Benzene Sulphonate Research Articles

The effect of surface modification on femtosecond optical Kerr effect of PBS nanoparticles

PbS nanoparticles modified by a polymer (P–PbS) was prepared, and the transient nonlinear optical properties studied by femtosecond optical Kerr effect (OKE) spectroscopy for the first time. A very large nonlinear optical effect ( χ (3)∼5.6×10 −12 esu) with response time comparable to the laser pulse (∼165 fs) was observed. Comparing with PbS nanoparticles stabilized with PVA and coated with sodium dodecyle benzene sulphonate (DBS), the optical nonlinearity of the PbS nanoparticles modified by the polymer is much larger than those of them. Thereafter, the corresponding nonlinearity mechanism was interpreted.

Influences of Electrolytes, Polymers and a Surfactant on Rheological Properties of Bentonite–Water Systems

Characteristic rheological properties, such as viscosity, shear stress, yield point, gel strength and thixotropy, of natural Ca- bentonite and Na-peptized bentonite were studied after adding LiCl, KCl, CaCl2, MgCl2·6H2O electrolytes; (NaPO3)n, polyvinyl pyrolidone (PVP) polymers and an anionic surfactant (linear alkyl benzene sulphonate, LABS). Changes in flow properties under the influence of various additives at different quantities were investigated in these slurries. The experimental results are discussed in terms of bentonite forms, types and concentrations of additives and influence of exchangeable cations. Bivalent and monovalent cations display entirely different rheological properties in two groups of muds. Furthermore, the difference in the degree of activity of PVP polymer on the viscosity of two mud systems depend on the clay mineral structure. The slurry prepared with Na-bentonite contains a minimum number of tactoids and a maximum number of sheet-bearing clay particles, which reduces the surface area of the clay minerals and increases viscosity by adding PVP polymer.

Surface atomic structures of Fe2O3 nanoparticles coated with cetyltrimethyl ammonium bromide and sodium dodecyl benzene sulphonate: an extended x-ray absorption fine-structure study

Fe2O3 nanoparticles coated with sodium dodecyl benzene sulphonate (DBS) or cetyltrimethyl ammonium bromide (CTAB) were prepared by using a microemulsion method in the system water/toluene. The nanoparticles were characterized by means of transmission electron microscopy and average particle sizes of 5.0 nm and 6.0 nm were found for DBS-modified and CTAB-modified nanoparticles respectively. The local atomic structures of these iron(III) oxide nanoparticles were probed by using the extended x-ray absorption fine-structure technique. Fe K absorption spectra were collected at beam line 4W1B of Beijing Synchrotron Radiation Facility. A structural model was proposed for describing their atomic structures. The Fe-O bond length at the surface of DBS-coated Fe2O3 nanoparticles was found to be similar to that in bulk Fe2O3, but there was about 0.04 Å expansion for the CTAB-coated Fe2O3 nanoparticles. On the basis of the model proposed in this paper, the thicknesses of the surface layers were estimated to be 0.5 nm and 0.7 nm, respectively, for the DBS-coated and CTAB-coated Fe2O3 nanoparticles. The anharmonicity of the atomic vibration and the asymmetry of atom-pair distribution were found to be larger at the surface of the nanoparticles than in the bulk material, while the Debye-Waller factors are almost the same for the surface and the core parts of the nanoparticles. It can be concluded that the atomic structure of the nanoparticle surface is ordered, but the atom-pair distribution is asymmetric.

The effects of contaminants on the behaviour of conductivity improvers in hydrocarbons

Dangerous accumulation of electrostatic charge can occur due to high-speed pumping and microfiltration of jet fuel. This can be avoided by increasing the electrical conductivity of the fuel using conductivity improver additives. However, marked variations occur in the conductivity response of different fuels when doped to the same level with conductivity improver. This has been attributed to interactions of the conductivity improver with other fuel additives or fuel contaminants. The present work concentrates on the effects of fuel contaminants, in particular polar compounds, on the performance of the conductivity improver. Conductivity is the fuel property of prime interest. The conductivity response of model systems of the conductivity improver STADIS 450 in dodecane has been measured and the effect on this conductivity of additions of model polar contaminants sodium naphthenate, sodium dodecyl benzene sulphonate, and sodium phenate has been measured. The sodium salts have been found to have a complex effect on the performance of STADIS 450, reducing the conductivity at low concentrations to a minimum value and then increasing the conductivity at high concentrations of sodium salts. This work has focused on characterising this minimum in the conductivity values and on understanding the reason for its occurrence. The effects on the minimum conductivity value of the following parameters are investigated: (a) time, (b) STADIS 450 concentration, (c) sodium salt concentration, (d) mixed sodium salts, (e) experimental method, (f) a phenol, (g) individual components of STADIS 450. The complex conductivity response of the STADIS 450 to sodium salt impurities is discussed in terms of possible inter-molecular interactions.

Risk in cleaning: chemical and physical exposure

Cleaning is a large enterprise involving a large fraction of the workforce worldwide. A broad spectrum of cleaning agents has been developed to facilitate dust and dirt removal, for disinfection and surface maintenance. The cleaning agents are used in large quantities throughout the world. Although a complex pattern of exposure to cleaning agents and resulting health problems, such as allergies and asthma, are reported among cleaners, only a few surveys of this type of product have been performed. This paper gives a broad introduction to cleaning agents and the impact of cleaning on cleaners, occupants of indoor environments, and the quality of cleaning. Cleaning agents are usually grouped into different product categories according to their technical functions and the purpose of their use (e.g. disinfectants and surface care products). The paper also indicates the adverse health and comfort effects associated with the use of these agents in connection with the cleaning process. The paper identifies disinfectants as the most hazardous group of cleaning agents. Cleaning agents contain evaporative and non-evaporative substances. The major toxicologically significant constituents of the former are volatile organic compounds (VOCs), defined as substances with boiling points in the range of 0°C to about 400°C. Although laboratory emission testing has shown many VOCs with quite different time-concentration profiles, few field studies have been carried out measuring the exposure of cleaners. However, both field studies and emission testing indicate that the use of cleaning agents results in a temporal increase in the overall VOC level. This increase may occur during the cleaning process and thus it can enhance the probability of increased short-term exposure of the cleaners. However, the increased levels can also be present after the cleaning and result in an overall increased VOC level that can possibly affect the indoor air quality (IAQ) perceived by occupants. The variety and duration of the emissions depend inter alia on the use of fragrances and high boiling VOCs. Some building materials appear to increase their VOC emission through wet cleaning and thus may affect the IAQ. Particles and dirt contain a great variety of both volatile and non-volatile substances, including allergens. While the volatile fraction can consist of more than 200 different VOCs including formaldehyde, the non-volatile fraction can contain considerable amounts (>0.5%) of fatty acid salts and tensides (e.g. linear alkyl benzene sulphonates). The level of these substances can be high immediately after the cleaning process, but few studies have been conducted concerning this problem. The substances partly originate from the use of cleaning agents. Both types are suspected to be airway irritants. Cleaning activities generate dust, mostly by resuspension, but other occupant activities may also resuspend dust over longer periods of time. Personal sampling of VOCs and airborne dust gives higher results than stationary sampling. International bodies have proposed air sampling strategies. A variety of field sampling techniques for VOC and surface particle sampling is listed.

Studies on Sodium Dodecyl Benzene Sulphonate in the Presence of Additives

Studies on Sodium Dodecyl Benzene Sulphonate in the Presence of Additives

Styrene and methylmethacrylate oil-in-water microemulsions

A simple procedure for the preparation of styrene-in-water and methylmethacrylate (o/w) micro-emulsions was established. This consisted of the preparation of a w/o emulsion using a low HLB number surfactant (Synperonic NP4, nonyl phenyl with 4 mol ethylene oxide) and a small amount of an anionic surfactant (Aerosol OT, diethyl hexyl sulphosuccinate, or sodium dodecyl benzene sulphonate). The w/o emulsion was then titrated with an aqueous solution of a high HLB number surfactant (Synperonic NP15, nonyl phenyl with 15 mol ethylene oxide). The droplet size and polydispersity were determined using photon correlation spectroscopy (PCS). The temperature range within which a microemulsion remained stable decreased with increase in the concentration of styrene or methylmethacrylate and this could be explained in terms of the phase diagram of the microemulsion system. Conductivity measurements as a function of temperature showed that the systems are oil-in-water microemulsions.

Vitrification and water induced crystallization of zinc(II) dodecylbenzene sulphonate

Crystallization of zinc(II) dodecyl benzene sulphonate has been suppressed by either the removal of water of hydration or the rapid cooling of the compound from the liquid crystalline state. The anisotropic structure is preserved in the solid state when the hydrated compound in the LC phase is rapidly quenched, while removal of the water of hydration at temperatures in or above the LC phase and the subsequent slow cooling produces a stable isotropic structure.

Interaction of Gelatin and Sodium Dodecyl Benzene Sulphonate at Oil and Water Interfaces

Interaction between sodium dodecyl benzene sulphonate (SDBS) and gelatin ivas studied in relation to emulsification behaviour and emulsion stability. We chose two different oils to study influences of oil phase characteristics, namely, tricresyl phosphate (TCP) as an oil with polar and slightly hydrophilic nature, and n-dodecane (n-C12) as its apolar contrast. Our interfacial tension measurements showed that both TCP and n-C12 give critical values (i.e., cac and cmc) very close to I hose of surface tension measurement. This result indicates that the complexation behaviour in bulk solution is independent of the presence or the nature of the oil phase. Absolute tension values above the cmc and slope value at the cmc in gelatin free systems, however, imply SDBS’s weaker adsorption to TCP than to n-C12 Our emulsification results for the TCP system revealed the existence of an optimal point for emulsion stability in the SDBS concentration region between the cac and the cmc. Above this point, emulsion stability deteriorates remarkably. The behaviour is in line with our findings from the dynamic sorption experiments (ellipsomelry, TIRF, and SPR) reported elsewhere, which showed a rapid desorption of gelatin from the hydrophobic surfaces above the cac. The results suggest that the adsorption of gelatin/surfactant complexes at the interface is a key factor for stability of the polar oil emulsion system. Contrary to that, the n-C12 system did not show any deterioration, even above the cmc, which is presumably due to a strong double layer effect from the firmly adsorbed layer of SDBS at the interface.

The effect of an anionic surfactant on the rheology and stability of high volume fraction O/W emulsion stabilized by PVA

The effect of the addition of an anionic surfactant (sodium dodecyl benzene sulphonate) on the rheology and storage stability of concentrated O/W emulsions stabilized by poly (vinyl alcohol) is reported. It was found that the surfactant markedly reduced the magnitudes of the storage modulii of the emulsions. This could be attributed to a reduction in the interfacial tension resulting from the formation of polyelectrolyte type complexes between the PVA and NaDBS at the O/W interface. The results were compared to the equation (given by Princen) relating concentrated emulsion rheology to the interfacial tension and droplet size. Reasonable agreement was found, though there was a small difference in the constants in the equation given by Princen and those found here. The agreement suggested that the emulsions were deforming above a critical volume fraction and that the rheological properties were dominated by the dilation of the interface during shear. Microelectrophoresis measurements showed that the addition of the surfactant conferred a charge onto the PVA stabilized droplets as a result of the formation of the polyelectrolyte complex. The NaDBS was found to reduce the long-term stability of the emulsions compared to emulsions containing PVA alone.

Mixed Micelle Formation and Co-adsorption of Anionic/Non-ionic Surfactant Mixtures on Rutile

Mixed micelle formation between the anionic surfactant p-dodecyl benzene sulphonate and the non-ionic surfactants Brij-58, Brij-78 and Brij-99, having the same number of oxyethylene units but a varying number of hydrophobic groups, has been studied using surface tension and NMR spectroscopic measurements. Both hydrophobic–hydrophobic and hydrophilic–hydrophilic interactions play an important role in mixed micelle formation leading to greater non-ideality. The effect of mixed micelle interactions on the adsorption of these surfactants from their mixtures on rutile have been investigated using adsorption and zeta potential measurements. Adsorption above the CMC level is dictated by the relatively higher tendency of mixed micellization over mixed aggregation at the solid/liquid interface.

Derivatisierungsmethoden für LAS

Different methods for the derivatization of linear alkyl benzene sulphonate (LAS) are presented. They are checked with respect to their performance, expenditure of time, reproducibility, quantitative conversion and the final analytical determination. The investigations are carried out using a GC/MSD-System. The methods are compared to get a quick survey for the choice of the derivatization way.

A regional chemical fate and exposure model suitable for Denmark and its coastal sea

A generic screening level model for the regional environmental fate and exposure of industrial organic chemicals has been developed for Denmark and its coastal sea. The model is a further development of a European generic model proposed by the Commission of the European Union (EU) for use in chemical risk assessment. The EU model is a “Mackay-type” level III model with four compartments: air, soil, freshwater and freshwater sediments. To better represent the geography of Denmark that consists of islands and a peninsula a six-compartment model was constructed by adding a seawater compartment and a marine sediment compartment to the standard EU-model. To obtain a realistic mean hydraulic retention time of freshwater, the freshwater compartment was reduced to represent lakes only, treating emissions to rivers downstream lakes as emissions directly to the sea. The sea compartment was confined to the transition between the Baltic and the North Sea that receives the major part of the Danish wastewater discharges and is a physically well-defined entity. Case studies with lindane, chloroform, pentachlorophenol (PCP), hexachlorobenzene, linear alkyl benzene sulphonates (LAS), 1-dodecanol, and trichlorethylene (TCE) demonstrated that in scenarios with significant local waterborn emission of volatile compounds predictions with the six compartment model could be significantly different from those obtained with the standard EU model. For LAS, lindane, PCP, TCE and chloroform, limited sets of available monitoring data were in fair agreement with model predictions. A sensitivity analysis showed among others that the local emissions as well as the imports across the model boundary were important determinants. A tentative risk assessment based on regional PEC (predicted environmental concentration)/PNEC (predicted no effect concentration) ratios indicated that there should be no environmental risk at the regional scale for chloroform, PCP, and TCE in Denmark. For LAS the calculated PEC/PNEC ratios were between 2–18% for soil, water and sediment when EU standard assessment factors were used to estimate the PNEC.

An analysis of the absorption of alkyl benzene sulphonate by algal residues

The extraction of agar-agar from Gracilaria debilis produced a residue which was examined as a potential biosorbent for the removal of linear alkyl benzene sulphonate (LAS) from aqueous solution. Tests were carried out at 25°C and a range of pH values. The results were analysed as Langmuir isotherms. The compliance between the data and the theoretical equation was good and the results indicated that the adsorption was favoured by lower pH values. The maximum adsorption capacity was 76·34 mg g −1. This needs to be compared with a value of 75·85 mg g −1 determined previously for the adsorption of a branched chain alkyl benzene sulphonate by activated carbon. The rates of LAS removal were also measured and it was found that the rates were increased by lowering the pH.

The use of seed pods from Albizia lebbek for the removal of alkyl benzene sulphonates from aqueous solution

The paper presents the results of a preliminary investigation into the use of Albizia lebbek seed pods as a biosorbent for the removal of linear alkyl benzene sulphonate (LAS) from aqueous solution. It also compares the adsorption characteristics with those of an algal residue. The results showed that at 25°C, the greatest specific adsorption (mg/g) was achieved at low (ca 3) pH values. The results also showed that there was a good compliance with both the Langmuir and the Freundlich equations. Based on the Langmuir equation, the maximum adsorption capacity was 25·43 mg/g. An examination of the kinetics of the adsorption showed that the overall process could be described by the Lagergren equation and that the rate constant ( K) increased with the initial concentration of the LAS ( C 0). An analysis based on the K C 0 relationship suggested that at C 0 values of less than 58 mg/litre the Albizia lebbek would be a more appropriate material than the algal residue. Intraparticulate diffusion rates were also measured and were also found to increase with C 0.

Clinoptilolites of Western Anatolia as Detergent Builders

The use of clinoptilolites of Western Anatolia in detergents as phosphate substitutes was investigated. The cations present in the clinoptilolite samples were first exchanged with sodium ions. The washing characteristics of detergent mixtures containing surfactants, clinoptilolite, sodium carbonate and sodium sulphate were analysed. The stains of coffee, tea and tomato paste were tested. The washing tests were repeated for different surfactants, i.e. linear alkyl benzene sulphonate, sodium alkyl sulphate and alcohol ethoxylate and for different co-builders, i.e. sodium carbonate and EDTA. In addition, the effects of detergent dose and detergent formulation on washing were investigated. Other factors affecting the degree of soil removal such as shaking time, temperature and water hardness were also studied. The contribution of clinoptilolite to the washability was compared with zeolite A, zeolite X and sodium tripolyphosphate. Increasing the shaking time and temperature improves the degree of cleaning. LAS was the most effective surfactant for use with clinoptilolite. The washing performance of the detergent mixtures used in the present work was found to be comparable with that of commercial detergents at low washing temperatures.

Nickel Electro- crystallization: Influence of Unsaturated Organic Additives on the Mechanism of Oriented Crystal Growth

The addition of organic compounds to the electrolytic baths during the electrodeposition of metals affects the structure and the properties of the deposits, leading to the preparation of coatings with defined characteristics. In this work, a complete study of the action of the organic additives on the crystalline orientation of the nickel electrodeposits was carried out. The selection of the organic compounds was made in order to investigate the effect of the stereochemical structure and unsaturated bonds on the nickel electrocrystallization process. It was found that the presence of acetylenic compounds (butyne-2-diol 1,4 and propyne-2-ol) in nickel plating baths leads to the predominance of high inhibited modes of crystal growth. Propyne-2-ol seems to be more active, as the geometry of its molecule favours the adsorption of the additive on the metallic surface and, thus, its faster hydrogenation. With the additon of phenylpropyl alcohol, a strong perturbation of the oriented crystal growth of the nickel crystallites occurs. The adsorption of the phenyl group on the metallic surface and its hydrogenation is responsible for the predominance of high inhibited textures. In the case of coumarin, the complexity of its molecule makes its adsorption more difficult, resulting in the development of [100] textured deposits even at high concentrations of the additive. Finally, when sodium benzene sulphonate or saccharin are added to the bath, the presence of sulphur in their molecules influences the nickel electrodeposition process through a different mechanism.

Application of immobilized microorganisms in the biodegradation of alkyl sulphate and linear alkyl benzene sulphonate surfactants

Application of immobilized microorganisms in the biodegradation of alkyl sulphate and linear alkyl benzene sulphonate surfactants

CoMFA analysis of biodegradability.

CoMFA (comparative molecular field analysis) has been used to correlate the biodegradability of several classes of compounds. The technique uses an atomic probe to detect the steric and electrostatic fields around a molecule. Good cross-validated correlations were obtained for some series (alcohols, carboxylic acids and linear alkyl benzene sulphonates). Correlations were weaker for esters and benzene sulphonates, and were non-existent for phenols. These results may reflect the unreliability of biodegradation data, but may also be a result of molecular misalignment in the CoMFA procedure. CoMFA appears to be a potentially very useful method for the prediction of biodegradability.

Modelling the kinetics of biodegradation of anionic surfactants by biofilm bacteria from polluted riverine sites: A comparison of five classes of surfactant at three sites

The capacity of epilithic bacteria from different riverine sites to biodegrade representatives of five classes of anionic surfactants, was quantified by analysis of biodegradation kinetics in die-away tests. The sampling sites in the River Ely, South Wales were located near a sewage treatment plant outfall. Indigenous stones from the riverbed were removed from sites immediately beneath the outfall (BO), and at sites 15 m upstream (BU) and 50 m downstream (BD). The five surfactants used were sodium dodecyl sulphate (representing primary linear alkyl sulphates, PLAS), Empicol R ESB3 S (alkyl ethoxy sulphates, AES), potassium undecyl-2-sulphate (secondary linear alkyl sulphates, SLAS), sodium 1-dodecane sulphonate (primary alkane sulphonates, PAΣ) and 5-phenyl dodecane sulphonate (linear alkyl benzene sulphonates, LABΣ). Irrespective of sampling site, the order of biodegradability assessed as the reciprocal of half-time for surfactant disappearance was PLAS > AES > SLAS > PAΣ > LABΣ. Within each surfactant class, the half-time decreased in the order BU > BD > BO. Non-linear regression analysis of the die-away data to several kinetic models which combined disappearance of surfactant by zero, first order or Michaelis-Menten kinetics, with growth (exponential or logistic) of competent cells, yielded as best fit the model involving exponential growth of competent cells with first-order disappearance of substrate. This model generated two biologically-significant parameters: K 1 which is equivalent to first-order rate constant in the die-away test at t = 0 (i.e. before growth distorts the population from its indigenous composition); and r, the specific growth rate of the biodegrading population in the die-away flask. For a given site, K 1 decreased in the order PLAS > AES > SLAS > PAΣ > LABΣ, reflecting their relative biodegradability. Values of r for the primary sulphate esters (PLAS and AES) were always greater than values for the other surfactants, especially the sulphonates (PAΣ and LABΣ), indicating that different sub-populations existed for the biodegradation of these classes. Moreover, lack of inter-site variation in this pattern suggested similar distributions of surfactant-biodegrading populations at each site. Values of { K 1 viable-cell count }, which is a measure of surfactant-biodegrading activity per unit of population, fell into two groups: higher values (i.e. > 10 −9h −1 cfu −1 ml) with little inter-site variation (∼3-fold) for sulphated surfactants, and lower values (mostly < 10 −10 h −1 cfu −1 ml) with much greater inter-site variation (> 30-fold) for sulphonates. These results indicated that the capacity to biodegrade sulphated surfactants was more widely distributed in bacteria than was the capacity to biodegrade sulphonates. This situation may have evolved as a result of selective pressure from exposure of bacteria to environments in which natural analogues of sulphated surfactants, but not of aryl sulphonates or LABΣ, are commonly present.