Biodegradation of toluene at high initial concentration in an organic–aqueous phase bioprocess with nitrate respiration

2010 ◽  
Vol 45 (11) ◽  
pp. 1758-1762 ◽  
Author(s):  
Mehrdad Farhadian ◽  
David Duchez ◽  
Geneviève Gaudet ◽  
Christian Larroche
Keyword(s):  
Aqueous Phase ◽  
Nitrate Respiration ◽  
Initial Concentration ◽  
High Initial Concentration

Extraction of hafnium(IV) with organophosphorus reagents from solutions of mineral acids mixtures

1979 ◽  
Vol 44 (12) ◽  
pp. 3656-3664
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola ◽  
Rostislav Kolouch
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Synergic Effect ◽  
Salting Out ◽  
Initial Concentration ◽  
Mixed Complexes ◽  
Synergic Extraction ◽  
Mineral Acids

Extraction of hafnium(IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids for constant ionic strength, I = 2, 4, 6, or 8, and for cHf 4 . 10-4 mol l-1. The organic phase was constituted by solutions of some acidic or neutral organophosphorus reagents or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. A pronounced synergic extraction of hafnium proceeds only on applying organophosphorus reagents from an aqueous phase whose acidity is not lower than 3M-(HClO4 + HNO3) or 5M-(HClO4 + HCl). The synergic effect was not affected markedly by a variation of the initial concentration of hafnium in the range 1 . 10-8 -4 .10-4 mol l-1, it lowered with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H+ ions. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.

Glomerular uracil nucleotide synthesis

1988 ◽  
Vol 255 (4) ◽  
pp. F635-F646 ◽  
Author(s):  
P. Cortes ◽  
F. Dumler ◽  
N. W. Levin
Keyword(s):  
Protein Glycosylation ◽  
Rapid Rate ◽  
Membrane Material ◽  
Nucleotide Synthesis ◽  
Initial Concentration ◽  
High Initial Concentration ◽  
Uracil Nucleotide ◽  
Sugar Derivatives ◽  
Derivatives Of

The biosynthesis of basement membrane material requires the sugar derivatives of uridine 5'-triphosphate (UTP) for protein glycosylation. Uridine and orotate utilization for the biosynthesis of uracil ribonucleotides was studied in isolated rat glomeruli incubated in vitro. At a 1 microM concentration total orotate utilization was 9.6 +/- 1.8 pmol.min-1.mg DNA-1 (1 mg DNA approximately 0.175 X 10(6) glomeruli), 51% of the total amount metabolized was used in ribonucleotide formation, and there was a significant UTP accretion. Except at a high initial concentration (50 microM), exogenous uridine failed to increase the UTP pool due to rapid uridine breakdown by a cytosolic phosphorylase. Inhibition of this enzyme with benzylacyclouridine resulted in increased biosynthesis and accretion of UTP, and in a 17-fold higher concentration of uridine, primarily produced from performed sources of nucleosides. Continuous addition of exogenous uridine to maintain its concentration at 1 microM resulted in a total uridine utilization of 550 +/- 30 pmol.min-1.mg DNA-1. Uridine salvage for ribonucleotide biosynthesis was only 3% of the total metabolized. In contrast to uridine, and presumably due to UTP pool compartmentation, orotate incorporation into uridine 5'-diphosphosugars was prominent. The metabolism of exogenous orotate was not decreased by the presence of large amounts of uridine and by an expanded UTP pool. It is concluded that when exogenous orotate is present, it is an important precursor for glomerular uracil ribonucleotide biosynthesis. Due to its rapid rate of catabolism, uridine cannot maintain ribonucleotide biosynthesis at a rate sufficient to result in UTP accretion unless it is provided continuously in substantial quantities.

Copper(II)-promoted solvolyses of nickel(II) complexes. III. Tetradentate Schiff base ligands containing various diamine segments

1973 ◽  
Vol 26 (7) ◽  
pp. 1475 ◽  
Author(s):  
WW Fee ◽  
JD Pulsford
Keyword(s):  
Schiff Base ◽  
Nickel Complex ◽  
Ligand Substitution ◽  
Steric Effects ◽  
Schiff Base Ligands ◽  
Initial Concentration ◽  
Tetradentate Schiff Base ◽  
High Initial Concentration ◽  
Leaving Groups ◽  
Complex Ligand

The large variations in the rates of the copper(II)-promoted solvolyses of various nickel(II) complexes, containing Schiff base ligands with varying diamine substituents, is attributed to steric effects. The important rate differences occur for reactants whose stereochemistries and electronic properties appear little different. However, the steric effects cannot be viewed definitely from either nickel-diamine dissociation or copper-diamine formation. Nickel reactants which may be distorted from planarity give trimeric products on reaction with copper in dmso and dmf, if the reactions are carried out at high initial concentration ratios of copper(II) to nickel complex. Ligand substitution studies indicate a differing reactivity sequence for the diamine-substituted ligands in their capacities as entering, compared to leaving, groups.

Removal of Oil Using Activated Carbon from Textile Sludge Biochars

2016 ◽  
Vol 818 ◽  
pp. 237-241
Author(s):  
Khairunissa Syairah Ahmad Sohaimi ◽  
Norzita Ngadi
Keyword(s):  
Waste Water ◽  
Activated Carbon ◽  
Oil Pollution ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Initial Concentration ◽  
Equilibrium Time ◽  
High Initial Concentration ◽  
Textile Sludge ◽  
Oil Wastewater

The study of oil pollution is crucial nowadays and considered as one of the critical issues as oil pollution gives bad effects especially to wastewater treatment facilities. For that purpose, this study investigated the potential of activated carbon from biochars of textile sludge precursors for oil removal. The activated carbons were produced from biochar obtained through the pyrolysis of textile sludge waste by chemical activation with 1M of phosphoric acid which denoted as AC-B-H3PO4. Apart from that, the performance of adsorptive properties of the activated carbon was tested using simulated cooking oil waste water in homogeneous form as the targeted adsorbate. The effect of adsorption contact time and initial concentration of simulated oil wastewater towards performances of AC-B-H3PO4 in removal of simulated oil wastewater were studied and compared with biochars700. The equilibrium time in adsorption of the simulated oil wastewater for both biochar700 and AC-B-H3PO4 was obtained in 30min. Meanwhile, the effects of initial concentration of simulated oil wastewater, biochars700 has earlier achieved equilibrium at 300mg/l up to 500 mg/l, while for AC-B-H3PO4, the adsorption capacity still increase at a high initial concentration of simulated oil waste water but in a slow rate. The results obtained showed that AC-B-H3PO4 has more potential for oil spills treatment than biochars due to its ability to treat the high initial concentration of simulated oil wastewater at the equilibrium time. The findings also provide for an alternative for low cost and effective adsorbent for the oil pollution treatment.

scholarly journals Synthesis and Application of Fe‑BTC Nanocomposites as Highly Efficient Photocatalysts in the Dye Degradation

2020 ◽  
Vol 9 (3) ◽  
pp. 63-68
Author(s):  
Manh Nguyen Ba ◽  
Tuan Vu Anh ◽  
Giang Le Ha
Keyword(s):  
Removal Efficiency ◽  
Dye Degradation ◽  
Ultrasonic Method ◽  
High Surface ◽  
High Surface Area ◽  
Reactive Dye ◽  
High Photocatalytic Activity ◽  
The Sustainable Development ◽  
Initial Concentration ◽  
High Initial Concentration

Nano Fe-BTC composites were successfully synthesized by hydrothermal treatment with an ultrasonic method. Samples were characterized by XRD, FTIR, BET, SEM, EDS, and XPS. SEM result showed nano Fe-BTC particles size of 10-30 nm. Nano Fe-BTC showed the high surface area (1258 m2/g) and pore volume (0.99 cm3/g). Fe-BTC nanocomposites were tested for the photocatalytic degradation of reactive dye (reactive yellow RY-145) in aqueous solution. Fe-BTC composites exhibited high photocatalytic activity. Thus, at the pH of 6.5 and the high initial concentration of 100 mg RY-145/L, removal efficiency reached the value of 98.13% after 60 min. of reaction. Moreover, nano Fe-BTC also showed high RY-145 removal efficiency after 3 catalytic regeneration. This contributes to the sustainable development and green chemistry.

scholarly journals Distribution of benzalkonium chloride into the aqueous phases of submicron dispersed systems: emulsions, aqueous lecithin dispersion and nanospheres

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Dorota Watrobska–Swietlikowska
Keyword(s):  
Aqueous Phase ◽  
Benzalkonium Chloride ◽  
Microbial Growth ◽  
Total Concentration ◽  
Active Form ◽  
Polysorbate 80 ◽  
Micellar Phase ◽  
Initial Concentration ◽  
Dispersed Systems ◽  
Submicron Emulsions

AbstractPartitioning of benzalkonium chloride (BAC) into the aqueous phases of submicron dispersed systems such as submicron emulsions, aqueous lecithin dispersion (WLD), and suspension of nanospheres (NLC) was studied. The aqueous phases of the investigated systems were obtained by ultracentrifugation and subsequently were subjected to ultrafiltration, which procedure allowed distinguishing between the fractions of free benzalkonium chloride (w) and those incorporated in the liposomal and micellar region (wlm). The fractions present in the oily phase and in the interphase of submicron emulsions were calculated. Despite the various composition of the investigated formulations and the initial concentration of BAC, w values were very small at 0.2–8.0%. The wlm value in submicron emulsions was increased by increasing the total concentration of preservative from 29.0 to 42.0%. Using polysorbate 80 instead of lecithin resulted in a distribution of BAC to aqueous–liposomal–micellar phase that was twice as high. The very low concentration of antimicrobial active form of benzalkonium chloride was analyzed in the aqueous phase of emulsions stabilized with lecithin as well as in aqueous lecithin dispersion and nanospheres (below 3%). Replacement of lecithin with polysorbate 80 in emulsions with polysorbate significantly increase (up to 8%) the fraction of benzalkonium chloride in the aqueous phase where microbial growth occurs.

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