Cold Water Detergency of Triacylglycerol Semisolid Soils: The Effect of Salinity,Alcohol Type,and Surfactant Systems

Cold water detergency of triacylglycerol semisolid soils is much more challenging than liquid vegetable oils due to poorer interaction between surfactants and semisolid soil. This research seeks to improve the removal efficiency of semisolid soils below their melting points using surfactant-based formulations containing different alcohol additives. To this end, cold water detergency of solid coconut oil and solid palm kernel oil was investigated in various surfactant/alcohol systems, including single anionic extended surfactants, single nonionic alcohol ethoxylate surfactants, and a mixture of anionic surfactants. A series of alcohols (2-butanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol) were added to the surfactant formulations to investigate cold water detergency improvement. While cold water detergency using surfactants alone was poor, it was considerably improved when optimum salinity (S*) and 1-heptanol, 1-octanol, or 1-nonanol were introduced to the studied surfactant formulations. The maximum detergency of solid coconut oil exceeded 90% removal in the 0.1 w/v% C_14-15-8PO-SO₄Na/0.2 w/v% 1-octanol/4 w/v% NaCl system (a final optimized surfactant system) at a washing temperature of 10°C versus 22.9 ± 2.2% in the surfactant alone (not at optimum salinity and no additive). Further analysis showed that improved cold water detergency using surfactant/intermediate-chain alcohols/NaCl could be correlated with high wettability (low contact angle) as well as favorable surfactant system-soil interaction as observed by lower interfacial tension values. In contrast, the improved cold water detergency was observed to be independent of dispersion stability. This work thus demonstrates that surfactant system design, including additives, can improve cold water detergency of semisolid soils and should be further explored in future research.     

Laundry Detergency of Solid Nonparticulate Soil or Waxy Solids: Part II. Effect of the Surfactant Type

In this work, methyl palmitate with a melting point around 30°C was used as a model of waxy soil. Its detergency was evaluated with a hydrophilic surface (cotton) or a hydrophobic surface (polyester) using different surfactants: alcohol ethoxylate (EO9), sodium dodecyl sulfate (SDS), methyl ester sulfonate (MES), methyl ester ethoxylate (MEE), and two extended surfactants (C_12,14-10PO-2EO-SO₄Na and C_12,14-16PO-2EO-SO₄Na). The detergency efficiency at a 0.2 wt.% surfactant and 5 wt.% NaCl gradually increased while redeposition gradually decreased with increasing washing temperature in most studied surfactant solutions; this was observed both above and below the melting point of methyl palmitate on both studied fabrics. If the methyl palmitate was heated above the melting point when deposited on the fabric, it was better able to penetrate into the fabric matrix as compared to deposition below the melting point, resulting in poorer detergency for heated deposition, particularly for washing temperatures lower than the melting point. Among the surfactants studied, the nonionic surfactant (EO9) showed the highest detergency efficiency (73–94%) at any washing temperature especially on the polyester fabric. For washing temperatures below the melting point, detergency performance correlated well with the contact angle of surfactant solution on the solid methyl palmitate surface for all studied surfactants when salinity was varied. In this work, conditions resulting in the highest detergency below the melting point corresponded to the highest detergency above the melting point, suggesting this as a systematic approach to formulating below the melting point of the soil. Charge of particles or fabric was not observed to be important to the detergency mechanism, but steric factors resulting from surfactant adsorption were observed to be important mechanistic factors in waxy solid detergency.     

Laundry Detergency of Solid Non-particulate Soil or Waxy Solids: Part I. Relation to Oily Soil Removal Above the Melting Point

In this work, methyl palmitate or palmitic acid methyl ester, a monoglyceride, was used as both a model solid fat below the melting point and as an oily soil above the melting point. An anionic extended surfactant [branched alcohol propoxylate sulfate sodium salt (C₁₂₃‐(PO)₄‐SO₄Na)] was used to remove methyl palmitate from cotton and from polyester. Above the melting point (~30 °C) of methyl palmitate, the maximum oily soil removal was found to correspond to the lowest dynamic interfacial tension, as is common with liquid soils. Below the melting point, the lower the contact angle of the wash solution against the soil (indicating higher wettability), the higher the solid fat soil detergency. The removed methyl palmitate was found to be mostly in unsolubilized droplets or particles with a small fraction of micellar solubilization for both solid and liquid forms. The presence of surfactant can prevent the agglomeration of detached methyl palmitate particles in both liquid and solid forms, reducing redeposition and enhancing detergency. Below the melting point, the surfactant aids the solution wetting the surfaces, then penetrating the waxy solid, causing detachment as small particles, and dispersion of these particles. Unlike particulate soil detergency, electrostatic forces are not the dominant factor in fatty soil detergency.     

污垢组成、布基、去污条件对去污力评价的影响

介绍了在Ｌａｕｎｄｅｒ－Ｏｍｅｔｅｒ去污机中“Ⅲ类”浓缩粉和标准粉对人工皮脂污布和标准污布的去污力,讨论了污垢组成,基质和洗涤条件对去污力的影响,进一步,将此种去污力与实际污布在洗衣机中的去污力进行了比较。结果表明,人工皮脂污布在Ｌａｕｎｄｅｒ－Ｏｍｅｔｅｒ去污机中的洗洒结果更换近实际污布在洗衣机中的洗涤结果。     

Optimized Microemulsion Systems for Detergency of Vegetable Oils at Low Surfactant Concentration and Bath Temperature

Triglycerides and vegetable oils are amongst the most difficult oils to remove from fabrics due to their highly hydrophobic nature; this is all the more challenging as cold water detergency is pursued in the interest of energy efficiency. Recently, extended surfactants have produced very encouraging detergency performance at ambient temperature, especially at low surfactant concentration. However, the salinity requirement for extended surfactants was excessive (4–14%) and there is limited research on extended‐surfactant‐based microemulsions for cold water detergency (below 25 °C). Therefore, extended‐surfactant‐based microemulsions are introduced in this study for cold temperature detergency of vegetable oils with promising salinity and surfactant concentration. The overall goal of this study is to explore the optimized microemulsion formulations with low surfactant and salt concentration using extended surfactant for canola oil detergency at both 25 and 10 °C. It was found that microemulsion systems achieved good performances (higher than those of commercial detergents) corresponding to IFT value 0.1–1 mN/m with the surfactant concentration as low as 10 ppm and 4% NaCl at 25 °C, and as low as 250 ppm and 0.1% (1000 ppm) NaCl at 10 °C. In addition, microemulsion systems were investigated with a different salt (CaCl₂, or water hardness, versus NaCl) at 10 °C, demonstrating that 0.025% CaCl₂ (250 ppm) can produce good detergency; this is in the hardness range of natural water. These results provide qualitative guidance for microemulsion formulations of vegetable oil detergency and for future design of energy‐efficient microemulsion systems.     

Microemulsion Formation and Detergency with Oily Soil: IV. Effect of Rinse Cycle Design

The objective of this work was to apply a microemulsion-based formulation for the removal of motor oil in laundry detergency at low salinity. To produce the desired phase behavior, three surfactants were used: alkyl diphenyl oxide disulfonate (ADPODS), sodium dioctyl sulfosuccinate (AOT) and sorbitan monooleate (Span 80). The mixed surfactant system of 1.5% ADPODS, 5% AOT and 5% Span 80 (13 parts ADPODS, 43.5 parts AOT, and 43.5 parts Span 80 of the total actives) was found to form a middle phase microemulsion (Type III) at a relatively low salinity of 2.83% NaCl. When this formulation was diluted, detergency performance increased with increasing total surfactant concentration and leveled off above about 0.1% total actives on the three types of fabrics studied (pure cotton, 65/35 polyester/cotton blend, and pure polyester). Detergency was found to improve with increasing hydrophilicity of the fabric with cotton being cleanest after washing and polyester the most difficult to clean. To achieve a specified oil removal, less rinse water can be used if a higher number of lower-volume rinses are employed. An interesting characteristic of microemulsion-based formulations is that a substantial fraction of oil removal occurs during the rinse cycle. In this work, this removal is shown to be due to the low oil/water interfacial tension during initial rinsing and is therefore strongly correlated to residual surfactant concentration in the rinse steps. As a result, the number of rinses and the volume of water per rinse can profoundly affect detergency in these systems.

Synergistic Effect of Mixed Surfactant Systems on Foam Behavior and Surface Tension

Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.     

Polymer‐Cationic Surfactant Interaction: 1. Surface and Physicochemical Properties of Polyvinyl Alcohol (PVA)‐S‐Alkyl Isothiouronium Bromide Surfactant Mixed Systems

Surface properties of polyvinyl alcohol (nonionic polymer) and three synthesized cationic surfactants, namely, S‐alkyl isothiouronium bromide at different mole fractions of 1:9, 3:7, 5:5, 7:3, and 9:1, were investigated. The values of the surface parameters were discussed according to the type of interaction between the cationic surfactant and type of polymer studied. The S‐alkyl isothiouronium bromide surfactant molecules are positively charged molecules, and the PVA chains contain hydroxyl groups that are partially negatively charged centers. The comparison between the surface properties of the individual cationic surfactants and their mixture with PVA polymer showed that the mixed systems have some advantages over the individual cationic surfactants.     

Extended UNIQUAC model for correlation and prediction of vapor-liquid-liquid-solid equilibria in aqueous salt systems containing non-electrolytes. Part B. Alcohol (ethanol, propanols, butanols)-water-salt systems

The Extended UNIQUAC model for electrolyte solutions is an excess Gibbs energy function consisting of a Debye-Hückel term and a term corresponding to the UNIQUAC equation. For vapor-liquid equilibrium calculations, the fugacities of gas-phase components are calculated with the Soave-Redlich-Kwong equation of state. The model only requires binary, temperature-dependent interaction parameters. It has previously been used to describe the excess Gibbs energy for aqueous electrolyte mixtures and aqueous electrolyte systems containing methanol. It has been found to be an adequate model for representing solid-liquid-vapor equilibrium and thermal property data for strongly non-ideal systems. In this work, the model is extended to aqueous salt systems containing higher alcohols. The calculations are based on an extensive database consisting of salt solubility data, vapor liquid equilibrium data, and liquid-liquid equilibrium data for solvent mixtures and for mixed solvent-electrolyte systems.The application of this model to represent the vapor-liquid-liquid-solid equilibria in aqueous systems containing various non-electrolytes (ethanol, 1-propanol, 2-propanol, 1-butanol, 2- butanol, 2-methyl 1-propanol, 2-methyl 2-propanol) and various ions (Na⁺, K⁺, NH₄⁺, Cl⁻, NO₃⁻, SO₄²⁻, SO₃²⁻, HSO₃⁻, CO₃²⁻, and HCO₃⁻) shows the capability of the model to accurately represent the phase behavior of these kinds of systems.     

Effect of organoclay purity and degradation on nanocomposite performance, Part 1: Surfactant degradation

The alkylammonium surfactants used to form commercial organoclays are known to begin to degrade at temperatures below the typical melt processing temperatures of some polymers. In this study, the thermal stability and degradation of various surfactants and their corresponding organoclays were investigated. Several factors, such as surfactant type and excess surfactant in the organoclay, that affect the thermal stability of surfactants on organoclays are explored. Nuclear magnetic resonance (NMR) spectroscopy was used to analyze the decomposition products. Thermogravimetric analysis (TGA) was used as the primary method to characterize the thermal stability of these surfactants and organoclays; the neat surfactants lose mass more rapidly, at a given temperature, than the corresponding organoclay. Washing the organoclay with methanol proved to be an effective way to remove the excess surfactant from the clay galleries. Such purification generally improves the thermal stability of the as-received organoclays. Depending on the availability of residual halide anions in the organoclay, the organoclays decompose via either S_N2 nucleophilic substitution or Hoffmann elimination pathways.     

Effect of a Spacer Group on Surface Activity, Salinity and Hardness Tolerance, Mimic Oil Washing Efficiency of Monododecyl Diaryl Disulfonate

Three anionic surfactants of the monododecyl diaryl disulfonate type (MDDADS-n, n = 0, 1, 2) were synthesized. The structural characters of MDDADS-n surfactants were verified by electrospray ionization/mass spectrometry. The effect of the spacer group on the surface activity, salinity and hardness tolerance and mimic oil washing efficiency were investigated. The results showed that the critical micelle concentration (CMC), surface tension at CMC, C₂₀ and the minimum area per molecule of the anionic surfactants increased when the spacer group length increased. There was less effect on mimic oil washing efficiency of MDDADS-n when the spacer group changed; meanwhile, they displayed higher mimic oil washing efficiency in salt solution (NaCl or CaCl₂) than that of sodium dodecylbenzenesulfonate (SDBS); all MDDADS-n surfactants showed much lower sensitivity to water hardness than SDBS, what would be beneficial to enhancing oil recovery in a high salinity oil field.     

Dissolution of Soap Scum by Surfactants. Part III. Effect of Chelant Type on Equilibrium Solubility and Dissolution Rate of Calcium and Magnesium Soap Scums in Various Surfactant Systems

Soap scum can be effectively removed by using an appropriate surfactant with a chelating agent at a high solution pH. The equilibrium solubilities and dissolution rates of two model soap scums [calcium stearate and magnesium stearate: Ca(C₁₈)₂ and Mg(C₁₈)₂] were investigated in aqueous solutions containing three different types of surfactants [methyl ester sulfonate (MES) as an anionic surfactant; alcohol ethoxylate (EO9) as a nonionic surfactant; and dimethyldodecylamine oxide (DDAO) as an amphoteric surfactant] in the presence of different biodegradable chelants: trisodium ethylenediamine disuccinic acid (Na₃EDDS) and tetrasodium glutamate diacetic acid (Na₄GLDA) compared with disodium ethylenediamine tetraacetate (Na₂EDTA), a chelant with poor biodegradability. The highest equilibrium solubility and dissolution rate of either soap scum were observed at high pH in the DDAO system with Na₄GLDA. In addition, the calcium soap scum had a similar to higher equilibrium solubility and a higher dissolution rate constant as compared with the magnesium soap scum.     

Dissolution of Soap Scum by Surfactant. Part II: Effects of NaCl and Added Chelant on Equilibrium Solubility and Dissolution Rate of Calcium Soap Scum in Amphoteric Surfactant Solutions

The effects of solution pH and NaCl on the equilibrium solubility and dissolution rate of a model soap scum (calcium octadecanoate or calcium stearate) in aqueous solutions of dimethyldodecylamine oxide surfactant (DDAO) with and without chelant disodium ethylenediaminetetraacetate are reported. The equilibrium solubility and dissolution rate of soap scum increased with increasing solution pH when the chelant was added in the DDAO system while in the chelant-free systems the opposite trend was observed. The added NaCl has an ambiguous effect on the solubility and dissolution rate of soap scum in the absence of chelant, but a small level of added NaCl reduces both solubility and the dissolution rate constant in the presence of chelant. Both equilibrium and kinetics of dissolution are maximized at high pH with DDAO/chelant and no added salt.     

On the Effect of pH,Temperature, and Surfactant Structure on Bovine Serum Albumin–Cationic/Anionic/Nonionic Surfactants Interactions in Cacodylate Buffer–Fluorescence Quenching Studies Supported by UV Spectrophotometry and CD Spectroscopy

Due to the fact that surfactant molecules are known to alter the structure (and consequently the function) of a protein, protein–surfactant interactions are very important in the biological, pharmaceutical, and cosmetic industries. Although there are numerous studies on the interactions of albumins with surfactants, the investigations are often performed at fixed environmental conditions and limited to separate surface-active agents and consequently do not present an appropriate comparison between their different types and structures. In the present paper, the interactions between selected cationic, anionic, and nonionic surfactants, namely hexadecylpyridinium chloride (CPC), hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), polyethylene glycol sorbitan monolaurate, monopalmitate, and monooleate (TWEEN 20, TWEEN 40, and TWEEN 80, respectively) with bovine serum albumin (BSA) were studied qualitatively and quantitatively in an aqueous solution (10 mM cacodylate buffer; pH 5.0 and 7.0) by steady-state fluorescence spectroscopy supported by UV spectrophotometry and CD spectroscopy. Since in the case of all studied systems, the fluorescence intensity of BSA decreased regularly and significantly under the action of the surfactants added, the fluorescence quenching mechanism was analyzed thoroughly with the use of the Stern–Volmer equation (and its modification) and attributed to the formation of BSA–surfactant complexes. The binding efficiency and mode of interactions were evaluated among others by the determination, comparison, and discussion of the values of binding (association) constants of the newly formed complexes and the corresponding thermodynamic parameters (ΔG, ΔH, ΔS). Furthermore, the influence of the structure of the chosen surfactants (charge of hydrophilic head and length of hydrophobic chain) as well as different environmental conditions (pH, temperature) on the binding mode and the strength of the interaction has been investigated and elucidated.     

砂姜黑土区施用氮磷钾肥对优质小麦产量的影响

在砂姜黑土上种植优质小麦时，氯磷有机肥或氯磷钾配施是高产优质的重要措施，施用氯磷钾肥的合适比例为16：9：8。     

Effect of Amino Acids on Micellization,Surface Activity and Micellar Properties of Nonionic Surfactant Hexadecyl Alcohol Ethoxylate (25EO) in Aqueous Solutions

The effects of amino acids (dl ‐glycine, dl ‐alanine, dl ‐phenylalanine, dl ‐serine, l ‐leucine, l ‐aspartic acid, l ‐lysine) on the micellization, surface activity, viscometric and aggregation properties of hexadecyl alcohol polyethoxylate (25EO) in aqueous solution were studied. The critical micelle concentration and free energy of micellization were evaluated and discussed. The surface excess concentration, the minimum area per molecule, the surface pressure at the critical micelle concentration and the standard free energy of adsorption were obtained from surface activity studies. On the basis of the determination of the relative viscosities on concentration, the viscosity B‐coefficients of the Jones–Dole semiempirical equation were calculated for the premicellar and postmicellar regions. The method of fluorescence quenching was used for determination of the micellar aggregation number of hexadecyl alcohol polyethoxylate (25EO) in aqueous solution in the presence of amino acids. It was found that among studied amino acids serine shows behavior that is different from that of the other neutral amino acids.     

Complexation of Surfactant/β‐Cyclodextrin to Inhibit Surfactant Adsorption onto Sand,Kaolin, and Shale for Applications in Enhanced Oil Recovery Processes. Part II: Dynamic Adsorption Analysis

Surfactant adsorption onto solid surfaces is problematic in some industrial processes, such as in surfactant flooding for enhanced oil recovery. In this work, it was hypothesized that the use of a surfactant delivery system could prevent surfactant adsorption onto solid surfaces. Therefore, the encapsulation of sodium dodecyl sulfate (SDS) into the hydrophobic core of β‐cyclodextrin (β‐CD) to generate a surfactant delivery system (SDS/β‐CD) was evaluated in this work. This complexation was characterized using optical and scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT‐IR). Dynamic adsorption evaluation was applied to determine the effectiveness of the complexation in inhibiting surfactant adsorption onto a variety of solid adsorbents including sand, and mixtures of sand–kaolin and sand–shale. Surfactant adsorption was also evaluated applying the quartz crystal microbalance technology (QCM‐D). The formation and morphology of the complexation was confirmed by optical microscopy, SEM, and FT‐IR. Dynamic adsorption tests demonstrated the effectiveness of the surfactant delivery approach in preventing the adsorption of surfactant (up to 74 % adsorption reduction). The QCM‐D technology confirmed these observations. Several mechanisms were proposed to explain the inhibition of surfactant adsorption including steric hindrance, self‐association of inclusion complexes, hydrophilicity increase, and disruption of hemimicelles formation.     

Hydrothermal pretreatment for deconstruction of plant cell wall: Part II. Effect on cellulose structure and bioconversion

Influences of both ultrastructural modification of cellulose after hydrothermal pretreatment and products derived from lignin‐carbohydrate complex (LCC) on the subsequent enzymatic digestibility and fermentation were studied in this study. Under hydrothermal conditions, it was found that the rearrangement of hydrogen bonding pattern in cellulose via allomorph and conformational changes which was mainly severity‐dependent increased the numbers of water‐exposed glycosidic bond and the formation of “amorphous‐like” cellulose fibril facilitated enzymatic hydrolysis. Pseudo lignin, soluble xylo‐oligomers, phenols and degradation products from high severity impeded enzymatic digestion. LCC and phenols which were rich in pH‐controlled prehydrolyzate did not sufficiently inhibit yeast while furans and some aromatics which were rich in high‐severity prehydrolyzate might be potential inhibitors. Trade‐off phenomenon was solved by pH‐controlled operation and high yields in both glucose (83–93%) and xylose (75–80%) were simultaneously obtained. The final ethanol yield from cellulose to ethanol reached as high as 84–93%. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1954–1964, 2018     

Low‐modulus siloxane–polyurethanes. Part II. Effect of chain extender structure on properties and morphology

A series of six polyurethanes were prepared to study the effect of silicon chain extender structure on properties and morphology of siloxane–polyurethanes. Polyurethanes were prepared by a two‐step bulk polymerization without a catalyst. The soft segment of the polyurethanes was based on an 80:20 (w/w) mixture of α,ω‐bis(6‐hydroxyethoxypropyl) polydimethylsiloxane (PDMS, MW 966) and poly(hexamethylene) oxide (MW 714). The hard segment was based on 4,4′‐methylenediphenyl diisocyanate (MDI) and a 60:40 molar mixture of 1,4‐butanediol (BDO) and a silicon chain extender. Silicon chain extenders (SCE) investigated were 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD), 1,3‐bis(3‐hydroxypropyl)1,1,3,3‐tetramethyldisiloxane (BPTD), 1,4‐bis(3‐hydroxypropyl)1,1,3,3‐tetramethyldisilylethylene (HTDE), 1,3‐bis(6‐hydroxyethoxypropyl)1,1,3,3‐tetramethyldisiloxane (BETD). All polyurethanes were clear and transparent with number average molecular weights between 72,000 to 116,000. Incorporation of the silicon chain extender resulted in polyurethanes with low‐modulus and high elongation. This was achieved without significant compromise in ultimate tensile strength in all cases, except BETD. Differential scanning calorimetry (DSC) results showed that the silicon chain extenders did not significantly disrupt the hard segment crystallinity, but exhibited a unique morphological feature where SCE‐based hard segments formed separate domains, which may be the primary reason for achieving low modulus without significant compromise in strength. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1092–1100, 2003     

High intakes of Cr, Ni, and Zn in clinker: Part II. Influence on the hydration properties

This work presents the results of the hydration of cements with high intakes of Cr, Ni, and Zn. The cements were produced from clinkers that were doped with 200 to 25,000 ppm of heavy metal. Investigations on the clinkers were presented in Part I. In this paper the rate of heat generation of the cements in the first 2 days was analysed by differential scanning calorimetry. The hydration products were investigated by scanning electron microscopy combined with energy-dispersive X-ray spectrometer and also by X-ray powder diffraction. The initial setting of some samples was tested, as well as the strength. The results show that heavy metals only have an influence on the hydration properties of the cements if the dosage is much higher than in ordinary Portland cement.