共查询到20条相似文献,搜索用时 15 毫秒
1.
Zheng-Lin Zhu 《Journal of surfactants and detergents》1998,1(2):251-252
The stability of NaOCl in the presence of aqueous flavoring essences (lemon, mint, osmanthus flowers, pineapple, and vanilla)
at 40±1°C was studied. Data from determination of OCl− showed: (i) The stability of NaOCl solution decreased in the presence of essences in the order: mint> lemon and osmanthus
flowers>pineapple>vanilla (P<0.01); (ii) OCl− loss with the addition of lemon after incubation for 15 d was significantly greater in solutions with initial pH of 13.50
compared with those initially at pH 12.50 (P<0.01); and (iii) OCl− loss was not significantly influenced by the difference in initial pH value with or without the addition of other essences. 相似文献
2.
José M. Aquino Romeu C. Rocha-Filho Nerilso Bocchi Sonia R. Biaggio 《Journal of Applied Electrochemistry》2010,40(10):1751-1757
The electrochemical degradation of the anthraquinonic dye Acid Blue 62 in a filter-press reactor on a Ti/Pt/β-PbO2 anode was investigated using the response surface methodology with the variables: current density, pH, [NaCl], and temperature.
The system’s modeling was carried out with the charge required for 90% decolorization (Q
90) and the chemical oxygen demand removal percentage after a 30 min electrolysis (COD
30), with good correlations between predicted and observed values. Best conditions for decolorization were attained in acidic
solutions (pH = 4) with medium to high [NaCl] (1.0–2.0 g L−1) and lower temperature due to the prevalent oxidant species HOCl and Cl2. Optimal conditions for COD
30 removal were attained at high current densities in pH > 5 solutions with high [NaCl], when the prevalent oxidant species
are HOCl and OCl−. The lowest charge per unit volume of the electrolyzed solution necessary for total mineralization was attained at pH 11. 相似文献
3.
Relationship of structure to properties of surfactants. 16. Linear decyldiphenylether sulfonates 总被引:1,自引:0,他引:1
Milton J. Rosen Zhen Huo Zhu Xi Yuan Hua 《Journal of the American Oil Chemists' Society》1992,69(1):30-33
The properties of some well-characterized sodium linear decyldiphenylether (C10DPE)sulfonates have been studied. Among the properties investigated are dynamic and equilibrium surface tension, critical
micelle concentration (CMC), area per molecule at the aqueous solution/air interface, wetting time by the Draves technique,
foaming by the Ross-Miles method, solubilization, and hydrotropy. The decyldiphenylether moiety appears to be equivalent to
a terminally substituted straight alkyl chain of 16 carbon atoms. The trialkyl- and dialkyl-mono-sulfonates have solubilities
of < 0.01 g/dm3 in water, but are readily soluble in hexane. The didecyldiphenyl ether disulfonate (DADS) has a very low CMC value (1.0 ×
10−5 mol dm−3) in aqueous 0.1 N Na+ solution (NaCl), characteristic of surfactants with two hydrophilic and two hydrophobic groups. It also has a much larger
area per molecule at the aqueous solution/air interface than the monodecyldiphenyl-ether monosulfonate (MAMS) and a much higher
surface tension at the CMC. MAMS has a much lower surface tension at a surface age of 1 second (γ1s) than either DADS or the monodecyldiphenylether disulfonate (MADS). In agreement with γ1s and γeq values, wetting times increase in the order: MAMS < DADS < MADS and initial foam heights decrease in the order: MAMS > DADS
> MADS. Solubilization for three water-insoluble surfactants decreases in the order: DADS > MAMS > MADS, while hydrotropy
is most pronounced with the disulfonates. 相似文献
4.
Sebnem Selen Isbilir Hakki M. Ozcan Hulya Yagar 《Journal of the American Oil Chemists' Society》2008,85(3):227-233
Lipase was isolated from bay laurel (Laurus nobilis L.) seeds, some biochemical properties were determined. The bay laurel oil was used as the substrate in all experiments.
The pH optimum was found to be 8.0 in the presence of this substrate. The temperature optimum was 50 °C. The specific activity
of the lipase was found to be 296 U mg protein−1 in optimal conditions. The enzyme activity is quite stable in the range of pH 7.0–10. The enzyme was stable for 1 h at its
optimum temperature, and retained about 68% of activity at 60 °C during this time. K
m
and V
max values were determined as 0.975 g and 1.298 U mg protein−1, respectively. Also, storage stability and metal effect on lipolytic activity were investigated. Enzyme activity was maintained
for 9, 12, and 42 days at room temperature, 4 and −20 °C, respectively. Ca2+, Co2+, Cu2+, Fe2+, and Mg2+ lightly enhanced bay laurel lipase activity. 相似文献
5.
Karanam Srinivasa Rao Shashi Anand Paladugu Venkateswarlu 《Korean Journal of Chemical Engineering》2010,27(5):1547-1554
Syzygium cumini L. leaf powder and Cd(II) loaded samples were characterized using FTIR and SEM techniques. The biosorption of cadmium ions
from aqueous solution was studied in a batch adsorption system as a function of pH, contact time, adsorbate, adsorbent, anion
and cation concentrations. The biosorption capacities and rates of transfer of cadmium ions onto S. cumini L. were evaluated. The kinetics could be best described by both linear and nonlinear pseudo-second order models. The isothermic
data fitted to various models in the order Freundlich>Redlich-Peterson>Langmuir>Temkin. The maximum adsorption capacity of
S. cumini L. leaves at room temperature was estimated to be 34.54 mg g−1. The negative values of ΔG0 indicated the feasibility of the adsorption process. The endothermic nature was confirmed by the positive value of the enthalpy
change (ΔH0=3.7 kJ mol−1). The positive value of entropy change (ΔS0=16.87 J mol−1 K−1) depicted internal structural changes during the adsorption process. 相似文献
6.
Pseudo two-dimensional finite element models were developed to predict the hypochlorite (chloric(I)) (HOCl + OCl−) production by electrolysis of near-neutral aqueous sodium chloride solution, in reactors with (a) an anode and cathode in
the form of plates, and (b) a lead dioxide-coated graphite felt anode and titanium plate cathode. The model was used to investigate
the feasibility of using a porous anode to achieve high single pass conversions in oxidising chloride ions. For the model
reactor with planar anode, the effects of diffusion, migration and convection on the mass transport of the reacting species
were considered, whereas with the porous anode, a supporting electrolyte (Na2SO4) was notionally present to eliminate the migrational contribution to reactant transport. For an electrolyte flow rate of
10−6 m3 s−1 (Re = 10 for plate electrodes, Re
porous = 0.76 for porous anode), a cell voltage of 3.0 V and an inlet NaCl of 100 mol m−3, the single-pass conversion of Cl− was predicted to increase from 0.45 for the reactor with a planar anode to 0.81 for the reactor with a porous anode. For
the same operating conditions, the overall current efficiency was also predicted to increase from 0.71 to 0.77 by replacing
the plate with the porous anode. 相似文献
7.
Preparation and properties of sulfonate salt-type cleavable surfactants with a 1,3-dioxane ring 总被引:7,自引:0,他引:7
Guan-Wu Wang Xian-You Yuan You-Cheng Liu Xue-Gong Lei 《Journal of the American Oil Chemists' Society》1994,71(7):727-730
A series of di-anionic cleavable surfactants were prepared by the condensation of aldehydes with 2,2-bis(hydroxymethyl)-1,3-propanediol, followed by reaction with 1,3-propanesultone in the presence of sodium hydride. Surfactant
5a had a different1H nuclear magnetic resonance spectrum in D2O than products 5b−d. This was rationalized by its different conformation, which originates from the self-coiling of its alkyl
chain. The critical micelle concentrations, Krafft points and hydrolysis properties of these surfactants were determined. 相似文献
8.
Poly(vinyl chloride) (PVC) membrane electrodes to determine monomer concentrations of tetradecyltrimethylammonium ion (TTA+) and hexadecylpyridinium ion (HPy+) based on neutral ion-pair carrier complexes of tetradecyltrimethylammonium dodecyl sulfate (TTA+-DS−) and hexadecylpyridinium dodecyl sulfate (HPy+-DS−), respectively, are reported here. The electrodes exhibit a Nernstian slope of 59 mV per decade for TTA+ and a sub-Nernstian slope of 34.5 mV per decade for HPy+ ions. The TTA+ ion-selective electrode (ISE) and the HPy+-ISE can determine the monomer units down to concentrations as low as 4.0×10−4M and 1.66×10−5 M, respectively. The effect of various additives, such as the anionic polyelectrolyte sodium dextran sulfate and macrocyclic
β-cyclodextrin, on the surface activity exhibited by the cationic surfactants TTA+-DS− and HPy+-DS−, in the presence of background concentrations of NaCl was also examined with surfactant-selective sensors. The Gibbs free
energy of micelle formation (ΔG
m
) of both surfactants in the presence of various additives was calculated and found to be less favorable with respect to an
increase in the amount of additives due to less availability of cationic surfactant monomer units. The ion-pair complexes
TTA+-DS− and HPy+-DS− were found to behave as selective carrier compounds in PVC membranes in determining the concentration of monomer units of
both TTA+ and HPy+, respectively. The proposed sensors worked well at a fairly acidic pH of 1–6.5 with response time of 60 s. The sensors responded
well to the surfactant ions even in the presence of additives at lower concentration. The lifetime of the sensors is 3 mon. 相似文献
9.
Biosorption Characteristics in the Mixed Heavy Metal Solution by Biosorbents of Marine Brown Algae 总被引:1,自引:0,他引:1
The biomass of nonliving, dried marine brown algaeU. pinnatifida, H. fusiformis, andS. fulvellum harvested in the sea near Cheju Island, Korea were studied for their sorption ability of copper, zinc, and lead. The metal
uptakes by biosorbent materials increased with increasing initial metal concentration and pH in the range of Ci 0.0510 mM. The higher metal uptakes were obtained in the range of pHs 4.0–5.3, 4.0–6.0, and 3.0–6.0 for copper, lead, and
zinc, respectively. The metal uptakes by biosorbent materials decreased in the following sequence:U. pinnatifida> H. fusiformis> S. fulvellum. The maximum metal uptake values ofU. pinnatifida for Cu2+, Pb2+, and Zn2+ in the single metal solution are 2.58, 2.6, and 2.08 meq/g in the range of pHs 5.3–4.4, respectively. The metal uptakes by
biosorbent materials in the mixed metal solution decreased greatly in comparison to each metal uptake in the single metal
solution. 相似文献
10.
MING CHEN HUI-LAN WANG JING GU GUO-WANG DIAO 《Journal of Applied Electrochemistry》2007,37(3):331-337
The water-soluble p-sulfonated sodium salt of calix[8]arene (III) was synthesized. The product was characterized by FT-IR, NMR and UV–Vis spectra.Then
the electrochemical behaviors of p-sulfonated sodium salt of calix[8]arene in NaAc+HAc (pH = 4) buffer solution was studied. In aqueous solution, p-sulfonated calix[8]arene can be oxidized when the potential is more than 0.7 V vs SCE. It was confirmed that the reaction
was a two-electron irreversible electrochemical reaction. The transfer coefficient, α, was measured as 0.7. At 25°, the diffusion
coefficient of p-sulfonated calix[8]arene was determined as 8.6 × 10−7 cm2 s−1. The diffusion activation energy of p-sulfonated calix[8]arene was 18.9 kJ mol−1 at pH = 4. 相似文献
11.
Deepti Tikariha Birendra Kumar Namrata Singh Kallol K. Ghosh Pierluigi Quagliotto 《Journal of surfactants and detergents》2011,14(4):555-562
The micellization behavior of gemini surfactants i.e. alkanediyl-α,ω-bis(cetyldimethylammonium bromide) (C16-s-C16,2Br− where s = 3, 4, 10) in 10% (v/v) ethylene glycol solution was investigated by surface tension and conductometric measurements at
300 K. The critical micelle concentration, degree of micellar ionization, surface excess concentration, minimum surface area
per molecule of surfactant, surface pressure at the CMC and Gibbs energy of adsorption of the dimeric surfactants have also
been determined in the presence of different salts (NaCl, NaBr and NaI). The critical micelle concentration and degree of
micellar ionization values decrease significantly in the presence of sodium halides and follows the sequence NaCl < NaBr < NaI.
The free energy, enthalpy and entropy of micellization of dimeric surfactants in 10% (v/v) ethylene glycol solution were determined
using the temperature dependence of the critical micelle concentration. The standard free energy of micellization was found
to be negative in all the cases. 相似文献
12.
Modified aqueous solutions of Mo-V-phosphoric heteropoly acids (HPAs) are used as high-performance catalysts for the oxidation
of substrates from different classes with oxygen. The oxidation of n-butenes to methyl ethyl ketone (MEK) with oxygen in the presence of aqueous solution (6 × 10−3 M Pd + 0.25 M HPA-7′), where HPA-7′ is a modified HPA whose molecular formula is H12P3Mo18V7O85, is an industrially important process. At the first Pd-catalyzed stage of the process, n-C4H8 is oxidized with HP acid. At the second stage, the catalyst is regenerated and the reduced form of HPA-7′ is oxidized with
atmospheric oxygen, closing the catalytic cycle. In such two-stage redox processes, HPA solutions act as reversible oxidizers
whose physicochemical properties are continuously changing. The modified solutions of HPAs are attractive because of their
thermal stability and increased regeneration rates. However, no data have yet been reported in the literature about their
physicochemical and corrosive properties. This undoubtedly hinders the practical application of processes involving these
solutions. Using the 0.25 M HPA-7′ solution as an example, we show how the physicochemical properties of the catalyst change.
During the first stage of the process, the pH, density (ρ), and viscosity (η) of the HPA solution increase to their maxima,
but its redox potential (E) decreases to its minimum. At the second stage, E increases, while ρ, η, and pH decrease to their initial values. Thus, in the processes with the alternating reduction and
oxidation of the HPA-based catalyst solution, the changes in the physicochemical properties of the catalyst are completely
reversible. We first have obtained the data on the corrosive properties of the modified HPA-7′ solution with respect to metals
and alloys widely used in industrial processes. The corrosion stability of various engineering materials against 0.25 M solution
of HPA-7′ was found to decrease in the series Ti (∼0.009 mm year−1) > 06KhN28MDT > 10Kh17N13M2T > 12Kh18N10T > KhN65MV (∼0.68 mm year−1). The unique ability of the modified Mo-V-P HPA solutions to recover completely their properties after regeneration with
oxygen permits one to use them successfully for long periods of time in the many-cycled processes. This opens up good prospects
for the development of industrial homogeneous catalytic oxidative processes involving these HPAs. 相似文献
13.
We report the synthesis and properties of two surfactants with a novel head group based on glycine. A monocarboxylic surfactant
N-glycine methyl ester (2-dodecen-1-yl succinamic acid) (I) was prepared by ring opening of an n-alkyl succinic anhydride. Hydrolysis of the ester functionality yields a dicarboxylic acid II. The sodium salts of I and II were effective surfactants at neutral pH giving a low minimum surface tension (<30 mN m−1 at 20 °C). At high pH (~12) the surface activity of both surfactants is reduced compared to neutral pH, indicating that at
neutral pH an ‘acid soap’ is formed. The pK
a of the acid form of the surfactants was determined. Addition of calcium ions reduced the CMC of II but did not reduce the surface tension above the CMC. The resistance of II to calcium ion precipitation was measured at pH 7. 相似文献
14.
Hakima Azira Amel Tazerouti Jean Paul Canselier 《Journal of surfactants and detergents》2008,11(4):279-286
Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported
and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more
thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized
method very similar to the Ross–Miles foaming tests to identify which surfactants are suitable for applications requiring
high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained
for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate
used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of
dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized
in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which
also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions
a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications
requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the
critical micellar concentrations and at 25 °C for both the samples.
相似文献
Amel TazeroutiEmail: |
15.
Tomokazu Yoshimura Yasuhiro Kiridoshi Yoshifumi Koide Hideto Shosenji Kunio Esumi 《Journal of surfactants and detergents》2002,5(2):159-164
N-(α-Carboxyalkyl)acrylamide telomer-type surfactants (xC
n−1
AmAc where n is alkyl chain length=6, 8, 10, 12; and x is degree of polymerization=3.3–13.1) were synthesized by the telomerization of monomer (C
n−1
AmAc) in the presence of the corresponding alkanethiol as a chain transfer agent and then investigated for their surface-active
properties. xC
n−1
AmAc telomers lowered the surface tension of aqueous solutions that were at pH 9–10. The critical micelle concentrations (CMC)
of the telomers were lower than those of the monomers with the same alkyl chain length, and the CMC values shifted to lower
concentrations with both increasing alkyl chain length and polymerization degree. xC9AmAc with x=3.3–6.3 gave the highest efficiencies in lowering the surface tension. The cross-sectional molecular areas per molecule of
xC
n−1
AmAc telomers were smaller than the values estimated on the assumption that they are assemblies of C
n−1
AmAc monomer units. The foaming abilities and the foam stabilities were both in the orders of xC7AmAc>xC9AmAc>xC5AmAc>xC11AmAc. Mixtures of aqueous solutions of xC
n−1
AmAc telomers and toluene formed oil-in-water emulsions. The emulsion-stabilizing abilities were in the orders of xC7AmAc>xC5AmAc>xC9AmAc=xC11AmAc. The addition of Ca2+ to the mixed solutions of telomers and toluene resulted in formation of water-in-oil type emulsions. Thus, the surface-active
properties of the telomers were influenced significantly by the alkyl chain length and the polymerization degree of the telomers.
In addition, these properties could be correlated with the hydrophilic-lipophilic balance (HLB); the highest surface activities
were observed by using xC
n−1
AmAc with HLB of 14–18. 相似文献
16.
K. Gharanjig M. Sadeghi-Kiakhani A. R. Tehrani-Bagha A. Khosravi F. M. Menger 《Journal of surfactants and detergents》2011,14(3):381-389
The solubility of naphthalimide-based monoazo dyes containing N-ethyl and N-ethanoic acid groups was investigated in the presence of a conventional monomeric counterpart (DTAB) and two cationic gemini
surfactants (12-4-12 or 14-4-14) individually. The effective parameters on dye solubility such as temperature, time and concentration
of surfactants were investigated by UV–Visible spectrophotometry. The results demonstrate that the solubility of both dyes
was considerably increased at concentrations above the surfactant CMC. The wavelength for the maximum absorbance of dyes in
the aqueous solution shifts toward longer wavelengths with changes in the concentration of the cationic surfactants. A kinetic
study of solubilization of dyes in cationic surfactants solution showed that the rate of solubilization follows the pseudo-first-order
reactions. Rates of solubilization were in the range of 0.5 × 10−3 to 6.8 × 10−3 min−1 for both dyes. The disperse dye containing a carboxylic acid group (dye 2) has a higher solubility rate than the dye containing
an alkyl group (dye 1). The type of surfactant has a very low effect on adsorption of dye 1 onto the polyester fibers, whereas
changing the surfactant type from DTAB to 12-4-12 or 14-4-14 causes adsorption of dye 2 on polyester to decrease. 相似文献
17.
G. E. Totten E. D. Goddard G. H. Matteson M. L. Wanchisen 《Journal of the American Oil Chemists' Society》1986,63(12):1586-1589
The effect of varying counterion structure on the aqueous solution viscosity of various cationic surfactants was systematically
examined for compounds of the type: CH3(CH2)
x
N(CH3)3YAr. Ar = functionally substituted aryl moieties and Y = carboxylate (CO2
−), sulfinate (SO2
−) or sulfonate (SO3
−).
Aqueous solution viscosity, which is assumed to be a measure of ion pair stability, is clearly affected by anion and cation
structure, temperature, concentration and stoichiometry. An ortho substituent to the anionic functionality, e.g. hydroxyl,
substantially increases ion pair stabilization. Ion pair stability is also enhanced by increasing the solution concentration,
decreasing temperature, increasing cation/anion ratio or by increasing the alkyl (x) chain length. 相似文献
18.
次氯酸钠水溶液稳定性及增稠体系研究 总被引:10,自引:1,他引:9
研究了温度、pH值、金属离子和表面活性剂对次氯酸钠水溶液稳定性的影响。在 2 5℃以下 ,pH >12 4时次氯酸钠溶液较稳定 ;金属离子的存在促进其分解。并找到了能够在次氯酸钠中稳定存在的表面活性剂WC 2A1(十二烷基二苯醚二磺酸钠 )。同时对有效氯含量、非离子表面活性剂 (GMY)及阴离子表面活性剂 (L - 30 )、pH值对次氯酸钠水溶液黏度的影响作了研究 ,得出了所需黏度的配方 :w(GMY) =7%~ 8% ,w(L - 30 ) =2 %~ 3%。 相似文献
19.
Activity and stability of an alkaline lipase fromPenicillium cyclopium var.album (PG 37) were studied in surfactant and detergent solutions. Three anionic surfactants [Na salts of C12SO4 ? (sodium dodecyl sulfate), C12ØSO3/? (linear alkyl benzene sulfonate), and C11COO? (laurate)] and four homologous series of nonionic surfactants of C12–15 polyoxethylenated fatty alcohols (AEO3, AEO5, AEO7, and AEO9) were evaluated. At a concentration range of 3.2–40 μM, sodium dodecyl sulfate and laurate stimulated the activity of PG 37 lipase. At concentrations greater than 5.6 μM, linear alkylbenzene sulfonate inhibited PG 37 lipase activity. Nonionic surfactants, AEO5 and AEO7, in the concentration range of 0.25–20 mM, enhanced and stabilized the activity of PG 37 lipase. The presence of PG 37 lipase in detergent formulaton improved detergency ~20%. The mechanism of inhibition of the lipolytic activity of PG 37 lipase is proposed to be partly due to the formation of inactive (BR)n-E complex between the hydrophobic moiety of the surfactants and the surface of the lipase. Conversely, formation of a soluble (RB)n-E complex between the hydrophilic group of the surfactant and lipase may account for the increased lipolytic activity of PG 37 lipase. 相似文献
20.
Cheryl H. Rodriguez Chanin Chintanasathien John F. Scamehorn Chintana Saiwan Sumaeth Chavadej 《Journal of surfactants and detergents》1998,1(3):321-328
The effect of sodium octanoate (SO) and pH on the precipitation of sodium dodecyl sulfate (SDS) with calcium (hardness tolerance)
in water was investigated. SO can exist as octanoate anion (O−) or as the protonated nonionic fatty acid (HO) with the HO/O− ratio increasing with decreasing pH. At intermediate pH levels, SO or SO/SDS systems are composed of mixtures of anionic
and nonionic surfactants, resulting in enhancement of micelle formation due to nonideal mixed micelle formation. Above the
critical micelle concentration (CMC), the highest hardness tolerance at each pH level occurs at a mole ratio of 80∶20 SDS/SO
due to synergism in the SDS/SO mixtures. This synergism also results in an increase in hardness tolerance of SDS with decreasing
pH above the CMC. 相似文献