Analysis of Linear Alkylbenzene Sulfonate in Waste Water and Sludge by High Performance Liquid Chromatography: An Exercise of Validation

Linear alkylbenzene sulfonate (LAS) an ingredient of many household and industrial detergents can reach the environment after disposal of raw sewage. Its correct detection and quantification in different environmental samples is a critical issue for evaluating its environmental fate. This paper outlines a validation of an entire analytical procedure of LAS in environmental samples, including extraction, pre-concentration and HPLC detection and quantification with fluorescence detection.

Degradation of Pesticides Wastewater by Silyl Based Cationic Surfactants

New stable silayl cationic surfactants have been studied for the destruction of toxic organophosphorus pesticides. Hexadecyl, dodecyl trimethyl silane ammonium chloride or iodide surfactants were synthesized and evaluated in the degradation of pesticides such as Diazinon, Malathion or Chlorpyrifos. The hydrolytic efficiency of each surfactant was tested by measuring the kinetics of model substrates cleavage under a pseudo-first order reaction. The iodo silayl based surfactants showed more destructive power than the chloro derivatives. Meanwhile, the hexadecyl moiety showed more effective pesticide degradation than the corresponding dodecyl moiety.

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Investigation of the Structure-Directing Effect of Surfactants on the Distribution of Silicate Species Using <Superscript>29</Superscript>Si-NMR Spectroscopy

Silicate anions were studied using ²⁹Si NMR to investigate the structure-directing effect of a surfactant (sodium dodecylsulfate-SDS) on the distribution of silicate species present in alkaline silicate solutions. The distribution of the anions in the presence of polyelectrolytes was also investigated by ²⁹Si NMR through the use of different bases including tetramethyl ammonium hydroxide (TMAOH) and sodium hydroxide (NaOH). Both SDS and the polyelectrolytic solutions were shown to stabilize low molecular weight silicate species and thus inhibit polymerization.

Synthesis of Polyaniline/Pd Nanoparticles via Ligand Exchange

Polyaniline/Pd nanoparticles were synthesized via ligand exchange. Pre-prepared water soluble starch/Pd nanoparticles were treated with polyaniline, and washed with water, leading to the small and well-dispersed polyaniline/Pd nanoparticles. The redox state of polyaniline was preserved during the ligand exchange reaction.

Application of manure to no-till soils: phosphorus losses by sub-surface and surface pathways

The acceleration of surface water eutrophication attributed to agricultural runoff has focused attention on manure management in no-till. We evaluated losses of phosphorus (P) in sub-surface and surface flow as a function of dairy manure application to no-till soils in north-central Pennsylvania. Monitoring of a perennial spring over 36 months revealed that dissolved reactive P (DRP) concentrations increased 3- to 28-fold above background levels whenever manure was broadcast to nearby field soils. A study conducted with 30-cm deep intact soil cores indicated that incorporation of manure by tillage lowered P loss in leachate relative to broadcast application, presumably due to the destruction of preferential flow pathways. More P was leached from a sandy loam than a clay loam soil, although differences between soils were not as great as differences between application methods. In contrast, rainfall simulations on 2-m² field runoff plots showed that total P (TP) losses in surface runoff differed significantly by soil but not by application method. Forms of P in surface runoff did change with application method, with DRP accounting for 87 and 24% of TP from broadcast and tilled treatments, respectively. Losses of TP in leachate from manured columns over 7 weeks (0.22–0.38 kg P ha⁻¹) were considerably lower than losses in surface runoff from manured plots subjected to a single simulated rainfall event (0.31–2.07 kg TP ha⁻¹). Results confirm the near-term benefits of incorporating manure by tillage to protect groundwater quality, but suggest that for surface water quality, avoiding soils prone to runoff is more important.

Synthesis of Unsymmetrical Bolaform Surfactants with a Sulfonate Group and a Carboxyl Group

Three unsymmetrical bolaform surfactants with different aromatic rings and a ω-carboxyalkyl chain were synthesized and their molecular structures were characterized by ESI–MS and ¹H NMR. The percentages of conversion of alkylation were judged by the iodine value measurements and the effect of reaction temperature on sulfonate content of synthesized products has also been discussed.

New Hydrophobic Intermediates of Aminodiester-Type via a Green,Michael-Addition Reaction

The conjugate Michael addition of methylamine to alkyl acrylates can be performed under mild conditions without a catalyst to obtain new hydrophobic intermediates of aminodiester-type. The reactants used strictly in 1:2 molar ratio provide almost quantitative yield of aminodiesters without formation of undesired aminoesters and any other by-products. Aminodiesters can be purified if necessary by classical methods. The alkyl chain length in the acrylates used has no influence on the results.

Self-Metathesis of 1-Octene Using Alumina-Supported Re<Subscript>2</Subscript>O<Subscript>7</Subscript> in Supercritical CO<Subscript>2</Subscript>

In this contribution we describe the use of heterogeneous catalysts for the liquid-phase self-metathesis of 1-octene in supercritical CO₂. Our work aims at addressing the mass-transfer problems associated with such reaction systems. By coupling a heterogeneous supported Re₂O₇ catalyst with the use of scCO₂, the self-metathesis of 1-octene takes place by and large much more rapidly than in traditional solvent media, and furthermore, by using scCO₂ the overall efficiency and sustainability of the transformation can be improved.

A Unified Survey of Applicability of Theories of Mixed Adsorbed Film and Mixed Micellization

Mixed micelles are an ever-interesting field in applied as well as academic research. An interesting problem is to determine the composition of the mixed monolayer and the micellar phase and interaction parameters among the individual components. Several theories have already been put forward to address these problems. In this work, we attempt to apply several theories to several experimental systems already published. Experimental elucidation of the proportion of individual components in such a mixed state of aggregation is impossible up till now to the best of our knowledge.

Synthesis and Physicochemical Investigation of Long Alkylchain Betaine Zwitterionic Surfactant

An effective and economic two-step route was developed to synthesize the long alkyl chain betaine zwitterionic surfactant directly from natural fatty acids. The optimal processing conditions for synthesizing the intermediate and final product were probed and the yields of 96.4% and 88.3% were obtained for each step, respectively. The surface active behavior of the synthesized decylbetaine surfactant was investigated using the surface tension method. The related thermodynamic parameters were calculated and discussed. The fluorescence probe technology was applied to determine the micropolarity of decylbetaine micelles.

Interactions of Sodium Dodecyl Benzene Sulfonate and Sodium Dodecyl Sulfate with Gelatin: A Comparison

The interaction of SDS/SDBS in aqueous gelatin solutions is studied above the gelation temperature by viscosity and circular dichroism (CD) measurements. The steep rise observed in the relative viscosity can be due the structural transitions leading to micellar growth of higher order. Circular dichroism spectra indicated that gelatin helped in inducing the sphere→rod transition, without suffering any conformational changes within it. The findings are particularly significant in terms of the head group contribution, hydrophobic interaction and the formation of formulated complexes.

Effects of Pin-up Oxygen on [60]Fullerene for Enhanced Antioxidant Activity

The introduction of pin-up oxygen on C₆₀, such as in the oxidized fullerenes C₆₀O and C₆₀O_n, induced noticeable increase in the antioxidant activity as compared to pristine C₆₀. The water-soluble inclusion complexes of fullerenes C₆₀O and C₆₀O_n reacted with linoleic acid peroxyl radical 1.7 and 2.4 times faster, respectively.

Review on Anionic/Cationic Surfactant Mixtures

It is commonly known that cationic and anionic surfactants cannot be mixed without the risk of precipitation or instability. However, many studies have shown that not only is it possible to combine cationic and anionic surfactants, but also that this combination can present synergic properties. Mixtures of anionic and cationic surfactants have many unique properties that can be very useful when used properly. The aim of this report is to present relevant information concerning the interaction between anionic and cationic surfactants. A bibliographic review on anionic/cationic mixtures is presented here in order to better understand their properties and possible synergic effects, as this is of practical importance for the chemical industry.

Synthesis and Characterization of some Alkyl Polyglycosides Surfactants

Alkyl polyglycosides (APGs) of different hydrocarbon chain lengths were prepared using an indirect method involving the condensation of fatty alcohol with dextrose. The chemical structures of the prepared compounds were confirmed using different spectroscopic techniques, primarily Fourier transform infrared spectroscopy, nuclear magnetic resonance and mass spectroscopy. The surface properties of the solutions containing different concentrations of the prepared APGs were determined at different temperatures. The results of the spectroscopic analysis demonstrate that these materials were prepared through the correct techniques, producing pure materials. The results of the critical micelle concentration (CMC) determination demonstrate that the surface properties of these compounds depend mainly on the nature of their hydrophobic component.

Analysis of Minor Products in Linear Alkylbenzene Sulfonation. Comparison Between the Traditional Gravimetric Method and High Performance Liquid Chromatography (HPLC) Procedures Versus High Temperature Gas Chromatography (HT-GC)

During the sulfonation process of the linear alkylbenzene (LAB) other products like sulfones and anhydrides are also formed in addition to the linear alkylbenzene sulfonic acid (HLAS). Most of them are transformed in different degrees during the aging and hydrolysis steps of the overall sulfonation process [Moreno et al. (2003) J Surfactant Deterg 6(2):137–142]. The use of HPLC technique since 1988 and earlier the use of high temperature gas chromatography (HT-GC) enable the separation and quantification of all the components of the free oil (FO) of the sulfonic acids—anhydrides; LAB and sulfones. The purpose of this paper is to review the current knowledge about the free oil analysis and to discuss a new analytical procedure based on the HT-GC to quantify the free oil content. We will compare the results obtained using this new method with other analytical procedures (traditional gravimetry) and near infrared (NIR) spectroscopy.

Gamma Irradiation of Silicones

Silicones in various forms have been utilized in biomedical applications over the past several decades. While silicone elastomers are currently the most common silicone biomaterial, low molar mass cyclic silicones, low molar mass linear silicones, silicone oligomers, silicone polymers and silicone gels have each found applications as biomaterials. For the biomedical applications of silicones, it is required that the materials be sterilized prior to application or implantation. Common methods of sterilization include steam sterilization, ethylene oxide sterilization, electron beam sterilization and gamma sterilization. In this review we will describe the behavior of various silicones upon exposure to gamma radiation.

Transition Metal Pnictide-Halides: A Class of Under-Explored Compounds

In terms of application, mixed anion compounds have attracted far less attention than mixed cation systems. Interest in the catalytic properties of nitrides has been driven, in part, by their accessibility through new, improved synthesis routes. Although attention in this area extends beyond simple binary systems, to our knowledge, studies have not yet probed the influence of mixed anion compounds. Accordingly, in this review we describe the structures and synthetic routes to transition metal pnictide-halides, which are predominantly nitride-based. It can be anticipated that some of these materials may have interesting catalytic properties, although they have yet to be explored.

Enhancement of the Antitumour Activity for the Synthesised Dodecylcysteine Surfactant using Gold Nanoparticles

In this paper, the surfactant dodecylcysteine hydrochloride was synthesised. The surface parameters of the synthesised surfactant were studied using a surface tension technique. The surface parameters show a good surface activity of the prepared surfactant in aqueous solution. The self-assembling behaviour of the synthesised surfactant comparing with that of cysteine compound on the prepared gold nanoparticles was confirmed using transmission electron microscope (TEM) measurements. The effect of self-assembling of this surfactant on the size of gold nanoparticles was studied using TEM images. The antitumour activity of the prepared surfactant without and with the gold nanoparticles was investigated. The results show that the antitumour activity of the prepared surfactant was enhanced with the presences of the gold nanoparticles.

Micellization of Cetyl Triphenyl Phosphonium Bromide Surfactant in Binary Aqueous Solvents

The effect of the different binary aqueous organic solvents viz. 1,4-dioxane, acetonitrile, dimethylsulfoxide, ethylene glycol, and methanol, on the micelle formation and thermodynamics of a cationic surfactant cetyl triphenyl phosphonium bromide has been studied conductometrically at 298–318 K. From the conductivity data critical micelle concentration, degree of counter ion dissociation (α) and thermodynamic parameters of micellization have been determined. It is observed that micellization tendency of the surfactant decreases in the presence of binary aqueous solvents. The entropies of micellization are all positive, and they compensate the enthalpies of the process.

Macro- and Microemulsion Silicone Softeners on Polyester Fibers: Evaluation of Different Physical Properties

In this research, polyester fabrics were treated with three concentrations (10, 20 and 30 g/L) of macro- and microemulsions of silicones in water at 30 °C by the padding method. The treated fabrics were then dried/cured at 130 °C for 40 s. Some of the physical and chemical properties of the samples are discussed. The drapeability of treated samples was lower and found to depend on the silicone particle size. Moisture absorbency of treated samples was also lower. Colorimetric properties of softener treated fabrics were evaluated with a reflectance spectrophotometer. Scanning electron microscope (SEM) examinations showed an aggregation of silicone particles on the fiber surface.