Dispersion Of SiO2 Nanoparticles Research Articles

Microstructural evolution of the inner oxide layer of a Si-modified austenitic stainless steel exposed to oxygen-saturated lead-bismuth eutectic (LBE): Toward the origin of LBE penetration

Microstructural evolution of inner oxide layer of a Si-modified austenitic stainless steel exposed to oxygen-saturated static lead-bismuth eutectic (LBE) at 550 °C up to 3000 h has been investigated. A dual-phase separated structure consisting of Fe-Cr spinel and (Fe, Cr)1-xNix phase is formed in inner oxide layer, attributed to partitioning of Ni and Cr associated with Fe-Cr spinel formation. SiO2 is preferentially formed preceding the Fe-Cr spinel at internal oxidation frontier, leading to dispersed SiO2 nanoparticles within Fe-Cr spinel. The mechanism of LBE penetration into inner oxide layer is further developed based on preferable dissolution process of (Fe, Cr)1-xNix phase.

Improvement of carbon fiber/phenolic composite properties by low-loading graphene oxide and SiO2 nanoparticles

As an ablative thermal protection material, the mechanical properties and ablative resistance of carbon fiber/phenolic (C-Ph) composite should be improved to meet the high requirements in deep space exploration. Herein, the properties of C-Ph composites were improved by the synergistic effect of low-concentration graphene oxide (GO) solution and low mass fraction of SiO2 nanoparticles. Compared to the unmodified C-Ph composite, the compressive strength of the modified composites was increased by 40.75 % and the linear and mass ablation rates were reduced by 17.78 % and 43.95 %, respectively. The introduction of GO effectively improved the interfacial bonding between the fiber and phenolic resin. Meanwhile, the uniformly dispersed SiO2 nanoparticles resisted the applied loads, thus synergistically enhancing the mechanical properties of the composites. In terms of improving ablation resistance, GO promoted the graphitization of fibers and enhanced the stability of the char layer. Concurrently, SiO2 nanoparticles reacted with the carbon matrix under high temperatures to form ablation-resistant SiC, thus synergistically enhancing the ablative properties of the composite.

Bioinspired Organic Porous Coupling Agent for Enhancement of Nanoparticle Dispersion and Interfacial Strength.

Composite materials have significantly advanced with the integration of inorganic nanoparticles as fillers in polymers. Achieving fine dispersion of these nanoparticles within the composites, however, remains a challenge. This study presents a novel solution inspired by the natural structure of Xanthium. We have developed a polymer of intrinsic microporosity (PIM)-based porous coupling agent, named PCA. PCA's rigid backbone structure enhances interfacial interactions through a unique intermolecular interlocking mechanism. This approach notably improves the dispersion of SiO2 nanoparticles in various organic solvents and low-polarity polymers. Significantly, PCA-modified SiO2 nanoparticles embedded in polyisoprene rubber showed enhanced mechanical properties. The Young's modulus increases to 30.7 MPa, compared to 5.4 MPa in hexadecyltrimethoxysilane-modified nanoparticles. Further analysis shows that PCA-modified composites not only become stiffer but also gain strength and ductility. This research demonstrates a novel biomimetic strategy for enhancing interfacial interactions in composites, potentially leading to stronger, more versatile composite materials.

Synthesis and performance assessment of silica dispersed nano-composite polymer gel electrolyte for high-performance solid-state supercapacitors

Nano-composite polymer gel electrolyte (NCPGE) films are prepared by incorporating liquid electrolyte (EC-PC-TEABF4) into polyvinyldinefloroide co-hexafluoropropylene (PVDF-HFP) polymer with dispersed SiO2 nano-particles using solution cast technique. The NCPGE is optimized for the highest ionic conductivity by varying wt% of SiO2 nanoparticles in PGE [(1:4){PVDF-HFP + EC-PC-TEABF4}]. Highest conductivity of 8.2 × 10−3 Scm−1 is found for optimized composition [(1:4){PVDF-HFP + EC-PC-TEABF4} + SiO2 (15 wt%)] of NCPGE. Structural and morphological studies have been done using XRD, FTIR, and SEM. Frequency dependent dielectric behaviour is understood using dielectric constant and modulus analysis in a wide range of frequencies. The ionic transference number is 0.96 and an electrochemical potential window of ∼ 3.5 V has been obtained. Fabrication of electric double layer capacitor (EDLC) is done by sandwiching NCPGE between activated carbon (AC) electrodes. The electrochemical performance of fabricated supercapacitor is evaluated by impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge techniques. Results show significant improvement in the quality of synthesized electrolyte.

Enhancement of phenol recovery from wastewater by nanofluid utilizing liquid-liquid extraction method in a membrane-based contactor

This study aims to investigate the effect of adding nanoparticles (NPs) to phenol solvent on the recovery of phenol from wastewater by applying the liquid-liquid extraction technique in a contactor of a hollow fiber membrane. The resulting solution, called nanofluid, is composed of dispersed SiO2 nanoparticles in a 10% (v/v) tributyl phosphate (TBP) /kerosene mixture. The solvent loaded with phenol was regenerated using NaOH solution in a stripping hollow fiber membrane contactor. The stability of SiO2 NPs in the nanofluid was also investigated. Furthermore, the influence of operating conditions, such as NPs concentration, organic phase flow rate (Qorg), aqueous phase flow rate (Qaqu), and inlet phenol concentration on extraction efficiency (ηextrac), extraction flux (Jextrac), and stripping efficiency (ηstripp) were evaluated. The results showed that after 24 h, approximately 80% of the initial dispersion of SiO2 NPs into the nanofluid was achieved. Furthermore, it was observed that adding NPs to the TBP/kerosene solution improved ηextrac, Jextrac, and ηstripp. Among the studied NPs concentrations, 0.02 wt% exhibited higher values of ηextrac, Jextrac, and ηstripp. Additionally, it was found that increasing Qorg led to a significant increase in ηextrac and Jextrac, but a decrease in ηstripp. Conversely, increasing Qaqu led to a decrease in both ηextrac and ηstripp, but an increase in Jextrac. At an inlet phenol concentration of 1000 ppm and with Qorg and Qaqu at the same value of 150 mL min−1, the use of a solvent containing 0.02 wt% SiO2 NPs resulted in ηextrac of 97.8% and ηstripp of 97.7%.

Electrical Treeing and Partial Discharge Behavior in Epoxy Nanocomposites With In Situ Synthesized SiO2

The electrical treeing resistance of epoxy-SiO2 nanocomposites prepared by synthesizing functionalized SiO2 nanoparticles directly in epoxy was investigated and compared to pure epoxy [diglycidyl ether of bisphenol-A (DGEBA)]. Partial discharge (PD) measurements indicate a transition of initially nonconducting trees to conducting trees in both the pure epoxy and the nanocomposites. A correlation between the synthesis precursors and the PD behavior over time indicates that the presence of ions and remnant precursors hasten the transition to conducting trees and lower the voltage of tree inception. The resistance to tree growth was found to be dependent on the synthesis conditions of the nanocomposites. Slower tree growth was observed in nanocomposites prepared under neutral conditions, with a homogenous dispersion of SiO2 nanoparticles (30–50 nm, 5 wt%). The presence of ions from alkaline conditions and/or poor dispersion of SiO2 resulted in faster and more linear tree growth and lower initiation voltages than for pure epoxy.

Electret elastomer-based stretchable triboelectric nanogenerators with autonomously managed power supplies for self-charging systems

Stretchable power sources capable of accommodating large deformations are urgently demanded for various stretchable and wearable electronics. In this work, we report a stretchable electret-based triboelectric nanogenerator (SEB-TENG) consisting of elastomeric electret as electrification materials and organo-hydrogels as electrodes. The electret elastomer, prepared by uniformly dispersing SiO2 nanoparticles in the elastomer matrix and thermally injecting static charges, obtains a high surface potential, high tensile strain (796%), and long stability. Then, the SEB-TENG device also achieves high stretchability (423%) and high charge density (0.2 mC m−2). Furthermore, a power management module (PMM) is designed to maximize the energy utilization of the SEB-TENG. The integrated self-charging system can be sufficiently used to constantly power a watch, or charge a Li-ion coin cell which subsequently provides sustainable power supplies to a digital thermometer. This work provides a viable approach to simultaneously achieve high output performances and high stretchability of integrated power sources.

Performance of energy storage unit equipped with vase-shaped fins including nanoparticle enhanced paraffin

Inventing new fins with vase-shaped to incorporate in the storage enclosure has been suggested in current work to decline the energy consumption. Combination of heat storage with shape of triplex tube with parabolic solar unit makes the efficiency to intensify. The properties of paraffin were intensified with dispersing SiO2 nanoparticles. Different proposed models contain various ranges of fraction of nano-powders and three arrangements of vase-shaped fins. Finite volume method with involvement of both conduction and convection modes was applied to scrutinize the system numerically and its accuracy was assessed by comparing the outputs with previous article. The best arrangement for the target of maximum efficiency and minimum time of charging was the third style of fins (Diameter ratio (DR) = 1) in which fins are attached to both hot surfaces and with inclusion of nano-powders, it takes 20.91 min to achieve full melting. With changing the features of paraffin due to dispersing nano-powders, the melting time reduces around 3.83 % when DR = 1. Moreover, with the change of style of fins from DR = 0.6 to DR = 1, the melting time drops around 6.06 %.

Effect of La2O3 content on the oxygen barrier ability of the HfB2‐SiC coating at 1973 K

AbstractTo inhibit the destructive evolution of the HfB2‐SiC coating during oxidation, La2O3 was added to modify the oxygen‐blocking capability of the HfB2‐SiC coating. The effect of La2O3 content on the oxygen barrier capacity of HfB2‐SiC was investigated. The addition of 5 vol.% La2O3 lowered the oxidation activity and strengthened the inert oxygen barrier capacity of the HfB2‐SiC coating, which made the oxygen permeability and maximum weight change rate of the coating decrease by 30.32% and 73.97%, respectively. Due to the solid solution reaction of the dispersed La2O3, HfO2, and SiO2 nanoparticles, a stable Hf‐B‐La‐Si‐O multiphase glass was formed on the surface of the coating. Besides, the high‐melting‐point particles, such as HfO2, La2Hf2O7, and HfSiO4, dispersed in the glass layer as hard particles and formed a mosaic structure based on the Hf‐B‐La‐Si‐O compound, which increased the cumulative protection efficiency of the HfB2‐SiC coating to 98.5% and reduced the inert factor value by 84.57%. However, the excessive consumption of SiO2 glass by La2O3 results in dendritization of the generated glass when the La2O3 content is above 10 vol.%, which reduced the self‐healing capability of the generated glass and instead weakened the oxygen barrier properties of the HfB2‐SiC‐La2O3 coatings.

Development and Testing of Castables with Low Content of Calcium Oxide.

Colloidal silica is used in many kinds of industry. It is an aqueous dispersion of SiO2 nanoparticles. SiO2 colloidal solutions are commercially available in different concentrations, with different particle sizes and are stabilized with different ions. Colloidal SiO2 was used in this study as a cement replacement in refractory castable. The present study, in its first stage, offers an assessment of five different SiO2 colloidal solutions. The particle size of the solutions was 15 nm, the particle concentration was 30% and 40% and the colloidal solutions were stabilized with Na+, OH− and Cl− ions. The effect of the colloidal solutions on selected characteristics of the refractory pastes and on their mineralogical composition after firing at 1000 °C and 1500 °C was described. The most suitable SiO2 colloidal solution from the first stage was subsequently used for the refractory castable test samples’ preparation in the second stage. Refractory castables, unlike paste, contain a coarse aggregate (grog) up to a grain size of 6 mm. Four types of coarse refractory grog were evaluated. Their effect on selected characteristics of the refractory castable and on its mineralogical composition after firing at 1000 °C and 1500 °C was described. The selected characteristics, within the scope of this study, include bulk density, apparent porosity, cold modulus of rupture and linear changes after firing. Finally, the study describes the effect of the sol particle concentration and the effect of pore size distribution on corrosion resistance and on the internal structure of the material. Mineral and chemical compositions and microstructures of both the raw materials and designed aggregates were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction and scanning electron microscopy. An analysis of the transition zone between corrosive media (K2CO3) and tested castables showed better corrosion resistance for a sol-gel castable than an ultra-low cement castable.

Experimental, comparative and statistical study of heat transfer and drag reduction of Water/Polyisobutylene/nanoSiO2 poly-nanofluid through a horizontal pipe

Turbulent flow of fluid samples (polymeric solution, nanofluid and Poly-nanofluid (PNF)), into a horizontal pipeline was investigated to achieve heat transfer properties and drag reduction. Water, Polyisobutylene (PIB) and nanoSiO2 were the materials used in this study. PNFs prepared by dispersing SiO2 nanoparticles (with concentration range of 0.1–1 wt.%) into dilute Water/PIB solution (with concentration range of 10–50 ppm). The effect of polymer and nanoSiO2 presence on heat transfer properties such as convective heat transfer coefficient and Nusselt number were evaluated and Reynolds number changes were studied in this research. At the same time the effect of concentration and Reynolds number on the Nusselt number and drag reduction evaluated by utilizing a statistical method called analysis of variance (ANOVA).

Synthesis and characterization of cooling biodegradable nanofluids from non-edible oil for high voltage application

Mineral oil has been serving well as a cooling and insulation oil in high voltage power equipment but with a setback when considering environmental friendliness whenever there is spillage due to its poor carbon profile. Several works have been done on the enhancement of dielectric properties of green alternative with different nanoparticles but little attention was placed on its cooling properties which is one of the major functions of the oil. Also, to prevent food competition, esters from a non-edible seed oil should be given more consideration. This work, therefore, investigates the cooling properties of synthesized insulating nanofluid using Neem oil ester as the base fluid together with (Insulating) SiO2 and (semiconductive) WO3 nanoparticles. The nanoparticles were characterized using FTIR and XRD to confirm their functional groups and crystallite size respectively. Transesterification of the oil was done using sodium methoxide and the nanofluid samples were prepared by dispersing the nanoparticles into the oil. The nanoparticles were varied from 0.2 wt% to 1 wt%. The pour point, flash point and viscosity were measured according to ASTM standards. An increase in the pour point, flash point and viscosity were observed at every loading of the nanoparticle. The nanofluid with dispersed SiO2 nanoparticles were observed to possess superior properties as a cooling liquid in high voltage power equipment when compared with the fluid with WO3 nanoparticles because of its low viscosity, low pour point and good flash point. After the ageing, the synthesized fluids still retained their properties which is better than the mineral oil.

Synthesis of a coupling agent containing polyurethane chain and its influence on improving the dispersion of SiO2 nanoparticles in epoxy/amine thermoset

SiO2 nanoparticles (NPs) were modified with as-synthesized coupling agent containing isocyanate-terminated polyurethane (PUCA) to enhance the interaction between SiO2 NPs and DGEBA/DDM matrix in purpose of promoting the dispersion condition of the SiO2 NPs in cured resin. Uniform dispersion of the PUCA-SiO2 NPs was observed in the cured resin which was in obvious contrast with that of the raw SiO2 NPs and the IPTS-SiO2 NPs according to the visible light transmittance and TEM observation. The tensile behaviors of the PUCA-SiO2 composites were found obviously promoted than that of the raw SiO2 and IPTS-SiO2 composites. DMA results showed that the Tg of the PUCA-SiO2 composite was 8.9 °C and 5.8 °C higher than that of the raw, IPTS-SiO2 composite. SEM observation of the fracture surfaces showed that PUCA-SiO2 composite possessed the densest crack texture. This work showed that grafting the polyurethane chain to the surface of the inorganic NPs is an effective way to obtain uniform dispersion of the inorganic NPs in resin matrix.

N-Enriched Porous Carbon/SiO2 Composites Derived from Biomass Rice Husks for Boosting Li-Ion Storage: Insight into the Effect of N-Doping.

A N-enriched porous carbon/SiO2 (SiO2 /NC) composite from rice husks was prepared by ball milling and tested as a stable anode for lithium ion batteries (LIBs), in which the homogeneous dispersion of SiO2 nanoparticles and carbon matrix, and high level of N-doping can be realized simultaneously. The influence of N-doping on a series of SiO2 /NCs was systematically studied; this proved that the porosity, N-doping content, and electronic conductivity of SiO2 /NC can be controlled by adjusting common nitrogen sources (urea and melamine) and doping routes, including dry and wet milling, to reach a desirable balance of high capacity, long-term cyclability, and rate property. The optimized SiO2 /NC composite delivers a stably reversible capacity of 581 mA h g-1 at the high current load of 1.0 A g-1 at the 1000th cycle. The novel Li-storage mechanism of active silica in a composite was first proposed after observation of the N-doping effect that the redox reaction between SiO2 and Li+ is accelerated to transform into an alloying reaction of generated Si and Li+ , thus enhancing the reversible capacity. Moreover, kinetics analysis confirms that there is a combined Li-storage mechanism of battery-capacitive pattern in composite that contributes to fast charge transfer and ion diffusion during cycle.

Thermal Conductivity Enhancement of Silica Nanofluids for Ultrafast Cooling Applications: Statistical Modeling and Economic Analysis

Effectively dispersed spherical metallic or non-metallic nanoparticles at low mass concentrations in water, oil, or ethylene glycol may enhance the thermal conductivity of the mixture over the basefluid values. Focusing on the dilute suspensions of effectively dispersed SiO2 nanoparticles in water, the thermal conductivity of nanofluids was measured and statistical and economic analysis was performed. Stable nanofluids were prepared by dispersing dry SiO2 particles directly in water using sonication. The thermal conductivity of nanofluid with mass concentrations of 0.01 % to 1 % was estimated using a unique ultrasonic velocity measurement technique at various temperatures over 25 °C to 65 °C for every 10 °C rise. Impacts of concentration, temperature, and component materials on thermal conductivity enhancement were obtained. Experimental data are analyzed through statistical method and a simple linear regression model (with R2 > 0.99) of thermal conductivity is presented. Further, pricewise performance of nanofluids is performed to obtain the economic feasibility of SiO2–water nanofluids in heat transfer applications.

Preparation and properties of UV-curable polyurethane acrylate / SiO2 composite hard coatings

To achieve the high dispersion of SiO2 nanoparticles in polyurethane acrylate resin, the titanate coupling agent, PN-102, was used as the surface modifier to prepare the modified SiO2 nanoparticles (Si-PN102-5) with small particle size and good dispersion ability in PUA-6 resin. Accordingly, hydrophilic SiO2 (Si-380) and hydrophobic SiO2 (Si-115) were introduced into PUA-6 resin to prepare the corresponding composite coatings, so as to investigate the effects of SiO2 nanoparticles modified with different surface modifiers on the properties of PUA / SiO2 composite coatings. The properties of PUA / SiO2 composite coatings were characterized by the tests of FT-IR, AFM, SEM, DMA, TG and so on. The FT-IR and XPS results show that PN-102 had functionalized the Si-PN102-5 particle surface successfully. The TEM test displays that the particle size of SiO2 was almost unchanged before and after modification, maintaining at about 20–30 nm. The SEM, DMA and tensile test reveal that Si-PN102-5 not only blocks the interaction and accumulation of nanoparticles, but also enhances the interface interaction with polymer chains through chain entanglement, which endows Si-PN102-5-5% composite coatings with highest mechanical strength among the other prepared coatings, reaching to 11.0 ± 0.1 MPa in tensile strength and 9.4 ± 3.0% in elongation at break. The pencil hardness of the prepared Si-PN102-5-5% composite coating could reach to 5H which is higher than the commercial PUA-6 based coating, and it also displayed good adhesion (4B) and flexibility (3 mm). The TG results show that all of prepared composite coatings display good thermal stability with a decomposition temperature of higher than 250 °C.

Effects of SiO2 Nanoparticle Dispersion on The Heat Storage Property of the Solar Salt for Solar Power Applications

The effects of SiO2 nanoparticles on the heat storage properties of Solar Salt (NaNO3-KNO3) are studied using experimental and molecular dynamics (MD) simulations. The experiment results show the specific heat capacity of the molten salt-based nanofluids is higher than that of the pure base salt. We focus on the inference regarding the possible mechanisms behind the enhancement of the specific heat capacity which are considered more acceptable by the majority of researchers, the energy and force in the system are analyzed by MD simulations. The results demonstrate that the higher specific heat capacity of the nanoparticle is not the reason leading to the heat storage enhancement. Additionally, the analysis of potential energy and system configuration shows that the other possible mechanisms (i.e., interfacial thermal resistance theory and compressed layer theory) are only superficial. The forces between the nanoparticle atoms and base salt ions construct the constraint of the base salt ions, further forms the interfacial thermal resistance, and the compressed layer around the nanoparticle. This constraint has a more stable state and requires more energy to deform it, leading to the improvement of the heat storage property of nanofluids. Our findings uncover the mechanisms of specific heat capacity enhancement and guide the preparation of molten salt-based nanofluids.

Self-assembly of superstructures at all scales

Summary Controllable assembly of molecular and nanoscale building blocks into uniform superstructures up to bulk dimensions remains a key challenge in the next phase of nanotechnology development. Here, we report the self-assembly of superstructures at all scales by taking advantage of the partial miscibility of water and 1-butanol to generate transient aqueous emulsion droplets that can encapsulate the target materials and introduce them into template holes. Further diffusion of water into 1-butanol depletes the emulsion droplets, assembling the building blocks into one well-defined superstructure in each hole. Superstructuring of various types and shapes of nanoparticles, biomolecules, and inorganic compounds could be achieved without the need for surfactants and chemical modifications. The versatility, scalability, low-cost, and accurate positioning are crucial advantages for the future development of advanced precision manufacturing.

Fabricación de hidrogeles entrecruzados de carboximetil celulosa-SiO2: Composición y estabilidad térmica hacia aplicaciones biomédicas

Nuevos e innovadores materiales para aplicaciones biomédicas y farmacéuticas deben considerar factores como la composición y estabilidad térmica para establecer las propiedades fisicoquímicas adecuadas para sistemas eficientes de liberación controlada de fármacos. En este estudio, hidrogeles de carboximetilcelulosa (CMC) son preparados incorporando nanopartículas de dióxido de sílice (SiO2) previamente modificadas con grupos de aminas primarias (-NH2), buscando evaluar la composición química y mejorar la estabilidad térmica. El método de carbodiimidas es utilizado para promover el entrecruzamiento de la CMC con la formación de enlaces amidas de grupos carboxilo (C=O) activados y su posterior enlace con grupos -NH2. La información morfológica muestra nanopartículas de SiO2 dispersas con superficie lisa, forma regular, y diámetro promedio de 104 nm. La composición del material y la estabilidad térmica son evaluadas mediante espectroscopia infrarroja de la transformada de Fourier y análisis termogravimétrico para establecer una perspectiva preliminar de hidrogeles funcionales para aplicaciones biomédicas y farmacéuticas. La formación de enlaces amidas es confirmado indicando entrecruzamiento exitoso de la estructura de la CMC con nanopartículas de SiO2-NH2, atribuido a la activación de los grupos C=O y su fuerte afinidad a los grupos -NH2. Esta interacción mejoró la estabilidad térmica de los hidrogeles entrecruzados de CMC-SiO2 hasta 469°C siendo el último evento de descomposición, resaltando la contribución de una mayor presencia de nanopartículas de SiO2-NH2. Estos resultados sugieren un adecuado proceso de fabricación de hidrogeles entrecruzados de CMC-SiO2 como material novedoso con propiedades fisicoquímicas prometedoras, contribuyendo en estos campos en sistemas de administración controlada de fármacos.

Synergistic effect of silica nanofluid and biosurfactant on bitumen recovery from unconventional oil

In this paper, the nanofluid (bionanofluid) was prepared by dispersing SiO2 nanoparticles (NPs) in water (biosurfactant-sophorolipid) solution. The nanofluid (bionanofluid) stability was measured through zeta potential measurement, DLS (dynamic light scattering) measurement and steady-state fluorescence measurement. The critical salt concentration (CSC) for bionanofluids was 3%. The results indicated that sophorolipid could improve the nanofluids stability in liquid, and the steady-state fluorescence measurement and zeta potential illustrated the sophorolipid adhered on the surface of the SiO2 nanoparticles, and then the steric hindrance between different nanoparticles increased significantly. It was also found that the silica nanoparticles and biosurfactant had obvious synergistic effect on bitumen recovery from unconventional oils. The nanofluids and bionanofluids viscosities increased with high nanoparticles concentration and high salinities. The bionanofluid alter the solid wettability from oil-wet to inter medium-wet, the contact angle (oil-minerals) increased from 58.5° (in deionized water) to 87.6° (bionanofluid solution). The bionanofluid could reduce the oil-water interfacial tension, and the interfacial tension was lower than the surfactant solution used only. The toluene/deionized water interfacial tension was 36.1 mN/m, when deionized water was replaced by the sophorolipid solution, the interfacial tension was 8.4 mN/m, but the interfacial tension of toluene/bionanofluid solution was decreased to 7.1 mN/m. The similar downward path of interfacial tension occurred when the oil phases were cyclohexane, n-heptane and bitumen. The oil/water interfacial tension decreased with higher surfactant concentration and nanoparticles concentration. In the end, the structural disjoining pressure was calculated to explain the synergistic effect. The structural adjoining pressure is proportional to the nanofluid velocity of enhancing oil (V C ). V C increased with the decrease diameter of nanofluids, but V C decreased with the decrease of effective nanofluids concentrations. The bionanofluids could decrease the nanofluids diameter and increase the nanofluids effective concentrations, leading to the increasing of V C ,structural adjoining pressure and the oil recovery.