Batch Cell Research Articles

Prussian Blue based flow-through (bio)sensors in power generation mode: New horizons for electrochemical analyzers

We report on advanced Prussian Blue (PB) based flow-through (bio)sensors operated in power generation mode. The performance of such (bio)sensors in wall-jet cell is significantly improved with respect to three-electrode regime in terms of up to 1.5 times higher sensitivity probably due to the enhanced mass transport compared to it in batch cell upon stirring. Most importantly, potentiostat-free operation upon short-circuiting PB modified electrode with Ag|AgCl reference through an ammeter drastically decreases noises, which results in up to 3 times increased signal-to-noise ratio compared to conventional three-electrode flow-through systems. These findings, as well as the simplicity of the proposed approach, are encouraging for the high throughput robust sensing and open new horizons for elaboration of electrochemical analyzers.

Carbon polyaniline capacitive deionization electrodes with stable cycle life

Electrode materials for capacitive deionization (CDI), an energy efficient method for desalination, were developed in this work. Waste-tire derived carbon (TC) coated with polyaniline was used to form a carbon polymer composite (CPC). CPC was used as an electrode in CDI configurations to determine the salt adsorption capability of the material. Chemical treatment of TC with KOH led to an enhancement in surface area to 952 m2/g and microporosity in the sub-2-nm range. This unique microstructure is considered to be beneficial for effective ion uptake in CDI applications. The capacitance of the electrodes was further enhanced through surface coating with polyaniline, resulting in a specific capacitance of 168.2 F/g. In batch cell testing with 1.2 V applied potential, the salt adsorption capacity (SAC), measured in mg of salt adsorbed per gram of active material, in a 1500–1700 ppm KCl solution was measured at 14.2 mg/g. Scale-up of the process with ionic-membrane-assisted CDI (MCDI) led to improvement in SAC at 18.9 mg/g. Further, cycling tests revealed that the electrodes had comparable or better longevity compared to other CDI materials, retaining >92.8% charging capacity after 300 cycles. High adsorption capacities for other salts such as LiCl, NaCl, MgCl2 and CaCl2 have been found.

Removal of Manganese Ions (Mn2+) from a Simulated Wastewater by Electrocoagulation/ Electroflotation Technologies with Stainless Steel Mesh Electrodes: Process Optimization Based on Taguchi Approach

This study depicts the removal of Manganese ions (Mn2+) from simulated wastewater by combined electrocoagulation/ electroflotation technologies. The effects of initial Mn concentration, current density (C.D.), electrolysis time, and different mesh numbers of stainless steel screen electrodes were investigated in a batch cell by adopting Taguchi experimental design to explore the optimum conditions for maximum removal efficiency of Mn. The results of multiple regression and signal to noise ratio (S/N) showed that the optimum conditions were Mn initial concentration of 100 ppm, C.D. of 4 mA/cm2, time of 120 min, and mesh no. of 30 (wire/inch). Also, the relative significance of each factor was attained by the analysis of variance (ANOVA) which indicates that the percentage of contribution followed the order: time (47.42%), C.D. (37.13%), Mesh number (5.73%), and Mn initial Conc. (0.05%). The electrolysis time and C.D. were the most effective operating parameters and mesh no. had a fair influence on Mn removal efficiency, while the initial conc. of Mn. had no significant effect in the studied ranges of control factors. Regression analysis (R2= 90.16%) showed an acceptable agreement between the experimental and the predicted values, and confirmation test results revealed that the removal efficiency of Mn at optimum conditions was higher than 99%.

Comparing the electrocatalytic reduction of CO2 to CO on gold cathodes in batch and continuous flow electrochemical cells

The electrocatalytic reduction of CO2 on gold cathodes was found to differ significantly between a standard batch electrochemical cell and a flow cell incorporating a porous gold cathode. While the well-known influence of KHCO3 concentration on product selectivity was observed in the batch cell, the selectivity of the CO2 reduction reaction was shown to be independent of KHCO3 concentration in the flow cell. The Faradaic efficiency for CO production was found to be 80–90% regardless of the KHCO3 concentration whereas in the batch cell it decreased from 75% to 35% as the KHCO3 concentration is increased from 0.05 to 0.5 mol L−1. The current density was found to be independent of the KHCO3 concentration and similar in both cells (−4 to −10 mA cm−2 at −1.3 V vs Ag|AgCl). As the KHCO3 concentration effect is normally attributed to changes in the local pH at the cathode–electrolyte interface brought about by the buffering action of the electrolyte, the results found in this work suggest that pH buffering can be suppressed or manipulated in some cell/electrode configurations. In the flow cell used in this work, it is suggested that poor transport of the KHCO3 through the porous cathode support to the active surface results in higher local pH than that found at the surface of a cathode immersed in a traditional batch cell.

Galvanic deposition of Pd2+ ion in chloride solution by using different three dimensional electrodes

The influence of different three-dimensional (3D) electrodes in recovering palladium from chloride ion solution by using a galvanic batch cell is presented in this study. Palladium is reduced at the cathode and zinc is oxidized at the anode. The performances of 3D electrodes used as cathodes in this study, namely reticulated vitreous carbon (RVC) and porous graphite (PG) were assessed based on the percentage of palladium removal. The results show that RVC produced a better performance than PG in recovering palladium from the chloride solution with Pd2+ concentration decreased from initial values to less than 0.1mgL−1 after 2h, in the order of RVC>PG. Cyclic voltammograms show that RVC and PG undergo redox reaction within the range 1500mV to −200mV. It was also found that RVC treated with H2SO4 has a higher conductivity than PG, thus it improves the electrocatalytic activity of the cathode. Surface morphology analysis confirms that Pd is deposited on both RVC and PG.

Continuous Fermentation of a Prodigiosin-Producing <i>Serratia marcescens </i>Strain Isolated from Soil

A red-pigmented bacterial strain NS-17 was isolated from soil, and physiological and biochemical characteristics and 16S rDNA analysis established this organism as a strain of Serratia marcescens. The red pigment isolated from cells of NS-17 was identified as prodigiosin. By analyzing factors affecting the production of prodigiosin, modified medium and culture conditions were set up, and a continuous fermentation method was carried out to take advantage of the mass production of foam during fermentation. Continuous fermentation was achieved in the following conditions: 32℃, 1:1 ventilation ratio, and medium with a nutrient concentration 5-fold higher than that of the fermentation medium (with half the inorganic salt concentration) supplied as a feed medium at a flow rate of 8 mL/min. For the first time of continuous fermentation of Serratia marcescens coupling with foam flotation, a high yield of prodigiosin was obtained. After 56 h of culturing, the total harvest of cells was enhanced 2.33-fold compared to that of batch fermentation, the total amount of prodigiosin was enhanced 2.70-fold compared to that of batch fermentation, and cells and prodigiosin were concentrated in the efflux broth automatically.

Effect of fluoroquinolone resistance mutation Thr-82→Ile on Clostridioides difficile fitness.

Fluoroquinolone resistance is common among epidemic Clostridioides difficile PCR ribotype (RT) 027 and may have contributed to outbreaks of C. difficile infection (CDI). We investigated the impact of fluoroquinolone mutations on the bacterial fitness (BF) of C. difficile RT027 isolates. The BF of seven RT027 mutants with reduced susceptibility to moxifloxacin (moxifloxacin MIC 4-32 mg/L) was compared with their susceptible (moxifloxacin MIC 1-2 mg/L) progenitor strains in competitive batch culture (CBC), cell cytotoxicity and maximal growth rate assays. Comparative fitness dynamics of one gyrA Thr-82→Ile-harbouring isolate (CD3079M) versus the parent strain (CD3079) were also investigated in a continuous co-culture (CC) chemostat model. Mutant and parent strain populations were assessed every 24 h over 8 days using selective and non-selective agars. Sequencing was performed using NEBNext® Ultra™ chemistry and Illumina® HiSeq 3000 technologies. BF was significantly increased in all Thr-82→Ile isolates (w = 1.08-1.22) in CBC assays (P = 0.002). Gly-429→Val and Gln-434→Lys (gyrB) also showed no burden to fitness (w = 1.24 and 1.18, respectively), but Asp-71→Tyr conferred reduced fitness (w = 0.80). CC results for strains CD3079 and CD3079M (Thr-82→Ile) supported CBC findings; mutant-to-parent ratios differed significantly by 96 h (x¯=1.80, P = 0.025). The absence of a fitness cost associated with the most prevalent fluoroquinolone resistance mutations may have contributed to the success of RT027. Furthermore, a demonstrable in vitro advantage over fluoroquinolone-susceptible parent strains in CC may contribute to the maintenance of RT027, even in the absence of fluoroquinolone selection pressure.

Batch dialysis of phosphoric acid. Quantification of acid and water transport through Fumasep-FAD membrane

Diffusion dialysis of model aqueous solutions of phosphoric acid was investigated in a two-compartment batch cell equipped with an anion-exchange membrane Fumasep-FAD. The transport of acid through the membrane was accompanied by a significant water transport in the same direction. In order to quantify both these phenomena, the permeability coefficient of the membrane for acid and proportionality coefficient between the flux of water and that of acid were determined from the experimental dependences of acid concentrations and liquid volumes in both the compartments upon time. This study proved that the membrane used is highly permeable for phosphoric acid, i.e., the permeability coefficient was found to be in the range from 0.67 × 10−5 to 3.25 × 10−5 m s−1. Moreover, water transport can satisfactorily be quantified by only one proportionality coefficient with the value of 7.11.

Cadmium Exposure, Active Smoking and DNA Methylation Profiles in Human Blood DNA Samples from the Strong Heart Study

BACKGROUNDExperimental studies suggest that exposure to cadmium may alter DNA methylation (DNAm). In addition, DNAm status at several genomic sites has been associated with smoking in methylome-wide epidemiologic studies. Cadmium in cigarettes has been proposed as a causative agent for multiple health outcomes. The objective of this study was to investigate the mediator role of cadmium in the association between smoking and genomic DNAm profiles in 2325 Strong Heart Study participants.METHODSDNAm was measured in 860079 loci using the Illumina Infinium Human MethylationEPIC platform. Data were preprocessed, including correction for batch effect and cell heterogeneity. Cadmium concentrations in urine were determined by Inductively Coupled Plasma Mass Spectrometry, corrected by creatinine and log-transformed. Associations for active smoking on DNAm were estimated using linear regression models adjusted by age, body mass index, sex, with and without cadmium levels when required. We used the “difference of coefficients” method and the mediation R package to estimate the relative contribution of cadmium to smoking-associated DNAm.RESULTS38.4 % of the participants were active smokers. Median urinary cadmium was 0.97 µg/g. At a Bonferroni significance level of 5.91e-08, we replicated well-known associations of active smoking with DNAm. Among the 1858 significant sites, the top 5 mediated effects (% of association attributed to cadmium) were observed for NFIB (cg03253449, 31.33 %), IFIH1 (cg19965693, 28.9 %), CDC42BPB (cg02003183, 27.71 %), HSD17B12 (cg14262884, 27.19 %) and AHRR (cg00731338, 21.37 %).CONCLUSIONSThe association of active smoking and DNA methylation in well-established smoking associated DNAm sites was partially attributed to cadmium. Our results suggest that cadmium might be a partial mediator of the association between smoking and health outcomes through epigenetic mechanisms. These results need to be replicated in an independent study population.

Application of a curated genome-scale metabolic model of CHO DG44 to an industrial fed-batch process

CHO cells have become the favorite expression system for large scale production of complex biopharmaceuticals. However, industrial strategies for upstream process development are based on empirical results, due to a lack of fundamental understanding of intracellular activities. Genome scale models of CHO cells have been reconstructed to provide an economical way of analyzing and interpreting large-omics datasets, since they add cellular context to the data. Here the most recently available CHO-DG44 genome-scale specific model was manually curated and tailored to the metabolic profile of cell lines used for industrial protein production, by modifying 601 reactions. Generic changes were applied to simplify the model and cope with missing constraints related to regulatory effects as well as thermodynamic and osmotic forces. Cell line specific changes were related to the metabolism of high-yielding production cell lines. The model was semi-constrained with 24 metabolites measured on a daily basis in n = 4 independent industrial 2L fed batch cell culture processes for a therapeutic antibody production.This study is the first adaptation of a genome scale model for CHO cells to an industrial process, that successfully predicted cell phenotype. The tailored model predicted accurately both the exometabolomics data (r2 ≥ 0.8 for 96% of the considered metabolites) and growth rate (r2 = 0.91) of the industrial cell line. Flux distributions at different days of the process were analyzed for validation and suggestion of strategies for medium optimization. This study shows how to adapt a genome scale model to an industrial process and sheds light on the metabolic specificities of a high production process. The curated genome scale model is a great tool to gain insights into intracellular fluxes and to identify possible bottlenecks impacting cell performances during production process. The general use of genome scale models for modeling industrial recombinant cell lines is a long-term investment that will highly benefit process development and speed up time to market.

New batch electro-coagulation process for treatment and recovery of high organic load and low volume egg processing industry wastewater

In this study, a new batch cell with undivided operating and processing units based on electrocoagulation was used for wastewater treatment of egg processing industries. In addition, the influence of operational parameters such as current density, retention time and type of electrode on the amount of chemical oxygen demand (COD), total suspended solids (TSS) and total coliform (TC) removal were investigated. The results showed that COD, TSS and TC removal efficiency increases with increasing current density and retention time. Of course it should be noted that, in the final evaluation of these parameters, the operational costs, electrochemical energy consumption (EEC) and electrode consumption costs should be considered. Maximum removal of COD (99), TSS (98.5) and TC (99.99) were achieved by an aluminum electrode in 10 min retention time and a current density of 6.6 mA cm−2. In addition, the aluminum electrode with EEC of 14.2 kW h m-3 and the anode consumption of 0.53 mg cm−2 is cost efficient as compared with an iron electrode. According to results, treatment of egg processing industry wastewater with a low volume of wastewater and high amount of organic load is carried out easily by electrocoagulation process (ECP) as compared to other common methods. Moreover, the proposed reactor has a high efficiency in the treatment of industries wastewater and produces an effluent with TSS and COD lower than 5 mg L-1 which has a standard quality for discharge in the environment. © 2018 Institution of Chemical Engineers

Optimization of solar-driven photo-electro-Fenton process for the treatment of textile industrial wastewater

This work deals with the evaluation of a solar-driven Photo Electro-Fenton (SPEF) process as an alternative for the effective degradation of an industrial textile wastewater sample. Experiments were carried out in a laboratory scale batch cell reactor, using boron-doped diamond (anode) and titanium (cathode) electrodes in monopolar configuration. The effect of the main operational parameters (pH, current density (j), conductivity (ơ), Fe2+ concentration and anode area to effluent volume ((A/V) ratio) on the COD removal and energy consumption were studied using a Box-Behnken experimental design. The SPEF process was optimized using the Response Surface Methodology. At optimum operational conditions (pH = 4, j = 40 mA/cm2, ơ = 5768 μS/cm and Fe2+ = 0.3 mM), the solar-driven process achieved total discoloration, COD reduction of 83% and TOC mineralization of 70%, after 15 min of electrolysis. The process yielded a highly oxidized (AOS = 2.24) and biocompatible (BOD5/COD > 0.4) effluent. Additionally, the most suitable effective surface area of the electrodes (A/V ratio) was determined (3.75 m−1). The analysis of operational costs was also performed. The SPEF process demonstrated to be an efficient alternative for the treatment of industrial wastewater effluent, allowing to achieve Colombian permissible discharge limits.

Rates of H2O2 electrogeneration by reduction of anodic O2 at RVC foam cathodes in batch and flow-through cells

The Electro-Fenton process for in-situ H2O2 electrogeneration is impacted by low O2 utilization efficiency (<0.1%) and the need of acid for pH adjustment. An electrochemical flow-through cell can develop localized acidic conditions, coupled with simultaneous formation and utilization of O2 to enhance H2O2 formation. Multiple electrode configurations using reticulated vitreous carbon (RVC) foam and Ti/mixed metal oxides (MMO) are proposed to identify the optimum conditions for H2O2 formation in batch and flow-through cells. A pH of 2.75 ± 0.25 is developed locally in the flow-through cell that supports effective O2 reduction. Up to 9.66 mg/L H2O2 is generated in a 180 mL batch cell under 100 mA, at pH 2, and mixing at 350 rpm. In flow-through conditions, both flow rate and current significantly influence H2O2 production. A current of 120 mA produced 2.27 mg/L H2O2 under a flow rate of 3 mL/min in a 3-electrode cell with one RVC foam cathode at 60 min. The low current of 60 mA does not enable effective H2O2 production, while the high current of 250 mA produced less H2O2 due to parasitic reactions competing with O2 reduction. Higher flow rates decrease the retention time, but also increase the O2 mass transfer. Furthermore, 3-electrode flow-through cell with two RVC foam cathodes was not effective for H2O2 production due to the limited O2 supply for the secondary cathode. Finally, a coupled process that uses both O2 and H2 from water electrolysis is proposed to improve the H2O2 yield further.

Isobaric heat capacity of nanostructured liquids with potential use as lubricants

Abstract Isobaric molar heat capacity (Cp) of eight ionic liquids (ILs) was measured from 283.15 K to 338.15 K with a micro DSC III calorimeter with a heating rate of 0.25 K·min−1 using batch cells. Cp values were determined with an expanded uncertainty about 2%. Four of the selected ILs are imidazolium based with the anions hexylsulfate, trifluoromethanesulfonate, tris(pentafluoroethyl)trifluorophosphate and bis(trifluoromethylsulfonyl)imide whereas the other three are pyrrolidinium-based ILs with trifluoromethanesulfonate, tris(pentafluoroethyl)trifluorophosphate or bis(trifluoromethylsulfonyl)imide anions. The last one is tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate. Phase transitions in the temperature range are only observed for 1-butyl-2,3-dimethylimidazolium trifluoromethanesulfonate and tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate; isobaric molar heat capacities are determined in solid phase for both ILs. The results showed that Cp values increase with temperature and they present the usual strong dependence with the molar mass of the IL: Cp increases with the molecular weight of the IL. Moreover, it was found that isobaric specific heat capacities, cp, for phosphate-based ILs are the lowest, followed by imide-based ones, and ILs with anions containing sulphur atoms show the highest cp values. Finally, a group contribution method was used for predicting molar heat capacity for three of the studied ILs obtaining good agreement with experimental data.

Improving α, ω-dodecanedioic acid productivity from n-dodecane and hydrolysate of Candida cells by membrane integrated repeated batch fermentation

The aim of the present study is to develop an effective production process for α, ω-dodecanedioic acid (DC12) biosynthesis using n-dodecane and hydrolysate of Candida cells as substrates by membrane integrated repeated batch fermentation. Cells and n-dodecane were simultaneously recycled during the filtration of fermentation broth (FB) with a 150 kDa ceramic membrane under a cross-flow velocity of 4 m/s and a trans-membrane pressure of 0.2 MPa, and it was also revealed that the cells in the broth could alleviate the membrane fouling during the FB filtration. Moreover, the hydrolysate of the collected cells could be successfully used as a nitrogen source to replace 50% yeast extract for decreasing the DC12 production cost. With repeated-batch culture in a membrane bioreactor, the maximal DC12 productivity could be enhanced by 57.8% compared with the batch culture, meanwhile n-dodecane and cells could be recovered and used for the next fermentation cycle.

Direct electrolysis of waste newspaper for sustainable hydrogen production: an oxygen-functionalized porous carbon anode

Biomass electrolysis enables hydrogen (H2) production at onset voltages of less than 1 V, depending on the fuel species. However, biofuel derived from biomass not categorized as food and produced from environmentally friendly processes is needed for the development of sustainable strategies. In addition, the biofuel should not require special and expensive procedures for processing. The present report describes the direct electrolysis of waste newspaper for H2 production. Cellulose and lignin included in the newspaper were subject to dissolution and hydrolysis in a phosphoric acid solvent at the anode in a temperature range of 100–175 °C. The resulting decomposition products were electrolyzed to H2 and carbon dioxide (CO2), at low onset voltages (ca. 0.2 V) and high current efficiencies (H2: 1.0, CO2: 0.9). Carbon black functionalized with carbonyl groups showed greater catalytic activity than a Pt/C catalyst for the anode reaction. H2 yield reached ca. 0.2 g per 1 g of newspaper in a batch cell. H2 was produced continuously in a current-density range of 0.15–0.25 A cm−2 while maintaining plateau-like voltage behavior in a flow cell. The energy consumed for electrolysis at a current density of 0.15 A cm−2 was as low as 1.27 kWh (Nm3)−1.

Kinetic models for the electrochemical decolouration of two reactive azo dyes

In this work, the indirect oxidation of two azo dyes (Colour Index Reactive Orange 4 and 13) was performed in an electrochemical batch cell in the presence of chloride as an electrolyte. The effect of different operational parameters on the electrochemical treatment was tested. Kinetic plots consisting of two linear portions were obtained in some experiments. The rate constants and the breaking point between the two linear portions were modelled to evaluate the influence of dye concentration, conductivity and pH. Good correlation between the experimental and the modelled constants and breaking points was observed. Models showed that the dye concentration is the most significant factor in the electrochemical treatment of both dyes, although conductivity and pH were also significant either individually or in interaction with other factors.

A Use of Polymer Inclusion Membrane as Anion Exchange Membrane for Recovery of Cu(II) Ions Based on an Electrogenerative System

In this study, polymer inclusion membrane (PIM) was utilized as a novel ion exchange membrane for recovery of Cu(II) ions from an aqueous solution. The recovery of Cu(II) ions from copper(II) chloride solutions was proceed using a batch cell operated in an electrogenerative system. The recovery of Cu(II) ions was examined by using a three dimensional cathodes which are reticulated vitreous carbon (RVC) and porous graphite (PG). The effect of initial concentration of Cu(II) chloride, the presence of oxygen, types of membrane and time taken were investigated. Polymer inclusion membrane (PIM) with a composition of poly(vinyl chloride) (PVC) 60 wt% (m/m):Aliquat 336 30 wt% (m/m):dioctyl phthalate (DOP) 10 wt% (m/m) together with RVC as the cathode produced highest recovery of Cu(II) ions after 4 h of experiment with 99.9% of Cu(II) ions recovery. Highly capable low cost PIM can be used to replace expensive commercially available anion exchange membranes without neglecting the performances and final results. PIM has a clear advantage over a commercially available anion exchange membrane especially in terms of high chemical stability, high dimensional ability, low diffusion of solute, ease of PIM's preparation and low cost of production. Result obtained by using PIM as an ion exchange membrane is comparable with the use of a commercially available ion exchange membrane. Therefore PIM has a massive potential to be applied in an electrogenerative system.

Influence of different 3-D electrodes towards the performance of gold recovery by using an electrogenerative process

In this study, gold was recovered by using an electrogenerative process employing a batch cell. This system is based on Galvanic cell which it does not require any external power supply but it produces an electrical energy by a spontaneous chemical reaction in which gold is reduced at cathode and zinc is oxidized at anode. The performances of three-dimensional electrodes, reticulated vitreous carbon (RVC) and porous graphite sheet (PG) were used as cathodes and investigated based on the time and percentage of gold recovery. In batch cell system, RVC served as the best cathode material, having the highest recovery rate with >99% of gold being recovered in 1 h operation for gold concentration of 100 mg L−1. Cyclic voltammetry and mass transfer studies were conducted to study the characteristics of these cathodes for gold deposition. Based on the cyclic voltammograms, RVC and PG undergoes redox reaction within range 1200 mV to −600 mV. Finally, based on the cyclic voltammograms, it was found that gold reduction was observed at 0.2–0.1 V of potential range while oxidation peak was occurred at a potential range between 0.8 and 1.0 V.

Superior Robust Ultrathin Single-Crystalline Silicon Carbide Membrane as a Versatile Platform for Biological Applications.

Micromachined membranes are promising platforms for cell culture thanks to their miniaturization and integration capabilities. Possessing chemical inertness, biocompatibility, and integration, silicon carbide (SiC) membranes have attracted great interest toward biological applications. In this paper, we present the batch fabrication, mechanical characterizations, and cell culture demonstration of robust ultrathin epitaxial deposited SiC membranes. The as-fabricated ultrathin SiC membranes, with an ultrahigh aspect ratio (length/thickness) of up to 20 000, possess high a fracture strength up to 2.95 GPa and deformation up to 50 μm. A high optical transmittance of above 80% at visible wavelengths was obtained for 50 nm membranes. The as-fabricated membranes were experimentally demonstrated as an excellent substrate platform for bio-MEMS/NEMS cell culture with the cell viability rate of more than 92% after 72 h. The ultrathin SiC membrane is promising for in vitro observations/imaging of bio-objects with an extremely short optical access.