pinecone/core-2020-05-10-deduplication huggingface dataset:
Assessment of aged biodegradable polymer-coated nano-zero-valent iron for degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

BACKGROUND: This study reports on the effects of aging on suspension behavior of biodegradable polymer-coated nano-zero-valent iron (nZVI) and its degradation rates of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under reductive conditions. The polymers investigated included guar gum, potato starch, alginic acid (AA), and carboxymethyl cellulose (CMC). Polymer coating was used to mitigate nZVI delivery hindrance for in situ treatment of RDX-contaminated groundwater.

RESULTS: The RDX degradation rates by bare nZVI and starch-coated nZVI suspensions were least affected by aging although these suspensions exhibited the least favorable dispersion behavior. CMC, AA, and guar gum coating improved nZVI rates of degradation of RDX but these rates decreased upon aging. The best suspension stability upon aging was achieved by CMC and AA. Guar gum with loadings rates one order of magnitude lower than that of CMC and AA achieved good iron stabilization but significantly higher RDX degradation rates.

CONCLUSION: It is demonstrated that both migration and reactivity of polymer-stabilized nZVI should be explicitly evaluated over a long period before application in the field. Guar gum coated nZVI appeared best suited for in situ application because it maintained good suspension stability, with RDX degradation rates least affected by aging compared with the other polymers tested. © 2012 Society of Chemical IndustryPublishedN/
Approaches to rehabilitation of radioactive contaminated territories

BACKGROUND: Accidents at nuclear fuel cycle plants may lead to contamination of areas of land and water. Cheap and available sorbents including natural aluminosilicates can be used for rehabilitation and decontamination of large volumes of radioactively contaminated water, including drinking water, prevention of migration of radionuclides into ground and surface waters through the soil and returning contaminated soil to farming. RESULTS AND DISCUSSION: A comparative study of sorption properties of various natural and surface-modified aluminosilicates with respect to caesium is made. It is shown that sorption features of surface-modified aluminosilicates for Cs were improved by 100-1000 times compared with respective natural aluminosilicates. It is shown that surface modification of glauconite by a mixed nickel-potassium ferrocyanide phase allows it to considerably increase its specificity (caesium distribution coefficients (2.9 ± 0.8)Ч103 mL g-1 for natural and (4.5 ± 0.5)Ч105 mL g-1 for modified glauconite) as well as making it selective to caesium in the presence of other alkaline ions and also provides irreversible caesium sorption. CONCLUSIONS: Due to improved features, modified aluminosilicates can be more successful than natural ones when used for rehabilitation of radioactive contaminated territories (including agriculture) and water areas, as well as for decontamination of liquid radioactive wastes and for creation of geochemical barriers in solid radioactive waste storage. © 2013 Society of Chemical Industry
Improvement of a fed-batch process for high level xylanase production by a Bacillus strain

In this paper, the improvement of a fed-batch fermentation from the point of view of an industrial xylanase production process is described. The Bacillus strain chosen for this study is able to produce high quantities of a xylanase that is suitable to be used as bleach boost agent in chlorine-free bleaching sequences of paper pulp. It was found that xylo-oligosaccharides hydrolysis products from xylan by xylanase action were indispensable for induction of the enzyme synthesis, but that their presence in quantities of only 0.1g dm^-3 xylose equivalents led to catabolite repression. A substrate-limited fed-batch process, that is the most adapted, was furthermore improved with regard to nutrient requirement of the microorganism, especially the nitrogen source. A process with constant supply of a culture medium containing xylan, peptone and mineral nitrogen was able to produce 20240nkatcm^-3 with a productivity of 910nkatcm^-3 h^-1, which places the process among the best ever reported
VOC emissions from the composting of the organic fraction of municipal solid waste using standard and advanced aeration strategies

Background: the emission of volatile organic compounds (VOC) during the composting process is mainly responsible for the odors generated in these types of waste treatment plants. In this work, VOC emissions from the source‐separated organic fraction of municipal solid waste (OFMSW) composting process have been investigated in 50 L pilot reactors operating under different aeration control strategies during the active decomposition stage. - Results: the VOC emissions from traditional aeration control options such as oxygen feedback control or cyclic on‐off aeration have been compared with VOC emissions under an oxygen uptake rate (OUR) control strategy. Total VOC emission (mg C m⁻³) and VOC composition (%) have been determined during the first active decomposition stage of composting. Study of VOC composition indicated a high presence of terpenes. Carcinogenic compounds, such as furans, have occasionally been found at very low concentration. Results indicate some differences in VOC composition according to the aeration strategy used. - Conclusions: the evolution of total VOC emissions was relatively similar, being high in the first days of the process. However, the results obtained show some differences in VOC composition depending on the aeration strategy used. The OUR controller provided a more steady emissions profile, which will help the performance of further gas treatment operations, specially biological systems
Obtaining microbial communities with exoelectrogenic activity from anaerobic sludge using a simplified procedure

BACKGROUND: The microbial fuel cell (MFC) technology transforms the chemical energy present in substrates into electricity. Starting-up these systems, i.e. enriching the anodic community in exoelectrogenic bacteria, is a lengthy process or requires expensive equipment. - RESULTS: An easy and low-cost procedure based on a sediment MFC was developed to select microbial communities with exoelectrogenic activity from the anaerobic sludge of a waste water treatment plant (WWTP). The configuration was based on a simple vessel working as a single chamber MFC with a cathode of stainless steel wool in the liquid surface and a submerged graphite fibre brush as anode. In 30 days of operation, a biofilm with remarkable exoelectrogenic activity was grown on the anode of the MFC. This graphite fibre brush anode was able to supply 0.9Wm-2 when working in an air-cathode MFC (AC-MFC) for 45 days. - CONCLUSION:The procedure presented was demonstrated to be a successful, low-costandlow-maintenance procedure to obtain exoelectrogenic activity and had performances comparable with other more costly and complex inoculation procedures. The Sed-MFC does not require a potentiostat, external aeration, stirring, membranes or an enriched inoculum in the exoelectrogenic biomass
Effect of phase modifiers on boron removal by solvent extraction using 1,3 diolic compounds

Abstract: BACKGROUND: Among the polyols, 1,3 diols are selective and efficient extractants for boron but significant solubility of these into aqueous solutions restricts their application in large scale separation processes. Solvent modifiers can be used to reduce extractant loss to the aqueous phase. Efficiency of the diolic extractants for boron separation have been tested in the presence of different solvent modifiers. RESULTS: Compared with other modifiers studied, decanol gives better stability to diolic molecules in the Kerosene phase and exhibits a reduced negative effect on the extraction of boron. Next to decanol, the low viscous 2,6-dimethyl-4-heptanone can be used as solvent modifier. In successive extraction studies, 2-butyl-2-ethyl-1,3-propanediol (BEPD) showed better stability among the diols studied in the presence of decanol in the organic phase. CONCLUSION: Quantitative removal of boron was achieved from industrial waste solutions such as a spent phosphate passivation bath and a cutting fluid, using 0.6 mol L-1 BEPD and 0.6 mol L-1 2,2,4-trimethyl-1,3-pentanediol (TMPD) in 25% decanol/Kerosene organic phasePreprin
Boron removal from aqueous solutions using alginate gel beads in fixed-bed systems

BACKGROUNDA column sorption study was carried out using calcium alginate gel beads as adsorbent for the removal of boron from aqueous solutions. The breakthrough curve was obtained as a function of pH, initial concentration of boron, feed flow rate, adsorbent mass and column diameter. The breakthrough capacity values and adsorption percentage of calcium alginate gel for boron were calculated. Column data obtained at different conditions were described using the Adams-Bohart model and bed-depth service time (BDST), derived from the Adams-Bohart equation to predict breakthrough curves and to determine the characteristic column parameters required for process design.; RESULTSThe maximum adsorption percentage of boron on calcium alginate gel beads using an initial concentration of boron of 50 mg L-1 at pH 11 and room temperature (201 degrees C) was calculated to be 55.14%.; CONCLUSION<p id=Peer ReviewedPostprint (published version
Exergy analysis of energy-intensive production processes: Advancing towards a sustainable chemical industry

Exergy analysis is becoming a very powerful strategy to evaluate the real efficiency of a process. Its application in the chemical industry is still at an early stage but many interesting remarks can be obtained from the recent research in the most energy intensive processes of the chemical industry: the production of chemicals, the cement industry, the paper industry and, the iron and steel industry. The present review analyzes the opportunities and challenges in those sectors by considering exergy analyses as the first required step (although not sufficient) to advance towards a more sustainable chemical industry. Social, environmental and economic factors play a role in the critical evaluation of a process and exergy could be considered as the property that joins together those three cores of sustainability
Microbial community dynamics in two-chambered microbial fuel cells : effect of different ion exchange membranes

BACKGROUND: The utilization of different kinds of ion exchange membrane is a common practice in bioelectrochemical systems such as two-chambered microbial fuel cells (MFCs). However, little is known about the effect of membrane materials on the anodic microbial community diversity.; RESULTS: The effect of two cationic and one anionic exchange membranes (Nafion N-117, Ultrex CMI-7000, and Ultrex AMI-7000) on the microbial community dynamics of Eubacteria and Archaea has been assessed in two-chambered MFCs. The experimental results indicated that the eubacterial community in the anodic chamber was not affected by the membrane materials, being predominantly populations of Bacteroidetes (Porphyromonadaceae) and -proteobacteria (Alcaligenaceae and Comamonadaceae). On the other hand, the archaeal counterpart appears to be highly dependent on the type of membrane used, as was evidenced by the selective enrichment of Methanosarcina sp. in the MFC equipped with the membrane Nafion N-117 which was the MFC that showed the highest current production.; CONCLUSIONS: The results obtained in the present study suggest that membrane materials affect archaeal diversity whereas both anodofilic eubacteria and methanogenic archaea populations could play an important role in the overall MFC process performance.Peer ReviewedPostprint (author’s final draft
Molecular imprinting in hydrogels using reversible addition-fragmentation chain transfer polymerization and continuous flow micro-reactor

Abstract
BACKGROUND

Stimuli responsive imprinted hydrogel micro-particles were prepared using reversible addition-fragmentation chain transfer polymerization for targeting genotoxic impurity aminopyridine in aqueous environment using a continuous flow micro-reactor.
RESULTS

The feasibility of operation with a continuous flow micro-reactor for particles production was demonstrated. A comparative evaluation was carried out between batch and micro-reactor produced imprinted and non-imprinted hydrogels. Experimental results proved that molecular imprints generated by free radical polymerization and controlled radical polymerization showed outstanding performance in adsorption behavior: the q value estimate was about 1000 times higher than the value presented by other researchers. Solid phase extraction results further evidenced the promising imprinting with hydrogels using free radical polymerization and controlled radical polymerization by retaining c. 100% of 3-aminopyridine. The imprinting factor of 4.3 presented in this research appears to be the best value shown so far.
CONCLUSION

The imprinted materials were successfully prepared both in batch and with a continuous flow micro-reactor. The inclusion of a reversible addition-fragmentation chain transfer agent in controlled radical polymerization was important in optimizing the experimental conditions in the continuous microfluidic approach. Though the reversible addition-fragmentation chain transfer agent was very useful in controlling the reaction kinetics, imprinted micro-particles showed the existence of both non-specific and imprinted sites. It is worth extending this work to demonstrate the impact of reversible addition-fragmentation chain transfer agents in molecular imprinting, considering also operation in a continuous flow micro-reactor to obtain tailored smart hydrogel particles. © 2015 Society of Chemical IndustryFCT and FEDER under Programme COMPETE
(Project PEst-C/EQB/LA0020/2013), QREN, ON2 and FEDER
(Project NORTE-07-0162-FEDER-000050) and QREN, ON2 and
FEDER (Project NORTE-07-0124-FEDER- 0000014 - Polymer Reaction
Engineering)The authors thank FCT and FEDER under Programme COMPETE
(Project PEst-C/EQB/LA0020/2013), QREN, ON2 and FEDER
(Project NORTE-07-0162-FEDER-000050) and QREN, ON2 and
FEDER (Project NORTE-07-0124-FEDER- 0000014 - Polymer Reaction
Engineering). P.K. thanks NORTE-07-0124-FEDER-0000014 for
the Post Doctoral grant
Analysis of the crystallization process of a biopharmaceutical compound in the presence of impurities using process analytical technology (PAT) tools

This is the peer reviewed version of the following article: SIMONE, E., ZHANG, W. and NAGY, Z., 2016. Analysis of the crystallization process of a biopharmaceutical compound in the presence of impurities using process analytical technology (PAT) tools. Journal of Chemical Technology and Biotechnology, 91 (5), pp.1461-1470., which has been published in final form at http://dx.doi.org/10.1002/jctb.4743. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."BACKGROUND. The crystallization of biopharmaceuticals can be problematic since, because the biosynthesis of these compounds is very difficult to control, they can contain a significant amount of impurities that have to be eliminated. In fact, impurities can lead to changes in the properties of the drug that can significantly reduce its effectiveness or even put the user in danger. The aim of this work is to exploit process analytical technology (PAT) tools to study the crystallization step of vitamin B12 crude product extracted via fermentation. RESULTS. Linear cooling crystallization experiments were performed using different conditions. The effects of solvent, cooling rate, seeding and purity of the initial material on the final size distribution and purity of the crystals were investigated through the use of UV/Vis spectroscopy, focused beam reflectance measurement (FBRM) and the CryPRINS software (Crystallization Process Informatics System). It was found that impurities strongly inhibit the growth of vitamin B12 crystals, promoting nucleation and leading to poor final crystal size distribution. CONCLUSION. Slow cooling can help to increase the purity of the final product but also generates a broad crystal size distribution because of secondary nucleation. Preparing the solution with material already crystallized once and using purified seeds helped to obtain a narrower crystal size distribution and also to reduce breakage
Electromagnetic Stirring in a Microbioreactor with Non-conventional Chamber Morphology and Implementation of Multiplexed Mixing

?? 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Background: Microbioreactors have recently emerged as novel tools for early bioprocess development. Mixing lies at the heart of bioreactor operation (at all scales), and the successful implementation of micro-stirring methods is thus central to the further advancement of microbioreactor technology. The aim of this study was to develop a micro-stirring method that aids robust microbioreactor operation and facilitates cost effective parallelization. Results: We developed a microbioreactor with a novel micro-stirring method involving the movement of a magnetic bead by sequenced activation of a ring of electromagnets. The micro-stirring method offers flexibility in chamber designs and we demonstrate mixing in cylindrical, diamond and triangular shaped reactor chambers. Mixing times between the cylindrical and diamond-shaped chamber compared well, with the shortest mixing times in both being 3.4 s. Ease of micro-bubble free priming, a typical challenge of cylindrical microbioreactor chambers, was obtained with diamond shaped chamber. Consistent mixing behaviour was observed between the constituent reactors in a duplex system, and batch and continuous culture fermentation of Staphylococcus carnosus successfully performed. Conclusion: A novel stirring method using electromagnetic actuation offering rapid mixing and easy integration with microbioreactors was characterized. The gained design flexibility enables fabrication of chambers suitable for microfluidic operation, and a duplex demonstrator highlights potential for cost-effective parallelization. Combined with a previously published cassette-like fabrication of microbioreactors, these advances will facilitate the development of robust parallelized systems for both batch and chemostat bioreactor operation
Biogas upgrading from vinasse digesters: a comparison between an anoxic biotrickling filter and an algal-bacterial photobioreactor

Producción CientíficaBiological technologies for biogas upgrading such as anoxic biotrickling filters (BTF) and algal–bacterial photobioreactors (PBR) constitute a cost-effective, environmentally friendly alternative to conventional physical–chemical methods. Nonetheless, there is a lack of studies comparing their performance when treating real biogas.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA024U14)This research was supported by FAPESP, Brazil (Process number: 2009/15984-0) and CONACyT México (No. Reg: 237873)
Powdered Ca-activated zeolite for phosphate removal from treated waste-water

Background: A powdered zeolitic material synthesised from fly ash (FA) (NaP1-FA) and its calcium modified form (CaP1-NA) were studied as sorbent materials for the recovery of phosphate from treated waste-water effluents. Phosphate-sorption equilibrium experiments were performed by varying the experimental conditions, including solution pH, phosphate concentration, and the presence of competing ions. Results: The maximum phosphate-sorption capacities were 57 ± 5 and 203 ± 11 mgP–PO4g-1 for NaP1-FA and CaP1-NA, respectively. The sorption capacities of both zeolites in the pH range expected for waste-water effluents (pH 7 to 9) were slightly dependent on pH, exhibiting maxima at pH 8. Phosphate removal proceeds through two main mechanisms: (a) surface complexation with ≅AlOH and ≅FeOH groups of the zeolitic structure or unreacted minerals from the FA; and (b) the formation of Ca–phosphate phases, mainly brushite. Conclusions: The removal mechanisms were confirmed by XRD analyses and P speciation. The stabilities of the phosphate-loaded zeolite samples evaluated by the extraction experiments confirmed their potential availabilities in soil applications. Finally, the higher solubility of brushite compared with that of Hap makes this zeolitic material promising as a novel inorganic zeolite/CaP1-NA/brushite fertiliserPostprint (author's final draft
Micro-coagulation effects on direct ultrafiltration of challenging raw river water

Background\ud
\ud
The feasibility and competitiveness of substituting the conventional pre-treatment of drinking water treatment plants (dioxichlorination, coagulation/flocculation, settling, sand filtration) by raw river water direct ultrafiltration (UF) was addressed.\ud
\ud
Results\ud
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A full scale UF module was operated continuously for 2 years, treating highly variable surface water. The sustainable hydraulic conditions leading to a greater water yield from the direct UF treatment scheme under different scenarios were defined. Summer periods enabled the attainment of higher filtration fluxes, although raw river water showed greater turbidity and total suspended solids content. Winter periods presented higher dissolved organic carbon concentration, with greater biopolymers content, which have been claimed as main membrane foulants. A preliminary micro-coagulation of FeCl3 (<1.5 mg Fe(III) L-1) enabled supporting harsher hydraulic conditions and thus, implementing similar conditions throughout the year. Impacts of micro-coagulation were more pronounced on filtration, particularly in winter, but a positive effect was also noticed in hydraulic and chemical cleaning stages, increasing the efficiency of the former and decreasing by half the frequency of the latter.\ud
\ud
Conclusion\ud
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Direct UF proved to be competitive with the current conventional pre-treatment, leading to a significant reduction in reagents needs and sludge production and an increased and more stable product water quality. © 2016 Society of Chemical IndustryPeer ReviewedPostprint (author's final draft
A Streptomyces lividans SipY defficient strain as a host for protein production : standardization of operational alternatives for model proteins

Background: Extracellular protein production by Gram-positive bacteria, such as Streptomyces, may be complementary to current established protein production processes. The performance of a Streptomyces lividans mutant strain, deficient in the major signal peptidase (SipY) is investigated for the production of proteins secreted via the secondary Tat pathway. - Results: The SipY deficient strain has shown advantages over the wild type strain, in terms of extracellular productivity, specific activity and rheological behaviour. Two operational modes, batch and fed-batch, have been studied using mannitol as carbon source. The results showed that two successive mannitol additions in fed-batch mode led to improved secretory protein production using Streptomyces agarase as a model protein. This production process was also explored for the Tat secretory protein S. lividans laccase. The predicted sequence for the pre-laccase coding sequence has been cloned into the mutant strain under the control of the agarase promoter. Batch and fed-batch laccase production, using either mannitol or glucose as carbon source, have been developed and quantified. - Conclusions: The usefulness of a Streptomyces lividans SipY deficient strain as protein producer has been demonstrated. A proposed operating mode with substrate additions has been employed for the optimisation of Tat proteins production, although some adjustments might be necessary depending on the secretory protein