Evaluation of catalysts and membranes for high yield biohydrogen production via electrohydrogenesis in microbial electrolysis cells (MECs)

2008 ◽  
Vol 58 (4) ◽  
pp. 853-857 ◽  
Author(s):  
Shaoan Cheng ◽  
Bruce E. Logan

Hydrogen gas can be produced from fermentation end products such as acetic acid through the electrohydrogenesis process in microbial electrolysis cells (MECs). In many MEC reactors, precious metal catalysts and expensive cation exchange membranes are often used. Here we examine Co- and FeCo-based alternatives to Pt, and compare the performance of an anion exchange membrane with that of a cation exchange membrane (Nafion™ 117). It is found that these alternative catalysts have 40–80% better performance than uncatalysed surfaces, but they do not equal the performance of Pt based on our electrochemical tests using cyclic voltammetry. It was also found that the anion exchange membrane (AEM) performance was equal to that of cation exchange membrane (CEM) at applied voltages of 600 mV or less in MEC tests, but that it exceeded performance of the CEM at voltages above 600 mV. These results demonstrate choosing catalysts will require both analysis of performance and materials costs, but that performance is improved for producing H2 gas in MECs using AEMs.

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 145 ◽  
Author(s):  
Liliana Villafaña-López ◽  
Daniel M. Reyes-Valadez ◽  
Oscar A. González-Vargas ◽  
Victor A. Suárez-Toriello ◽  
Jesús S. Jaime-Ferrer

Salinity gradient power is a renewable, non-intermittent, and neutral carbon energy source. Reverse electrodialysis is one of the most efficient and mature techniques that can harvest this energy from natural estuaries produced by the mixture of seawater and river water. For this, the development of cheap and suitable ion-exchange membranes is crucial for a harvest profitability energy from salinity gradients. In this work, both anion-exchange membrane and cation-exchange membrane based on poly(epichlorohydrin) and polyvinyl chloride, respectively, were synthesized at a laboratory scale (255 c m 2) by way of a solvent evaporation technique. Anion-exchange membrane was surface modified with poly(ethylenimine) and glutaraldehyde, while cellulose acetate was used for the cation exchange membrane structural modification. Modified cation-exchange membrane showed an increase in surface hydrophilicity, ion transportation and permselectivity. Structural modification on the cation-exchange membrane was evidenced by scanning electron microscopy. For the modified anion exchange membrane, a decrease in swelling degree and an increase in both the ion exchange capacity and the fixed charge density suggests an improved performance over the unmodified membrane. Finally, the results obtained in both modified membranes suggest that an enhanced performance in blue energy generation can be expected from these membranes using the reverse electrodialysis technique.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Natalia Pismenskaya ◽  
Nadezhda Melnik ◽  
Ekaterina Nevakshenova ◽  
Kseniya Nebavskaya ◽  
Victor Nikonenko

The desalination of dilute NaCl solutions with heterogeneous Russian commercial and modified ion-exchange membranes was studied in a laboratory cell imitating desalination channels of large-scale electrodialysers. The modification was made by casting a thin film of a Nafion-type material on the surface of cation-exchange membrane, and by processing with a strong polyelectrolyte the surface of anion-exchange membrane. It was shown that the modifications resulted in an increase of mass transfer coefficient and in a decrease in water splitting rate, both by up to 2 times. The effect of mass transfer growth is explained by higher surface hydrophobicity of the modified membrane that enhances electroconvection. The decrease in water splitting rate in the case of cation-exchange membrane is due to homogenization of its surface layer. In the case of anion-exchange membrane the effect is due to grafting of quaternary ammonium bases onto the original membrane surface layer. The suppression of water splitting favors development of electroconvection. In turn, intensive electroconvection contributes to deliver salt ions to membrane surface and thus reduces water splitting.


2012 ◽  
Author(s):  
Mahadevan. M. ◽  
Lay Pee Lin ◽  
Zainal Abidin M. Y. ◽  
Mohamad Roji Sarmidi

Elektrodialisis merupakan suatu proses yang menggunakan perbezaan keupayaan elektrik sebagai daya penggerak yang menyebabkan pergerakan ion-ion dalam sesuatu elektronit. Membran yang digunakan dalam proses ini akan membenarkan sama ada cas-cas positif atau negatif sahaja melaluinya bergantung kepada kumpulan berfungsi yang terikat pada membran. Objektif projek penyelidikan ini adalah untuk menghasilkan membran pertukaran kation yang digunakan dalam proses elektrodialisis. Membran-membran pertukaran kation yang dihasilkan terbahagi kepada lima jenis, dan diberi nama sebagai BERL–30, 40, 50, 60, dan 70. Kelima-lima jenis membran ini berbeza dari segi kandungan resin yang berfungsi sebagai vektor pertukaran cas kation. Di samping penyediaan membran, penyelidikan ini juga meliputi aspek pencirian membran tersebut serta perbandingan dengan membran komersial. Kriteria yang dikaji adalah ketebalan membran, sifat kebolehtelapan membran, kapasiti pertukaran ion, kapasiti kepekatan ion kumpulan berfungsi, morfologi struktur membran, ujian kestabilan kimia dan kandungan air membran. Secara keseluruhannya, didapati peratus kandungan resin yang tinggi boleh meningkatkan kapasiti pertukaran ion, peratus kebolehtelapan membran serta kapasiti kepekatan ion kumpulan berfungsi. Antara membran yang dihasilkan, membran pertukaran kation jenis BERL–70 merupakan membran yang berpotensi dalam penggunaan proses elektrodialisis. Kata kunci: Membran pertukaran kation, polisulfona, resin pertukaran ion, ciri-ciri membran, elekrodialisis The objective of this work is to prepare an anion exchange membrane from polysulfone binder–ion exchange resin, which can be used in electrodialysis process. The cation exchange membranes were prepared by the solution casting method. The prepared anion exchange membranes are different from the conventional cation exchange membranes because its functional group is not derived from chlorosulfonic acid but from the absorption of anion exchange resins. The content of resins in each set of the prepared cation exchange membrane varied and were named as BERL–30, 40, 50, 60, and 70. In addition, the performance and behaviour of the prepared anion exchange membrane were evaluated and compared with the commercial cation exchange membranes. The physico-chemical properties of anion exchange membrane were determined by measuring the membrane thickness, permselectivity, and concentration of ion exchange capacity, chemical stability, water content, and scanning electron microscope (SEM). It was found that the increase in the quantity of resin (%) would increase the capacity of ion exchange, percentage of permselectivity, and capacity concentration of ion exchange group. The experimental results showed that cation exchange membrane has the potential to be used in electrodialysis process. Keywords: Cation exchange membrane, electrodialysis, polysulfone, ion exchange resin, membrane characterisation


2018 ◽  
Vol 20 (3) ◽  
pp. 81-86 ◽  
Author(s):  
Magdalena Lech ◽  
Anna Trusek

Abstract The aim of this work was to develop the method of lactic acid (LA) separation from fermented whey. CMI-7000 Cation Exchange Membrane and AMI-7001 Anion Exchange Membrane were employed in electrodialysis process. Experiments showed that the selected membranes separated organic acids effectively (including LA) from other organic ingredients present in medium. Selecting an appropriate volume of a receiving chamber could lead to LA concentration. Moreover, membrane fouling during separation was investigated. This phenomenon is negligible which is the main advantage of this process. As it was shown during batch processes, with the voltage increase, the rate of electrodialysis increases as well. It prompts to a reduction of residence time in electrodialyzer during a continuous separation.


2008 ◽  
Vol 42 (23) ◽  
pp. 8630-8640 ◽  
Author(s):  
Bruce E. Logan ◽  
Douglas Call ◽  
Shaoan Cheng ◽  
Hubertus V. M. Hamelers ◽  
Tom H. J. A. Sleutels ◽  
...  

2009 ◽  
Vol 34 (9) ◽  
pp. 3612-3620 ◽  
Author(s):  
Tom H.J.A. Sleutels ◽  
Hubertus V.M. Hamelers ◽  
René A. Rozendal ◽  
Cees J.N. Buisman

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