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Gustavo A. Madero, Mexico

Vazquez-Larios A.L.,Energy and Environmental Research Center | Solorza-Feria O.,CINVESTAV | Poggi-Varaldo H.M.,Energy and Environmental Research Center | De Guadalupe Gonzalez-Huerta R.,ESIQIE del IPN | And 3 more authors.
International Journal of Hydrogen Energy

The objective of this work was to evaluate the effect of the cathodic catalyst (either chalcogenide or Pt) on bioelectricity production from actual municipal leachate in a microbial fuel cell equipped with an anode made of granular graphite (MFC-G) and seeded with an inoculum enriched in Mn(IV)-reducing bacteria. Each face (I and II) of the MFC-G was characterized by separate (I and II), in series, and parallel connection. Parallel connection of faces increased the maximum volumetric power up to 1239 and 1799 mW m-3 for RuxMoySez and Pt, respectively. In general parallel connection of electrode faces significantly decreased the Rint (44 and 77 Ω for RuxMoySez and Pt, respectively). In the batch operation where the cells were connected to external resistances (Rext) the average volumetric powers PV-ave in the second cycle of batch operation were 1005 ± 5 and 1317 ± 687 mW m-3 whereas organic matter removal efficiencies of 70 and 85% were registered for the RuxMoySez and Pt, respectively. During the repetitive batch operation of the cells loaded with an actual leachate there was preliminary evidence of an in-cell enrichment process. In principle, the MFC with catalyst RuxMoySez exhibited a performance 24% and 20% lower than that with Pt (on PV-ave and organic matter removal basis, respectively). This would point to a trade-off or compromise solution, since the cost of RuxMoySez catalyst is 70% lower than that of Pt. © 2014 Hydrogen Energy Publications, LLC. Source

Hernandez-Flores G.,National Polytechnic Institute of Mexico | Poggi-Varaldo H.M.,National Polytechnic Institute of Mexico | Solorza-Feria O.,Ibidem | Ponce-Noyola M.T.,Ibidem | And 3 more authors.
International Journal of Hydrogen Energy

The aims of this research were: (i) to develop and test a new, low cost, organic membrane (LCM) in an air-cathode, single chamber microbial fuel cell (MFC), and (ii) to compare its characteristics with those of an MFC equipped with a Nafion® 117 membrane (NF). The internal resistances (Rint) were 112 and 110 Ω using LCM and NF, respectively, whereas the maximum volumetric powers (PV,max) were 2146 and 14,246 mW/m3 for LCM and NF, respectively. The relatively low value of Rint of the MFC equipped with LCM was encouraging. Furthermore, the Rint of the NF-equipped MFC was of the same order. PV,max delivered with LCM was 15% of that with NF. However, the cost ratio LCM/NF was very low, ($14/m2)/($1733/m2) ∼ 0.8%. These results point out to a trade-off between sacrificing some power output of the cell (85%) but achieving outstanding savings on membrane costs (99.2%). © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Hernandez-Flores G.,National Polytechnic Institute of Mexico | Poggi-Varaldo H.M.,National Polytechnic Institute of Mexico | Solorza-Feria O.,National Polytechnic Institute of Mexico | Ponce Noyola M.T.,National Polytechnic Institute of Mexico | And 2 more authors.
International Journal of Hydrogen Energy

The aim of this work was to establish a mathematical model based on Tafel equation to quantitatively relate the maximum volumetric power (P V,max ) as well as the internal resistance (R int ) in a microbial fuel cell (MFC) with the specific surface area of the graphite anodes (As'), and either their conductance C or electrolytic conductivity σ of the material. The anodic chambers of the cells were packed with different anodic materials (graphite rods (GR), triangles of graphite (GT) and graphite flakes (GF), in order of increasing As'). The R int decreased and the P V,max increased for cells equipped with GR, GT and GF anodes. There was a correspondence of either the decrease of R int or the increase of P V,max with the increase of the log of As' of the graphite anodic materials.The fitting of the models was characterized in terms of determination coefficient R 2 , the p value, and the Ranking. The best fitting model for P V,max was PV,max=a0'+a1'×logAs'; with R 2 =0.8872, p=0.005, and Ranking=100%. The inclusion of C as second fitting variable slightly improved the R 2 ; however, the term with C did not have a theoretical origin. For R int the best fitting model was Rint=b0'+b1'×logAs'. The model of P V,max was validated with independent results from literature with satisfactory fitting results (R 2 =0.8704; p=0.0022; Ranking=100%). © 2015 Hydrogen Energy Publications, LLC. Source

Robles-Gonzalez I.V.,Energy and Environmental Research Center | Rios-Leal E.,Energy and Environmental Research Center | Sastre-Conde I.,IRFAP | Fava F.,University of Bologna | And 2 more authors.
Process Biochemistry

The purpose of our study was 2-fold: (i) to evaluate the effect of dominant electron acceptor [either aerobic, methanogenic, or sulfate-reducing slurry bioreactor (SB)] and biostimulation with sucrose on lindane removal from heavy soil and (ii) to assess the effect of the type of combined environments [partially aerated methanogenic (PAM) and simultaneous methanogenic-sulfate reducing (M-SR)] and addition of silicone oil as solvent on lindane removal from a clayish agricultural soil with high levels of organic matter. In the first experiment, the main effect of electron acceptor was significant (p < 0.0001); lindane removals followed the order SR > A ≫ M SBs. On the other hand, co-substrate sucrose was not significant (p = 0.67). Yet, the interaction was moderately significant (p < 0.007); co-substrate influence was distinct depending on the type of electron acceptor. In our case, co-substrate slightly improved lindane removal in both anoxic SBs (SR and M units), whereas lindane removal in A-SB with sucrose was lower than A-SB without sucrose. Metabolites from lindane transformation in our single electron acceptor SBs were consistent with lindane metabolites reported in the literature for anaerobic and aerobic degradation of the insecticide. In the second experiment, both factors [simultaneous electron acceptor (SEA) combination and solvent addition] were significant (p < 0.0001). Removal of lindane in SEA-SBs, PAM and M-SR without silicone oil was low (∼16%). On the other hand, the order of lindane removals in SBs with oil silicone M-SR SB was significantly superior (65%) to that of PAM SB (39%). Finally, in our work, SBs with SEA where one of the anaerobic metabolites is methanogenic were not as successful as SBs with single electron acceptors for removal of lindane from heavy soil. © 2011 Elsevier Ltd. All rights reserved. Source

Camacho-Perez B.,CINVESTAV | Rios-Leal E.,CINVESTAV | Rinderknecht-Seijas N.,ESIQIE del IPN | Poggi-Varaldo H.M.,CINVESTAV
Journal of Environmental Management

The scope of this paper encompasses the following subjects: (i) aerobic and anaerobic degradation pathways of γ-hexachlorocyclohexane (HCH); (ii) important genes and enzymes involved in the metabolic pathways of γ-HCH degradation; (iii) the instrumental methods for identifying and quantifying intermediate metabolites, such as gas chromatography coupled to mass spectrometry (GC-MS) and other techniques.It can be concluded that typical anaerobic and aerobic pathways of γ-HCH are well known for a few selected microbial strains, although less is known for anaerobic consortia where the possibility of synergism, antagonism, and mutualism can lead to more particular routes and more effective degradation of γ-HCH. Conversion and removals in the range 39%-100% and 47%-100% have been reported for aerobic and anaerobic cultures, respectively. Most common metabolites reported for aerobic degradation of lindane are γ-pentachlorocyclohexene (γ-PCCH), 2,5-dichlorobenzoquinone (DCBQ), Chlorohydroquinone (CHQ), chlorophenol, and phenol, whereas PCCH, isomers of trichlorobenzene (TCB), chlorobenzene, and benzene are the most typical metabolites found in anaerobic pathways. Enzyme and genetic characterization of the involved molecular mechanisms are in their early infancy; more work is needed to elucidate them in the future.Advances have been made on identification of enzymes of Sphingomonas paucimobilis where the gene LinB codifies for the enzyme haloalkane dehalogenase that acts on 1,3,4,6-tetrachloro 1,4-cyclohexadiene, thus debottlenecking the pathway. Other more common enzymes such as phenol hydroxylase, catechol 1,2-dioxygenase, catechol 2,3-dioxygenase are also involved since they attack intermediate metabolites of lindane such as catechol and less substituted chlorophenols. Chromatography coupled to mass spectrometric detector, especially GC-MS, is the most used technique for resolving for γ-HCH metabolites, although there is an increased participation of HPLC-MS methods. Scintillation methods are very useful to assess final degradation of γ-HCH. © 2011 Elsevier Ltd. Source

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