scholarly journals ZSM-5 Filled Polyether Block Amide Membranes for Separating EA from Aqueous Solution by Pervaporation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Jin Gu ◽  
Xinran Zhang ◽  
Yunxiang Bai ◽  
Le Yang ◽  
Chunfang Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ethyl Acetate ◽  
Separation Factor ◽  
The Other ◽  
Total Flux ◽  
Feed Concentration ◽  
Similar Variation ◽  
Other Hand

ZSM-5 filled polyether block amide membranes (PEBA), PEBA/ZSM-5, were prepared and used to recover aroma, ethyl acetate (EA), from aqueous solution by pervaporation (PV). The membranes demonstrated high EA permselectivity, and with the increase of ZSM-5 loading, the separation factor increased initially and then decreased, while the total flux demonstrated the similar variation until the ZSM-5 loading was 10 wt%, at which it reached the lowest value. After that, it began to increase again. On the other hand, the separation factor, and total flux of the PEBA/ZSM-5 membrane containing 10 wt% ZSM-5, PEBA/ZSM-5-10, increased with the increase of feed concentration and temperature. The best PV performance, separation factor and total flux of PEBA/ZSM-5-10 membrane were 185.5 and 199.5 gm−2h−1, respectively, with feed concentration of 5 wt% EA at 50°C.

Synthesis of ZrO2 Nanotubes by Anodization of Zr Foil

2015 ◽  
Vol 799-800 ◽  
pp. 125-129
Author(s):  
Mary Donnabelle L. Balela ◽  
April Alexa S. Lagarde ◽  
Stephen Jann A. Tamayo ◽  
Nikko S. Villareal ◽  
Ann Marielle Parreno
Keyword(s):  
Aqueous Solution ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Preparation ◽  
The Other ◽  
Preparation Methods ◽  
X Ray ◽  
Anodization Time ◽  
Other Hand ◽  
Scanning Electron

Zirconia (ZrO2) nanotubes were synthesized by anodization of zirconium (Zr) foil in NH4Fand (NH4)2SO4 aqueous solution. Different surface preparation methods (electropolishing and etching) were applied on the Zr foil prior to anodizaton. In addition, the anodization time and NH4F concentration were varied. The structure and morphologies of the nanotubes and their crystallinity were confirmed using scanning electron microscope and x-ray diffractometer, respectively. ZrO2 nanotubes with large diameters and thick walls were formed at lower NH4F concentration and longer anodization time. On the other hand, smaller nanotubes with thinner walls were produced when the NH4F concentration was increased. The synthesized nanotubes were predominantly tetragonal ZrO2 with small amounts of monoclinic ZrO2.

scholarly journals VTOS Cross-Linked PDMS Membranes for Recovery of Ethanol from Aqueous Solution by Pervaporation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jin Gu ◽  
Yunxiang Bai ◽  
Lin Zhang ◽  
Lirong Deng ◽  
Chunfang Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Separation Factor ◽  
Pdms Membrane ◽  
Total Flux ◽  
Cross Linking ◽  
High Separation Factor ◽  
Ethanol Aqueous Solution ◽  
High Ethanol ◽  
Feed Temperature ◽  
High Separation

PDMS membranes were prepared by cross-linking with vinyltriethoxysilane (VTOS) on polyacrylonitrile (PAN) substrate to increase hydrophobicity and improve pervaporation (PV) performance. It was shown that the membranes had high ethanol permselectivity and flux. The effects of cross-linking temperature, the content of cross-linking agent, and feed temperature on PV performance of VTOS cross-linked PDMS membranes were investigated. For 6 wt% ethanol aqueous solution, the PDMS membrane had the high separation factor of 15.5 and total flux 573.3 g·m−2·h−1, respectively, when the feed temperature was 40°C, H-PDMS : VTOS : DBTDL = 1 : 0.2 : 0.02 and cross-linking temperature was 80°C.

X-IRRADIATION OF RIBOSE AND DEOXYRIBOSE DERIVATIVES

1962 ◽  
Vol 40 (1) ◽  
pp. 1553-1565
Author(s):  
D. K. Myers
Keyword(s):  
Aqueous Solution ◽  
Nucleic Acids ◽  
The Other ◽  
Free Sugar ◽  
Blood Samples ◽  
Other Hand ◽  
Dilute Aqueous Solution ◽  
X Irradiation ◽  
In Cells

During X-irradiation of ribosides and deoxyribosides in dilute aqueous solution, purine and sugar moieties were destroyed at approximately the same rate. Pyrimidine moieties, on the other hand, were destroyed more rapidly, resulting in a fairly rapid liberation of free sugar during irradiation of pyrimidine ribosides or deoxyribosides. No marked differences in the rates of destruction of ribose and deoxyribose derivatives were observed in these experiments.Similar reactions were observed during irradiation of blood samples. However, acid-soluble ribonucleotides in the blood proved to be much more sensitive than the nucleic acids or proteins to destruction by X-radiation. The significance of these findings is discussed with relation to the damage produced in cells by X-irradiation.

Octahedral cobalt(III) complexes of the chloropentammine type. XXI. The preparation, properties, and reactions of some Chloro(amine)bis(ethylenediamine)cobalt(III) salts containing unidentate glycinenitrile and glycinamide as influencing ligands

1970 ◽  
Vol 23 (6) ◽  
pp. 1175 ◽  
Author(s):  
SC Chan ◽  
FK Chan
Keyword(s):  
Aqueous Solution ◽  
Pure State ◽  
The Other ◽  
Base Hydrolysis ◽  
Other Hand ◽  
Kinetics Of

Salts of one isomeric series of chloro(amine)bis(ethylenediamine)cobalt(111) type of cations have been prepared from trans-dichlorobis(ethy1enediamine)-cobalt(111) chloride by replacing one of its chloro ligands with either glycinenitrile or glycinamide. These complexes have been assigned a cis-configuration on the basis of spectral observations. For the glycinenitrile system, the cis-chloro(cyano-methylamine)bis(ethylenediamine)cobalt(111) cation rearranges to the trans-chloro(aminoacetonitrile) isomer in aqueous solution at rates very much higher than those for the aquation of both forms. This isomerization is retarded by acid and accelerated by base. The kinetics of base hydrolysis are also reported. On the other hand, for the glycinamide system, the corresponding isomerization proceeds at rates comparable to those of chloride release, the latter leading to the formation of the chelated N,O-glycinamidebis(ethylenediamine)cobalt(111) species. Consequently, it has not been possible to isolate the other linkage isomer in the pure state. Furthermore, although the aquo(glycinamide)bis(ethylenediamine)cobalt(111) species is not formed in non-basic spontaneous chloride release, its hydroxo counterpart can be readily obtained by base hydrolysis. The mechanistic implications of these observations are discussed.

scholarly journals Papillary Variation in Coliform Bacteria

1941 ◽  
Vol 41 (5-6) ◽  
pp. 497-508 ◽  
Author(s):  
F. H. Stewart
Keyword(s):  
Neutral Red ◽  
The Other ◽  
Coliform Bacteria ◽  
Short Exposure ◽  
Logarithmic Phase ◽  
Liquid Media ◽  
Similar Variation ◽  
Short Summary ◽  
Other Hand

Papillaryvariation includes all heritable changes of character which take place in the papillae of bacterial colonies and the corresponding variations in liquid media.The following is a short summary of what is known about these variations. Papillary variation was first observed inB. coli-mutabile, and other coliform bacteria show the same variations. This race forms white colonies on lactose neutral-red plates. After 1–5 days’ incubation minute papillae, which become red and increase in size, appear on their surfaces. Subcultures from thesepapillae give colonies of two kinds, white and red. The white colonies continue to throw red, the reds breed true (Neisser, 1906; Massim, 1907). Similar variation to different sugars occurs in other related bacteria:B. dysentenaeSonne varies to lactose,B. dysentenaeMexner to maltose,B. paracolonto saccharose,B. coh-mutabile, B. acidi-lacticiandB. typhosusto dulcite (Twort, 1907; Reiner Miiller, 1909; Burn, 1910; Stewart, 1926, 1927). Vacation takes place only on the sugar concerned, but, once it has taken place, the character remains fixed, even after long growth on other media. Variation is not determined by length of exposure to the sugar. It occurs at (or after) the end of the logarithmic phase. If this phase is kept going by daily subculture (in the appropriate sugar) the bacteria of the chain carried on from culture to culture do not vary, however long they are exposed (Stewart, 1927; Deere, Dulaney & Michelson, 1939). On the other hand, if the logarithmic phase is curtailed by heavy inoculation of a culture, variation occurs early (Stewart, 1927). If the bacterium is grown on a plate without sugar until the colonies are well formed and the sugar is then added, with care not to disturb the colonies, variants appear after very short exposure (Stewart, 1927, 1928). A variation 33–2 may be completed in, two distinct steps; thus a race ofB. typhosusformed white colonies on dulcite with pink papillae, subcultures from which gave white and pink colonies; the pink colonies formed dark red papillae from which on subculture came pink and dark red colonies, the latter bred true.

X-IRRADIATION OF RIBOSE AND DEOXYRIBOSE DERIVATIVES

1962 ◽  
Vol 40 (11) ◽  
pp. 1553-1565 ◽  
Author(s):  
D. K. Myers
Keyword(s):  
Aqueous Solution ◽  
Nucleic Acids ◽  
The Other ◽  
Free Sugar ◽  
Blood Samples ◽  
Other Hand ◽  
Dilute Aqueous Solution ◽  
X Irradiation ◽  
In Cells

During X-irradiation of ribosides and deoxyribosides in dilute aqueous solution, purine and sugar moieties were destroyed at approximately the same rate. Pyrimidine moieties, on the other hand, were destroyed more rapidly, resulting in a fairly rapid liberation of free sugar during irradiation of pyrimidine ribosides or deoxyribosides. No marked differences in the rates of destruction of ribose and deoxyribose derivatives were observed in these experiments.Similar reactions were observed during irradiation of blood samples. However, acid-soluble ribonucleotides in the blood proved to be much more sensitive than the nucleic acids or proteins to destruction by X-radiation. The significance of these findings is discussed with relation to the damage produced in cells by X-irradiation.

SUPPLEMENTARY NOTE TO THE SATURNIANS

1895 ◽  
Vol 27 (11) ◽  
pp. 316-316
Author(s):  
A. Radcliffe Grote
Keyword(s):  
Outer Margin ◽  
The Other ◽  
South American ◽  
Supplementary Note ◽  
The South ◽  
Similar Variation ◽  
Other Hand ◽  
Distinct Genus ◽  
Asiatic Species

Since writing my paper (Can. Ent., 263, ante) I have been able to examine a specimen of the Asiatic A. selene. The moth differs from luna, chiefly in the pointed apices of fore wings, the outer margin sweeping inwardly in an even curve. I cannot consider this character of generic value, since precisely the same separates the South American Eacles magnifica from our E. imperialis. In the same species of certain Papilionides, a similar variation has been noted. The exterior bands appear faintly also in certain examples of luna, while the whiter colour is shown by the variety Rossi. Whether this tendency to white is reversionary in its nature, may be questioned. The tails are more developed in the Asiatic species, but (without denuding) I cannot find any neurational differences. I conclude, then, that Leach's term Actias is also applicable to A. luna. On the other hand, the European isabellœ seems to admit of a distinct genus.

Synthesis of 2-Acetoacetyl- and 2-OxaIoacetyl-1,3-indandiones and Related Compounds

1988 ◽  
Vol 43 (7) ◽  
pp. 897-900 ◽  
Author(s):  
W. S. Hamama ◽  
M. Hammouda ◽  
E. M. Afsah
Keyword(s):  
Ethyl Acetate ◽  
Mannich Reaction ◽  
Selenium Dioxide ◽  
The Other ◽  
Molar Ratio ◽  
Diethyl Oxalate ◽  
Phenyl Hydrazine ◽  
Claisen Condensation ◽  
Other Hand ◽  
Related Compounds

Abstract Claisen condensation of 2-acetyl-1,3-indandione (1) with ethyl acetate afforded the 2-acetoacetyl-1,3-indandione (2) which upon treatment with benzylamine and paraformaldehyde in a molar ratio of (1:1:2) and (1:2:4) afforded the piperidinone and the diazabicyclic derivative (4) and (5) respectively. On the other hand, Claisen condensation of 1 with diethyl oxalate yielded two products (6) and (9). The behaviour of 6 towards phenyl hydrazine, and of 9 towards selenium dioxide and double Mannich reaction were also investigated.

STEROIDS AND RELATED PRODUCTS: XIX. THE SYNTHESIS OF 3,9,12,20-TETRAOXYGENATED 9,12-seco STEROIDS. PART III. 11-AZA STEROIDS. PART I

1962 ◽  
Vol 40 (11) ◽  
pp. 2153-2162 ◽  
Author(s):  
Ch. R. Engel ◽  
S. Rakhit
Keyword(s):  
Methyl Ester ◽  
Ethylene Glycol ◽  
Ethyl Acetate ◽  
Good Yield ◽  
Boron Trifluoride ◽  
Osmium Tetroxide ◽  
Periodic Acid ◽  
Boron Trifluoride Etherate ◽  
The Other ◽  
Other Hand

The smooth conversion of 3β-acetoxy-5α-pregnane-12,20-dione (IV), readily available from hecogenin (I), to Δ9(11)-3β,20β-diacetoxy-5α-pregnan-12-one (VIII) is reported. Ozonolysis of this product in ethyl acetate gave, in almost 90% yield, 3β-hydroxy-20β-acetoxy-9-oxo-9,12-seco-11-nor-5α-pregnan-12-oic acid (XI), further characterized by its ester derivatives XIa and XIb. The conversion of the seco acid XI to Δ8(9)-3β-hydroxy-20β-acetoxy-9-amino-9,12-seco-11-nor-5α-pregnen-12-oic acid lactam (12 → 9) (XII) and thence to Δ8(9)-N-acetyl-3β,20β-diacetoxy-11-aza-5α-pregnene (XIVa), the first 11-aza steroids to be known, is described. On the other hand, Δ9(11)-3β,20β-diacetoxy-5α-pregnen-12-one (VIII) is readily transformed to the 9α,11α-glycol VII with osmium tetroxide and thence, with periodic acid, to 3β,9α-dihydroxy-20β-acetoxy-11-oxo-11,12-seco-5α-pregnan-12-oic acid (X), characterized as the methyl ester Xa and diacetoxy methyl ester Xb, and easily converted to the acetoxy hydroxy keto dicarboxylic seco acid XIII. In the course of this work it is shown that, whereas ketalization of the saturated 12,20-diketone IV with ethylene glycol and boron trifluoride etherate gives a good yield of the 12-monoketal (in accordance with the reports of the literature), treatment of the analogous 16-unsaturated 12,20-diketone with the same reagents under the same conditions leads not to ketal formation but to addition of ethylene glycol in position 16.

scholarly journals Study of Struvite Crystal Growth with The Addition of Tartaric Acid

2021 ◽  
Vol 328 ◽  
pp. 01003
Author(s):  
Dyah Suci Perwitasari ◽  
Sintha Soraya Santi ◽  
Stefanus Muryanto ◽  
J Jamari ◽  
AP Bayuseno
Keyword(s):  
Aqueous Solution ◽  
Crystal Growth ◽  
Tartaric Acid ◽  
Rate Constant ◽  
The Other ◽  
Molar Ratio ◽  
Other Hand ◽  
Constant Rate ◽  
Manufacture Industry ◽  
Crystal Mass

The purpose of this study was to study the growth of struvite crystals from the effect of adding tartaric acid additives to an aqueous solution containing Mg2+, NH4+, and PO43-with a molar ratio of 1:1:1. The results of the study, it was found that the more the concentration of tartaric acid additive was added, it got smaller the rate constant was. By decreasing the value of the constant rate, the growth of struvite crystals also decreased then the growth of struvite crystals became inhibited. On the other hand, struvite has the potential to be used as a fertilizer. The concentration of tartaric acid also had a significant effect on controlling the production of struvite. The optimum crystal mass was obtained at a concentration of 20 ppm tartaric acid, a temperature of 40oC and a stirrer rotation of 300 rpm so that it can be applied in manufacture industry of struvite fertilizer.

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