Search Results (17)

The stability of nitrogen gas foam hinders its applicability in petroleum applications. Fly ash nanoparticles and clay improve the N₂ foam stability, and flue gas foams provide a cost-effective solution for carbon capture, utilization, and storage (CCUS). This study examines the stability, volume, and bubble structure of foams formed using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS), along with the cationic surfactant cetyltrimethylammonium bromide (CTAB), selected for their comparable interfacial tension properties. Analysis of foam stability and volume and bubble structure was conducted under different CO₂/N₂ mixtures, with half-life and initial foam volume serving as the evaluation criteria. The impact of fly ash and clay on SDS-N₂ foam was also evaluated. The results showed that foams created with CTAB, SDBS, and SDS exhibit the greatest stability in pure nitrogen, attributed to low solubility in water and limited gas diffusion. SDS showed the highest foam strength attributable to its comparatively low surface tension. The addition of fly ash and clay significantly improved foam stability by migrating to the gas–liquid interface, creating a protective barrier that reduced drainage. Both nano fly ash and clay improved the half-life of nitrogen foam by 11.25 times and increased the foam volume, with optimal concentrations identified as 5.0 wt% for fly ash and 3.0 wt% for clay. This research emphasizes the importance of fly ash nanoparticles in stabilizing foams, therefore optimizing a foam system for enhanced oil recovery (EOR). Full article

Soil washing is an efficient method to remove polybrominated diphenyl ethers (PBDEs) from contaminated soils. The obtained solutions from soil-washing still contain PBDEs, requiring further treatment before disposal or reuse. Although photolysis is effective for PBDE degradation in solutions, the concurrent formation of toxic polybrominated dibenzofurans (PBDFs) may limit its practical application. In this study, 2,8-dibromodibenzofurans (2,8-BDF) formation rate and mechanisms during 2,4,4′-tribromodiphenyl ether (BDE-28) photolysis in various simulated soil-washing solutions was investigated. Results revealed significant effects of solubilizers on 2,8-BDF formation. The nonionic surfactants polysorbate (TW80), polyoxyethylene octylphenyl ether (TX series), and the cationic surfactant cetyltrimethylammonium bromide (CTAB) resulted in low 2,8-BDF formation rate (1–5%), while the β-cyclodextrin led to the highest 2,8-BDF formation rate (about 28%). The nonionic surfactants polyoxyethylene dodecyl ethers (Brij series), and the anionic surfactants sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), also showed a high level of 2,8-BDF formation rate (7–17%). Solubilizer structure and its interaction with BDE-28 determined the 2,8-BDF formation. The role of the micelle microenvironment on 2,8-BDF formation was verified via an experiment and molecular dynamics simulation. The organic region of micelle exhibited high hydrogen donation ability, which inhibited 2,8-BDF formation. The results indicated distinct risks of PBDE photolysis in various soil-washing solutions, providing an important reference for solubilizer selection and the application of photolysis on the treatment of soil-washing solutions containing PBDEs. Full article

Bamboo, recognized as a nutrient-dense biomass material, exhibits a high susceptibility to mold infestations, which can result in discoloration and a notable decrease in longevity, thereby posing potential health risks to humans. In this study, melamine-formaldehyde resin (MFR) was utilized to load 3-iodo-2-propargyl-butyl-carbamate (IPBC) via in situ polymerization, resulting in the preparation of microcapsules suitable for anti-mold protection of bamboo. The mold resistance of Aspergillus niger, Trichoderma viride, and Penicillium citrinum were evaluated. A scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier-transform infrared spectrometer (FTIR), and thermogravimetric analysis (TG) were used to characterize and analyze the formation process, surface morphology, structural composition, and thermal stability of the microcapsules. The effects of different surfactants (Span 80, Tween 80, SDBS, SDS, GA) on the microscopic morphology of the anti-mold microcapsules were investigated. The results show that microcapsules prepared with Tween 80 as the surfactant exhibited good mold resistance. After coating MFR with IPBC, the drug loading of I-MFR is 20%, with an encapsulation efficiency of 80%, demonstrating excellent anti-mold performance. The microcapsules show favorable anti-mold performance and have broad application prospects in bamboo protection. Full article

Hydrophobic coatings from chitosan–surfactant composites (ca. 400 nm thick by UV-Vis spectroscopy) for possible corrosion protection were developed on glass and zinc substrates. The surfactants (sodium dodecyl sulfate, SDS or sodium dodecylbenzenesulfonate, and SDBS) were added to the chitosan by two methods: mixing the surfactants with the aqueous chitosan solutions before film deposition or impregnating the deposited chitosan films with surfactants from their aqueous solutions. For the mixed coatings, it was found that the lower surface tension of solutions (40–45 mN/m) corresponded to more hydrophobic (80–90°) coatings in every case. The hydrophobicity of the impregnated coatings was especially significant (88° for SDS and 100° for SDBS). Atomic force microscopy studies revealed a slight increase in roughness (max 1.005) for the most hydrophobic coatings. The accumulation of surfactants in the layer was only significant (0.8–1.0 sulfur atomic %) in the impregnated samples according to X-ray photoelectron spectroscopy. Polarization and electron impedance spectroscopy tests confirmed better barrier properties for these samples (40–50% pseudo-porosity instead of 94%). The degree of swelling in a water vapor atmosphere was significantly lower in the case of the impregnated coatings (ca. 25%) than that of the native ones (ca. 75%), measured by spectroscopic ellipsometry. Accordingly, good barrier layer properties require advantageous bulk properties in addition to surface hydrophobicity. Full article

Bi₂S₃ has gained considerable attention as a semiconductor for its versatile functional properties, finding application across various fields, and liquid phase exfoliation (LPE) serves as a straightforward method to produce it in nano-form. Till now, the commonly used solvent for LPE has been N-Methyl-2-pyrrolidone, which is expensive, toxic and has a high boiling point. These limitations drive the search for more sustainable alternatives, with water being a promising option. Nonetheless, surfactants are necessary for LPE in water due to the hydrophobic nature of Bi₂S₃, and organic molecules with amphoteric characteristics are identified as suitable surfactants. However, systematic studies on the use of ionic surfactants in the LPE of Bi₂S₃ have remained scarce until now. In this work, we used sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS) and sodium hexadecyl sulfonate (SHS) as representative species and we present a comprehensive investigation into their effects on the LPE of Bi₂S₃. Through characterizations of the resulting products, we find that all surfactants effectively exfoliate Bi₂S₃ into few-layer species. Notably, SDBS demonstrates superior stabilization of the 2D layers compared to the other surfactants, while SHS becomes the most promising surfactant for obtaining products with high yield. Moreover, the resulting nano-inks are used for fabricating films using spray-coating, reaching a fine tuning of band gap by controlling the number of cycles, and paving the way for the utilization of 2D Bi₂S₃ in optoelectronic devices. Full article

Soil is the main aggregation site of polycyclic aromatic hydrocarbons and an important pathway of migration to other media. In this paper, the adsorption behavior of pyrene and seven different types of surfactants on kaolinite surfaces was studied by molecular dynamics simulation and desorption testing. The molecular dynamics simulation results showed that pyrene was more easily adsorbed on the 001 (-) side of kaolinite. SDBS, SDS, TW80, and TX-100 had strong interactions with pyrene, encapsulating pyrene molecules in aggregates. However, when the concentration of surfactant was too high, the desorption of pyrene molecules on a kaolinite surface will be inhibited. The desorption of pyrene molecules will be inhibited in the presence of BS-12, TW80, and TX-100, while the desorption process can be promoted by using CTAC, DDBAC, SDBS, and SDS as soil remediation agents. The removal rate of pyrene gradually increased with the increase of SDS dosage, while for SDBS, the removal rate showed a trend of first increasing and then decreasing. When the concentration of SDS was 0.014 mol/L, the elution rate of pyrene reached 72.86%. The molecular dynamics simulation results were similar to the desorption test results, verifying the reliability of molecular dynamics simulation. The research results provide theoretical support for the selection of surfactants in the remediation process of pyrene-contaminated soil. Full article

Technological advancement, on the one hand, leads to the enhanced quality of the final product but on the other hand, generates a good quantity of effluent. The wastewater containing dyes which emanates from the textile industry is a cause of worry. Hence, this paper focuses on the treatment of dyeing wastewater using the foam separation process as it offers several advantages over other traditional methods. Methylene blue (MB), owing to its ill effects on the entire ecosystem, has been considered as a model dye in this research work. The objective of this work is to remove MB from wastewater and at the same time, its recovery in the foam phase. The ability of sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) to perform separation of MB was compared. The following operating parameters were identified: contact time, initial pH of a feed solution, surfactant dose, volumetric flow rate of air, volume of liquid in the column, and concentration of dye; which greatly influence the separation parameters (% removal and enrichment ratio). Keeping in mind the importance of recovering MB from dilute solutions, the method to enhance foam drainage was devised by inserting an inverted funnel in the foam phase. In the presence of inverted funnel, the concentration of MB in the foamate doubled in comparison to the conventional column (without an inverted funnel). The comparison between SDS and SDBS divulged SDBS as a better surfactant to get concentrated solution of MB in the foamate, but the quantity of SDBS required was more. The optimization of operating variables was also done by using the Taguchi method and Grey relational analysis. Finally, the concentration of MB was discovered to be the most responsive operating parameter for both separation parameters. Full article

The thermal conductivity and stability of any nanofluid are essential thermophysical properties. These properties are affected by many parameters, such as the nanoparticles, the base fluid, the surfactant, and the sonication time used for mixing. In this study, multi-walled carbon nanotubes (MWCNTs) were selected as additive particles, and the remaining variables were tested to reach the most suitable nanofluid that can be used to cool photovoltaic/thermal (PVT) systems operating in the harsh summer conditions of the city of Baghdad. Among the tested base fluids, water was chosen, although ethylene glycol (EG), propylene glycol (PG), and heat transfer oil (HTO) were available. The novelty of the current study contains the optimization of nanofluid preparation time to improve MWCNTs’ PVT performance with different surfactants (CTAB, SDS, and SDBS) and base fluids (water, EG, PG, and oil). When 1% MWCNT mass fraction was added, the thermal conductivity (TC) of all tested fluids increased, and the water + nano-MWCNT advanced all TC (EG, PG, and oil) by 119.5%, 308%, and 210%, respectively. The aqueous nanofluids’ stability also exceeded the EG, PG, and oil at the mass fraction of 0.5% MWCNTs by 11.6%, 20.3%, and 16.66%, respectively. A nanofluid consisting of 0.5% MWCNTs, water (base fluid), and CTAB (surfactant) was selected with a sonication time of three and quarter hours, considering that these preparation conditions were practically the best. This fluid was circulated in an installed outdoor, weather-exposed PVT system. Experiments were carried out in the harsh weather conditions of Baghdad, Iraq, to test the effectiveness of the PVT system and the nanofluid. The nanofluid-cooled system achieved an electrical efficiency increase of 88.85% and 44% compared to standalone PV and water-cooled PVT systems, respectively. Additionally, its thermal efficiency was about 20% higher than that of a water-cooled PVT system. With the effect of the high temperature of the PV panel (at noon), the electrical efficiency of the systems was decreased, and the least affected was the nanofluid-cooled PVT system. The thermal efficiency of the nanofluid-cooled PVT system was also increased under these conditions. This success confirms that the prepared nanofluid cooling of the PVT system approach can be used in the severe weather of the city of Baghdad. Full article

Interactions between polymers (P) and surfactants (S) in aqueous solution lead to interfacial and aggregation phenomena that are not only of great interest in physical chemistry but also important for many industrial applications, such as the development of detergents and fabric softeners. Here, we synthesized two ionic derivatives—sodium carboxymethylcellulose (NaCMC) and quaternized cellulose (QC)—from cellulose recycled from textile wastes and then explored the interactions of these polymers with assorted surfactants—cationic (CTAB, gemini), anionic (SDS, SDBS) and nonionic (TX-100)—commonly used in the textile industry. We obtained surface tension curves of the P/S mixtures by fixing the polymer concentration and then increasing the surfactant concentration. In mixtures where polymer and surfactant are oppositely charged (P⁻/S⁺ and P⁺/S⁻), a strong association is observed, and from the surface tension curves, we determined the critical aggregation concentration (cac) and critical micelle concentration in the presence of polymer (cmc^p). For mixtures of similar charge (P⁺/S⁺ and P⁻/S⁻), virtually no interactions are observed, with the notable exception of the QC/CTAB system, which is much more surface active than the neat CTAB. We further investigated the effect of oppositely charged P/S mixtures on hydrophilicity by measuring the contact angles of aqueous droplets on a hydrophobic textile substrate. Significantly, both P⁻/S⁺ and P⁺/S⁻ systems greatly enhance the hydrophilicity of the substrate at much lower surfactant concentrations than the surfactant alone (in particular in the QC/SDBS and QC/SDS systems). Full article

Recognizing the extreme speeds of reactions with microwaves, anionic forms of surfactants (sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS)) have been intercalated successfully by ion-exchange reactions in binary Li-Al and ternary Li-M-Al (M = Mg, Co, Ni, Cu, and Zn) layered double hydroxide (LDH) systems with the aid of microwaves. The samples have been characterized extensively. The basal spacings of 28.2 and 30.4 Å have been estimated for Li-Al-DS and Li-Al-DBS LDH samples, respectively, suggesting a perpendicular arrangement of DS⁻ and DBS⁻ anions in the interlayer space. The characteristic vibration bands of both LDH and the surfactant (DS⁻ and DBS⁻) in the FTIR spectra confirmed the binding mode of surfactant molecules within the interlayers. DS⁻-intercalated Li-Al LDH showed lower thermal stability than the DBS⁻-intercalated sample. The nitrate-intercalated Li-M-Al (M = Mg, Co, Ni, Cu, and Zn) LDHs were ion-exchanged with SDS and SDBS to yield DS⁻-and DBS⁻-intercalated systems. The expanded basal spacings and a change in crystallite morphology confirmed the vertical intercalation of DS⁻ and DBS⁻ in Li-M-Al LDHs. ICP-AES and elemental analyses determined the metal contents and the surfactant content. FTIR spectra of intercalated samples confirmed the surfactant’s presence in the interlayer. The presence of Co, Ni, and Cu in Li-M-Al LDHs has been confirmed from UV-visible spectra. The Li-Al-DBS sample adsorbed iodine efficiently from methanol solutions, and the Langmuir model could explain the adsorption data in a better way. The adsorption followed pseudo-second-order kinetics. Full article

This work deals with electroactive conducting polymers (ECPs) used as a complementary component on purely capacitive silicon nanowires protected by a 3 nm alumina layer. Accordingly, in this work, we use a fast and simple deposition method to create a pseudocapacitive material based on the electropolymerization in aqueous micellar media (SDS and SDBS 0.01 M) of hydroxymethyl-EDOT (EDOT-OH) onto 3 nm alumina-coated silicon nanowires (Al₃@SiNWs). The composite material displays remarkable capacitive behavior with a specific capacitance of 4.75 mF·cm⁻² at a current density of 19 µA·cm⁻² in aqueous Na₂SO₄ electrolyte. Full article

Metal–organic frameworks (MOFs) featuring porous structures and large specific surface areas have shown great potential in removing organic pollutants from wastewater via adsorption processes. Although the particle size of MOFs determines the adsorption performance (something known as the size-dependent effect), engineering it into desirable dimensions for enhancing the adsorption performance is a great challenge. Here, we develop a practical and facile approach to regulate the particle size of copper benzene-1,3,5-tricarboxylate (Cu-BTC) adsorbents with high tunability by screening the functional modulator of various surfactants adding in hydrothermal synthesis procedure. The effect of surfactant type and concentration on the particle size of Cu-BTC was systematically investigated. The results show that the nonionic surfactant polyvinylpyrrolidone (PVP) demonstrated the greatest ability to control the particle size of Cu-BTC among other counterparts (e.g., N, N, N-trimethyl-1-dodecanaminium bromide (DTAB), polyethylene glycol (PEG1000), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) and hexadecyl trimethyl ammonium bromide (CTAB)). By increasing the PVP concentration to 0.14 mmol L⁻¹, the average particle size of Cu-BTC could be correspondingly reduced by more than ten times, reaching to a comparative smaller value of 2.4 μm as compared with the reported counterparts. In addition, the PVP allowed a large increase of the surface area of Cu-BTC according to porosity analysis, resulting in a great enhancement of methylene blue (MB) adsorption. The PVP-modulated Cu-BTC showed fast adsorption kinetics for MB removal accompanied with a maximum adsorption capacity of 169.2 mg g⁻¹, which was considerably competitive with most of the analogs reported. Therefore, our study may inspire concepts for engineering the particle size of Cu-BTCs with improved properties for more practical applications. Full article

Reports on fungicide-based agronanochemicals in combating disastrous basal stem rot disease in the oil palm industry are scant. Herein, we describe the potential of fungicide nanodelivery agents based on hexaconazole-micelle systems produced using three different surfactants; sodium dodecylbenze sulfonate (SDBS), sodium dodecyl sulfate (SDS) and Tween 80 (T80). The resulting nanodelivery systems were characterized and the results supported the encapsulation of the fungicide into the micelles of the surfactants. We have investigated in detail the size-dependent effects of the as-synthesized micelles towards the inhibition growth of Ganoderma Boninense fungi. All the nanodelivery systems indicate that their size decreased as the surfactant concentration was increased, and it directly affects the fungal inhibition. It was also found that Tween 80, a non-ionic surfactant gave the lowest effective concentration, the EC₅₀ value of 2, on the pathogenic fungus Ganoderma boninense compared to the other anionic surfactants; SDBS and SDS. This study opens up a new generation of agronanofungicide of better efficacy for Ganoderma disease treatment. Full article

Developing stable nanofluids and improving their thermo-physical properties are highly important in heat transfer applications. In the present work, the stability, thermal conductivity, and rheological properties of tungsten disulphide (WS₂) nanoparticles (NPs) with ethylene glycol (EG) were profoundly examined using a particle size analyzer, zeta-sizer, thermal property analyzer, rheometer, and pH measuring system. WS₂ NPs were characterized by various techniques, such as XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Spectroscopy), FESEM (Field emission scanning electron microscopy), and high-resolution transmission electron microscopy (HRTEM). The nanofluids were obtained with the two-step method by employing three volume concentrations (0.005%, 0.01%, and 0.02%) of WS₂. The influence of different surfactants (Sodium dodecyl sulphate (SDS), Sodium dodecylbenzenesulfonate (SDBS), Cetyltrimethylammonium bromide (CTAB)) with various volume concentrations (0.05–2%) on the measured properties has also been evaluated. Pristine WS₂/EG nanofluids exhibit low zeta potential values, i.e., −7.9 mV, −9.3 mV, and −5 mV, corresponding to 0.005%, 0.01%, and 0.02% nanofluid, respectively. However, the zeta potential surpassed the threshold (±30 mV) and the maximum values reached of −52 mV, −45 mV, and 42 mV for SDS, SDBS, and CTAB-containing nanofluids. This showed the successful adsorption of surfactants onto WS₂, which was also observed through the increased agglomerate size of up to 1720 nm. Concurrently, particularly for 0.05% SDS with 0.005% WS₂, thermal conductivity was enhanced by up to 4.5%, with a corresponding decrease in viscosity of up to 10.5% in a temperature range of (25–70 °C), as compared to EG. Conversely, the viscoelastic analysis has indicated considerable yield stress due to the presence of surfactants, while the pristine nanofluids exhibited enhanced fluidity over the entire tested deformation range. The shear flow behavior showed a transition from a non-Newtonian to a Newtonian fluid at a low shear rate of 10 s⁻¹. Besides this, the temperature sweep analysis has shown a viscosity reduction in a range of temperatures (25–70 °C), with an indication of a critical temperature limit. However, owing to an anomalous reduction in the dynamic viscosity of up to 10.5% and an enhancement in the thermal conductivity of up to 6.9%, WS₂/EG nanofluids could be considered as a potential candidate for heat transfer applications. Full article

Poly(N-methylaniline) (PNMA) is a polyaniline derivative with a methyl substituent on the nitrogen atom. PNMA is of interest owing to its higher solubility in organic solvents when compared to the unsubstituted polyaniline. However, the electrical conductivity of polyaniline derivatives suffers from chemical substitution. PNMA was synthesized via emulsion polymerization using three different anionic surfactants, namely sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and dioctyl sodium sulfosuccinate (AOT). The effects of surfactant structures and concentrations on electrical conductivity, doping level, crystallinity, morphology, and thermal stability were investigated. The re-doping step using perchloric acid (HClO₄) as a dopant was sequentially proceeded to enhance electrical conductivity. PNMA synthesized in SDBS at five times its critical micelle concentration (CMC) demonstrated the highest electrical conductivity, doping level, and thermal stability among all surfactants at identical concentrations. Scanning electron microscopy (SEM) images revealed that the PNMA particle shapes and sizes critically depended on the surfactant types and concentrations, and the doping mole ratios in the re-doping step. The highest electrical conductivity of 109.84 ± 20.44 S cm⁻¹ and a doping level of 52.45% were attained at the doping mole ratio of 50:1. Full article