Industrial Surfactants Research Articles

Special issue: Industrial surfactants R&D—A tribute to George A. Smith

Special issue: Industrial surfactants R&D—A tribute to George A. Smith

Low-temperature decomposable industrial surfactant for stabilization of few-layered graphene in water

Surface-active agents, such as surfactant molecules, are essential for stabilizing liquid-exfoliated graphene and other 2D nanosheets in water through electrostatic or steric repulsion. It is important to note that surfactants are no longer necessary for solutions converted into thin films for electronic devices, sensors, and composite applications. High-temperature (∼400–500 °C) thermal annealing is one of the performed methods to remove surfactant molecules. However, the surfactant residues present on the graphene nanosheets by post-annealing may adversely impact the electronic properties of the graphene film, potentially resulting in additional doping and defects. To address this challenge, we report a low-temperature decomposable (∼320 °C), eco-friendly and industrially viable surfactant, i.e., coco-glucoside, for the efficient liquid-phase exfoliation and stabilization of graphene nanosheets in water. Compared with the well-studied surfactants in liquid exfoliation such as sodium dodecyl benzene sulphonate (SDBS) and sodium cholate (SC), ∼90 % of this surfactant molecules completely decomposed at ∼320 °C in an air atmosphere for coco-glucoside. Electrical conductivity studies suggested that annealing at 320 °C enhanced the conductivity by 15 times for the coco glucoside-stabilized graphene film; however, marginal change in the conductivity was observed for the SDBS and SC-stabilized graphene film. To demonstrate the viability of the concept, a wallpaper-based rapid fire alarm application utilizing coco glucoside-stabilized graphene/cellulose paper was demonstrated.

Molecular insights into fragrance release from SDS and SLES micelles

Understanding the interaction between fragrance and surfactant micelles is essential for formulators to develop performing fragrant products. The equilibrium of fragrances in micellar solution of two commonly used surfactants in home and body care industries, namely sodium dodecyl sulphate (SDS) and sodium lauryl ether sulphate (SLES), has been investigated. The difference between SDS and SLES in the release of fragrant compounds is assessed by headspace measurements and explained at a molecular level by the different solubilization sites of the perfume within the micellar systems. Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy (DOSY NMR) shows that SLES micelles solubilize less fragrance than SDS. Subsequently, a shift from fragrance positioning through the water phase from SDS to SLES system is shown with COSMOmic calculations. This study brings knowledge on fragrance/surfactant interactions and shows the interest of using a computational method to screen and compare fragranced surfactants systems allowing formulators to anticipate the performance of their products.

Sustainable Enzymatic Desizing of Cotton with Bio-surfactant Extracted from Soapnut

Surfactant is one of the major consuming auxiliaries in textile processing. The rising demand for petroleum-based surfactants is in focus and it is tremendously utilized to fulfil the need for surfactants in textile industries. These petroleum-based surfactants are one of the major pollutants of textile wastewater. Many attempts have been made to replace this with low toxicity to make the process sustainable. The present investigation works on the same objective to replace the petroleum-based surfactant from desizing by using soapnut extract as a wetting agent. The process was optimised by using a modern statistical technique of Response Surface Methodology [RSM]. The initial designing was conducted using 10 g/l soapnut extract and 2% enzyme for 30 min at 75 °C and found satisfactory results. Additional desizing experiments were performed to optimize the process using RSM with weight loss as the primary outcome. An optimised desizing recipe provided by DOE numerical optimisation, viz., a concentration of 10 g/l soapnut extract and 2% enzyme at 75 °C for 40 min, was performed to validate. The findings demonstrate that optimum weight loss (6.58%) and desirable levels of absorbency (14 s), whiteness (73.52), yellowness (22.84 indices, bending length (2.1 cm), Flexural rigidity (98.13 mg.cm), while minimally affecting tensile strength (10.77). Enzymatic desizing with synthetic or soapnut-extracted wetting agents yields identical results and satisfies performance standards for industrial use. The Sustainable way of enzymatic desizing of cotton with bio-surfactant extracted from soapnut may be the green alternative to synthetic surfactant-based desizing.

Unraveling How Antimicrobial Lipid Mixtures Disrupt Virus-Mimicking Lipid Vesicles: A QCM-D Study.

Single-chain lipid amphiphiles such as fatty acids and monoglycerides are promising antimicrobial alternatives to replace industrial surfactants for membrane-enveloped pathogen inhibition. Biomimetic lipid membrane platforms in combination with label-free biosensing techniques offer a promising route to compare the membrane-disruptive properties of different fatty acids and monoglycerides individually and within mixtures. Until recently, most related studies have utilized planar model membrane platforms, and there is an outstanding need to investigate how antimicrobial lipid mixtures disrupt curved model membrane platforms such as intact vesicle adlayers that are within the size range of membrane-enveloped virus particles. This need is especially evident because certain surfactants that completely disrupt planar/low-curvature membranes are appreciably less active against high-curvature membranes. Herein, we conducted quartz crystal microbalance-dissipation (QCM-D) measurements to investigate the membrane-disruptive properties of glycerol monolaurate (GML) monoglyceride and lauric acid (LA) fatty acid mixtures to rupture high-curvature, ~75 nm diameter lipid vesicle adlayers. We identified that the vesicle rupture activity of GML/LA mixtures mainly occurred above the respective critical micelle concentration (CMC) of each mixture, and that 25/75 mol% GML/LA micelles exhibited the greatest degree of vesicle rupture activity with ~100% efficiency that exceeded the rupture activity of other tested mixtures, individual compounds, and past reported values with industrial surfactants. Importantly, 25/75 GML/LA micelles outperformed 50/50 GML/LA micelles, which were previously reported to have the greatest membrane-disruptive activity towards planar model membranes. We discuss the mechanistic principles behind how antimicrobial lipid engineering can influence membrane-disruptive activity in terms of optimizing the balance between competitive membrane remodeling processes and inducing anisotropic vs. isotropic spontaneous curvature in lipid membrane systems.

Fast catalytic degradation of an industrial surfactant driven by Hemi-micellization on facile synthesized CuS nanoflower

Fast catalytic degradation of an industrial surfactant driven by Hemi-micellization on facile synthesized CuS nanoflower

РERSISTENT ORGANIC POLLUTANTS OF ECOSYSTEMS

. Тhе development of synthetic organic chemistry is always determined bу creating of new compounds and application in medicine (pharmaceutics), production of cleaning, cosmetic remedies and nutrient additives. The production and application of such compounds are of minimum harm for people and environment regarding to special toxicological and sanitary requirements are concerned. However, multi-tonnage production of lacquers, dyes, rubber, pesticides, disinfectors, plastics, mineral and synthetic lubricants and their stabilizers, industrial surfactants and detergents, fluorocarbons, organometallic compounds make a great harm to environment. In this article the physico-chemical and toxicological characteristics of the most important persistent organic pollutants (РОР) have been described. The possible approaches and technologies of РОР disposal have bееn considered іn the framework of Stockholm Convention. Research show that when determining the most appropriate method of POPs detoxification, it is necessary to take into account, in addition to technological, some more economic and social factors, pay attention to ensuring human health.

Biotechnological potential of microbial bio-surfactants, their significance, and diverse applications.

Globally, there is a huge demand for chemically available surfactants in many industries, irrespective of their detrimental impact on the environment. Naturally occurring green sustainable substances have been proven to be the best alternative for reducing reliance on chemical surfactants and promoting long-lasting sustainable development. The most frequently utilized green active biosurfactants, which are made by bacteria, yeast, and fungi, are discussed in this review. These biosurfactants are commonly originated from contaminated sites, the marine ecosystem, and the natural environment, and it holds great potential for environmental sustainability. In this review, we described the importance of biosurfactants for the environment, including their biodegradability, low toxicity, environmental compatibility, and stability at a wide pH range. In this review, we have also described the various techniques that have been utilized to characterize and screen the generation of microbial biosurfactants. Also, we reviewed the potential of biosurfactants and its emerging applications in the foods, cosmetics, pharmaceuticals, and agricultural industries. In addition, we also discussed the ways to overcome problems with expensive costs such as low-cost substrate media formulation, gravitational techniques, and solvent-free foam fractionation for extraction that could be employed during biosurfactant production on a larger scale.

Removal of perfluorooctanoic acid by MWCNT-modified carbon-doped titanium dioxide in a peroxymonosulfate/simulated sunlight system

Perfluorooctanoic acid (PFOA) is widely used as an industrial surfactant and has been detected in various aquatic systems. Herein, a series of multiwalled carbon nanotube (MWCNT)-modified carbon-doped TiO2 catalysts (xCNT/C-TiO2) were prepared through a one-step calcination process and applied as adsorptive photocatalysts. Characterization and density functional theory (DFT) calculation results revealed that carbon doping introduced impurity energy levels between the band structures of TiO2. Moreover, the MWCNTs acted as photosensitizers that expanded the wavelength absorption range. The xCNT/C-TiO2 composites achieved efficient adsorption through multiple pathways (metal-ligand interaction, electrostatic attraction, π-anion interaction, and hydrophobic adsorption), and the adsorbed PFOA was degraded by the simulated sunlight/xCNT/C-TiO2/peroxymonosulfate (PMS) systems. The 2CNT/C-TiO2 sample exhibited the highest PFOA removal efficiency and degraded more than 90 % of the organic contaminant (2 mg/L, defluorination rate of 39.2 %) in 3.5 h. Furthermore, PFOA could be removed during repeated usage of the catalyst system without chemically regenerating the photocatalyst. The enhanced adsorption and photocatalytic removal by xCNT/C-TiO2 were due to the following reasons: (i) the MWCNTs in the composites provided a different adsorption pathway than the pre-existing monodentate mode and introduced more hydroxyl groups that could adsorb PFOA; (ii) the carbon doping in the TiO2 lattice reduced the band gap, leading to the more efficient utilization of visible light; (iii) MWCNTs inhibited the recombination of photogenerated charge carriers caused by doping, and this also promoted the production of active species and the direct oxidation of PFOA by photo-induced holes. Finally, enhanced monodentate adsorption mode and photodegradation mechanism were proposed based on experimental results and DFT calculations.

Prediction of intensity of dispersion in surfactant solutions in vertical sparged bubble column

AbstractDispersion of liquid in bubble column is an important process in chemical and allied industries. In the present work, the dispersion characteristics of liquid phase in a bubble column is studied in three different surfactant solutions. A comparative analysis on the dispersion characteristics of liquid phase in different surfactants has been carried out. The gas holdup and mixing time are also analysed. The effect of different physiochemical properties and operating variables on the dispersion coefficient and gas holdup is examined. A novel model for the estimation of dispersion due to bubble motion has been developed which incorporates the effect of gas holdup, liquid viscosity and circulation velocity. The contribution of dispersion coefficient due to the bubble motion in overall dispersion is also examined. The value of velocity distribution parameter in three different surfactant solutions is also compared. Generalised correlations for gas holdup, dispersion coefficient and mixing time are also developed based on the physicochemical properties of liquid. This research may be useful for the selection and application of these three surfactants in industries. This article will also help researchers for designing multiphase flow system where role of dispersion due to the motion of bubbles is significant.

Alkylphenols cause cytotoxicity and genotoxicity induced by oxidative stress in RTG-2 cell line

Alkylphenols ethoxylates are industrial surfactants, and the release in the environmental matrices produces degraded products, of which nonylphenol (NP) and octylphenol (OP) were the most common. They can be classified as endocrine disruptors since the estrogenic potential is widely recognized, but some others toxic aspects are in discussion. This study aimed to evaluate the toxicity of NP, OP, and mixtures of both through cellular, biochemical and genetic biomarkers in fish gonadal cell line RTG-2 exposed to nominal concentrations of 0.05; 0.5; 5; 50, and 100 μg mL−1 of each chemical and their mixtures of 0.05, 0.5; 5 μg mL−1 concentrations. After 24 h, the cells were collected for cytotoxic (neutral red – NR; crystal violet - CV, resazurin assay – RA and lactate-dehydrogenase - LDH), antioxidant system (glutathione-s-transferase – GST; superoxide-dismutase – SOD; glutathione-peroxidase – GPx and malondialdehyde – MDA) and genotoxic assays (alkaline comet assay and Fpg-modified alkaline comet assay). The chemicals and their mixtures were cytotoxic at 50 and 100 μg mL−1, in general aspect, but LDH showed cytotoxicity since 0.05 μg mL−1. The GST and SOD showed an activity increase trend in most tested groups, while GPx decreased at 5 μg mL−1 of the mixture. The MDA increase in all groups resulted in lipid peroxidation. The reactive oxygen species caused DNA damage for all groups. The tested chemicals and concentrations have been found in the freshwater systems. They can induce cell toxicity in several parameters that could impair the gonadal tissues considering the RTG-2 responses.

Surfactant pollution, an emerging threat to ecosystem: Approaches for effective bacterial degradation

The use of surfactants in households and industries is inevitable and so is their discharge into the environment, especially into the water bodies as effluents. Being surface-active agents, their utilization is mostly seen in soaps, detergents, personal care products, emulsifiers, wetting agents, etc. Anionic surfactants are the most used class. These surfactants are responsible for the foam and froth in the water bodies and cause potential adverse effects to both biotic and abiotic components of the ecosystem. Surfactants are capable of penetrating the cell membrane and thus cause toxicity to living organisms. Accumulation of these compounds has been known to cause significant gill damage and loss of sight in fish. Alteration of physiological and biochemical parameters of water decreases the amount of dissolved oxygen and thus affecting the entire ecosystem. Microbes utilizing surfactants as substrates for energy form the basis of the biodegradation of these compounds. The main organisms for surfactant biodegradation, both in sewage and natural waters, are bacteria. Several Pseudomonas and Bacillus spp. have shown efficient degradation of anionic surfactants namely: sodium dodecyl sulphate (SDS), linear alkylbenzene sulphonate (LAS), sodium dodecylbenzenesulphonate (SDBS). Also, several microbial consortia constituting Alcaligenes spp., Citrobacter spp., etc. have shown efficacy in the degradation of surfactants. The biodegradation efficiency studies of these microbes/microbial consortia would be of immense help in formulating better solutions for the bioremediation of surfactants and help to reduce their potential environmental hazards.

Determination of total reducible organofluorine in PFAS-impacted aqueous samples based on hydrated electron defluorination

Per- and polyfluoroalkyl substances (PFASs) is a large group of thousands of anthropogenic chemicals. Recently, measurement of total organic fluorine (TOF) to reflect the total PFASs has been recommended in limits and advisories. In this study, a total reducible organofluorine (TROF) assay is developed based on hydrated electron (eaq−) conversion of PFASs into inorganic fluorine combined with ion chromatograph, which is a common and widespread instrument. The eaq− is generated in UV/sulfite system with alkaline condition, and the concentration of TROF (CF_TROF) is the difference of fluoride concentration before and after assay. Method validation uses perfluorooctanesulfonic acid, perfluorooctanoic acid and their main alternatives, and F− recoveries are 76.6%–101%, except for perfluorobutanesulfonic acid (48.5%). Method application of TROF assay uses industrial surfactant products and fluorochemical industry-contaminated water, meanwhile, target PFAS analysis and total oxidizable precursors (TOP) assay are concurrently conducted. Concentrations of PFASs detected in target analysis and TOP assay were converted to fluorine equivalents concentrations (CF_Target and CF_TOP). ∑CF_Target and ∑CF_TOP account for 0.80%–36% of CF_TROF in industrial samples, 0.12%–54% in environmental water and 9.7%–14% in wastewater. The TROF assay can be used to initially judge whether PFASs contamination occurred near a hotspot with known sources. The CF_TROF could infer the extent of PFAS contamination in PFAS-impacted samples and estimate the fraction of uncharacterized PFAS.

Effect of surfactant micelle size on the dispersibility of aqueous carbon black particle suspensions prepared by ultrasonication

The effective preparation of particle suspensions is crucial. Herein, we focused on the preparation of carbon black particle aqueous suspensions through ultrasonication to investigate the dispersing mechanisms. Various industrial surfactants were used for the preparation, which resulted in two types of dispersion systems. The first type caused the sizes of the particles in the aqueous solutions to decrease when short ultrasonic irradiation times were employed; however, re-agglomeration occurred after longer times were implemented. The second type employed a long ultrasonication dispersing time and was able to achieve and maintain the smallest-sized particles observed without any re-agglomeration occurring. DLS determined the size of the particles, while PFG-NMR assessed the sizes of the surfactant micelles. Upon comparing these two sizes, we found an obvious relationship between the two regarding their changes during the ultrasonication dispersing process. To better understand these phenomena, the DLVO theory was considered and zeta potential measurements were conducted

Micellar catalysis beyond the hydrophobic effect: Efficient palladium catalyzed Suzuki-Miyaura coupling of water and organic solvent insoluble pigments with food grade surfactants

Micellar catalysis is having a dramatic impact in improving the sustainability of a wide variety of chemical transformations, including most of the popular palladium mediated carbon–carbon and carbon–nitrogen bond forming reactions. The Suzuki-Miyaura coupling is one of the earliest examples of micellar catalyzed reactions and it is still a very much active research field even at industrial scale. So far, micellar catalysis proved particularly efficient in enabling the high yield, low catalyst loading and mild reaction condition coupling of hydrophobic reagents in a water solution of selected surfactants. In this paper we show that the use of aqueous solutions of a mixture of food grade lecithin and the industrial surfactant Tween 80 not only enables efficient coupling in water of hydrophobic chemicals, but also provides a very resourceful tool for the functionalization of water and organic solvent insoluble pigments of interest for the dye and printed electronic industries.

Ion flotation of heavy metal ions by using biodegradable biosurfactant as collector: Application and removal mechanism

• By using the biosurfactant LS, ion flotation can be used to remove heavy metal ions . • The ability of LS to remove heavy metal ions is better than that of SDS . • The high flotation removal performance of LS is due to its structural advantages. • The carboxyl group and amide of LS react with metal ions. • LS reacts with Pb(II) and generates a four-membered ring complex. Ion flotation was used to remove copper(II), lead(II) and chromium(III) from simulated wastewater using a new biodegradable biosurfactants, namely, sodium N-lauroylsarcosinate (LS), and the synthetic surfactant sodium dodecyl sulfate (SDS) as collectors. The use of LS resulted in better removal of metal ions than that achieved with SDS. It was found that the removal efficiency of single metal ions can reach more than 95%. The results showed that the complex formed by surfactant and metal ion was flocculent and loose in structure, which may be the main reason for the slow ion flotation speed. XPS and IR analysis showed that there was a complex reaction between the sulfonic group of SDS and the carboxyl group of LS with metal ions. These findings indicate that the new biosurfactant LS has a better treatment effect on wastewater containing heavy metal ions and compared with industrial surfactants (such as SDS), LS is degradable and environmentally friendly, potentially leading to better industrial application. DFT theory further confirmed the experimental results. The calculated results show that LS has higher complexation ability for Pb(II) than dose SDS. LS reacts with Pb to form a four-membered ring complex containing two O atoms, which has higher stability than the complex containing SDS.

Enhanced salt thickening effect of the aqueous solution of peaked-distribution alcohol ether sulfates (AES)

Alcohol Ether Sulfates (AES) are emerging as a potent category of surfactant in consumer product industry owing to their much better hard water resistance, foaming/wetting ability, and less irritating than alkyl sulfate. These excellent performances are attributed to the presence of oxyethylene (EO) chain between the hydrophilic and the hydrophobic portions which endows AES the combined advantages of both nonionic and anionic surfactants. Most strikingly, addition of NaCl would considerably enhance the viscosity of the aqueous solution of AES, which is very important for a better retention of the surfactant to the interacting substrate. Recent study shows that the number distribution of EO groups considerably affects this salt-thickening performance, yet its mechanism is not clear. We report in this work that the narrower number distribution of the EO groups in the AES chains would generate an order alignment of the stretched EO chains, which can then bind with Na+ efficiently to form supramolecular crown ethers. In contrast, as the EO numbers are polydispersed, it is hard for them to align orderly, resulting in poor supramolecular crown ether formation ability with Na+. As a result, the wormlike micelles formed in the AES with narrower EO number distribution has much pronounced salt-thickening effect. This finding may help people in relating fields to create products with desired performance.

Current trends in protein-surfactant interactions: A review

The protein-surfactant interactions have been investigated for a long time due to their increased effectiveness in cleanliness and industrial processes. Moreover, Covid-19 outbreak has revolutionized the significance of protein-surfactant interactions, as soaps were proved the best cleansers and safe during this period. In this review article, an overview of physico-chemical aspects of protein-surfactant interactions along with various techniques has been discussed. In addition, the effect of different factors such as co-solvent, temperature, pH, chain length of surfactants, salt, and their impact on critical micelle concentration (CMC) of surfactant, structure, binding, thermodynamic parameters, and stability was also explained. This review will help the scientific community in understanding how to improve the effectiveness and applications of proteins and surfactants in pharmaceutical and other industries as protein-surfactant interactions can explain the significant phenomena of hydrophobic and electrostatic interactions.

Establishment of regularities of electroflotation extraction of non-ferrous metal (Cu, Ni, Zn, Co, Fe) hydroxides from wastewater of various compositions in the presence of industrial surfactants

Establishment of regularities of electroflotation extraction of non-ferrous metal (Cu, Ni, Zn, Co, Fe) hydroxides from wastewater of various compositions in the presence of industrial surfactants

Iron-activated persulfate oxidation degrades aqueous Perfluorooctanoic acid (PFOA) at ambient temperature

Perfluorooctanoic acid (PFOA, C8HF15O2) is an industrial surfactant that is highly resistant to natural breakdown processes such as those mediated by heat, hydrolysis, photolysis, and biodegradation. Many efforts have been developed to breakdown PFOA to less harmful species due to its widespread human exposure and potential toxicity. However, these methods require high temperature or specialized equipment with serious disadvantages of high energy cost for long-term use. We investigated the effectiveness of PFOA degradation by ferrous iron-activated persulfate oxidation (IAPO) under various aqueous geochemical conditions. Approximately 64% of PFOA (initial concentration = 1.64 μmol L−1) was degraded after 4 h under illuminated anoxic conditions at ambient temperature. This degradation rate and magnitude support the potential use of IAPO as a novel inexpensive and environmentally friendly method to remediate PFOA in soil and groundwater.