Band 59, Heft 3

Every day, dirty dishes and cutlery have to be cleaned in millions of households worldwide. From a scientific point of view, the question of “how” is particularly interesting, because everyday household chores hold great potential for saving resources. This review summarises the current state of knowledge about dishwashing. In general, electric dishwashing proves to be significantly more resource-efficient than manual dishwashing, with comparable or better cleaning results. However, the extent of this depends on consumer behaviour. Therefore, best practice tips (BPT) for manual and electric dishwashing as well as ideas for educating consumers are also collected in this review.

Sodium oxalate (Na 2 C 2 O 4 ) is an excellent phosphorus-free agent, but in sodium oxalate-containing detergents with sodium dodecylbenzene sulfonate (SDBS) and sodium carboxymethyl cellulose (CMC), significant ash deposition occurs on cotton fabrics. SDBS is the main anionic surfactant in modern detergents and cotton fiber is the most commonly used textile fiber. In this study, sodium lignosulfonate (LS) was investigated for its ability to prevent redeposition in SDBS-Na 2 C 2 O 4 -CMC-LS formulations. The effects of LS on ash content, whiteness, optimum washing temperature, calcium oxalate morphology, zeta potential and surface tension were carefully analyzed. The results showed that the addition of LS significantly improved the prevention of ash deposits on cotton fibers. The ash content was less than 0.46% and a small amount of particles were scattered on the cotton fibers. LS showed good dispersibility but had little effect on the washing power and zeta-potential.

The aim of the present study was to formulate a fluconazole cream for the treatment of Candida albicans. The optimized cream formulation was prepared using stearic acid, oleic acid, beeswax and borax. The uniform distribution of the active ingredient fluconazole could be confirmed in all formulated creams. The FC-C-C formulation showed satisfactory spreadability and extrudability. FC-C-C delivered (95.07 ± 15.85)% in only 36 h, and the formulation released the drug by an anomalous diffusion mechanism. The viscosity of FC-C-C was found to be (63.20 ± 0.83) cP. The antifungal study and animal studies confirmed that the prepared formulation is non-irritant and has an enhanced antifungal activity that reduces the side effects of fluconazole. The studies confirm that the prepared formulation may be useful for the treatment of Candida albicans .

The influence of surfactant synergism between sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine Oxide (DDAO) on zinc corrosion in 0.05 M hydrochloric acid (HCl) solutions at 25 °C was investigated. Firstly, solutions of SDBS and DDAO with mole fractions of 0.00, 0.25, 0.50, 0.75 and 1.00 were prepared and their surface tension and critical micelle concentration (CMC) values in water and in 0.05 M HCl were measured as a function of total surfactant concentration. The SDBS/DDAO mixed system exhibited a strong synergism in 0.05 M HCl with a highly negative interaction parameter β (average β  = −23.46), according to regular solution theory. Secondly, the adsorption of single surfactants SDBS and DDAO and SDBS/DDAO surfactant mixture on 2.0% zinc powder was investigated by the depletion method to find out the role of synergism in the adsorption tendency of these surfactants on the zinc surface and thus their corrosion inhibiting effect. The adsorption tendency of single surfactant and the mixed surfactant systems onto 2.0% zinc powder followed the order: SDBS > 0.75 SDBS/0.25 DDAO ≈ 0.25 SDBS/0.75 DDAO > DDAO > 0.50 SDBS/0.50 DDAO. Finally, the corrosion of zinc was investigated using the potentiodynamic polarization technique. It was found that SDBS and DDAO act as efficient corrosion inhibitors for zinc in 0.05 M HCl solution with increasing corrosion inhibition efficiency when they are mixed. Additionally, images of scanning electron microscopy were obtained for zinc sheets in solutions containing single and mixed SDBS/DDAO surfactants in the presence and absence of 0.05 M HCl. The microscopic images show an improvement in the protection of the zinc surface against acid attack in the presence of single and mixed SDBS/DDAO surfactants.

In the present work, sodium 2-laurylamido isobutyrate was synthesized from 2-aminoisobutyric acid, NaOH and lauroyl chloride by the Schotten-Baumann condensation. Fourier transform infrared spectroscopy, mass spectroscopy and nuclear magnetic resonance spectroscopy were used to characterize the products, and confirming the successful synthesis of sodium 2-laurylamido isobutyrate. The influence of temperature on the surface tension of sodium 2-laurylamido isobutyrate was studied, comparing the chemical properties of the surface with those of sodium N-lauroyl sarcosinate. The results indicate that both surfactants have a similar p C 20 , while the critical micelle concentration (CMC) and the surface tension at the critical micelle concentration ( γ CMC ) of sodium 2-laurylamido isobutyrate are higher than those of sodium N-lauroyl sarcosinate. Further studies on the thermodynamic parameters of sodium 2-laurylamido isobutyrate and sodium N-lauroyl sarcosinate indicate that the formation of micelles is a spontaneous exothermic process mainly driven by entropy. According to the dynamic surface tension of sodium 2-laurylamido isobutyrate and sodium N-lauroyl sarcosinate, the molecular adsorption of the two components mixture change from the initial diffusion controlled adsorption to the later mixed dynamic controlled adsorption.

The aim of the present work is to develop a fast and simple methodology of analysis of the degree of ethoxylation (ethylene oxide content – EO) of linear C12–C15 fatty alcohol ethoxylates using Fourier transform infrared spectroscopy with attenuated total reflectance accessory. The spectra were recorded in the range of 2000 cm −1 to 600 cm −1 , with 64 scans and a resolution of 4 cm −1 . The calibration of a linear model using the partial least square regression method applied to the spectral data allowed determination of the ethylene oxide content of the samples. The regression coefficient obtained for the model was R 2  = 0.9948 and the precision of the model was 0.014. The methodology is an important tool for quality control of non-ionic surfactants used in manufacturing of a broad range of final products in the chemical industry.

The microflotation experiments were systematically carried out to investigate the inhibitory effect of citric acid (CA) on the flotation behavior of hornblende and magnesite. When the mixture consisted of sodium oleate and dodecyl phosphate was utilized as a mixed trapping reagent, CA could obviously inhibit the hornblende flotation but had little inhibitory effect on magnesite flotation. The desilication of magnesite flotation was accomplished when CA was employed as the hornblende inhibitor. Moreover, to reveal the adsorption mechanism of CA on the surfaces of hornblende and magnesite, a series of surface analysis techniques, such as X-ray photoelectron spectroscopy (XPS), zeta potential and Fourier transform infrared spectroscopy (FTIR), were conducted. Based on the zeta-potential and FTIR analyses, it is revealed that CA or CA together with collector (sodium oleate and dodecyl phosphate mixture) was applicable for the magnesite flotation tests. In the meanwhile, the introduced CA had obviously hindered the adsorption of sodium oleate and dodecyl phosphate mixtures on the hornblende surface, resulting in a significant difference in the flotation performance of hornblende and magnesite minerals. Moreover, XPS measurements revealed that the strong adsorption of CA on the hornblende surface can be ascribed to its affinity for the negative electron groups of CA and Ca ions.