Alkyl Polyglucoside Research Articles

Alkyl polyglycosides derived from α-olefins via Fisher glycosidation and their adsorption and aggregation behavior in aqueous solution

The effective and stable use of α-olefins is a topic of great research interest due to their abundant reserves, and the fact that the hydrolysis and epoxidation reaction of these substances produces hydroxyl group as a key linking group plays an important role in the synthesis of surfactants. Consequently, a series of alkyl polyglycosides (DC08PG, DC10PG, and DC12PG) were synthesized as non-ionic surfactants via the glycosidation reaction of long-chain 1, 2-vicinal diol with different carbon numbers and glucose. The results showed that 1, 2-vicinal diol exhibited increased reactivity in glycosidation due to their unique molecular structure. Furthermore, it was observed that the degree of polymerization (DP) achieved was notably elevated, registering at 1.63, surpassing the DP of 1.37 typically prepared using conventional methods. This enhancement was paralleled by a demonstrable increase in hydrophilicity, as evidenced by the hydrophile-lipophile balance number (HLB), resulting in a substantial improvement in the water solubility of the product, the transmission rate > 90 %. For adsorption and aggregation behavior, DC12PG showed a smaller cross-sectional area (Amin), larger saturation adsorption (Γmax), and could aggregate to form micelles at low concentrations, and short-term dynamic adsorption properties (DST) was prominent. At the same concentration, for foam properties, DC12PG with longer alkyl chains produced higher and more stable foam; for emulsification properties, the emulsification time was 298 s; for wetting properties, the contact angle was 61.59° in 30 s. This analysis will help to reveal the intrinsic connection between the molecular structure and properties of surfactants.

Addressing the non‐ideality of an application relevant surfactant mixture within the hydrophilic–lipophilic‐deviation concept

AbstractIn cleaning products, selecting the right surfactants for the specific soil or contamination is crucial. The hydrophilic–lipophilic deviation (HLD) concept serves as a useful formulation tool by describing the interactions between surfactants, oil and water. However, for mixtures of ionic and non‐ionic surfactants, the HLD concept assumes ideal mixing behavior, which does not hold true. Therefore, interactions between different surfactants must be considered. This can be achieved by introducing the interaction term GEX/RT. Evaluating this interaction term using a set of equilibrated surfactant/oil/water (SOW) systems under various conditions is both time‐consuming and resource intensive. This work aims to demonstrate the rapid determination of this interaction term using the dynamic phase salinity inversion (DSPI) method. We determined the phase behavior of a ternary surfactant system, consisting of sodium dioctyl sulfosuccinate, alkyl polyglucoside, and fatty alcohol ethoxylate, through both equilibrated systems and the DSPI method. Differences between the theoretical HLD calculations and actual experiments allowed us to access interaction terms. To validate GEX/RT obtained by DSPI, we employed net‐average‐curvature concept to model the interfacial tension under different conditions. Spinning drop measurements showed excellent agreement between theoretical and measured values, confirming the applicability of DSPI for determining interactions in this surfactant system.

Retraction Note: Alkyl polyglycosides enhanced the dark fermentation of excess sludge and plant waste to produce hydrogen: performance and mechanism.

Retraction Note: Alkyl polyglycosides enhanced the dark fermentation of excess sludge and plant waste to produce hydrogen: performance and mechanism.

Study on the effect of spatial adsorption orientation on the preferential selection mechanism of dust suppression surfactants

Surfactants are widely used in the field of coal dust control. However, the dust suppression effect of different surfactants varies significantly, and the preferential selection mechanism of dust suppressants for mining is not clear. In this study, the water/surfactant/lignite system was constructed by molecular simulation to investigate the adsorption behavior of surfactants with different structures on the lignite surface at the molecular level. The reasons for the differences in the wettability adsorption of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), fatty alcohol polyoxyethylene ether-9 (AEO-9), and alkyl polyglycoside (APG1214) on the lignite surface were also investigated based on the quantum chemical calculations and macroscopic experimental analysis. The results showed that the adsorption orientation of surfactant molecules at the solid–liquid interface exerted a pivotal influence on the surface wettability of lignite. According to molecular orbital and electrostatic potential analysis, surfactant molecules with LUMO distributed in the tail chain were more inclined to form a positive adsorption orientation than that concentrated in the polar headgroups; and the stronger the interaction between the polar headgroups and the coal surface with the like charge, the more stable the adsorption of surfactant molecules with the positive arrangement at the interface was. Furthermore, the stronger potential difference between SDS molecules and the hydroxyl-rich structure of the APG1214 molecules are conducive to the formation of hydrogen bonds with water molecules. Wettability experiments showed that the ability of surfactants to improve the wettability of coal dust was positively correlated with the adsorption orientation.

Micellar Microextraction with Alkyl Polyglucosides for the Preconcentration and Spectrophotometric Determination of Phosphate Ions in Aqueous Media

Micellar Microextraction with Alkyl Polyglucosides for the Preconcentration and Spectrophotometric Determination of Phosphate Ions in Aqueous Media

Feasibility of Using Polymers to Improve Foam Flow Performance in Vertical Pipes: Application to Liquid Unloading in Gas Wells

Foam unloading is a cost-effective technique for removing liquid from low-energy gas wells, but it faces challenges due to the instability of foam at the wellbore. Surfactants alone struggle to create and maintain durable foam films under wellbore conditions. Polymers are known to enhance foam stability by increasing lamella thickness and viscosity, but their impact on foam unloading has not been well explored. This study investigates the effects of Xanthan Gum (XG) and Polyvinylpyrrolidone (PVP) polymers on stability and unloading efficiency of the foams made by Alkyl Polyglycoside surfactant. The research evaluates foam stability and examines the bubble size and lamella thickness under varying salinity conditions. Additionally, the study evaluates foam unloading efficiency by determining unloaded mass rate, critical gas velocity and Weber number. Results show that polymer concentration, type and molecular weight significantly affect foam morphology and stability. Xanthan Gum at 1000 ppm demonstrated the smallest bubble size and greatest foam stability. This concentration also achieved the highest unloaded mass, 30% more than the surfactant-only case. Regarding the molecular weight of the polymers, HPVP demonstrated an ability to generate smaller bubbles in comparison with LPVP. Consequently, HPVP exhibited superior performance in liquid unloading, surpassing LPVP by a margin of 8.5%. The addition of polymers reduced critical gas velocity, with 1000 ppm of XG yielding the lowest value. Initially, the Weber numbers for polymer-stabilised foams were higher than the surfactant-only case (XG: 208.01, LPVP: 17.70, HPVP: 26.38 vs. APG: 2.25) due to the Marangoni effect but decreased during the unloading process (XG: 788.58, LPVP: 1850.26, HPVP: 1702.01 vs. base case: 4046.42), indicating improved stability and performance. Overall, the study demonstrates that polymers can significantly improve foam stability and performance, maintaining foam integrity throughout the unloading process if engineered properly prior to their application.

Removal of Lead Cations by Novel Organoclays Derived from Bentonite and Amphoteric and Nonionic Surfactants.

For many decades, natural and modified clay minerals have been used as adsorbents to clean up aquatic and soil ecosystems contaminated with organic and inorganic pollutants. In this study, organoclays based on bentonite and various amphoteric and nonionic surfactants were synthesized and tested as effective sorbents for lead ions. The maximum values of R were obtained when describing the sorption processes using the Langmuir model, which ranged from 0.97 to 0.99. The adsorption of lead ions by these organoclays was investigated using different sorption models including the Langmuir, Freundlich, and BET. It was found that, according to the values of limiting adsorption to the Langmuir equation, the synthesized organoclays formed an increasing series: organoclay with cocamide diethanolamine < bentonite < organoclay with lauramine oxide < organoclay with sodium cocoiminodipropionate < organoclay with disodium cocoamphodiacetate < organoclay with alkyl polyglucoside. The Gibbs energy for all of the analyzed samples was calculated and found to be negative, indicating the spontaneity of the cation adsorption process in the forward direction. The maximum value of the adsorption capacity of lead cations on organoclay-based bentonite with alkyl polyglucoside was 1.49 ± 0.05 mmol/g according to the Langmuir model, and 0.523 ± 0.003 mmol/g as determined by the BET model. In the process of modifying bentonite, there was an increase in negative values of the zeta potential for organoclays compared to the initial mineral, which clearly enhanced their electrostatic interactions with the positively charged lead ions. It was hypothesized, based on the physicochemical principles, that exchange adsorption is the main mechanism for lead absorption. Based on chemical approaches, organoclays based on amphoteric surfactants absorb lead mainly through the mechanisms of electrostatic attraction, ion exchange, and complexation as well as the formation of insoluble precipitates. Organoclays based on nonionic surfactants, on the other hand, absorb lead through mechanisms of complexation (including chelation) and the formation of insoluble chemical precipitates. The comparison of isotherms from different models allows us to find the most accurate match between the model and the experimental data, and to better understand the nature of the processes involved.

Enhanced rheology and firefighting performance of fluorine-free soft foams through the assembly of cellulose nanofibres and cellulose nanocrystals at the air–liquid interface

In this work, we developed soft and highly stable perfluorocarbon-free foams based on cellulose nanofibres (CNFs), cellulose nanocrystals (CNCs) and alkyl polyglycoside (APG). Neither the CNCs nor the CNFs can effectively stabilise the APG foam, which is reflected in the spontaneous degradation of the foam. Interestingly, blending these two nanocelluloses and foaming resulted in an ultrastable foam. The reflective optical interference technique was used to visualise liquid flow in the liquid film, and the results showed that the foam film with a thickness of only a few tens of nanometres gained excellent mechanical stability by tuning the assembly of CNCs and CNFs at the air–liquid interface. Moreover, the interfibril interactions at the Plateau borders reduce the bubble coarsening rate and drainage rate. In pool fire extinguishing tests, increasing the total concentration of CNCs and CNFs improved the foam stability, but increasing the viscosity led to a decrease in the foam spreading rate. Thus, a formulation with 0.4 % nanocellulose has poorer firefighting performance than a formulation with 0.15 % nanocellulose. When the ratios of CNCs and CNFs are properly controlled, the burnback performance of perfluorocarbon-free foam is better than that of state-of-the-art fluorinated AFFFs for n-heptane pool fires. The sustainability of the firefighting process is considerably improved by switching to the nonperfluorinated liquid foam developed in this work.

Interactions and oil recovery performance of a prepared extended amphoteric surfactant combining with a nonionic surfactant under high salinity condition

The extended amphoteric surfactant (named C12P3E3NS), characterized by FTIR and 1H NMR, was prepared by amination and sulfonation in order to enhance oil recovery (EOR) for the low-permeability oil reservoirs. The surface and interfacial tensions of its combination systems with nonionic surfactant (APG0810, an Alkyl Polyglycoside), obtained by tension meter, were evaluated to obtain an optimized surfactant system for enhancing oil recovery. The compound system (named C12A) with 40 % mole fractions of C12P3E3NS, exhibiting the strongest interaction behavior and highest expansion modulus, possesses the best abilities of reducing the interfacial tension to ultra-low (10-3 mN/m order of magnitude) at a salinity of 10 wt%, and owns certain abilities of emulsifying crude oil. Meanwhile, the contact angle, measured by the contact angle measuring instrument, can be altered from 108.50°to 55.07°by the compound system C12A, confirming its better wetting alteration ability of transforming the capillary force from resistance to driving force. Eventually, displacement efficiency, obtained from core displacement tests, reveals that the compound surfactant system C12A can decrease the pressure by 15.80 % and its corresponding oil recovery factor is 15.25 % after water flooding, demonstrating its favorable displacement performance and potential application in medium or high salinity reservoirs.

Evaluation of a binary amphiphile/solvent mixture for the formulation of an ecological detergent as an alternative for removing fat from natural fiber surfaces

The application of a binary amphiphile/solvent blend composed of a natural surfactant (alkyl polyglucoside) and the green solvent ethyl lactate (EL) as an active component in the formulation of a new ecological detergent has improved the washing process conditions. Foaming properties of the detergent were optimal, with foam stability (R5) values of 76.17% and 78.61% for the best formulations. It is common practice to add substances that can regulate the pH to 9 to enhance the washing efficiency. This was reflected in the results of this study, where pH and the interaction between pH and surfactant type significantly influenced the percentage of residual fat. Currently, commercial detergents recommend a 1% dilution. However, studies have evaluated a 0.5% dilution. Therefore, it opted to evaluate new concentrations of 0.4% and 0.3%. Optimization of the factorial design resulted in dirt removal rates exceeding 91%, while the lowest percentage of residual fat (< 0.37%) was achieved at 25 °C, pH 9, and 0.3% detergent doses without lipase. Furthermore, illustrations of the surface morphology of the washed fibers demonstrated that the samples were not adversely affected by the formulated detergent or the washing process conditions. The alkyl polyglucoside/ethyl lactate binary blend was shown for the first time to exhibit strong interactions, possessing excellent residual fat and soil removal properties, suggesting its potential use in the formulation of green detergents for washing natural and synthetic textile fibers as a replacement for detergents based on ethoxylated fatty alcohols.

Antilisterial effect of alkyl polyglycosides biosurfactant and modes of action

Several outbreaks of Listeria monocytogenes originated mainly from contaminated contact surfaces. Thus, this study investigated the antilisterial effect of natural surfactants in terms of their use as a 2-in-1 sanitizing washer on a food contact surface and evaluated their modes of action. The antilisterial activity of alkyl polyglycosides (APGs), namely capryl glucoside (CA), coco glucoside (CG), and decyl glucoside (DG), was evaluated based on the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) using broth dilution assay. The results showed that CG had the strongest antilisterial activity. Therefore, CG was selected for further investigation. The time-kill assay showed a lethal effect of 0.5 % (w/w) CG by inactivating 4 Log reduction (99.99 %) of L. monocytogenes within 3 s. Furthermore, 1 % (w/w) CG with slight mechanical force in washing (by shaking) was efficient for sanitizing a stainless-steel coupon surface based on its ability to cause a total reduction of deposited L. monocytogenes (99.9 %) within 10 min. Scanning electron microscopy and applying Fourier-transform infrared spectroscopy revealed that CG chemically disrupted the cell wall and plasma membrane of L. monocytogenes within 5 min after a gentle wash. The results showed it had potent antimicrobial activity and was bactericidal against L. monocytogenes. Overall, our results supported the use of CG as a natural antibacterial surfactant to alter the chemical sanitizer and the possibility of its practical use in the food industry and for household use.

Primary alcohol-induced coacervation in alkyl polyglucoside micellar solution for supramolecular solvent-based microextraction and chromatographic determination of phthalates in baby food

This study reports for the first time the phenomenon of supramolecular solvent formation based on alkyl polyglucoside as an amphiphile and primary alcohol as a coacervation agent. The physical properties (density, kinematic viscosity, phase diagram for ternary system) of the supramolecular solvent were investigated, and a mechanism for its formation was proposed. A green and simple microextraction procedure for preconcentration and determination of phthalates in baby foods packaged in plastic packaging was developed as proof-of-concept example. The microextraction procedure assumed separation of analytes from solid phase sample in micellar solution of decyl glucoside and in situ formation of supramolecular solvent for analytes preconcentration after addition of n-heptanol. The determination of phthalates in obtained extracts was implemented by high-performance liquid chromatography with UV–Vis detection. The limits of detection, calculated from a blank test based on 3σ, were determined to be 10 μg kg−1 for dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, and di-n-octyl phthalate. The developed procedure did not require filtration of sample suspension, and assumed the use of green and biodegradable substances for the supramolecular solvent formation across a wide pH range.

A CO2-Modified Surfactant for Chemical Flooding

Summary Carbon dioxide (CO2) modification of a nonionic surfactant alkyl polyglycoside (C-APG) was conducted based on a commercial APG product under mild synthesis conditions, including a low temperature (50°C) and a low pressure (2.5 bar). Using this method, CO2 was incorporated into APG molecules through the formation of carbonyl structures. The effectiveness and performance of C-APG as a novel surfactant for enhanced oil recovery (EOR) application in carbonate reservoirs were investigated and compared with its precursor—the unmodified APG. The key factors in the chemical structure of C-APG were characterized by Fourier transform infrared spectroscopy (FTIR) to confirm successful CO2 modification. The properties, including compatibility, surface tension, wettability alteration, interfacial tension (IFT), phase behavior, and static and dynamic adsorption of both APG and C-APG, were evaluated by various techniques and methods. Crude oil displacement efficiency of the surfactants was investigated via spontaneous imbibition, visualized micromodel, and coreflooding tests, respectively. Both surfactants were compatible with a high-salinity water (HSW), they exhibited a similar critical micelle concentration (CMC) of 8.5 mg/L and 13.5 mg/L for APG and C-APG, respectively, and had the same contact angle of around 135°. Interestingly, C-APG was found more effective in reducing IFT between oil and water phases. The IFT of oil in the C-APG solution was 0.058 ±0.001 mN/m, one order of magnitude lower than the value of 0.47 ±0.02 mN/m obtained from the solution of original APG, suggesting a better performance of C-APG in chemical flooding for oil displacement. A Winsor Type I microemulsion was formed by APG within the salinity range, while a transition of Type I to Type II microemulsion was observed for C-APG. The static adsorption of APG and C-APG at 2 g/L in carbonate were 0.93 mg/g rock and 1.08 mg/g rock, and the adsorption decreased to 0.11 mg/g rock and 0.13 mg/g rock under dynamic conditions for APG and C-APG, respectively. The spontaneous imbibition test demonstrated a higher oil imbibition recovery of 18.0% from C-APG solution compared to the result of 10.2% obtained from APG solution. A micromodel test showed that more crude oil was displaced by injection of APG or C-APG solution after waterflooding, while C-APG injection exhibited a stronger emulsification. The oil displacement by coreflood test showed that C-APG injection led to a lower differential pressure and a higher cumulative oil production (48%) compared to APG chemical flooding with a cumulative oil production of 41%. The produced fluids containing displaced crude oil from C-APG flooding, and subsequent waterflooding demonstrated very strong emulsification compared to the fluids produced after APG injection. This study demonstrates the significant potential of C-APG in two aspects—CO2 reduction and chemical EOR for the upstream petroleum industry.

Characterization of aqueous foams of alkyl polyglycoside, GreenZyme, alpha-olefin sulfonate, and cetyltrimethylammonium bromide in the presence of divalent ions

In this study, the impacts of divalent ions (calcium and magnesium) on aqueous foam stability and its rheological properties are investigated. A biodegradable surfactant of alkyl polyglycoside, (APG) and a commercial enzyme (GreenZyme, GZ) are used and their performance were compared with synthetic surfactants of alpha-olefin sulfonate (AOS) and cetyltrimethylammonium bromide (CTAB). The findings of the study revealed that the stability of all foams decreased with increasing concentrations of divalent ions, GZ recorded the lowest foam stability in the presence of the two ions and precipitation occurred in the AOS solution. On the other hand, foams generated by APG achieved the highest stability and the foams generated by CTAB showed the second highest stability among the foaming agents. Through rheological analyses, APG and CTAB exhibited shear thinning behaviour and their behaviour were modelled using a power law model in which the model can incorporate the effects of temperature and salinity.

Impact of surfactants used in oil and gas extraction on produced water treatment by membrane distillation

Produced water from unconventional oil and gas reservoirs often contains non-ionic surfactants that are added to the hydraulic fracturing fluid to facilitate water release and enhance gas production. This study investigates the impact of currently used surfactants (i.e., nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs)) and proposed alternative surfactants on the performance of membrane distillation (MD) for produced water treatment. The impact of NPEOs and OPEOs on wetting of PTFE membranes was studied as a function of their concentrations and ethoxylate (EO) chain length in a lab-scale DCMD system. Additionally, alternative surfactants, including linear alcohol ethoxylates (LAEs), branched secondary alcohol ethoxylates (BAEs), and alkyl polyglycosides (APGs), were evaluated for their potential to replace NPEOs and OPEOs. Experimental results indicate that the increase in the number of EO units in NPEOs decreased their tendency to cause membrane wetting by reducing their interaction with hydrophobic surfaces. It was also observed that LAEs and APGs that are environmentally friendly alternatives did not cause membrane wetting. This study provides valuable insights into the underlying mechanisms of surfactant-membrane interactions and offers guidelines for surfactant alternatives that can potentially improve hydraulic fracturing and lower environmental concerns while facilitating the use of MD for produced water treatment and recovery.

A transparent hydrophilic coating for long-lasting anti-fogging with self-cleaning and antibacterial properties

Transparent substrates with anti-fogging properties endowed by surface hydrophilic modification have been proved to applied in various fields. In this study, a superhydrophilic coating (PAT coating) was generated on glass substrate via dip coating technique using a solution comprising polyvinyl alcohol (PVA), alkyl polyglycoside (APG1214), and tetraethoxysilane (TEOS). The plentiful hydroxyl groups present in PVA and APG1214 endow the PAT coating with high hydrophilicity for excellent anti-fogging and self-cleaning properties, and facilitate to form a stable homogeneous hydrogen-bonded crosslinked network. Meanwhile, the in situ generated tetraethoxysilane hydrolysate (TEOH) from hydrolysis of TEOS acts as a crosslinker, which can covalently connect the organic components to the glass substrate. As a result, the resulting PAT coating displays excellent stability during various mechanical and chemical durability tests. In addition, the coating exhibits antibacterial adhesion properties owing to the broad-spectrum antibacterial property of APG1214. Importantly, the PAT coating can be easily prepared with readily available and economical raw materials through a simple method under mild conditions that does not require complicated separation and purification, thereby enabling its potential industrial application.

Production of Rhamnolipids using WFSO and its application in the development of antifungal nanoemulsion using Hydnocarpus Wightiana, Garcinia Cambogia - Seed oils

Presently, Industrial-scale demands for manufacturing rhamnolipids (RhLs) are not so developed; probably due to the high cost of the substrates and the rare demand for costlier surfactants. Therefore, the use of waste frying oils (WFSO) as substrates in RhLs manufacturing using Pseudomonas aeruginosa could be a notable substitute for the regularly used sources of oils and fatty acids to minimize manufacturing charges. WFSO as a byproduct normally consists of Linoleic acid as a prime fatty acid constituent. In the present work, P. aeruginosa yielded RhLs at an uttermost concentration of 7.4 g L−1; while constructional characteristics proved the presence majority of di-RhLs in the mixture. Also, on testing, the SFT (Surface Tension) reduced to 34.6±0.1 mN m−1; and an interfacial tension against heptane went down to 5.2±0.05 mN m−1. The oils from kernels of Hydnocarpus Wightiana and Garcinia cambogia were extracted separately; further, the detailed analysis showed the presence of their corresponding active fatty acids. In the initial screening of antifungal efficacy against Fusarium oxysporum (fusarium wilt) and Diplodia maydis (Diplodia ear and stalk rot of maize), RhLs shown the minimum inhibitory concentration (MIC) between 250 and 500 ppm, both extracted oils shown the MIC between 5 % and 10 %. Therefore, we decided to prepare the nanoemulsions (NEs) using 0.5 % RhLs, and 10 % of each respective extracted oil; which upon analysis showed the globule size as low as 110.9 nm and 147.0 nm respectively. The turbiscan study revealed that NEs made using RhLs as an adjuvant were found more stable than the alkyl polyglucosides, and the nanoemulsions containing RhLs showed higher levels of antifungal activity against F. oxysporum and D. maydis in the antifungal study. Thus, a successful utilization of the WFSO for the production of RhLs; and reduction in the probable water or soil pollution was achieved, as well as our RhLs bio-synthesis cost was much less as compared to the existing manufacturing process.

Effects of residual foaming agent and defoamer on defoaming-flocculation-filterpress characteristics of earth pressure balance shield muck.

Foaming agents as a combination of several components are usually used as soil conditioning during earth pressure balance shield (EPBS) tunnelling. These residues in waste EPBS muck lead to a series of new challenges for in-situ recycling, i.e., foams overflow flocculation tank. This study investigates the effects of residual foaming agent components and defoamers on defoaming-flocculation-filterpress characteristics of EPBS muck using an improved flocculation and filterpress system. Residual foam height (Hf), defoaming ratio (DFR), antifoaming ratio (AFR), total suspended substance (TSS), turbidity, moisture content (MC), and zeta potential (ZP) were selected as characterization indices. The microstructure of filterpress cakes was analyzed using a scanning electron microscope. Results demonstrate that an enhancement within 0.0-1.0wt.% for sodium fatty alcohol polyoxyethylene ether sulfate (AES) and alpha olefin sulfonate (AOS) significantly reduces DFR and AFR. The MC and ZP decline, while the Hf and turbidity enhance. The combinations of nonionic surfactants alkyl polyglycoside (APG) and fatty alcohol-polyoxyethylene ether (AEO) in a concentration range of 0.0-1.0wt.% with 0.2wt.% AES causes the Hf, DFR, AFR, turbidity, and ZP to exhibit absolutely different variations. The MC with the growth in both APG and AEO presents a trend of first decreasing and then increasing. By increasing foam stabilizers sodium carboxymethyl cellulose (CMC) and guar gum (GG) within 0.02-0.10wt.%, the AFR, TSS, and ZP enhance in varying degrees, while the Hf, DFR, and MC gradually reduce. With the increase of defoamers hydroxyl silicone oil-glycerol polyoxypropylene ether (H-G) and dimethyl silicone oil-glycerol polyoxypropylene ether (D-G) within 0.002-0.010wt.%, the DFR and AFR are significantly improved, while the TSS, turbidity, MC, and ZP display varying degrees of reduction. Moreover, defoaming-flocculation-filterpress mechanisms of EPBS muck are explored to provide a useful reference for actual in-situ recycling projects.

Effect of alkyl glucoside concentration on functional group structure and adsorption characteristics of anthracite.

To investigate the influence of different concentrations of surfactants on the adsorption of anthracite, the nonionic surfactant alkyl polyglucoside (APG) was selected. The study examined the adsorption characteristics of different concentrations of APG on the surface of anthracite. The results revealed the existence of two modes of APG adsorption on anthracite. Under the action of 0.06 wt% APG, APG was found to adsorb in a monolayer state on the anthracite surface, with a saturation adsorption capacity of 20.06mg/g. When the solution concentration exceeded 0.14 wt%, APG exhibited a double-layer saturation adsorption state on anthracite, with a saturation adsorption capacity of 71.71mg/g. Molecular dynamics simulations complemented these findings, demonstrating that low concentrations of APG could reduce the mobility of water molecules and enhance the hydrophilicity of anthracite. With an increase in the number of APG molecules, multi-layer adsorption occurred on the anthracite surface, making it more hydrophobic. Therefore, the differences in wettability of anthracite induced by different concentrations of APG were primarily attributed to the spatial distribution of the surfactant at the water/coal interface. This study analyzed the adsorption capacity of the surfactant through adsorption experiments and Fourier-transform infrared spectroscopy (FTIR) experiments. Molecular dynamics simulations were conducted to construct six concentration levels of water/APG/anthracite systems. Various aspects, including APG adsorption configurations, interaction energies, relative concentrations of each component, and the diffusion coefficient of water molecules, were discussed to elucidate the reasons for the differential wettability of anthracite induced by different concentrations of APG.

Preliminary study for Polycyclic aromatic Hydrocarbons mobilization from contaminated marine sediment using synthetic and natural surfactants

The persistent presence of Polycyclic Aromatic Hydrocarbons (PAHs) in soils and sediments due to their chemical properties requires new methods to mobilize and make them more available for remediation purposes. In this work, the evaluation of the abilities of eight different non-ionic sugar-based and totally biodegradable surfactants, such as synthetic alkyl polyglycosides (APGs), biological sophorolipids (SLs) and biological rhamnolipids (RLs), was conducted in order to provide a preliminary guideline for the selection of the surfactant and the technical approach for PAHs extraction from the sediment. The reference sample was a marine sediment collected from Bagnoli (Naples, Italy) that was characterized to evaluate the level of PAHs contamination, which resulted equal to 3.51 g Kg−1 of total PAHs in the sediment. By using surfactants solutions with a surfactant concentration five times greater than critical micelle concentration (Cs = 5x CMC), a preliminary washing test in batch configuration was conducted, then followed by multiple consecutive washes (MCW) of the sediment to assess the solubilization of PAHs from the sediment by the action of selected surfactants. The results show an evident advantage given by the employment of each studied surfactant in mobilizing PAHs, compared to distilled water as benchmark. In detail, the synthetic alkyl polyglycosides APG2 led to a 3.4 % of total PAHs mobilization in the preliminary washing test with a maximum peak of 9.8 % for a single compound. The MCW test demonstrates that more consecutive washes can increase the amount of total PAHs removed, with a similar contribution from each wash, and that biosurfactants can be more attractive after several washes thanks to the increased capacity of PAHs mobilization. Interestingly, the high efficiency of surfactant to mobilize PAHs makes the soil washing a more attractive technology for removing PAHs from the marine sediments.