Enhancing stability and odor control of water-based foam for pesticide site restoration using xanthan gum

Enhancing protein-based foam stability by xanthan gum and alkyl glycosides for the reduction of odor emissions from polluted soils

The stability and decontamination of surface radioactive contamination of biomass-based antifreeze foam

BACKGROUNDBleomycin foam is an effective sclerotherapy method for venous malformations. The preparation method is rather complicated, and the volume and stability of the foam are limited.OBJECTIVETo modify the currently used method for preparing bleomycin foam, to simplify the preparation procedure, and to produce foam with greater volume and increased stability.MATERIALS AND METHODSExperiment 1: 6.0 IU of bleomycin powder was dissolved in different human serum albumin (HSA):saline solution (SS) ratios of 0.5:1.5, 0.75:1.25, 1:1, 1.25:0.75, 1.5:0.5, 1.75:0.25, and 2:0 in volume; then, an air:liquid ratio of 2:1 was used to create foam using the Tessari method. Experiment 2: 6.0 IU of bleomycin was dissolved directly in 2.0 mL of HSA; then, air:liquid ratios of 1:1, 2:1, 3:1, and 4:1 were used to create foam using the Tessari method. The optimum proportions of HSA:SS and air:liquid were screened by comparing the foam half-life (FHL).RESULTSExperiment 1: the optimum proportion of HSA:SS was 2:0, and the FHL was 7.5 minutes. Experiment 2: the optimum proportion of air:liquid was 3:1, and the FHL was 9.0 minutes.CONCLUSIONThe modified method is simpler and could produce more stable bleomycin foam with greater volume.

Stability and water control of nitrogen foam in bulk phase and porous media

The foam stability (drainage half-life) of α-olefin sulfonate (AOS) with partially hydrolyzed polyacrylamide (HPAM) or xanthan gum (XG) solution was evaluated by the Warring Blender method. With the increase of polymer (HPAM or XG) concentration, foam stability of the surfactant–polymer complexes increased, and the drainage half-life of AOS-XG foam was higher than that of AOS-HPAM foam at the same polymer and surfactant concentration. With the addition of polymer (HPAM or XG), the viscoelasticity of bulk solution and the liquid film were enhanced. The viscoelasticity of AOS-XG bulk solution and liquid film were both higher than that of AOS-HPAM counterparts.

Foam fracturing is an effective method for the development of unconventional reservoirs. However, due to lamellar film, high pressure differences within foam films, and the strong diffusivity of the internal phase, foam is prone to suffering from unstable phenomena such as rupture, drainage, disproportionation, etc., thus leading to uncontrollable foam flow behavior in the tube and formation. In this work, cellulose nanofibrils (CNFs) were used to enhance foam fracturing fluid. The target is not only to obtain a stable foam system, but also to control its rheology, proppant-carrying and leak-off behavior. The stability of the N2 foam fracturing fluid with CNFs was firstly explored via static tests by measuring its foam volume and liquid drainage. Then, the viscosity of foam fracturing fluids with different foam quality was measured using a tube viscometer under conditions of use, to evaluate the rheology of foam with CNFs. Subsequently, the proppant-carrying capacity was evaluated by observing suspension state of proppants in foam over time. The microscopic images of the foam with proppants were collected to analyze the interaction between bubbles and proppant. Finally, the dynamic filtration behavior and core damage of foam with CNFs were investigated by using a dynamic filtration apparatus. The results of the static tests showed that the stability of foam was significantly enhanced by the addition of CNFs, and the liquid drainage and gas diffusion could be effectively inhibited. Upon foam evolution, bare surfactant foam formed a polyhedral structure rapidly, while the CNFs enhanced foam maintained spherical and dense for a long time. The viscosity of foams with and without cellulose nanofibrils showed a shear thinning behavior. With the addition of CNFs, the viscosity of foam was improved by 3 - 6 times compared with bare surfactant foam and its value was increased with foam quality changing from 60% to 80%. The results of proppant-carrying tests indicated that the proppants suspension in foam was improved obviously as the cellulose nanofibrils were added. For CNFs-stabilized foam, the aqueous film of bubbles became thicker and the mechanical strength of foam structure was improved, thus enhancing the proppant suspension in the foams. Moreover, the filtration control performance of CNFs foam was also improved compared with bare surfactant foam. The filtration coefficient of CNFs foam fracturing fluid decreased with increasing CNFs concentration at a filtration pressure difference of 3 MPa, and core damage was maintained at a relatively low level. Additionally, the filtration coefficient of CNFs-stabilized foam and its core damage could be reduced with the increase of foam quality from 60% to 80%. The stability, rheology, proppant-carrying and dynamic filtration control of foam fracturing fluid enhanced by cellulose nanofibrils were explored in this work. The results show that the addition of CNFs effectively improves the stability of the foam, thus enabling the rheology, proppant-carrying and the dynamic filtration to be well controlled, which provides a high-performance and eco-friendly foam fracturing fluid.

ABSTRACTThe present study focuses on the drainage property of aqueous film-forming foam stabilized by different types and concentrations of foam stabilizers. Aqueous film-forming foam (AFFF) formulation concentrates are prepared based on the main components of fluorocarbon surfactant, hydrocarbon surfactant, and organic solvents. Carboxymethylcellulose sodium (CS), xanthan gum (XG), and lauryl alcohol (LA) are selected as foam stabilizers of the AFFF. Surface tension, viscosity, and foamability tests of the AFFF solutions are conducted to evaluate the effect of foam stabilizers on the properties of AFFF solutions. Particularly, an apparatus is established based on the law of connected vessel in order to obtain the instantaneous mass of liquids drained from foams. The drainage features of the AFFFs containing different foam stabilizers are analyzed and compared with each other. The results indicate that AFFF drainage is significantly affected by the type and the concentration of foam stabilizers. The addition of CS and XG to AFFF results in a deceleration of foam drainage, while foam drainage is accelerated by the addition of LA. The variations of surface tension, viscosity, and liquid fraction of foams are the main reasons for the varying foam drainage rate. This study provides a direct connection between chemical components and fundamental properties of AFFF.

Nanopolymer microspheres have been widely studied in the development of low-permeability reservoirs as an effective material to improve foam stability. However, there are few studies on the foam stability mechanism of nanopolymer microspheres. In this work, the effect of surface hydrophobicity of fluorescent nanopolymer microspheres PARC(Flu-Ac) on the stability of CO2 foam was investigated by using foam performance as an evaluation index. The mechanism of foam stabilization by PARC(Flu-Ac) with different degrees of hydrophobicity was clarified by studying the drainage rate, micromorphology, interfacial rheology of foam, and adsorption behavior of microspheres on the foam liquid film. The results show that PARC(Flu-Ac)-5 microspheres with neutral wettability have the best foam stabilization effect. At 94 °C, the foam volume of CO2 foam is 630 mL and the foam half-life is 30.12 min. PARC(Flu-Ac)-5 microspheres have a high desorption energy and can stably adsorb at the gas-liquid interface to form a solid layer. The microspheres improve the mechanical strength of the foam and reduce the direct contact of the fluid, thus providing space resistance for thinning the liquid film and the diffusion of gas between bubbles. In addition, the microspheres can slow the thinning rate of the liquid film through the release of free water. The stability of the foam is significantly improved. This study further clarifies the enhancement mechanism of nanopolymer microspheres on the stability of CO2 foam, which has excellent guiding significance for the application of CO2 foam in low-permeability oil fields.

PurposeCeliac disease patients cannot consume gluten-containing diets; thus, gluten-free products should be offered to meet the nutritional needs of these patients. The purpose of this study was to produce gluten-free tarhana for celiac disease patients using corn flour instead of wheat flour and investigate some physicochemical properties of tarhana. Hydrocolloids were used to compensate for technological deficiencies caused by the absence of gluten.Design/methodology/approachHydrocolloids including guar gum, xanthan gum and locust bean gum were added at concentrations of 0.5% and 1.0% to the corn flour. The substituted corn flour samples were used to produce tarhana powder.FindingsThe pH and acidity measurements were carried out in 0th, 24th and 48th h of fermentation, and for all samples, the pH gradually decreased during fermentation, whereas the acidity increased. According to the color measurements (L, a and b values), it was observed that there was no significant difference (p = 0.588) between the gums in terms of L values in tarhana dough samples. Water retention capacity values of control, guar gum 1%, xanthan gum 1% and locust bean gum 1% were found to be 1.1, 1.1, 0.7 and 1.2 mL/g, respectively. The viscosity measurements were carried out at three different temperatures (30°C, 45°C and 60°C), and the viscosity values were found to decrease significantly (p = 0.000) with the increase in temperature for all the samples studied. The highest viscosity values were obtained by 1.0% xanthan gum (4,333 mPa s) and 0.5% locust bean gum (3,575 mPa s) added tarhana samples for 3 rpm at 30°C. Xanthan gum addition showed the lowest foam capacity values (0.04 mL/mL) among the samples. The samples with guar gum, xanthan gum and locust bean gum are recommended with regard to consistency and foam stability in the production of tarhana.Originality/valueThis study confirms that the use of gums in tarhana, a gluten-free system, is beneficial for the technological aspect. The unfavorable properties that can be seen because of the absence of gluten in corn flour tarhana can be compensated with the use of hydrocolloids, and tarhana can be recommended to celiac disease patients.

Xanthan and locust bean gums are polysaccharides able to produce aqueous solutions with high viscosity and non-Newtonian behaviour. When these solutions are mixed a dramatic increase on viscosity is observed, much greater than the combined viscosity of the separated polysaccharide solutions. In this work the influences of different variables on the viscosity of solutions of mixtures of xanthan/locust bean gum have been studied. Total polysaccharide concentration, xanthan and locust bean ratio on mixture and temperature at which the gum was dissolved (dissolution temperature) for both xanthan and locust bean gums have been considered. Under these different operational mixture conditions shear rate and time have also been considered to describe the rheological behaviour of the solutions studied. The high viscosity increase observed in these mixtures is due to the interaction between xanthan gum and locust bean gum molecules. This interaction takes place between the side chains of xanthan and the backbone of the locust bean gum. Both xanthan molecule conformation in solution – tertiary structure – and locust bean gum structure show great influence on the final viscosity of the solution mixtures. Xanthan conformation changes with temperature, going from ordered structures to disordered or chaotic ones. Locust bean gum composition changes with dissolution temperature, showing a dissolved galactose/mannose ratio reduction when temperature increases, ie the smooth regions – zones without galactose radicals – are predominantly dissolved. The highest viscosity was obtained for the solution mixture with a total polysaccharide concentration of 1.5 kg m−3 and a xanthan/locust ratio of 2:4 (w/w) and when xanthan gum and locust bean gum were dissolved at 40°C and 80°C, respectively. © 1999 Society of Chemical Industry

Temperature changes in CO2 foam-fracturing construction can easily affect surfactant foam stability. To investigate the effect of temperature on the foam stability of different types of surfactants, this study measured the foam half-life and viscosity of four typical surfactants, CTAB, LAS-30, HSB1214, and TX-10, using a novel self-designed and built foam performance measurement device. The effects of temperature on foam half-life and viscosity were studied. The results show that as the temperature increased, the half-life shortened, and the viscosity of the liquid phase decreased, which led to a decrease in foam stability. Moreover, using Materials Studio, a type of molecular simulation software, an interfacial model of the foam film was constructed to calculate the IFE and the self-diffusion coefficient of water molecules at 300 ps after the equilibrium of the foam system to investigate the mechanism of temperature influence on the stability of the foam. The results show that, for CTAB, LAS-30, HSB1214, and TX-10, the temperature increases from 15 °C to 45 °C, the IFE is enhanced by −50.05%, −59.10%, −64.21%, and −44.26%, respectively, the interfacial system changes from a low-energy state to a high-energy state, and the interfacial stability decreases. Meanwhile, Dwater increased 1.10-fold, 0.78-fold, 1.43-fold, and 0.64-fold, respectively, which accelerated the diffusion and migration of water molecules, weakened the intermolecular forces, and accelerated the instability of the foam system.

Foam pollution in the tailwater discharge from coastal power plants poses a significant challenge. However, the mechanisms underlying foam formation and stability remain understudied, which hinders the development of effective control strategies. This study investigated the impacts of temperature and algal concentration on foam stability in tailwater discharge from coastal power plants through simulation experiments to elucidate mechanisms of foam stability. A laboratory simulation device was developed to adjust temperature and algal concentration and measure foam layer height, half-life, bubble diameter, surface tension, and viscosity. This device was used to replicate foam scenarios typical of coastal power plant tailwater discharge to analyze the effects of temperature and algal concentration on foam stability through comprehensive data collection and analysis across various operational conditions. The findings revealed that foam stability decreased with increasing temperatures (15–45 °C). However, during hot summer months, higher temperatures (range of 30–40 °C) hindered foam dissipation owing to algal blooms and the release of surface-active substances. The functional relationship between foam stability index (half-life, foam layer height, bubble diameter) and temperature and algae concentration was established, which provides a scientific basis for predicting foam stability under different conditions. This research elucidates the complex dynamics of foam in the tailwater discharge from coastal power plants and provides insights for developing more effective foam control strategies, potentially mitigating adverse impacts on the marine ecosystem. In future research, by adding experimental conditions such as pH, ionic strength, and different types of protein polysaccharides, a more comprehensive understanding of the mechanism of bubble generation can be achieved, providing more accurate foam suppression optimization solutions for future engineering practices.

Stability study of aqueous foams under high-temperature and high-pressure conditions relevant to Enhanced Geothermal Systems (EGS)

Summary Foam drilling offers advantages such as reduced formation damage and faster drilling in underbalanced drilling (UBD) operations. The efficacy of foam drilling is influenced by factors including pressure, temperature, salt content, foam quality, and pH levels. However, a gap exists in the evaluation of foam properties under rigorous conditions, particularly those involving high pH and mixed salt environments common in drilling scenarios, highlighting the need for further research. In this study, a high-pressure, high-temperature (HPHT) foam analyzer and rheometer were employed to examine the stability and rheological behavior of ammonium alchohol ether sulfate (AAES) foam under simulated alkaline drilling conditions. The foaming solution, designed to replicate such conditions, consisted of synthetic seawater (SW) with a salt mixture totaling approximately 67.70 g/L and a 0.5 wt.% foaming agent adjusted to a pH of 9.5. This approach differs from the individual salt studies prevalent in existing literature and provides a unique perspective on foam stability and behavior. Driven by environmental sustainability considerations, the effects of eco-friendly surfactant AAES and various drilling fluid additives: polyanionic cellulose (PAC), carboxymethyl cellulose sodium (CMC), and xanthan gum (XG), were investigated for foam formulation. The apparent viscosity of the AAES foam was evaluated at different pressures and temperatures across varying shear rates. A consistent decrease in foam viscosity with increasing shear rates was observed, irrespective of pressure and temperature. An increase in foam viscosity was also noted with higher pressures (from 14.7 psi to 3,000 psi) at low shear rates, with values rising from 8.04 cp to 14.74 cp, and from 3.71 cp to 5.79 cp at high shear rates of 1,000 s⁻¹. Increasing foam quality from 65% to 85% resulted in significant improvements in viscosity, approximately 37% at low shear rates and about 79% at high shear rates. The introduction of additives to AAES foam at 1,000 psi and 90°C led to a substantial increase in viscosity, with PAC showing the most significant enhancement: 33.28 cp at low shear rates and 18.15 cp at high shear rates. Conversely, the viscosity of both base AAES foam and additive-enhanced foams decreased with rising temperatures, although PAC exhibited the greatest resistance to viscosity variations due to temperature changes. The addition of PAC also resulted in a notable increase in foam yield stress, potentially leading to more efficient cuttings transport and hole cleaning. Furthermore, foam stability was significantly improved by the additives, with XG and CMC doubling stability to 48 minutes, and PAC resulting in a threefold increase in half-life to 65 minutes. This study presents AAES and the tested additives as viable components for eco-friendly foam formulations, promoting enhanced properties suitable for UBD applications.

Foam unloading is a cost-effective technique for removing liquid from low-energy gas wells, but it faces challenges due to thefoam stability 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, however 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 estimates 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.