Reverse Osmosis Concentrate Research Articles

Use of electrodialysis and reverse osmosis for the recovery and concentration of ammonia from swine manure

This project aimed at producing a concentrated nitrogen fertilizer from liquid swine manure using electrodialysis (ED) and reverse osmosis (RO), as a mean to help resolve the excess nutrient problem faced by many swine producers, and offer an alternative to chemical nitrogen fertilizer production. Different types of ED membranes were evaluated based on the NH4+ transfer rate, current efficiency and membrane stability. A combination of CMB/AMX membranes was retained due to its high NH4+ transfer rate and chemical stability. The maximum total ammonia concentration (NH3–N) achievable by ED was limited by water transport from the manure to the concentrate compartment, and ammonia volatilization (17%) from the open concentrate compartment. Results suggested that, under the conditions of this experiment, a maximum total NH3–N concentration of about 16g/L could be reached with the ED system. An ED concentrate (8.7g/L of total NH3–N) was also fed to TFC-HF reverse osmosis membranes. A mass balance analysis revealed that the RO permeate, which represented 49.6% of the initial volume, contained 8.6% of the ammonia. However, the RO concentrate contained only 66.6% of the initial total NH3–N, suggesting that 21.2% of the ammonia was volatilized during the concentration test with RO membranes. Ammonia concentration in the RO concentrate reached approximately 13g/L, which is similar to the maximum concentration that could be achieved by ED. These results suggest that the use of ED and RO membranes to recover and concentrate ammonia is potentially interesting but the process must include an approach to minimize ammonia volatilization or trap volatilized ammonia.

Arsenate adsorption to soils: Modelling the competition from humic substances

There is currently no agreement to what extent humic substances may compete with arsenate and other anions for oxide adsorption sites in soils, and how to model this interaction. In this study, batch experiments were made in which the competition between fulvic acid and arsenate was studied in a spodic Bs horizon. Additional experiments were performed in which the pH and concentration dependence of arsenate adsorption was studied in four soils. The results showed that fulvic acid decreased the adsorption of AsO 4, probably because of competition effects. The K d value of AsO 4 adsorption to the four studied soils differed by three orders of magnitude at pH 5. The introduction of an irreversibly sorbed component RO − into the Three-Plane CD-MUSIC model, and the optimisation of RO − using the K d of AsO 4 for one sample from each data set, permitted the use of the model to predict AsO 4 adsorption under different conditions. On the whole, the predictions were reasonably close to measured values, but the model failed in 3 of 4 soils at high surface coverage. A strong relationship between the optimised RO − value and the observed pyrophosphate-extractable C value supported the assumption that RO − can be considered as being an adsorbed humic functional group. The large concentrations of RO − compared to those of adsorbed PO 4 and SO 4 suggest that humic substances may be the most important competitors for anion adsorption sites in many soils.

Innovative Approaches to RO Concentrate Management: Beneficial Reuse and Concentrate Minimization

Innovative Approaches to RO Concentrate Management: Beneficial Reuse and Concentrate Minimization

Effects of maternal dietary supplementation with three sources of carotenoids on the retinyl esters of egg yolk and developing quail liver

The effects of supplementation of the maternal diet of quail with three natural sources of carotenoids (alfalfa nutrient concentrate (PX agro™), tomato powder and marigold extract) on the accumulation of retinol and retinyl esters in egg yolk and in the liver of the new hatchling and maternal were investigated. The present study showed that the vitamin A in quail egg yolk was present in 4 different forms, namely retinol (R 52–62%), retinyl linoleate (RL 9–11%), retinyl stearate (RS 4%), retinyl oleate (RO 11–15%) and retinyl palmitate (RP 13–22%). The retinyl ester profile of the liver of newly hatched quail (R 2–4%, RL 8–12%, RS 19–21%, RO 12–15%, RP 50–55%) differs from that of egg yolk but was similar to that of the liver of adult quail (R 1%, RL 5–6%, RS 21–28%, RO 9–12%, RP 54–63%). It has been shown that RO and RP concentrations in egg yolk and the liver of day old quail chick significantly increased as a result of carotenoid supplementation of the maternal diet.

3D analysis of high ozone production rates observed during the ESCOMPTE campaign

The development of environmental policies to reduce the ozone levels around large agglomerations requires a good understanding of the development of ozone episodes. In particular, it is necessary to know the location and photochemical activity of the plume where ozone is formed. Measurement campaigns make it possible not only to characterize the concentration fields of ozone and its precursors but also to identify the zones of strong ozone production, by means of specific measurements and kinetic calculations. The combination of the observation-based data with numerical simulations allows to better characterize photochemical pollution. This paper presents a study carried out within the ESCOMPTE program and based on the determination of ozone production rates by experimental and numerical methods: ground measurements of peroxy radicals, NO x at a rural site, airborne measurements of NO X and O 3, Eulerian modeling. The reported case is of particular interest since it corresponds to an episode with very different photochemical situations. The diurnal variations of the peroxy radical concentration are analyzed in relation to those of ozone and its precursors. Ozone production rates— P(O 3)–are studied over one particular day. The results show particularly high concentrations of RO 2+HO 2 at ground level (up to 200 pptv) under the influence of the urban and industrial plume, but also highlight very high production rates of ozone (60 to 80 ppbv h −1) a few tens of kilometers from the sources. The results show satisfactory agreement between the various approaches. Modeling provides a four-dimensional (4D) description of the plumes, in particular the relation between the ozone precursor concentrations and P(O 3) on the ground.

Isolation of humic and non-humic NOM fractions: structural characterization.

The combination of RO concentration and XAD-8/XAD-4 resin adsorption techniques was used to isolate the different constituents of the Natural Organic Matter (NOM) from inorganic salts. NOM fractions i.e. colloids, hydrophobic NOM (HPO humic substances), transphilic NOM (TPI) and hydrophilic NOM (HPI) fractions isolated from different surface waters were characterized using 13C NMR and FT-IR spectroscopy and HPLC/Size Exclusion Chromatography coupled with UV and DOC detection. Results showed that the isolation procedure was suitable to quantitatively isolate the different fractions of NOM.

食品産業における膜技術の新たな展開 野菜・果実加工プロセスにおける膜分離技術の展開

Membrane technology in the vegetable and fruit processing has been applied for concentration using RO membrane and for clarification using UF or MF membrane.Recent technological advances related to the development of new membrane system, advanced separation and recovery of valuable components, improvement quality, saving energy consumption and reduction of environmental negative impact, have expanded the range of membrane separation.We have developed two new membrane systems. One is RO concentration system for material including the solid. Conventional RO system has been used for only juice concentration including the solid below 0.5mm particle size, by this new RO system, it is possible to concentrate liquid including 0.5mm-10mm particle size solid.Another is electrodialysis system for reduction of nitrate in a green vegetable, the characteristic of this system is to be operated under high concentration (Brix20), low velocity and low temperature condition.

Osmotic dehydration coupled reverse osmosis concentration: steady-state model and assessment

A steady-state analysis was made for evaluating the RO concentration of sugar solutions assisted by flowing a brine solution in counter-current mode through the permeate side. Calculations show that membrane area requirements for high solute concentrations could be reduced by combining RO with osmotic dehydration. The area requirements are sensitive to salt concentration polarization on the permeate side, particularly when low feed pressures are used. It appears feasible to design membranes/modules with low enough values of permeate side concentration polarization to enable effective feed solution concentration

Basic investigation of integrating a membrane unit into high-pressure decaffeination processing

Abstract Within the large-scale industrial decaffeination processes using supercritical CO 2 , caffeine is stripped from the extracting agent CO 2 with water using a high-pressure washing tower. On account of the value of the product, the caffeine is recovered from the washwater with a distillation–crystallization process. A reverse osmosis membrane process appears to be very suitable to replace the energy consuming distillation step to recover the caffeine and supply a cleaned water stream to be returned to the washing tower. Although this combination of a membrane process with high-pressure extraction was suggested earlier, very little fundamental work and experimental data have been published so far. The presented study is concentrated on basic investigations of this process. The osmotic pressure of aqueous caffeine solutions was determined with cryoscopy and additional membrane experiments. Membrane test cells were used to study the maximum separation of binary caffeine–water solutions. The influence of temperature, pressure and caffeine concentration on membrane flow and rejection was investigated for commercially available RO flat sheet membranes. The results show that RO concentration of aqueous caffeine solutions is feasible with moderate pressures and temperatures up to 60°C. Additional experiments with a non-optimized plate module supplemented the investigation of separation performance with approximately 50% of the test cell flux. Flux measurements with an agitated membrane cell show that the permeation of water with high CO 2 concentrations impairs membrane performance. A reverse osmosis washwater recycling process should flash the washwater to atmospheric pressure before the membrane unit.

Effects of Drying on Chemical and Physical Characteristics of American Ginseng (Panax quinquefolius L.)

ABSTRACT The influence of air moisture content and temperature of the drying chamber on the color, major carbohydrates, and ginsenosides of Panax quinquefolius L. was investigated in 1994, and 1995. Increasing the rate of air moisture-reduction in the drying chamber (from an initial vapor pressure deficit (VPD) of 1.0 kPa to a final VPD of 4.0 kPa) from 264 h to 48 h had no effect on the chemical characteristics of ginseng and reduced drying time (to 8 percent moisture content) by only 38 h. The most efficient drying occurred with air moisture content reduced to about the 4.0 kPa VPD level in 48 h. Raising the drying temperature from 32° to 44°C reduced tissue drying time to 8 percent moisture content by 91.4 h, darkened root color, reduced concentrations of the malonyl-ginsenosides mRb1, mRb2, mRc, mRd and the neutral ginsenosides Re and Ro, and increased the concentration of gypenoside XVII. Ginsenosides Rb1, Rc, Rd and Rg1 were not affected by drying temperature. Ro and sucrose concentration in tissue increased and starch decreased as drying temperature was reduced from 38° to 32°C. Optimum temperature for drying ginseng was 38°C.

Protein kinase A regulation of cAMP phosphodiesterase expression in rat skeletal myoblasts.

We have been studying cAMP signaling in L6 myoblasts because of its potential role in regulating the differentiation of these cells into multinucleate myotubes. Previous studies have shown that treatment of L6 myoblasts with cAMP analogs causes an increase in cAMP phosphodiesterase activity. To assess the role of protein kinase A in this cAMP-mediated increase in cAMP phosphodiesterase activity, L6 myoblasts were transfected with a plasmid containing the cDNA for a mutant regulatory subunit of protein kinase A, which functions as a dominant negative inhibitor of this enzyme. The cDNA was under control of the metallothionein promoter in the construct. Induction of the mutant regulatory subunit with Zn2+ decreased cAMP-dependent protein kinase activity by 90%. Zn2+ treatment was also able to completely block the cAMP-mediated increase in phosphodiesterase activity, showing that this effect is mediated by protein kinase A. The activity of the cAMP-induced phosphodiesterase was inhibited by low concentrations of RO 20-1724, showing that it was a member of the type IV low Km cAMP phosphodiesterase family of enzymes. We used the polymerase chain reaction and consensus primers designed to amplify phosphodiesterase sequences to show that L6 myoblasts also contain mRNA for a type IV low Km cAMP phosphodiesterase designated PDE3.1. The levels of this mRNA were increased greatly by treatment with dibutyryl cAMP or forskolin in L6 myoblasts and also in differentiated L6 myotubes. Run-off transcription assays showed that this increase in PDE mRNA was regulated, at least in part, by an increase in the rate of transcription of the PDE3 gene. The induction of PDE3 message by cAMP was blocked when the L6 transfectants were treated with Zn2+ to induce protein kinase A inhibition. Therefore, some of the cAMP-mediated increase in phosphodiesterase activity seen in L6 myoblasts is due to a protein kinase A-mediated increase in PDE3 mRNA. This pathway may serve as a feedback mechanism to modulate the inhibitory effects of cAMP on myogenesis.

Ionic conductivity in a network of silicate glasses: Extension of a previous model to three-component glasses

In this paper we describe the ionic conductivity in silicate glasses by using equations which include non-linear behaviour as a function of ionic concentration. We analyzed binary-alkali silicate glasses, PbOSiO 2 and three-component glasses, namely Na 2OROSiO 2 (R = Mg, Zn, Ca, Pb, Sr, Ba). The alkali concentration varied in the molar concentration 15–35%, while in the case of three-component glasses the ratio between RO and Na 2O concentrations ranged from 0.1 to 3.1. Taking into account that the analyzed experimental results refer to a wide temperature (300 K < T < 900 K) and concentration ranges, the obtained theoretical agreement is satisfactory.

In vitro activity of RO 23-6240 (AM-833): A new fluoroquinolone

The in vitro activities of RO 23-6240 (AM-833) and four comparative fluoroquinolones were studied. Minimal inhibitory concentrations (MICs) of RO 23-6240, which inhibited at least 90% of strains, were ⩽0.03–1 μmg/ml for Staphylococcus aureus , Staphylococcus epidermidis , Enterobacteriaceae , Acinetobacter anitratus Aeromonas hydrophila , Branhamella catarrhalis , and Haemophilus influenzae , 2–8 μg/ml for Staphylococcus saprophyticus , streptococci, diphtheroids, and Pseudomonas spp., and 1–32 μg/ml for anaerobic species. MICs of ofloxacin, pefloxacin, norfloxacin, and ciprofloxacin paralleled those of RO 23-6240. With all five drugs, MICs were minimally affected by inoculum size and minimal bacterial concentrations (MBCs) were always within two dilution steps (log z) of MICS.

耐２‐プロパノン（アセトン）性逆浸透膜の開発研究

Reverse osmotic concentration of aqueous 2-propanone (acetone) solutions was carried out, using cellulose acetate membranes and composite membranes (PEC-1000, FT-30 and NS-100). Separation of acetone and flux through the membranes were measured within the following ranges : concentration of acetone (C1) = 1 to 10wt% and operating pressure (ΔP) = 4-7MPa.PEC-1000 gave the best acetone separation. Its separation was above 90%. However, pure water permeation flux after experiment was reduced to the one-tenth of the initial value, remaining the same salt rejection, because of the degradation of support membrane.The acetone-proof composite RO membranes (ON membranes) of which support membrane was polyimide OF membrane were prepared. Separation of acetone and flux through the ON membranes were measured at the following conditions : C1 = 1 and 2wt% and ΔP = 1.96MPa.The permeation fluxes after experimemt remained unchanged for ON membranes.Membrane constants were calculated by Spiegler-Kedem's membrane transport model. The deviation from their model was corrected by the compaction coefficients.The estimated acetone separation for ON membrane was almost the same as the experimental value obtained for NS-100 P3500 membrane. The estimated flux was about 6 times larger than that for PEC-1000.Its separation and flux through the ON membrane (1wt% aqueous acetone solution RO concentration at 5.5MPa) was 92%, 0.25mol·m-2, s-1, respectively.

PHARMACOKINETICS AND EFFICACY OF ONCE DAILY CEFTRIAXONE

Because of its spectrum and prolonged half-life ceftriaxone (RO) has been shown to be particularly useful in the treatment of pediatric infections including meningitis. In the United States it has been administered twice daily and the major side effect encountered has been diarrhea. RO 50mg/kg, administered once daily, was used to treat 18 non-meningitic infections in children aged 2.5 M to 13 yr. Etiologic agents included Staphylococcus aureus (9), Streptococcus pyogenes (8), non-enterococcal group D Streptococcus (1), Hemophilus influenzae b (3) (1 ampicillin resistant), Klebsiella pneumoniae (2), E. coli (2), Proteus vulgaris (1). Several patients had 2 organisms isolated. Infections seen included cellulitis (13)-periorbital (3), septicemia (2), urinary tract infections (4), epiglottitis (1). One patient had both a UTI and septicemia. Duration of therapy ranged from 5 to 9 days. The mean plasma RO concentrations obtained one hour after and within one hour before a dose were 193.8 ± 101μg/ml and 8.6 ± 6μg/ml. The mean half-life was 5.13 h ± 1.05. All patients had trough RO concentrations ⩾ 3.4μg/ml exceeding the minimal inhibatory concentration of the infecting organism. All patients were cured. No patients developed diarrhea although 2 patients had eosinophilia, 2 thrombocytosis and 3 elevated transaminases. Ceftriaxone appears safe and effective when used at the lower dose of 50mg/kg administered once daily to treat infections with susceptible organisms.

ChemInform Abstract: THE KINETICS OF THE INTERACTION OF PEROXY RADICALS. I. THE TERTIARY PEROXY RADICALS

Existing data on the self-reactions of tertiary peroxy radicals RO2 has been reanalyzed and corrected to deduce Arrhenius parameters for both termination and nontermination paths. For R = t-Butyl, these are logkt(M−1sec−1) = 7.1 - (7.0/θ) and logknt(M−1sec−1) = 9.4 - (9.0/θ), respectively, different from those recommended by other authors. The higher magnitudes observed for termination processes of tertiary peroxy radicals like those of cumyl and 1,1-diphenylethyl have been discussed in terms of a much greater cage recombination of cumyloxy radicals as contrasted with t-butoxy radicals. It is shown that for benzyl peroxy radicals, the R—O bond dissociation energy is sufficiently low (18–20 kcal) that reversible dissociation into R˙ + O2 opens a competing second-order path to fast recombination R˙ + RO ROOR. This path is probably not important for cumyl peroxy radicals under usual experimental conditions but can become important for 1,1-diphenyl ethyl peroxy radicals at (O2) < 10−3M. At very low RO concentrations (<10−5M), in the absence of added O2, an apparent first-order disappearance of RO can occur reflecting the rate determining breaking of the cumyl—O bond followed by the second step above. The thermochemistry of RO is used to show that the reaction of R2O4 2RO + O2 must be concerted and cannot proceed via RO which is too unstable and cannot form even from RO˙ + O2.

Free-Radical Oxidants in Natural Waters

Photooxidation of cumene (isopropylbenzene) and pyridine in dilute solution in natural waters gives products characteristic of reactions with alkylperoxy (RO(2).) and hydroxyl (HO.) radicals. On the basis of the rates of formation of the products, the average concentrations of RO(2). and HO. are estimated to be about 10(-9) and 10(-17) mole per liter, respectively. The concentration of RO(2). is large enough that, for some classes of reactive chemicals, oxidation can be an important process in natural waters.

The kinetics of the interaction of peroxy radicals. I. The Tertiary Peroxy Radicals

AbstractExisting data on the self‐reactions of tertiary peroxy radicals RO2 has been reanalyzed and corrected to deduce Arrhenius parameters for both termination and nontermination paths. For R = t‐Butyl, these are logkt(M−1sec−1) = 7.1 ‐ (7.0/θ) and logknt(M−1sec−1) = 9.4 ‐ (9.0/θ), respectively, different from those recommended by other authors. The higher magnitudes observed for termination processes of tertiary peroxy radicals like those of cumyl and 1,1‐diphenylethyl have been discussed in terms of a much greater cage recombination of cumyloxy radicals as contrasted with t‐butoxy radicals. It is shown that for benzyl peroxy radicals, the R—O bond dissociation energy is sufficiently low (18–20 kcal) that reversible dissociation into R˙ + O2 opens a competing second‐order path to fast recombination R˙ + RO → ROOR. This path is probably not important for cumyl peroxy radicals under usual experimental conditions but can become important for 1,1‐diphenyl ethyl peroxy radicals at (O2) &lt; 10−3M. At very low RO concentrations (&lt;10−5M), in the absence of added O2, an apparent first‐order disappearance of RO can occur reflecting the rate determining breaking of the cumyl—O bond followed by the second step above. The thermochemistry of RO is used to show that the reaction of R2O4 → 2RO + O2 must be concerted and cannot proceed via RO which is too unstable and cannot form even from RO˙ + O2.

Surface Tension, Density, Viscosity, and Electrical Resistivity of Molten Binary Alkaline‐Earth Borates

Results of an investigation of some properties of the systems CaO‐B2O3, SrO‐B2O3, and BaO‐B2O3 are reported. The formation of two liquids at low RO concentrations limited the range of compositions which could be measured. The values of surface tension and temperature coefficient of surface tension obtained for compositions where two immiscible liquids exist corresponded closely to those for pure B2O3. At RO concentrations above the two–liquid regions the surface tension rose sharply with increasing RO content. The densities in the liquid range as well as at room temperature were in the order Ba &gt; Sr &gt; Ca. The introduction of RO into B203 caused contractions in the glass network; the order of the contracting effect was Ca &gt; Sr &gt; Ba. Neither the method of Huggins or of Stevels was satisfactory for representing the density behavior of these glasses. The viscosity isotherms of barium borate liquids in the temperature range 850° to 950°C. showed maxima at about 22 to 23 mole yo BaO; the other two systems were too fluid for the counterbalanced sphere apparatus used in this work. The equivalent conductance increased with RO concentration; the order for both specific and equivalent conductance at corresponding concentrations was Ba &gt; Sr &gt; Ca.