and mechanism associated with wet ball milling of Pinus radiata substrate and consequences for saccharification at low enzyme loading

Significance Statement

In the recent article of Dr. Alankar Vaidya and colleagues from Scion which is a Crown Research Institute dedicated to improving the international competitiveness of the New Zealand forest industry. The authors describe an investigation of wet vibratory ball milling as an effective pretreatment, before the enzymatic saccharification of the most recalcitrant lignocellulosic substrates such as Pinus radiata softwood using relatively low enzyme inputs. In this study, wet ball milling mechanism is proposed (see the Figure), based on the observed micromorphological changes and changes in the cellulose crystallinity with different ball milling time. A mathematical model validates the proposed ball milling mechanism. This research work is now published in the journal, Bioresource Technology. According to the team, radiata pine wood chips obtained from a sawmill were treated with steam under pressure and then refined to produce substrate that was diluted with water prior to the ball milling.

One third of the glucan was converted to glucose at enzyme loadings as low as 2 FPU/g of dry substrate, after 60 minutes of ball milling. They attributed this rapid enzymatic conversion of cellulose exposed in fibrils torn from cell walls. They use scanning electron microscopy to characterize micromorphological changes in the substrates that were ball milled for different times. Based on the observed micromorphological changes, the cellulose present in the substrate is assigned to different categories. Carbon-13 NMR spectroscopy was also used in their study to investigate whether exposure of cellulose in the crystallites changed during the ball milling process.

Alankar A. Vaidya the first author in the paper said, ball milling performed for less than 120 min showed extensive fiber breakage and defibrillation of the broken fibers exposing more and more cellulose to enzymatic hydrolysis. However, over-milling caused compression of the porous fragments to compact globular particles with a granular texture, decreasing accessibility of enzymes to cellulose. From the carbon-13 NMR spectroscopy investigations, partial loss of interior cellulose in crystallites occur when the fiber breakage was completed. The authors found that wet ball milling performed for optimum time can provide highly digestible softwood substrate at low enzyme loadings. At a low enzyme loading of 2 FPU/g of substrate and milling time of 120 min a total monomeric sugar yield of 306 g/kg of substrate was obtained which is higher than conventional pretreatment method such as steam exploded wood.

About The Author

Dr Alankar Vaidya completed Masters in Biochemistry in 1993 and then Masters in Biotechnology from Indian Institute of Technology, Kharagpur in 1996.  His doctoral work was on Design, synthesis and evaluation of affinity polymers for separation of enzymes under the guidance of Dr R. A. Mashelkar (FRS, FNAS) in the year 2000. His entire doctoral work was protected under 4 US patents.  He went to AIST Tsukuba, Japan in 2000 on ITIT fellowship where he worked on synthesis and evaluation of stimuli sensitive polymers for nucleotide separation. Thereafter, he was awarded two separate postdoctoral fellowships first in 2002 to work on Crosslinked Imprinted Proteins (CLIP’s) in the Lab. of Prof. Lutz Fischer at University of Hohenheim, Stuttgart, Germany and thereafter he secured DARPA postdoctoral fellowship award in 2004 from DOE to work with Prof. Richard Gross at Polytechnic University of New York, Brooklyn, USA where he worked on immobilized enzyme mediated polymer synthesis.

In 2009 he joined Scion (formerly Forest Research Institute) as a Scientist working on interdisciplinary fields such as biochemical route to biofuels, forest biorefinery, microbial biopolymers and production, isolation and application of enzymes in biomass hydrolysis or biomass valorisation.  He is author of 40 + scientific international publications including 3 book chapters. He was also granted 6 US patents to his credit.   

About The Author

 

Ian Suckling received his PhD in Chemistry from the University of British Columbia in 1983. He is presently the Research Leader, Biofuels and Bioenergy at Scion and prior to this has held a number of leadership and managerial roles within Scion.

Dr. Suckling is currently the New Zealand representative on IEA Bioenergy Task 39 – Commercializing Liquid Biofuels. His research interests focus on wood and wood processing chemistry in both the biofuels and pulp and paper industries, with a particular interest in lignin. He is author of 100 + scientific publications.  

About The Author

Dr Lloyd Donaldson, senior scientist, received his Master’s degree with honours in Plant Science in 1986 from the University of Canterbury and his doctorate in Wood Science in 2002 also from the University of Canterbury, New Zealand. 

He has worked at Scion (previously the New Zealand Forest Research Institute) since 1980 as scientist on wood anatomy and wood quality. In 2003 he was elected a fellow of the International Academy of Wood Science and since 2004 has served as associate editor for the International Association of Wood Anatomists Journal. From 2007 to 2012 he was president of the New Zealand Microscopy Society, and from 2013 has been the president of the Rotorua Branch of the Royal Society of New Zealand. In 2011 he received the Charles Fleming senior scientist award, and at various times has been visiting scientist at Swedish University of Agricultural Sciences, Beijing Forestry University, Institute of Multidisciplinary Research, University of Belgrade, and INRA, Reims, France.

His main research interests include wood structure/quality/properties relationships with emphasis on lignin topo-chemistry and microfibril angle, wood formation especially lignification, developing new techniques for quantifying wood structure and properties using confocal and electron microscopy, microscopy of genetically modified tissue/plants for phenotype evaluation, microscopy of biomaterials, fluorescence & electron microscopy, molecular microscopy, digital image processing & analysis, and wood identification. He is author of 111 scientific publications including 89 journal articles and 13 book chapters. 

About The Author

John Lloyd, a scientist at Scion, received his master’s degree with honours in chemistry from the University of Auckland, New Zealand in 1971.  He has worked as a scientist in the fields of wood chemistry and wood and fibre processing since that time. His contribution to the present paper was in attrition, thermochemical pretreatment and analytical chemistry.

Wood extractives and their impact on fibre processing was his initial research interest before concentrating on research into the preparation of chemical wood pulp fibres and their processing.  During his career he has led or contributed to a large number of projects requiring both fundamental and applied research and industrial troubleshooting.  He has worked closely with pulp and paper companies in helping them understand their processes better and to improve product quality.

He is the author of more than 30 peer reviewed scientific publications as well as numerous conference papers and presentations. In recent years his research interests include exploring opportunities for wood as a source of chemicals, bio-based products and biofuels.

About The Author

Sylke Campion received her MS in Chemistry and Environmental Protection in Neustadt / Weinstrasse in Germany in 1982 and worked at the University of Munich at the Institute for Water Research for 5 years.

She joined Scion (formally known Forest Research Institute) in Rotorua, New Zealand in 1993 as a technical assistant. She started in the paper and pulp division, PAPRO, and was intensively involved with the application of enzymes in the bleaching and strengthening of wood fibre pulp. Later, as a Senior Technician, she was involved in the manufacturing and testing of fibre cement boards for five years and from 2009 she is actively participated in lignocellulosic bioethanol initiative programme where she is involved in the production of ball milled pulp samples for subsequent enzymatic hydrolysis and testing of their digestibility into simple sugars for further ethanol production.

She is author of 19 scientific peer-reviewed publications and 194 technical papers.

Journal Reference

Alankar A. Vaidya, Lloyd A. Donaldson, Roger H. Newman, Ian D. Suckling, Sylke H. Campion, John A. Lloyd, Karl D. Murton, Micromorphological Changes and Mechanism Associated with Wet Ball Milling of Pinus Radiata Substrate and Consequences for Saccharification at Low Enzyme Loading, Bioresource Technology 214 (2016) 132–137.

Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Rotorua 3046, New Zealand.

 

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Renewable Energy Global Innovations features: Polymeric Ionic Liquid Gel Electrolyte for Room Temperature Lithium Battery Applications

Significance Statement

Professor Bilal El-Zahab and doctoral students, Meer Safa, Amir Chamaani, and Neha Chawla from Florida International University (FIU) developed a free-standing gel polymer electrolyte (GPE) and evaluated its thermal and electrochemical properties in order to ascertain the overall performance of their synthesis in lithium battery applications. The new findings appeared in peer-reviewed journal, Electrochimica Acta.

The gel polymer electrolyte comprised of a pyrrolidinium-based polymeric ionic liquid (PIL), an imidazolium based ionic liquid [EMIM][TFSI], and the lithium salt [LiTFSI]. They compared two electrolytes: the gel polymer electrolyte and ionic liquid electrolyte to investigate stability and compatibility with lithium metal electrode using various electrochemical characterization techniques, including electrochemical impedance spectroscopy with further determination of their rate performance in a cell with LiFePO₄ cathode at room temperature.

Thermogravimetric analyses showed the prepared gel polymer electrolyte had a high thermal stability. The pair of polymeric ionic liquid and ionic liquid inside the gel polymeric electrolyte which contains ionic liquid and lithium salt content (LiTFSI) of about 80wt.% led to an improved ionic conductivity of approximately 3.35 mS×cm^-1 when measured at 25°C using electrochemical impedance spectroscopy.

The most notable improvement using the FIU team’s new gel polymer electrolyte was its improved cathodic limit and widened electrochemical stability window. The improved cathodic limit to below the plating potential of lithium made this gel polymer electrolyte a preferred choice in Li/LiFePO₄ cells. Moreover, the gel polymer electrolyte also showed higher lithium-ion transference number compared to the ionic liquid electrolyte indicating higher chemical affinity. This affinity was demonstrated using in Li/Li symmetrical cell that immensely outperformed the ionic liquid electrolyte.

The cyclic charge-discharge rate when observed at 40 cycles and 22°C showed that the gel polymer electrolyte batteries had a higher discharge capacity at higher C-rates compared to ionic liquid cells. The authors attribute this improved performance to the improved electrochemical and interfacial stability, and the increased Lithium transference number. The gel polymer electrolyte developed by the authors is an exciting development that can serve effectively as an electrolytic conductor with other lithium-ion electrodes.

About The Author

Mr. Meer Safa is a PhD candidate in Materials Science and Engineering at Florida International University working under the supervision of Dr. El-Zahab. He received his M.S. Materials Science and Engineering from Kungliga Tekniska Högskolan (KTH) in Sweden and his B.S. degree in Materials and Metallurgical Engineering from Bangladesh University of Engineering and Technology (BUET) in Bangladesh. His research concentrates on the synthesis of ionic liquids for the development of polymer electrolyte for lithium batteries and their electrochemical investigations. 

About The Author

Mr. Amir Chamaani is a Ph.D. candidate in Materials Science and Engineering at Florida International University. He received his M.S. in Nanomaterials Engineering from the Materials and Energy Research Center (MERC) in Tehran, Iran in 2011. He served as Research at MERC working on thin film anodes for Li-ion micro-batteries. He is currently a Dissertation Year fellow working under the supervision of Dr. El-Zahab on the development of polymer electrolytes, electrochemical, and materials characterizations of Lithium battery applications, especially Li-O₂ batteries. 

About The Author

Ms. Neha Chawla is a Ph.D. candidate in Materials Science and Engineering at Florida International University. She has received her M.S. in Materials Science and Engineering from Florida International University and her B.Eng. in Production Engineering from Mumbai University in India. She is currently working towards her Ph.D. under the supervision of Dr. El-Zahab developing cathodes for improved performance of lithium-oxygen batteries. 

About The Author

Dr. Bilal El-Zahab is an Assistant Professor of Mechanical and Materials Engineering at Florida International University (2012-present). He received in Ph.D. in Chemical Engineering from the University of Akron in Ohio and was a Postdoctoral Research Associate in Analytical Chemistry at Louisiana State University (2008-2010) and a Postdoctoral Associate in Chemical Engineering at Massachusetts Institute of Technology (2010-2012). His research interests include the development of advanced materials for energy storage and bioanaylical applications.  

Journal Reference

Meer Safa, Amir Chamaani, Neha Chawla, Bilal El-Zahab. Polymeric Ionic Liquid Gel Electrolyte for Room Temperature Lithium Battery Applications, Electrochimica Acta 213 (2016) 587-593.

Mechanical and Materials Engineering Department, Florida International University, Miami, Florida 33174, USA

 

 

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