Volume 51, Issue 3

Conventional surfactants are chemical species derived from various feed stocks and are consumed in large quantities for wide spread household as well as industrial applications. As most of the conventional surfactants have many limitations such as toxicity to humans and adverse effect on environment, the development of less irritant, less toxic, consumer-friendly surfactants is of immense importance. Arginine based surfactants, therefore, constitute a novel class of surfactants produced from renewable raw materials and can be seen as an alternative to conventional surfactants. Arginine based surfactants have good antimicrobial activity, good biodegradability and less human and aquatic toxicity. This review paper deals with the synthesis of different class of arginine based surfactants. Besides this, different biological and surface active properties of arginine based surfactants have also been described.

Colloidal systems containing droplets or bubbles are important for a wide variety of practical products and industrial processes i. e. control of filtration, cleaning emulsions, fire extinguishing foams, preparing foods or formulating personal care products. The study investigates the structure and stability of foam and emulsion obtained from different surfactants used as a potential compounds of fire fighting agent or removal of chemicals. The optical microscope Olympus BX51 (USA) for purpose of structure observation was used. The foamability of micellar surfactant solutions was tested with perforated disc beating method. Emulsions were prepared with 0.05 – 5 % solution of surfactants and diesel oil. The stability was monitored by measuring the volume of separated phases and recorded after 30 min since the homogenization was performed. The foamability as well as emulsion stability of the surfactant solutions depends on the chemical character of compounds.

The foaming capability, which is related to the ratio of surfactants, the dosage and the crystallization rate of ethylene glycol distearate (EGDS), is discussed. By the same progress, with the proportion of ammonium lauryl sulfate (AESA) being increased, the foam height of the body care product is linearly improved. The crystal features of EGDS and pearlescence quality of the body care products are strongly linked to the surface aspect, the size distribution of EGDS crystals and their level of aggregation. Comparing the different crystallization processes, when rapidly being cooled with cold water and stirred at the speed of exceeding to 1 000 rpm, the aggregation of the crystals is decreased, and the pearlescence of the body care product is poor. When being ordinary cooled at room temperature and stirred at the speed of no more than 500 rpm, the aggregation of the crystals is increased, and the pearlescence of the body care products is obvious. The microstructures reveal that the oil drops are pierced to smaller by the EGDS needle crystals. Then the smaller oils act as antifoaming agents to cut down the foam height of the body care product. Consequently, the foam height of the body care products with good pearlescent effect is decreased. Furthermore, being added silicone oil emulsion, the foam height falls faster because of demulsifying. The result shows that the silicone oil and the needle-like crystals have a negative synergistic effect on foaming in the body care products.

The wetting abilities of amine oxide surfactants (dodecyl dimethylamine oxide, DDMAO and dihydroxyethyl dodecylamine oxide, DDEAO), alcohol ether sulfate (AES), ethoxylated alcohols with different number of ethylene oxide units (AEO n , n = 3, 5, 7, 9) and mixtures of amine oxides with AES and AEO n were measured according to the canvas descending method. The effect of surfactant concentration, surfactant type, number of ethylene oxide unit and temperature on the wetting ability of mixed systems has been analyzed. The results show that the wetting abilities of DDEAO and DDMAO are better than those of AES, AEO 9 and AEO 3 , and similar to those of AEO 5 and AEO 7 . For all mixed systems, the optimum wetting ability appears at equal weight mixtures in the weight ratio range investigated. These mixtures show a synergistic effect. Higher temperatures imply higher wetting ability in aqueous mixtures of DDMAO with AES and AEO 3 at weight ratio = 1 : 1.

The aim of this study was to test whether the HPLC method for determining the n -octanol/water partition coefficient (log P ow ) data of chemicals could be applied to alcohol ethoxylates (non-ionic surfactants). In order to carry out this evaluation, the range of the standard calibration line first had to be extended from 0 – 6 (OECD 117) to 0 – 9. Experimental studies confirmed that the components of alcohol ethoxylates were eluted from the HPLC column in order of their predicted hydrophobicity. The HPLC method has proved to be particularly advantageous for the determination of log P ow values for alcohol ethoxylate products as it can generate data for highly hydrophobic material (log P ow > 6) and has sufficient resolving power to separate individual alcohol components from their ethoxylated moieties. This adapted HPLC method could be used to generate data for REACH submissions.

A low cost and environment-friendly agriculture waste material, orange peel, was investigated for the removal and accumulation of Pb(II) from water and wastewater. Orange peel treated with acid (AOP) as well as converted into carbon (COP) and the effect of various parameters on biosorption of Pb(II) on AOP and COP was studied. The biosorption of Pb(II) was found to be pH dependant in both cases and maximum biosorption of Pb(II) (100 %) on AOP was achieved at pH 6 and 60 min shaking time while using COP the maximum biosorption (100 %) was obtained at pH 5.5 and 80 min contact time. The monolayer biosorption capacities of AOP and COP were found to be 1 040 mg g −1 and 993 mg g −1 using Langmuir isotherm at room temperature respectively. Similarly Freundlich empirical constants, K F and n obtained for Pb(II) on AOP and on COP were 0.453 L g −1 , 1.90 and 0.334 L g −1 , 2.51 respectively. For the kinetic study of biosorption of Pb(II) on AOP and COP pseudo-first-order and pseudo-second-order intraparticle diffusion and Elovich models were applied. The data showed that pseudo-second-order model (R 2 = 0.9820) was the best choice among the kinetic models for description of biosorption of lead on AOP and COP. Thermodynamic parameters, the change of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of Pb(II) biosorption on AOP and COP were calculated and showed spontaneous endothermic behaviour of Pb(II) biosorption. The effect of interfering ions (Na + , K + , Mg 2+ , and Ca 2+ ) were also studied on biosorption of Pb(II) on AOP and COP. The concentration of HNO 3 solutions were optimized for recovery of Pb(II) after biosorption.

The corrosion and scale inhibition properties of acrylic acid-oxalic acid-allylpolyethoxy carboxylate (AA-APEM9) were investigated by determining the corrosion and scale inhibition efficiency, the Tafel polarization curve and significant control of CaCO 3 scales. The AA-APEM9 exhibits the highest inhibition efficiency of 81.4 % when the carbon steel immersion in 3 % NaCl solution. AA-APEM9 possess excellent CaCO 3 inhibition, approximately 70.2 % at threshold dosage of 6 mg/L. Compared to T-225, HPMA, PAA, PESA, AA-APEM9, possessing PEG, shows a superior inhibitory efficiency. AA-APEM9 has the best inhibition because of possessing the greatest degree of polymerization of PEG among it. SEM and TEM images indicate that AA-APEM9 changes highly the morphology and size of CaCO 3 crystals during the inhibition process. XRD analysis shows that the AA-APEM9 copolymer influence CaCO 3 crystal crystallinity. AA-APEM9 may be a potentially useful corrosion and scale inhibitor in a cooling water system.

In an attempt to control Ca 3 (PO 4 ) 2 and iron(III) scaling in cooling water systems, a water-soluble copolymer, acrylic acid-oxalic acid-allylpolyethoxy carboxylate-8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (pyranine) (AA-APEM-APTA) was examined as an environmentally friendly inhibitor. Structures of APTA, APEM, and AA-APEM-APTA were determined by FT-IR and 1 H-NMR. The observation shows that t he dosage of AA-APEM-APTA plays an important role on Ca 3 (PO 4 ) 2 inhibition. The performance of copolymer on inhibition of Ca 3 (PO 4 ) 2 precipitation was compared with that of current commercial inhibitors. It was shown that the copolymer exhibited an excellent ability to control inorganic minerals, with approximately 94.7 % Ca 3 (PO 4 ) 2 inhibition. Correlation coefficient R 2 of AA-APEM-APTA's is 0.9975. The effect on formation of Ca 3 (PO 4 ) 2 was investigated with combination of scanning electronic microscopy (SEM) and X-ray powder diffraction (XRD) analysis. The polymer had good dispersing ability with respect to iron(III). AA-APEM-APTA can be used to measure accurately polymer consumption on line besides providing excellent Ca 3 (PO 4 ) 2 inhibition and dispersing to iron(III).

To study the effect of tuned head group polarity on physicochemical properties of cetyl trimethyl ammonium bromide has been studied by conductance, surface tension and viscosity measurements. The critical micelle concentration was determined by conductance and surface tension measurements. Conductance measurement data was used to compute critical micelle concentration, average degree of micelle ionization and thermodynamic parameter of micellization. Surface tension data were further used to determine the surface excess concentration, minimum area per molecule at air-water interface. The decrease in effective Gibb's free energy with increase in head group polarity indicates that the micellization process is more favored over adsorption at the air-water interface. The intrinsic viscosity and hydration of micelle were observed to increase with increase in head group polarity and decrease with increase in temperature.

Studies of the interaction between water soluble PEO-PPO-PEO triblock copolymers (Pluronic ® polymers) and ionic/nonionic surfactants are of significant interest because the polymer–surfactant mixtures are used widely in industrial and domestic formulations. The aggregation behavior of Pluronic ® L64, EO 13 PO 30 EO 13 , in absence and presence of conventional nonionics (PEG1500, Tween80, Brij98) and block copolymeric nonionics (F68, F127, P123) was investigated by cloud point, surface tension, viscosity and UV-Visible spectroscopic measurements. Most of the studied nonionic surfactants increase the CP of Pluronic ® L64 through the formation of mixed micelles of L64 and nonionics, respectively. Only PEG1500 have decreased the CPs of Pluronic ® L64. In present study, the effects of PEG1500 and copolymeric F127 on aggregation behavior of Pluronic ® L64 were studied. The surface parameters of adsorption and micellization for Pluronic ® L64 and its mixtures with nonionics were also determined. Newer way, Indian solid gold, curcumin has been used to study the interaction between Pluronic ® L64 and nonionic surfactants. Results confirmed that Pluronic ® L64 interacts with copolymeric F127 through formation of mixed micelles between them, and conventional PEG1500 only increased the polarity of the medium and no noticeable interaction or formation of mixed micelles was observed.

ESIFORM Systems are used for surfactants, detergents and other chemicals in order to produce pastilles out of melted products, combining solidification with granulation. These pastilles are opposite to flakes, strips or spraying granulates free of dust, free flowing, easy to fill in and have nearly no tendency at all for blocking or agglomeration as well as they have a higher bulk density with an ideal shape when passing them over to the next step of further processing specially suitable for reliable transport in bulk handling systems such as bagging systems and big-bag filling stations.