Energy Conversion using electrolytic concentration gradients

2015 ◽  
Vol 1774 ◽  
pp. 51-62
Author(s):  
Subramaniam Chittur K ◽  
Aishwarya Chandran ◽  
Ashwini Khandelwal ◽  
Sivakumar A
Keyword(s):  
Energy Conversion ◽  
Dynamic Condition ◽  
Salinity Gradient ◽  
Cost Effective ◽  
Clean Energy ◽  
Ionic Concentration ◽  
Electrode System ◽  
Membrane Electrode ◽  
Concentration Gradients ◽  
Flow Rates

ABSTRACTSalinity gradient is an enormous source of clean energy. A process for potential generation from an ionic concentration gradient produced in single and multicell assembly is presented. The ionic gradient is created using a fuel cell type cell with a micro-porous ion exchange membrane, both anionic (AEM) and cationic (CEM). Various salinity gradients, Salt : Fresh, from 100 : 0 to 16000 : 0 was established using NaCl solution, in the electrode chambers. A potential of 20 mV/cm to 25 mV/cm can be realized at ambient temperatures and pressures for a bipolar AEM/CEM cell. The performance was optimized for various static and dynamic flow rates of the saline and fresh water. The cell performance can further be optimized for Membrane Electrode System (MES) morphology. A multicell unit was assembled and the results presented for various conditions like concentration gradients, flow rates and pressure. The thermodynamic and electrical efficiency needs to be evaluated for various gradients and flow rates. The relation with number of valance electrons/ ion and the potential generated changes for various dynamic condition of salinity. The higher the salinity gradient the larger is the potential generated. This is limited by the membrane characteristics. There exists a monotonic relation between the number of valence electron/ion/unit time and the potential generated up to about 16000 concentration. The membrane characteristics have been studied for optimal ion crossover for various gradients and flow. The graph between ln (gradient) versus Voltage provides insights into this process. This presents a very cost effective and clean process of energy conversion.

Space Charge Enhanced Ion Transport in Heterogeneous Polyelectrolyte/Alumina Nanochannel Membranes for High-Performance Osmotic Energy Conversion

2021 ◽  
Author(s):  
Chen-Wei Chang ◽  
Chien-Wei Chu ◽  
Yen-Shao Su ◽  
Li-Hsien Yeh
Keyword(s):  
Ion Transport ◽  
Space Charge ◽  
Energy Conversion ◽  
High Performance ◽  
Salinity Gradient ◽  
Clean Energy ◽  
Energy Resources ◽  
Global Energy ◽  
Energy Demands ◽  
Selective Membrane

Capturing osmotic energy from a salinity gradient through an ion-selective membrane is regarded as one of the renewable clean energy resources to solve the increasing global energy demands. However, suffering...

Nanomaterials and structures for the fourth innovation of polymer electrolyte fuel cell

2010 ◽  
Vol 25 (11) ◽  
pp. 2063-2071 ◽  
Author(s):  
Chanho Pak ◽  
Sangkyun Kang ◽  
Yeong Suk Choi ◽  
Hyuk Chang
Keyword(s):  
Energy Conversion ◽  
Polymer Electrolyte ◽  
Supported Catalysts ◽  
Clean Energy ◽  
Polymer Electrolyte Fuel Cell ◽  
Membrane Electrode ◽  
Conductive Membranes ◽  
Perfluorinated Membranes ◽  
Efficiency Cost ◽  
Energy Conversion Devices

Polymer electrolyte fuel cells (PEFCs) are drawing attention as energy conversion devices for next generations because of their highly efficient, environmentally benign, and portable features. In the last five decades, three distinguishable innovations were achieved in terms of proton conductive membranes and electrodes: introduction of perfluorinated membranes into PEFCs, adoption of ionomers for electrodes, and increased toughness of membranes by reinforced membranes. The efficiency, cost, and durability achieved from the past three innovations are still not enough to replace competing technologies such as combustion engines. In this review, the authors would elucidate the three different methods based on nanotechnology to overcome the limits: nanoporous carbon-supported catalysts, nanocomposite membranes, and nanostructured membrane electrode assemblies, which will bring the fourth innovation to PEFCs. With the innovation, PEFCs will fulfill the goals of being clean-energy conversion devices in the major applications of stationary, portable, and vehicle markets.

scholarly journals Large-scale, robust mushroom-shaped nanochannel array membrane for ultrahigh osmotic energy conversion

2021 ◽  
Vol 7 (21) ◽  
pp. eabg2183
Author(s):  
Chao Li ◽  
Liping Wen ◽  
Xin Sui ◽  
Yiren Cheng ◽  
Longcheng Gao ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Power Density ◽  
Single Molecule ◽  
Self Assembly ◽  
Large Scale ◽  
Mechanical Stability ◽  
Salinity Gradient ◽  
Clean Energy ◽  
Selective Layer ◽  
Nanochannel Array

The osmotic energy, a large-scale clean energy source, can be converted to electricity directly by ion-selective membranes. None of the previously reported membranes meets all the crucial demands of ultrahigh power density, excellent mechanical stability, and upscaled fabrication. Here, we demonstrate a large-scale, robust mushroom-shaped (with stem and cap) nanochannel array membrane with an ultrathin selective layer and ultrahigh pore density, generating the power density up to 22.4 W·m−2 at a 500-fold salinity gradient, which is the highest value among those of upscaled membranes. The stem parts are a negative-charged one-dimensional (1D) nanochannel array with a density of ~1011 cm−2, deriving from a block copolymer self-assembly; while the cap parts, as the selective layer, are formed by chemically grafted single-molecule–layer hyperbranched polyethyleneimine equivalent to tens of 1D nanochannels per stem. The membrane design strategy provides a promising approach for large-scale osmotic energy conversion.

scholarly journals Miniaturized Salinity Gradient Energy Harvesting Devices

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5469
Author(s):  
Wei-Shan Hsu ◽  
Anant Preet ◽  
Tung-Yi Lin ◽  
Tzu-En Lin
Keyword(s):  
Energy Harvesting ◽  
Energy Conversion ◽  
Membrane Fouling ◽  
Salinity Gradient ◽  
Electrical Energy ◽  
Clean Energy ◽  
Internal Resistance ◽  
Power Extraction ◽  
Gradient Energy ◽  
Energy Harvesting Devices

Harvesting salinity gradient energy, also known as “osmotic energy” or “blue energy”, generated from the free energy mixing of seawater and fresh river water provides a renewable and sustainable alternative for circumventing the recent upsurge in global energy consumption. The osmotic pressure resulting from mixing water streams with different salinities can be converted into electrical energy driven by a potential difference or ionic gradients. Reversed-electrodialysis (RED) has become more prominent among the conventional membrane-based separation methodologies due to its higher energy efficiency and lesser susceptibility to membrane fouling than pressure-retarded osmosis (PRO). However, the ion-exchange membranes used for RED systems often encounter limitations while adapting to a real-world system due to their limited pore sizes and internal resistance. The worldwide demand for clean energy production has reinvigorated the interest in salinity gradient energy conversion. In addition to the large energy conversion devices, the miniaturized devices used for powering a portable or wearable micro-device have attracted much attention. This review provides insights into developing miniaturized salinity gradient energy harvesting devices and recent advances in the membranes designed for optimized osmotic power extraction. Furthermore, we present various applications utilizing the salinity gradient energy conversion.

scholarly journals Effect of Stratification of Cathode Catalyst Layers on Durability of Proton Exchange Membrane Fuel Cells

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2975
Author(s):  
Zikhona Nondudule ◽  
Jessica Chamier ◽  
Mahabubur Chowdhury
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Catalyst Layer ◽  
Cost Effective ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Potential Cycling ◽  
Catalyst Layers ◽  
Exchange Membrane

To decrease the cost of fuel cell manufacturing, the amount of platinum (Pt) in the catalyst layer needs to be reduced. In this study, ionomer gradient membrane electrode assemblies (MEAs) were designed to reduce Pt loading without sacrificing performance and lifetime. A two-layer stratification of the cathode was achieved with varying ratios of 28 wt. % ionomer in the inner layer, on the membrane, and 24 wt. % on the outer layer, coated onto the inner layer. To study the MEA performance, the electrochemical surface area (ECSA), polarization curves, and electrochemical impedance spectroscopy (EIS) responses were evaluated under 20, 60, and 100% relative humidity (RH). The stratified MEA Pt loading was reduced by 12% while maintaining commercial equivalent performance. The optimal two-layer design was achieved when the Pt loading ratio between the layers was 1:6 (inner:outer layer). This MEA showed the highest ECSA and performance at 0.65 V with reduced mass transport losses. The integrity of stratified MEAs with lower Pt loading was evaluated with potential cycling and proved more durable than the monolayer MEA equivalent. The higher ionomer loading adjacent to the membrane and the bi-layer interface of the stratified catalyst layer (CL) increased moisture in the cathode CL, decreasing the degradation rate. Using ionomer stratification to decrease the Pt loading in an MEA yielded a better performance compared to the monolayer MEA design. This study, therefore, contributes to the development of more durable, cost-effective MEAs for low-temperature proton exchange membrane fuel cells.

scholarly journals Pilot-Scale Production of Chito-Oligosaccharides Using an Innovative Recombinant Chitosanase Preparation Approach

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 290
Author(s):  
Chih-Yu Cheng ◽  
Chia-Huang Tsai ◽  
Pei-Jyun Liou ◽  
Chi-Hang Wang
Keyword(s):  
Cell Density ◽  
Scale Up ◽  
Cost Effective ◽  
Pilot Scale ◽  
Ionic Concentration ◽  
Dihydrogen Phosphate ◽  
Scale Production ◽  
Sodium Dihydrogen Phosphate ◽  
Selective Precipitation ◽  
Pilot Scale Production

For pilot-scale production of chito-oligosaccharides, it must be cost-effective to prepare designable recombinant chitosanase. Herein, an efficient method for preparing recombinant Bacillus chitosanase from Escherichia coli by elimination of undesirable substances as a precipitate is proposed. After an optimized culture with IPTG (Isopropyl β-d-1-thiogalactopyranoside) induction, the harvested cells were resuspended, disrupted by sonication, divided by selective precipitation, and stored using the same solution conditions. Several factors involved in these procedures, including ion types, ionic concentration, pH, and bacterial cell density, were examined. The optimal conditions were inferred to be pH = 4.5, 300 mM sodium dihydrogen phosphate, and cell density below 1011 cells/mL. Finally, recombinant chitosanase was purified to >70% homogeneity with an activity recovery and enzyme yield of 90% and 106 mg/L, respectively. When 10 L of 5% chitosan was hydrolyzed with 2500 units of chitosanase at ambient temperature for 72 h, hydrolyzed products having molar masses of 833 ± 222 g/mol with multiple degrees of polymerization (chito-dimer to tetramer) were obtained. This work provided an economical and eco-friendly preparation of recombinant chitosanase to scale up the hydrolysis of chitosan towards tailored oligosaccharides in the near future.

scholarly journals OH− and H3O+ Diffusion in Model AEMs and PEMs at Low Hydration: Insights from Ab Initio Molecular Dynamics

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 355
Author(s):  
Tamar Zelovich ◽  
Mark E. Tuckerman
Keyword(s):  
Molecular Dynamics ◽  
Fuel Cell ◽  
Ab Initio ◽  
Cost Effective ◽  
Clean Energy ◽  
Proton Exchange ◽  
Ab Initio Molecular Dynamics ◽  
Anion Exchange Membranes ◽  
Diffusion Mechanisms ◽  
Dynamics Simulations

Fuel cell-based anion-exchange membranes (AEMs) and proton exchange membranes (PEMs) are considered to have great potential as cost-effective, clean energy conversion devices. However, a fundamental atomistic understanding of the hydroxide and hydronium diffusion mechanisms in the AEM and PEM environment is an ongoing challenge. In this work, we aim to identify the fundamental atomistic steps governing hydroxide and hydronium transport phenomena. The motivation of this work lies in the fact that elucidating the key design differences between the hydroxide and hydronium diffusion mechanisms will play an important role in the discovery and determination of key design principles for the synthesis of new membrane materials with high ion conductivity for use in emerging fuel cell technologies. To this end, ab initio molecular dynamics simulations are presented to explore hydroxide and hydronium ion solvation complexes and diffusion mechanisms in the model AEM and PEM systems at low hydration in confined environments. We find that hydroxide diffusion in AEMs is mostly vehicular, while hydronium diffusion in model PEMs is structural. Furthermore, we find that the region between each pair of cations in AEMs creates a bottleneck for hydroxide diffusion, leading to a suppression of diffusivity, while the anions in PEMs become active participants in the hydronium diffusion, suggesting that the presence of the anions in model PEMs could potentially promote hydronium diffusion.

A noble gas sensor platform: linear dense assemblies of single-walled carbon nanotubes (LACNTs) in a multi-layered ceramic/metal electrode system (MLES)

2018 ◽  
Vol 6 (5) ◽  
pp. 972-979 ◽  
Author(s):  
Tae-Yeon Hwang ◽  
Yomin Choi ◽  
YoSeb Song ◽  
Nu Si A. Eom ◽  
Seil Kim ◽  
...  
Keyword(s):  
Noble Gas ◽  
Cost Effective ◽  
Hydrogen Sensor ◽  
Metal Electrode ◽  
Electrode System ◽  
Sensor Platform ◽  
Walled Carbon Nanotubes ◽  
Effective Hydrogen ◽  
Layered Ceramic ◽  
Pt Catalyzed

Monodispersed nano Pt catalyzed linear dense assembly of SWCNTs bundles on a noble multi-layered electrode system for cost-effective hydrogen sensor.

scholarly journals Towards Biohydrogen Separation Using Poly(Ionic Liquid)/Ionic Liquid Composite Membranes

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 124 ◽  
Author(s):  
Andreia S.L. Gouveia ◽  
Lucas Ventaja ◽  
Liliana C. Tomé ◽  
Isabel M. Marrucho
Keyword(s):  
Ionic Liquid ◽  
High Performance ◽  
Cost Effective ◽  
Clean Energy ◽  
Composite Membranes ◽  
Feed Pressure ◽  
Starting Point ◽  
Poly Ionic Liquid ◽  
Separation Performances ◽  
H2 Selectivity

Considering the high potential of hydrogen (H2) as a clean energy carrier, the implementation of high performance and cost-effective biohydrogen (bioH2) purification techniques is of vital importance, particularly in fuel cell applications. As membrane technology is a potentially energy-saving solution to obtain high-quality biohydrogen, the most promising poly(ionic liquid) (PIL)–ionic liquid (IL) composite membranes that had previously been studied by our group for CO2/N2 separation, containing pyrrolidinium-based PILs with fluorinated or cyano-functionalized anions, were chosen as the starting point to explore the potential of PIL–IL membranes for CO2/H2 separation. The CO2 and H2 permeation properties at the typical conditions of biohydrogen production (T = 308 K and 100 kPa of feed pressure) were measured and discussed. PIL–IL composites prepared with the [C(CN)3]− anion showed higher CO2/H2 selectivity than those containing the [NTf2]− anion. All the membranes revealed CO2/H2 separation performances above the upper bound for this specific separation, highlighting the composite incorporating 60 wt% of [C2mim][C(CN)3] IL.

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