Presence Of Dodecyl Benzene Sulfonate Research Articles

A case study of aggregation behaviors of titanium dioxide nanoparticles in the presence of dodecylbenzene sulfonate in natural water

The present work aims to ascertain the mechanisms of surfactant (dodecylbenzene sulfonate; DBS) effects on the aggregation behaviors of TiO2 nanoparticles (TiO2-NPs) in natural water samples. Aggregation experiments were conducted at a TiO2-NPs concentration of 10mg/L in deionized water and in natural water samples via dynamic light scattering and Zeta potential determination. Average attachment efficiency was calculated to compare the aggregation behaviors of nanoparticles in the two aqueous media. Results showed that the effects of DBS on aggregation could be interpreted by both Derjaguin–Landau–Verwey–Overbeek (DLVO) and non-DLVO mechanisms. In natural water samples, aggregation did not occur rapidly and was able to develop slowly under all conditions, and the roles of DBS were obvious at high DBS concentration owing to the impacts of inherent components of natural water samples, such as colloids and natural organic compounds. Future aggregation studies should concentrate on multi-factor, multi-colloidal and dynamic aspects under similar environmental conditions.

Controlled facile synthesis and photocatalytic activity of ultrafine high crystallinity TiO2 nanocrystals with tunable anatase/rutile ratios

The superfine high crystallinity TiO2 nanocrystals with tunable anatase/rutile ratios have been synthesized in an ethanol aqueous solution of HCl and sodium dodecylbenzene sulfonate (DBS) by a “low temperature dissolution–reprecipitation process” (LTDRP) and solvethermal treatment composite method. The effect of the synthesis parameters on the crystal structure, crystal size and the photocatalytic properties of the TiO2 nanocrystallines were investigated. The growth and aggregation of TiO2 nanocrystallines can be inhibited, and the high crystallinity spherical nanoparticles with small size are generated in the presence of DBS. The ratios of anatase and rutile can be easily controlled by sample adjusting aging time. The pure phase anatase is obtained by solvethermal treatment without aging process, the contents and the crystallite size of rutile are increased with increase of the aging time and only rutile exists while aging time is 16h or more. The well-crystallized TiO2 nanocrystals exhibit higher photocatalytic activities. Their high photocatalytic activities could be attributed to high crystallinity, small crystal size (approximately 5nm for anatase and 8 to 15nm for rutile), the synergistic effect between anatase and rutile and strong electron-withdrawing characteristic of the sulfoacid radical of DBS.

High dielectric constant polyaniline/poly(acrylic acid) composites prepared by in situ polymerization

An ultra-high dielectric constant composite of polyaniline, PANI–DBSA/PAA, was synthesized using in situ polymerization of aniline in an aqueous dispersion of poly-acrylic acid (PAA) in the presence of dodecylbenzene sulfonate (DBSA). The water-soluble PAA served as a polymeric stabilizer, protecting the PANI particles from macroscopic aggregation. A very high dielectric constant of ca. 2.0 × 10 5 (at 1 kHz) was obtained for the composite containing 30% PANI by weight. The influence of the PANI content on the morphological, dielectric and electrical properties of the composites was investigated. The frequency dependence of dielectric permittivity, dielectric loss, loss tangent and electric modulus were analyzed in the frequency range from 0.5 kHz to 10 MHz. SEM micrograph revealed that composites with high PANI content (i.e., 20 wt%) consisted of numerous nano-scale PANI particles that were evenly distributed within the PAA matrix. The high dielectric constants of these composites were attributed to the sum of the small capacitors of the PANI particles.

The removal of reactive dyes from aqueous solutions using chemically modified mesoporous silica in the presence of anionic surfactant—The temperature dependence and a thermodynamic multivariate analysis

The three-parameter Sips adsorption model was successfully employed to modeled equilibrium adsorption data of a yellow and a red dye onto a mesoporous aminopropyl-silica, in the presence of the surfactant sodium dodecylbenzenesulfonate (DBS) from 25 to 55 °C. The results were evaluated in relation to the previously reported surface tension measurements. The presence of curvatures of the van ́t Hoff plots suggested the presence of non-zero heat capacities terms (Δ ads C p). For the yellow dye, it is observed that the values of Δ ads H are almost all positive and they decrease in endothermicity, in the absence and in the presence of DBS, from 25 to 55 °C. For the red dye, there is an increase in endothermicity in relation to the temperature increase. The negative Δ ads G values indicate spontaneous adsorption processes. Almost all adsorption entropy values (Δ ads S) were positive. This suggests that entropy is a driving force of adsorption. The adsorption thermodynamic parameters were also evaluated using a new 2 3 full factorial design analysis. The multivariate polynomial modelings indicated that the thermodynamic parameters are also affected by important interactive effects of the experimental factors and not by the temperature changes alone.

Anisotropic Growth of Conducting Polymers along Heparin-Modified Surfaces

We have studied the possibility of making biocompatible, conductive patterns on a substrate by controlling the lateral growth rate of conducting polymers upon electropolymerization. Surface modification with heparin was found to enhance the lateral growth of polypyrrole, especially in the presence of dodecylbenzenesulfonate, and thus the micropatterning of heparin around electrodes leads to the formation of polypyrrole patterns.

Aggregation and adsorption of reactive dyes in the presence of an anionic surfactant on mesoporous aminopropyl silica

A surface tension technique was used to determine the critical aggregation concentration (cac) of a yellow and a red dye in relation to the presence of the anionic surfactant sodium dodecylbenzene sulfonate (DBS) and to temperature changes in buffered aqueous solutions. The cac values of the yellow dye increase from 25 to 45 °C (from 41.37 to 50.32 mg L −1) and decrease from 45 to 55 °C (from 50.32 to 38.72 mg L −1). The cac values for the red dye/DBS aggregates decrease (from 124.52 to 88.50 mg L −1) from 25 to 55 °C. Adsorption of the two dyes onto a mesoporous aminopropyl silica (Sil–NH 2) was also studied. The adsorption of the yellow dye increases with an increase in temperature from 25 to 55 °C. In the presence of DBS the adsorption on Sil–NH 2 for the yellow dye decreases, and for the red dye increases from 25 to 55 °C. Adsorptions occurred below and above the cac of the anionic dyes/DBS aggregates. Adsorption of the dyes onto Sil–NH 2 fitted well to the Langmuir, Freundlich, and Redlich–Peterson adsorption models. However, in the presence of DBS, only the Freundlich model fit the experimental adsorption data at low dye concentrations (less than 400 mg L −1). In this case, the Redlich–Peterson model was only fitted to the red dye adsorption data. The magnitude of the Dubinin–Radushkevich energetic parameters ( E, from 7.00 to 15.00 kJ mol −1) indicates that the adsorption of the dyes onto Sil–NH 2, in the absence and in the presence of DBS, is controlled by water adsorbed/dye in solution ion-exchange interactions. It is observed that the values of Δ ads H are positive for both dyes and the values are quite similar to each other. The exception is the adsorption of the yellow dye in the presence of DBS, which is slightly exothermic. The Δ ads G values are all negative. However, the interactions of the dyes with Sil–NH 2 silica are more spontaneous in the presence of the surfactant. The positive adsorption entropy values ( Δ ads S ) for the interaction of the dyes suggest that entropy is a driving force of the dye adsorptions. However, the entropic contribution is higher for the adsorptions in the presence of DBS. It was suggested that the chemical structures of the dyes play an important role in the formation of the dye/DBS aggregates and in dye adsorption onto the aminopropyl silica.

Improving the throwing power of acidic zinc sulfate electroplating baths

The effect of some plating parameters, such as Zn2+ ion concentration, pH, current density, temperature and duration on the throwing power, as well as on the throwing index of acidic zinc sulfate baths has been investigated. The addition of p-anisidine (PA) and/or sodium dodecylbenzenesulfonate (DBS) has been examined as a possible means of improving the uniformity of deposit distribution. The additives cause a substantial increase in the overpotential for the reduction of Zn2+ ions and consequently improve the throwing power of the baths. The throwing power increases by a factor of four in the presence of DBS and a factor of one-and-a-half in the presence of PA. The inhibition of zinc reduction was assumed to occur via adsorption of the PA or DBS molecules on the cathode surface and the adsorption followed the Langmuir adsorption isotherm. The surface morphology of the zinc plated with and without the additives was examined by using scanning electron microscopy (SEM). © 2000 Society of Chemical Industry

Improving the throwing power of acidic zinc sulfate electroplating baths

The effect of some plating parameters, such as Zn2+ ion concentration, pH, current density, temperature and duration on the throwing power, as well as on the throwing index of acidic zinc sulfate baths has been investigated. The addition of p-anisidine (PA) and/or sodium dodecylbenzenesulfonate (DBS) has been examined as a possible means of improving the uniformity of deposit distribution. The additives cause a substantial increase in the overpotential for the reduction of Zn2+ ions and consequently improve the throwing power of the baths. The throwing power increases by a factor of four in the presence of DBS and a factor of one-and-a-half in the presence of PA. The inhibition of zinc reduction was assumed to occur via adsorption of the PA or DBS molecules on the cathode surface and the adsorption followed the Langmuir adsorption isotherm. The surface morphology of the zinc plated with and without the additives was examined by using scanning electron microscopy (SEM). © 2000 Society of Chemical Industry

Effect of Surfactants on Decoloration of Various Dyes by Peroxide Bleaching Agents

The effect of three surfactants, dodecylbenzenesulfonate (DBS), n-hexadecyltri methylammonium bromide (HTAB), and polyethylene glycol mono-p-octylphenyl ether (PEOPE), on the decoloration rates of C.I. Acid Orange 7, C.I. Basic Green 4, and C.I. Basic Orange 33 by peroxide bleaching agents such as sodium percarbonate and hy drogen peroxide is examined. The decoloration rate of Acid Orange 7 by peroxide bleaching agents accelerates in the presence of DBS, HTAB and PEOPE, especially near the cmc, with the maximum rate being observed in the presence of HTAB. However, the decoloration rate of Basic Orange 33 by hydrogen peroxide accelerates only when DBS is present near the cmc. There is no or less enhanced decoloration in the presence of HTAB or PEOPE. Interestingly, the decoloration rate of Basic Green 4 by hydrogen peroxide accelerates with increasing HTAB concentration, and in contrast, the rate de creases when DBS is present. These results indicate that decoloration rates by peroxide bleaching agents largely depend on interactions between the dyes and surfactants.

Photoassisted Degradation of Dye Pollutants. 3. Degradation of the Cationic Dye Rhodamine B in Aqueous Anionic Surfactant/TiO2 Dispersions under Visible Light Irradiation: Evidence for the Need of Substrate Adsorption on TiO2 Particles

The TiO2 photoassisted degradation of the cationic dye rhodamine B (RhB) has been examined in aqueous dispersions under visible light irradiation at wavelengths longer than 470 nm in the presence and absence of the anionic surfactant sodium dodecylbenzenesulfonate (DBS). RhB degrades slowly via a pH-independent process in TiO2 dispersions containing no DBS. The surfactant DBS adsorbs strongly on the TiO2 particles and significantly accelerates RhB degradation with initial rates reaching maximal values at the critical micelle concentration of DBS (cmc = 1.2 mM). In the presence of DBS, rates decrease with increase in pH, an effect directly attributable to variations in the extent of adsorption of RhB with changes in the surface charge of TiO2 particles. The zeta (ζ)-potentials of TiO2 particles in RhB/DBS/TiO2 dispersions (pH 2.1) show that DBS significantly enhances RhB adsorption and correlates with an enhancement in the rate of photodegradation of RhB. The results confirm the heretofore presumed but val...

Electropolymerization of 3,4-ethylenedioxythiophene and 3,4-ethylenedioxythiophene methanol in the presence of dodecylbenzenesulfonate

Electropolymerization of 3,4-ethylenedioxythiophene (EDT) and its hydroxymethyl derivative (EDTM) was carried out in sodium dodecylbenzenesulfonate aqueous solution by cyclic voltammetry and chronoamperometry on a platinum electrode. PEDTM seems to be irreversibly damaged at lower potentials than PEDT (+1.2 V/SCE versus +1.4 V/SCE, respectively). Moreover, scanning electronic microscopy (SEM) and surface profiling revealed a higher compaction for PEDTM films. Nevertheless, these films stopped growing for a charge of about 80 mC cm −2 as demonstrated by a UV-Vis spectrophotometric study.

Solid-Phase Spectrophotometric Determination of Cobalt(II) in Tap Water and Beverages Using 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-(3-sulfopropyl)amino)phenol after Preconcentration as the 1-(2-Pyridylazo)-2-naphthol Complex.

A sensitive and selective method for the determination of trace amounts of cobalt(II) is described. The method is based on the combined use of 1-(2-pyridylazo)-2-naphthol (PAN) and 2-(5-bromo-2-pyridylazo)-5-[N-propyl-N-(3-sulfo-propyl)amino]phenol (5-Br-PAPS). Cobalt(II) is first extracted on a membrane filter as the cobalt(III)-PAN complex and the complex is decomposed with acid. The cobalt is then extracted on a membrane filter as the cobalt(III)-5-Br-PAPS complex in the presence of dodecylbenzenesulfonate and determined by densitometry. The proposed method has been applied to the determination of cobalt in tap water and beverages.

Properties of electrochemically synthesized polymer electrodes—X. Study of polypyrrole/dodecylbenzene sulfonate

The electrochemical behavior of polypyrrole films electrosynthesized in the presence of dodecylbenzenesulfonate has been investigated by cyclic voltammetry and frequency response analysis. The results indicate that the kinetics of the redox process are mainly governed by diffusion of the cations and anions of the supporting electrolyte while the large surfactant anions remain immobilized in the polymer structure.