Chemical and spectroscopic characterization of marine dissolved organic matter isolated using coupled reverse osmosis-electrodialysis

The coupled reverse osmosis-electrodialysis (RO/ED) method was used to isolate dissolved organic matter (DOM) from 16 seawater samples. The average yield of organic carbon was 75 ± 12%, which is consistently greater than the yields of organic carbon that have been commonly achieved using XAD resins, C18 adsorbents, and cross-flow ultrafiltration. UV-visible absorbance spectra and molar C/N ratios of isolated samples were consistent with the corresponding properties of DOM in the original seawater samples, indicating that DOM samples can be isolated using the coupled RO/ED method without any bias for/against these two properties. Five of the samples were desalted sufficiently that reliable measurements of their 13C and 1HNMR spectra and their Fourier transform ion cyclotron resonance (FTICR) mass spectra could be obtained. The 13C and 1HNMR spectra of RO/ED samples differed distinctly from those of samples that have been isolated in much lower yields by other methods. In particular, RO/ED samples contained a relatively lower proportion of carbohydrate carbon and a relatively greater proportion of alkyl carbon than samples that have been isolated using cross-flow ultrafiltration. From the FTICR mass spectra of RO/ED samples, samples from the open ocean contained a much lower proportion of unsaturated compounds and a much higher proportion of fatty acids than coastal samples.This material is based upon work supported by the National Science Foundation (NSF) under Grants No. 0425624 and 0425603.Peer Reviewe

Chemical and spectroscopic characterization of marine dissolved organic matter isolated using coupled reverse osmosis-electrodialysis

The coupled reverse osmosis-electrodialysis (RO/ED) method was used to isolate dissolved organic matter (DOM) from 16 seawater samples. The average yield of organic carbon was 75 ± 12%, which is consistently greater than the yields of organic carbon that have been commonly achieved using XAD resins, C18 adsorbents, and cross-flow ultrafiltration. UV-visible absorbance spectra and molar C/N ratios of isolated samples were consistent with the corresponding properties of DOM in the original seawater samples, indicating that DOM samples can be isolated using the coupled RO/ED method without any bias for/against these two properties. Five of the samples were desalted sufficiently that reliable measurements of their 13C and 1HNMR spectra and their Fourier transform ion cyclotron resonance (FTICR) mass spectra could be obtained. The 13C and 1HNMR spectra of RO/ED samples differed distinctly from those of samples that have been isolated in much lower yields by other methods. In particular, RO/ED samples contained a relatively lower proportion of carbohydrate carbon and a relatively greater proportion of alkyl carbon than samples that have been isolated using cross-flow ultrafiltration. From the FTICR mass spectra of RO/ED samples, samples from the open ocean contained a much lower proportion of unsaturated compounds and a much higher proportion of fatty acids than coastal samples.This material is based upon work supported by the National Science Foundation (NSF) under Grants No. 0425624 and 0425603.Peer Reviewe

Chemical and spectroscopic characterization of marine dissolved organic matter isolated using coupled reverse osmosis-electrodialysis.

The coupled reverse osmosis-electrodialysis (RO/ED) method was used to isolate dissolved organic matter (DOM) from 16 seawater samples. The average yield of organic carbon was 75 +/- 12%, which is consistently greater than the yields of organic carbon that have been commonly achieved using XAD resins, C-18 adsorbents, and cross-flow ultrafiltration. UV-visible absorbance spectra and molar C/N ratios of isolated samples were consistent with the corresponding properties of DOM in the original seawater samples, indicating that DOM samples can be isolated using the coupled RO/ED method without any bias for/against these two properties. Five of the samples were desalted sufficiently that reliable measurements of their C-13 and H-1 NMR spectra and their Fourier transform ion cyclotron resonance (FTICR) mass spectra could be obtained. The C-13 and H-1 NMR spectra of RO/ED samples differed distinctly from those of samples that have been isolated in much lower yields by other methods. In particular, RO/ED samples contained a relatively lower proportion of carbohydrate carbon and a relatively greater proportion of alkyl carbon than samples that have been isolated using cross-flow ultrafiltration. From the FTICR mass spectra of RO/ED samples, samples from the open ocean contained a much lower proportion of unsaturated compounds and a much higher proportion of fatty acids than coastal samples

An ionicity rationale to design solid phase metal nitride reactants for solar ammonia production

Ammonia is an important fertilizer component and could be used as a convenient hydrogen carrier. This work studies a solar thermochemical reaction cycle that separates the reductive N[subscript 2] cleavage from the hydrogenation of nitrogen ions to NH[subscript 3] without using electricity or fossil fuel. The hydrolysis of binary metal nitrides of magnesium, aluminum, calcium, chromium, manganese, zinc, or molybdenum at 0.1 MPa and 200-1000°C recovered up to 100 mol% of the lattice nitrogen with up to 69.9 mol% as NH[subscript 3] liberated at rates of up to 1.45 x 10ˉ³ mol NH[subscript 3] (mol metal)ˉ¹ sˉ¹ for ionic nitrides. These rates and recoveries are encouraging when extrapolated to a full scale process. However, nitrides with lower ionicity are attractive due to simplified reduction conditions to recycle the oxidized reactant after NH[subscript 3] formation. For these materials diffusion in the solid limits the rate of NH3 liberation. The nitride ionicity (9.96-68.83% relative to an ideal ionic solid) was found to correlate with the diffusion constants (6.56 x 10[superscript -14] to 4.05 x 10[superscript -7] cm² sˉ¹) suggesting that the reduction of H[subscript 2]O over nitrides yielding NH[subscript 3] is governed by the activity of the lattice nitrogen or ion vacancies, respectively. The ionicity appears to be a useful rationale when developing an atomic-scale understanding of the solid-state reaction mechanism and when designing prospectively optimized ternary nitrides for producing NH[subscript 3] more sustainably and at mild conditions compared to the Haber Bosch process

Adaptation of Mycobacterium smegmatis to an industrial scale medium and isolation of the mycobacterial porinMspA

The adaptation of the organism to a simple and cost-effective growth medium is mandatory in developing a process for large scale production of the octamericporinMspA, which is isolated from Mycobacterium smegmatis. A fermentation optimization with the minimal nutrients required for growth has been performed. During the fermentation, the iron- and ammonium chloride concentrations in the medium were varied to determine their impact on the observed growth rates and cell mass yields. Common antibiotics to control contamination were eliminated in favor of copper sulfate to reduce costs. MspA has been successfully isolated from the harvested M. smegmatisusing aqueous nOPOE (noctyloligooxyethylene) at 65°C. Because of the extraordinary stability of MspA, it is possible to denature and precipitate virtually all other proteins and contaminants by following this approach. To further purify the product, acetone is used for precipitation. Gel electrophoresis confirmed the presence and purity of MspA. A maximum of 840µg (via Bradford assay) of pure MspA per liter of the optimized simple growth medium has been obtained. This is a 40% increase with respect to the previously reported culture medium for MspA

Reducing the energy demand of cellulosic ethanol through salt extractive distillation enabled by electrodialysis

One of the main challenges when a biochemical conversion technique is employed to produce cellulosic ethanol is the low concentration of ethanol in the fermentation broth, which increases the energy demand for recovering and purifying ethanol to fuel grade. In this study, two design cases implementing salt extractive distillation – with salt recovery enabled by a novel scheme of electrodialysis and spray drying – along with heat integrated distillation techniques of double-effect distillation and direct vapor recompression are investigated through process simulation with Aspen Plus® 2006.5 for reducing the thermal energy demand. Conventional distillation along with molecular sieve based dehydration is considered as the base case. Salt extractive distillation along with direct vapor recompression is found to be the most economical ethanol recovery approach for cellulosic ethanol with a thermal energy demand of 7.1 MJ/L (natural gas energy equivalents, higher heating value), which corresponds to a thermal energy savings of 23% and cost savings of 12% relative to the base case separation train thermal energy demand and total annual cost

Annual program review chemical recovery and corrosion : March 25-26, 1998

"March 25-26, 1998."Project F016-01. Control of evaporator fouling. Current trends in evaporator fouling / Wolfgang Schmidl, Wm. James Frederick -- Project F016-02. Recovery boiler modeling -- Project F016-03. Recovery boiler capacity improvements. Experimental study of the mechanisms of fine particle deposition in kraft recovery boilers / S. A. Sinquefield, L. L. Baxter, W. J. Frederick -- Project F017-04. Control of non-process elements in kraft pulp mills and bleach plants. Distribution of non-process elements in pulp mill and bleach process streams. 1. Calculating precipitation of inorganic species / W. J. Frederick, G. W. Schmidl, and C. P. Woitkovich, S. A. Sinquefield ; Solubility of aluminosilicates in kraft green and white liquors / P. N. Wannemacher, Wm. James Frederick, K. A. Hendrickson, K. L. Holman -- Project F017-06. Closed mill salt recovery / P. Pfromm Highlights of externally funded and PhD projects: Project 4182. Elimination of the calcium cycle: direct electrolytic causticizing of kraft smelt ; Project 4157-02. VOC control in kraft mills. Task B, Development of a membrane separation technology ; Project 4160. Recycling of bleach plant filtrates using electrodialysis ; Removal of inorganics from close-cycle papermachine white water ; Behavior of polymeric toner in recycling ; Removal of potassium from green liquor by ion exchange -- Project F017-07. Fundamentals of dregs removal / [Empie ... et al.] -- Project F017-08. VOC in Kraft mills. Volatile organic compounds (VOCs) in kraft mill streams. Part II, Protocol development to measure the contents and Henry's constants of VOC's in kraft mill streams / J.Y. Zhu, X.S. Chai, and B. Dhasmana ; Volatile organic compounds (VOCs) in kraft mill steams. Part III, Vapor-liquid phase equilibrium partitioning of methanol in black liquors / J.Y. Zhu and X.S. Chai -- Project F028. Gasification of black liquor / Kristiina Iisa -- Slides