Volume 52, Issue 6

Although microbial contaminations of domestic appliances are believed to gain importance, especially due to the trend towards lower cleaning temperatures, little is known about the existing microbial communities inside household washing machines. This study aimed to improve the knowledge of microbial composition of biofilms within household washing machines using a cultural-independent technology. Biofilms inside the detergent drawer and the rubber door seal of household washing machines were analysed using the 454-pyrosequencing method. The microbial community inside washing machines appeared to be highly diverse with Proteobacteria as the main prokaryotic and Basidiomycota and Ascomycota as the main fungal colonizers.

The aim of this study was to assess consumers' behavior in home hygiene with particular attention paid to hygiene in laundering. In this way, the applications of washing temperatures and detergents on textiles are evaluated. The data were obtained by using a questionnaire distributed at the “Action Day Sustainable Washing” arranged annually. The results of this sample provide a relevant insight into consumers' behavior: The consumer can generally estimate the level of infection risk coming from the different textiles. However, the majority of high risk textiles, such as cleaning cloths, are washed with detergents that do not contain any bleaching system. In view of the washing temperatures applied, the results indicate differences between the generations. This study clearly demonstrates the need for enhanced consumer communication regarding hygiene effectiveness in laundering.

From the viewpoints of prevention of garment damage as well as saving of electric energy and processing time in laundering, the possibility of time reduction by applying ultrasound has been discussed. The shake washing of polyester and cotton fabrics soiled with model oily and/or particulate contaminants together with their original fabrics was performed in an aqueous sodium dodecyl sulfate solution (SDS) without and with ultrasound. The soil removal and redeposition were evaluated from the change in the Kubelka-Munk function of the soiled and non-soiled fabric surfaces due to the washing. In the presence of ultrasound, the removal of oleic acid and carbon black from the polyester spun fabric was remarkably promoted, especially in the initial stage of the washing process. On the other hand, the soil redeposition gradually increased with wash time, especially for carbon black. Therefore, the removal and redeposition were compared between wash time 1 min and 5 min using some soils and fabrics. The soil removal was slightly larger for the 5 min-washing, whereas the soil redeposition was considerably prevented for the 1 min-washing. Comparing with a conventional washing with a drum type washer, the 1 min-shake/ultrasound combination washing had little impact damage in spite of having similar detergency power.

Oil-contaminated drill cuttings (OCDCs), often regarded as hazardous wastes, pose several environmental problems. Conventional methods exhibit certain drawbacks and limitations when used onsite. This paper developed a single-phase O/W microemulsion as a detergent and a practical processing method to treat OCDCs. The experimental results demonstrated that the oil retention could be reduced to a level that will allow offshore disposal. The used microemulsion and rinse water could be reused. The washed-out oil could be recycled to prepare oil based drilling fluid again when mixing with the same amount or greater of fresh base oil. Thus, the entire process of treatment was similar to microemulsion extraction. In the experiments, surfactant mixtures of sodium alcohol ether sulfate and n -butyl lactate were shown to form Winsor type I and type III microemulsions with N-pentyl propionate and linear Alpha Olefins C14 in the oil phase using a salinity scan. Two optimum formulas selected by the detergency performance were identified next to Winsor type III but still inside the Winsor type IV region, which is different from the lowest interfacial tension. By studying contact angle changes, one possible reason for this phenomenon was that for Winsor type III microemulsion, the higher concentration of surfactants cannot be washed away thoroughly with limited rinse water. The oil removal mechanism was also analyzed.

The aggregation behavior of promazine hydrochloride (PMZ) and bile salt (sodium taurocholate (NaTC)) mixtures at various compositions and temperature in pure and mixed states were studied using conductometry technique in aqueous solutions. The values of experimental and ideal critical micelle concentration ( cmc and cmc id ) propose attractive interactions in PMZ-NaTC mixtures. By applying the regular solution theory (RST) various physicochemical parameter such as micellar mole fraction in the mixed ( X 1 ) and ideal ( X 1 id ) state, interaction parameters ( β ), thermodynamic parameters of micellization as well as other related parameters have been evaluated and discussed in detail. The results show that the synergistic effect between drug and bile salt plays a crucial role in the redtdprefuction of the overall cmc value in aqueous solution at various composition of NaTC. The thermodynamic parameters recommend the discharge of water from the hydrophobic part of the PMZ at higher temperatures.

Simulations for the electrical percolation of AOT/iC 8 /H 2 O w/o microemulsions added with alkylamines have been carried out by means of multilayer perceptron. Five variables have been elected as inputs: amine concentration, molecular weight, log P, hydrocarbon chain length (as number of carbons), and pK a . As a result, a neural model consisting in five input neurons, two middle layers (with fifteen and ten neurons respectively) and one output neuron was chosen because of its better performance, with a RMSE of 0.54 °C for the prediction set, with R 2 = 0.9976.

The properties of a cationic slow-set emulsifier named INDULIN SBT in the absence and presence of Tween 40 and Tween 60 is investigated in this paper. After adding Tween 40 and Tween 60, the interfacial tension and dilatational modulus of SBT have remarkable changes. Compared with the pure SBT system, the interfacial properties of the mixed surfactant systems are improved obviously, especially if the ratio of the mixtures is 1 : 1. The Zeta potentials are also the lowest with favorable storage stability in these systems. At suitable ratios, synergistic adsorption may take place, resulting in remarkable enhanced interfacial properties. The combination of SBT and Tween 40 as well as Tween 60 could be used as surfactant mixtures applied in asphalt emulsions.

Polyaniline (PANI-EB) containing ZFe 2 O 4 (Z is an element in a divalent state; Z 2+ = Fe 2+ , Co 2+ , Ni 2+ , Mn 2+ , and Zn 2+ ) nanocomposites were successfully synthesized by using 1-butyl-3-methyl-imidazolium bromide [BMIM]Br and cetyl trimethylammonium bromide (CTAB) via in situ polymerization. Structural, morphological, spectroscopic and magnetic properties were investigated by transmission electron microscopy (TEM), X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM) respectively. The presence of polyaniline, [BMIM]Br and CTAB on the surface of the ZFe 2 O 4 nanoparticles was confirmed with FTIR. The purity of the products was proved by XRD. The results of thermogravimetric analysis indicated that the addition of ZFe 2 O 4 nanoparticles to PANI improved the thermal stability of the nanocomposites. The magnetization curves verify that the sample has ferromagnetic behavior at the temperature of 400 K. Magnetic measurements revealed that product has uniaxial anisotropy instead of expected cubic anisotropy according to the Stoner-Wohlfarth model.

The coupling of a silica static flat phase impregnated with an ionic liquid (1-methylimidazolium chloride) as stationary phase with 2-methyltetrahydrofuran an alternative green solvent of tetrahydrofuran as mobile phase has been very successful for a selective separation of sodium deoxycholate from other commonly used anionic surfactants. The proposed thin-layer chromatographic system is capable to analytically discriminate among the anionic surfactants in relation to their migration behaviour on an ionic liquid loaded silica layer. The surface structure and chemical composition of silica gel G modified by impregnation were examined with the aid of scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometry (EDX) respectively. Effects of concentration level of 1-methylimidazolium chloride as impregnant and its substitution by other ionic liquids (1,2,3-trimethylimidazolium methyl sulphate, 1-ethyl-3-methylimidazolium tetrafluoroborate) were also studied to decide the optimum experimental conditions for better separation possibilities. Chromatographic parameters such as ΔR F , the separation factor (α) and the resolution (R S ) for the separation and limit of detection were calculated. The developed method has been usefully applied for the identification of sodium deoxycholate and sodium lauryl sulphate in formulated and commercially available products (Colgate toothpaste and Head & Shoulder Shampoo).

The present paper describes the kinetics and mechanism for oxidation of D-arabinose by Cr(VI) in the presence of a micellar media. The anionic surfactant sodium dodecyl sulphate (SDS) and nonionic surfactant Triton-X-100 (TX-100) accelerate the process while the cationic surfactant N -cetylpyridinium chloride (CPC) retards the reaction. A suitable mechanism has been proposed. The reaction constants involved in different steps of the mechanism have been calculated. Formic acid and erythronic acid were reported as the products of oxidation of the sugar.

The photocatalytic degradation of copper(II) soaps derived from palmitic acid was carried out in the presence of semiconductor zinc oxide (ZnO) and was observed spectrophotometrically. The operational parameters such as concentration of soap, catalyst loading, light intensity, effect of solvent were investigated during the process. The studies suggest that the rate of the photocatalytic degradation increases with the increase in the concentration of soap to 800 ppm and then continuously decreases. Rate of degradation increases with the amount of semiconductor and with further increase in the amount of semiconductor, the rate becomes constant. The degradation is maximum at a light intensity of 38 mW cm −2 . An increase in the solvent polarity inhibits the rate of degradation. A tentative mechanism has also been proposed for the photocatalytic degradation of copper(II) palmitate soap.