Organic Surfactants Research Articles

Fouling and Mitigation Behavior of Foulants on Ion Exchange Membranes with Surface Property in Reverse Electrodialysis.

In this study, two different types of ion exchange membranes are used to investigate the tendency of membrane fouling with respect to surface roughness and hydrophilicity. Commercially available membranes reinforced by electrospun nanofiber have rough and hydrophilic surfaces, and lab-made pore-filling membranes exhibit a smooth and hydrophobic surface. Three different organic surfactants (i.e., cationic, anionic and non-ionic surfactants) are chosen as foulants with similar molecular weights. It is confirmed that membrane fouling by electrical attraction mainly occurs, in which anionic and cationic foulants influence anion and cation exchange membranes, respectively. Thus, less fouling is obtained on both membranes for the non-charged foulant. The membranes with a rough surface show a higher fouling tendency than those with a smooth surface in the short-term continuous fouling tests. However, during the cyclic operations of fouling and mitigation of the commercially available membranes, the irregularities of a rough membrane surface cause a rapid increase in electrical resistance from the beginning of fouling due to excessive adsorption on the surface, but the fouling is easily mitigated due to the hydrophilic surface. On the other hand, the membranes with a smooth surface show alleviated fouling from the beginning of fouling, but the irreversible fouling occurs as foulants accumulate on the hydrophobic surface which causes membrane fouling to be favorable.

Nonreducing terminal chimeric isomaltomegalosaccharide and its integration with azoreductase for the remediation of soil-contaminated lipophilic azo dyes

Lipophilic azo dyes are practically water-insoluble, and their dissolution by organic solvents and surfactants is harmful to biological treatment with living cells and enzymes. This study aimed to evaluate the feasibility of a newly synthesized nonreducing terminal chimeric isomaltomegalosaccharide (N-IMS) as a nontoxic solubilizer of four simulated lipophilic azo dye wastes for enzymatic degradation. N-IMS bearing a helical α-(1 → 4)-glucosidic segment derived from a donor substrate α-cyclodextrin was produced by a coupling reaction of cyclodextrin glucanotransferase. Inclusion complexing by N-IMS overcame the solubility issue with equilibrium constants of 1786–242 M−1 (methyl yellow > ethyl red > methyl red > azo violet). Circular dichroism spectra revealed the axial alignment of the aromatic rings in the N-IMS cavity, while UV–visible absorption quenching revealed that the azo bond of methyl yellow was particularly induced. Desorption of the dyes from acidic and neutral soils was specific to aqueous organic over alkali extraction. The dissolution kinetics of the incorporated dyes followed a sigmoid pattern facilitating the subsequent decolorization process with azoreductase. It was demonstrated that after soil extraction, the solid dyes dissolved with N-IMS assistance and spontaneously digested by coupled azoreductase/glucose dehydrogenase (for a cofactor regeneration system) with the liberation of the corresponding aromatic amine.

Engineered detection zone to enhance color uniformity on paper microfluidics fabricated via Parafilm®-heating-laser-cutting

In this article, we first report a simple fabrication technique to create Parafilm®-laminated microfluidic paper-based analytical devices (µPADs) with a high resolution and then introduce novel engineered detection zones (D-zones) to enhance color uniformity without any chemical modifications. The Parafilm®-heating-laser cutting fabrication method comprises of three steps: 1) flattening a Parafilm® layer on paper, 2) heating in an oven at 90 °C for 30 min, and 3) CO2 laser ablation of the patterns. This method enabled laminated µPADs with a minimum barrier width of 172 ± 15 µm, with resistance to various organic solvents and surfactant solutions. Using this technique, µPADs with two types of engineered D-zones were fabricated. The multi-inlet D-zone had four micro-inlets (<500 µm width), enabling sample entrance into the D-zone from four directions simultaneously towards the center. The segmented D-zone had four segments each with its own micro-inlet allowing for separate reactions to occur in miniaturized segments simultaneously. Using an enzymatic glucose assay for the colorimetric reaction, the multi-inlet and segmented D-zones significantly decreased color gradient from 28.77 ± 1.49 to 12.35 ± 1.18 and 8.95 ± 0.98 %, respectively, compared to the conventional devices. We further used the µPADs with segmented D-zones for the detection of glucose in artificial urine in the clinically relevant range of 2–50 mM, where R2 > 0.99 of the fitted curve showed an excellent correlation between the generated signals and the glucose concentrations. Also, compared to the conventional devices, the engineered D-zones showed improved precision and reproducibility and a better linear range. Finally, spiked real human urine samples were tested, demonstrating the applicability of the engineered devices for real-world applications. Overall, with a simple fabrication method and a novel design for color uniformity, this paper contributes to the advancement of µPADs and paves the way towards commercialization.

Collectively exhaustive electrochemical hydrogen evolution reaction of polymorphic cobalt selenides derived from organic surfactants modified Co-MOFs

Finding and exploring non-noble metal-based electrocatalysts for the promising power-to-hydrogen fuel technology through water splitting reactions is highly emerging. Herein, we report the preparation of cobalt-based metal-organic frameworks (Co-MOFs) using an oleylamine (OLA) and 1-dodecanethiol (DDT)-modified trimesic acid (TMA), and cobalt precursor. Then, the electrocatalytically active cobalt selenides were derived from the Co-MOFs by a water-organic solvent mixture-assisted single-step selenization process. Interestingly, the cobalt selenide obtained from the DDT-modified Co-MOF shows collectively exhaustive hydrogen evolution reaction (HER) performance with very small overpotentials of ∼161 and ∼206 mV to achieve 10 and 50 mA cm−2, respectively, due to the phase mixing characteristics of cobalt selenide and the synergistic interaction. The fast reaction kinetics were identified at the DDT-Co selenide electrode surface as confirmed by observing the lower charge-transport/interfacial resistance and Tafel slope value due to the high surface coverage of adsorbed hydrogen (Hads) atoms, evidenced by high interfacial chemical capacitance value, as a result of the high electrical conductivity and large electrochemically accessible active sites. The calculated activation energy (Ea) of HER further reveals a low kinetic energy barrier in the HER on the DDT-Co selenide, indicating high intrinsic catalytic activity due to the fast surface diffusion rate of Hads. Furthermore, the obtained cathodic transfer coefficient (αc) value strongly suggested that the HER on the surface of DDT-Co selenide (αc = 2) proceeds in the Langmuir-Hinshelwood reaction mechanism and follows the Volmer-Tafel pathway. The present work provides valuable insights into the modification of Co-MOFs and their impact on HER catalytic activity of cobalt selenide, and also the mechanistic investigation of HER based on electrochemical impedance spectroscopy analysis.

Dual-functional organic surfactant for the effective stabilization of nano aluminium

An innovative approach that uses the dual functional capping agent 1-aminohexanol to stabilize aluminium nanoparticles (Nano-Al) produced via the colloidal synthesis process is reported.

Research and Application of Functionalized Mesoporous Silica Supported Quaternary Ammonium Salt Nano-antibacterial Materials

Objective: Nano-mesoporous silica has the superior physical properties and special ordered mesoporous structure.It can be used to prepare a surface material with antibacterial activity. Methods: Nano-mesoporous silica has been prepared by TEOS as the silicon source and CTAB as template. In this study, mesoporous silica was synthesized by sol-gel method. In the last, amino surfactants were used as carriers to bind to long chain organic surfactants by surface modification. The mesoporous silica functionalized with long chain quaternary ammonium salt was characterized by infrared spectroscopy, laser particle size and Zeta potential test, and its antibacterial effect was tested. The results show that amino groups are introduced to the surface of mesoporous silica after removing the template, and then dodecyl hydroxyethyl dimethyl ammonium bromide is bound to the surface of mesoporous silica. The combined product has good water solubility and its particle size is about 240 nm.Zeta potential test shows that it can be ionized and has positive charge in pure water. The antimicrobial effect test showed that the material could inhibit the growth and reproduction of DH5α Escherichia coli obviously at room temperature(P<0.05), and had certain antimicrobial activity.

Synthesis of mesoporous zeolite Y using Sapindus rarak extract as natural organic surfactant for deoxygenation of Reutealis trisperma oil to biofuel.

Saponin is a plant-derived chemical with an amphiphilic glycoconjugate structure extracted from sapindaceae plants like Sapindus rarak. This study investigated saponin extract of Sapindus rarak as a natural template for formation of mesoporous zeolite Y. Surface area and mesoporosity of zeolite Y were improved with optimization of Sapindus rarak extract (SRE) concentration (Y-Ln; n = 2, 5, 10 or 15 mL), reaching 216.26 m2 mesoporous area and 0.214 cm3 g-1 mesoporous volume for Y-L10 samples. A different loading of Ni was impregnated onto Y-L10 zeolite to improve Lewis/Brønsted acidity as catalysts in the deoxygenation of Reutealis trisperma oil (RTO) into hydrocarbon fuels. Impregnating 15% Ni on NaY zeolite enhanced Lewis acidity to 0.4556 mmol g-1, producing 48.8% liquid oil with 85.43% degree of deoxygenation. A high selectivity towards C15 and C17 hydrocarbon was analyzed from liquid yield, indicating the contributing factor from Lewis acidity and mesoporosity to enhance deoxygenation and prevent the hydrocracking reaction.

Gold nanorods-loaded chitosan-based nanomedicine platform enabling an effective tumor regression in vivo

The clinical utility of 7-ethyl-10-hydroxycamptothecin (SN-38) is hampered by its low water solubility and reduced bioactivity at neutral or alkaline conditions. The rational design of an effective drug delivery system that can significantly enhance the therapeutic index of SN-38 and achieve complete tumor regression still remains a challenge. Herein, chitosan-based hybrid nanoparticles system co-loading with chemotherapeutic drug SN-38 and gold nanorods (AuNRs) was engineered for effective combinational photothermal-chemotherapy. To increase the solubility of SN-38, soluble polymeric prodrug poly (l-glutamic acid)-SN38 (l-PGA-SN38) was firstly synthesized and then complexed with chitosan to form stable nanomedicine via a mild and facile way without using any organic solvent or surfactant. Upon introducing AuNRs into chitosan-based nanomedicine by coordination interaction between the amine group of chitosan and AuNRs, the hybrid nanoparticles exhibited distinct synergistic therapeutic effect compared with single chemotherapy or photothermal treatment in vitro and in vivo. Almost complete tumor regression was achieved after 21-day treatment of the developed hybrid nanoparticles and showed no recurrence for at least 60 days.

Preparation of catalyst from natural montmorillonite mineral and its application in the synthesis of carbon nanosphere

In developed countries, nanoparticles derived from natural minerals and high-purity chemicals both are widely studied, while in developing countries like Mongolia, the natural minerals-based nanoparticles have more interest because of the low production cost and applicability of domestic natural minerals for their production. For the synthesis of natural mineral-based nanomaterials, it is important first to define the chemical composition and physical structure of local minerals and their possible processing route. We employed an environmentally friendly alkaline leaching procedure to recover silica from the clay mineral at 90°C for 24 hours. We applied an organic surfactant (CTAB) and a simple coprecipitation approach to form iron-doped silica nanoparticles. Consequently, we used iron-doped silica nanoparticles as a substrate and catalyst for the synthesis of carbon nanosphere at 750 °C for 1 hour in an argon and acetylene gas atmosphere. As a result, vast quantities of superhydrophobic carbon nanospheres (CNS) were obtained. The physicochemical properties of nanosilica substrate, non-functionalized carbon nanosphere, and functionalized carbon nanosphere (CNS) samples were characterized using XRD, XRF, SEM, EDS, TEM, and FTIR spectrometer. Iron-doped mineral-derived nanosilica particles demonstrated high catalytic efficiency and the potential to produce a large amount of value-added carbon nanospheres. Superhydrophobic CNS can be used in a variety of applications, particularly drug delivery; however, to use CNS in both aqueous and non-aqueous media, the superhydrophobic properties of CNS can be modified using different oxidizers. The changes in hydrophobicity of the CNS were examined and suggested possible oxidizing agents.

Optimization of Bacillus Licheniformis DSM13 for Biosurfactant Production Using Response Surface Methodology

Biosurfactants are surface-active compounds that can reduce surface tension in both aqueous solutions and hydrocarbon mixtures, which in recent times have become more valuable due to their lower toxicity and are generally referred to as green or organic surfactants. Such products are much better than chemical surfactants in terms of their enhanced biodegradation rates and the bioavailability of organic contaminants. Fungi, yeast and bacteria are mainly capable of producing microbial biosurfactants. Bacteria, especially Bacillus, are one of the most frequently applied and studied biosurfactant producers. This study investigated the kinetics of cell growth, the production of biosurfactants as well as the effect of and interactions between the (A) pH within the range of 4.1 to 9.8, (B) glucose concentration between 3.0 and 36.9 g/l, (C) surface tension and (D) emulsification index to maximize biosurfactant production. The analysis was carried out using a central composite design (CCD) model with four factors and five levels. The optimized medium (pH=8 and glucose concentration = 38 g/l) decreased the surface tension to 60 mN/m and increased the product yield up to 2.7 g/l.

Switchable Nanostructures Triggered by Noyori-Type Organometallics.

Janus particles (JPs) self-assembled by a typical small organic gemini surfactant in water were reported by us. After the addition of a small amount Noyori-type organometallics to an organic solvent, these gourd-shaped JPs became new nanostructures, such as nanotubes (NTs), nanoribbons (NRs), and new types of JPs. Significant changes in specific rotation occurred on the solution-like samples, triggered by chiral organometallics in 20 μL of ethyl acetate. Almost all of these organometallics-triggered nanostructures can be conveniently detached and reversed within 5 min due to the easy-phase separation of ethyl acetate from the emulsion and the chemical-selective unstable binding between the organometallics and carbonate group on the surfactant.

Fabrication of Uniform ZnO Hexagonal Nanorods in the Presence of Mg2+ and Conversion to ZnO@ZnS Heterojunctions for Spatial Charge Separation

AbstractLarge‐scale uninform ZnO hexagonal nanorods were obtained by tuning the molar ratio of Mg2+ and Zn2+ without any organic surfactant or any further treatment, then the ZnO@ZnS heterojunction were obtained by in‐situ sulfidation method. The photocatalytic activity of as‐prepared photocatalyst sample was evaluated by their photocatalytic of Congo Red (CR) in a fixed‐bed microreactor and photocatalytic hydrogen production. The photocatalytic experiments showed that Z@ZS‐4 possesses higher photocatalytic performance for a sulfidation time up to 4 h. Probable photogenerated charge transfer mechanism has been proposed, and the corresponding photoluminescence and photoelectrochemical measurements revealed the higher charge transfer rate across the Z@ZS‐4 interface.

Humic acid-mediated reduction in toxicity of Co3O4 NPs towards freshwater and marine microalgae in surfactant mixed medium.

The ever-increasing applications of Co3O4 nanoparticles (NPs) have posed a serious concern about their discharge in the aquatic environment and ecotoxic implications. Being toxic towards aquatic species, the impact of other aquatic components such as dissolved organic matter (DOM), salinity, and surfactants are not studied sufficiently for their effect on the stability and ecotoxicity of Co3O4 NPs. The present study aims at the influence of humic acid (HA) on the toxicity of Co3O4 NPs in freshwater (C. minutissima) and marine (T. suecica) microalgae under surfactants mixed medium. The measure of % reduction in biomass and photosynthetic pigment were used as toxicity endpoints. Among various tested concentrations of HA, 25mg/L HA was found suitable to minimize the NP's toxicity with or without the presence of surfactants. Co3O4 NPs mediated reduction in biomass of C. minutissima was significantly minimized by the cumulative effect of HA with T80 (51.68 ± 4.55%) followed by CTAB (46.23 ± 5.62%) and SDS (42.60 ± 2.46%). Similarly, HA with T80 (26.93 ± 6.38%) followed by SDS (17.02 ± 6.64%) and CTAB (13.01 ± 3.81%) were found to minimize the growth inhibitory effect of Co3O4 NPs in T. suecica. The estimation of chlorophyll - a content also indicated that microalgae treated with HA could maintain their photosynthetic ability more than control even in the co-presence of surfactants. Also, the reduced toxicity of Co3O4 NPs were attributed to an increase in hydrodynamic sizes of HA-treated Co3O4 NPs in both marine media (f/2) and freshwater media (BG11) due to increased aggregation and faster sedimentation of Co3O4 NPs.

The Review Article of Medicinal Uses Reetha and Shikakai

Historic textiles cannot be washed in a washing machine or with a commercial detergent. Washing of historic textiles in textile conservation is done after considering various factors such as the condition of the textile, age of textile, color fastness of dyes, type of fiber, and type of stain. Washing of historic textiles is done to remove unwanted materials such as dust, dirt, stains, etc, which may be damaging to the textile object. Organic surfactants have been used in India as detergents and shampoos for ages. They have been widely used in the laundry industry and researched for their medicinal properties. Moreover, organic surfactants are easily available, cheap, and eco-friendly. The aim of this study was to find out the main cleaning agent (saponin) present in reetha, shikakai (acacia concinna) by GC-MS and to find out the potential of reetha and shikakai as natural surfactants for washing historic textiles.

Sustainable strategies for waterborne electrospinning of biocompatible nanofibers based on soy protein isolate

Electrospun nanofibers have gained great interest in many fields of research from water and air filtration or food packaging to medical use as scaffolds for tissue engineering, drug delivery systems and wound bandages. Proteins such as soy protein isolate (SPI) are biodegradable and safe polymers that can be purified from renewable and sustainable sources, and are thus interesting as building blocks for sustainable and biocompatible nanofiber-based materials. Sufficient solvent evaporation and intermolecular entanglement are required for efficient nanofiber formation. Electrospinning of proteins is therefore often achieved using organic solvents, strong bases or surfactants, which limits the safety, sustainability and usability of protein-based nanofibers. In this work, green and biocompatible electrospun nanofibers with a high content of SPI (up to 75% (w/w)) were fabricated with polyethylene oxide (PEO) as a co-spinning polymer and with water being the only solvent, thus avoiding use of any organic solvent, strong base or surfactant. A thorough biophysical assessment based on microscopy and spectroscopies, and a rheological profiling of SPI suggested that disassembly of larger structures into smaller in the SPI suspension and increase of SPI solubility improved the electrospinnability of SPI. The content of SPI in the nanofibers affected the morphology as visualized by scanning electron microscopy, brittleness assessed by dynamic mechanical analysis, and aqueous stability of the nanofibers, which are key parameters for the future use of SPI-based nanofibers. The biocompatibility of the electrospun SPI/PEO nanofibers was demonstrated by exposure of human epithelial cell monolayers (TR146) to the nanofibers without loss of cell viability. We propose that the presented strategies can serve as a universal workflow for waterborne electrospinning of other proteins or protein isolates.

Gas-Phase Synthesis of PtMo Alloy Electrocatalysts with Enhanced Activity and Durability for Oxygen Reduction Reaction

The proton-exchange membrane fuel cell is a promising technology to effectively utilize hydrogen energy, which is the ideal alternative to fossil fuels. However, the high dependency on scarce Pt as an oxygen reduction reaction (ORR) electrocatalyst is still a severe barrier that hinders widespread commercialization. Herein, we propose a facile synthetic strategy facilitating mass production of Pt–Mo solid-solution alloy nanoparticles on a carbon support (PtMo/C) as a highly active ORR electrocatalyst. Without using organic surfactants or reducing agents, our synthesis process based on the gas-phase method in an inert atmosphere is cost-effective and does not require any post-treatment, unlike most reported solution-based reduction processes. Both molybdenum metal and carbon monoxide decomposed from molybdenum hexacarbonyl contribute to the reduction of the PtMo alloy during the annealing process. By elucidating the growth and synthesis mechanisms, we optimized the particle size of PtMo/C to approximately 3.1 nm, annealed at 800 °C (PtMo/C-800). Consequently, PtMo/C-800 shows high mass activity (146 mA mgPt–1), which is superior to that of commercial Pt/C, and excellent durability after accelerated degradation tests.

A water-soluble PAAs sizing agent for enhancing interfacial adhesion of carbon fiber reinforced polyphenylene sulfide composites (CF/PPS)

Due to low activity and poor wettability of carbon fiber (CF), the interaction between CF and polyphenylene sulfide (PPS) matrix is weak, which decreases the mechanical properties of CF reinforced PPS （CF/PPS） composites. In this article, the interfacial adhesion of CF/PPS composites was strengthened by using a water-soluble poly (amic acid) ammonium salt (PAAs) as sizing agent. This PAAs-based sizing agent had good compatibility with PPS and formed hydrogen bonds with CF activated by Meldrum’s acid. Significantly, the PAAs sizing agent can be soluble in water (up to 20 wt % high solid content) without organic solvents and surfactants, which shows huge potential in industrial applications. Experimental results demonstrated that the interlaminar shear strength (ILSS), flexural strengths, and moduli of modified CF/PPS composites increased by 19.5%, 24.9%, and 10.1%, respectively. According to the SEM images on fractured surfaces of composites, fiber and PPS resin were tightly packed, and the failure mechanism was interface deformation or resin breakage.

Hydrothermal In-Reservoir Upgrading of Heavy Oil in the Presence of Non-Ionic Surfactants

The most widely applied methods to unlock heavy oil and natural bitumen resources in the world are still based on steam injection techniques. Improving the efficiency of hydrothermal processes poses a great challenge. The co-injection of various additives is practiced to lower the steam-to-oil ratio (SOR), viscosity alteration and to improve heavy oil properties. Organic solvents, non-condensable gases, air and surfactants are the preferred chemicals to be combined with steam. This study provides an investigation of the surfactant-assisted hydrothermal upgrading of heavy oil at 200 °C. The thermal stability and salt resistivity of two non-ionic surfactants (SA–3 and Biolub Green) were investigated. Moreover, the improved performance of the surfactants was established by performing an SARA analysis, elemental analysis, FT-IR spectroscopy, and EPR analysis, and by studying the viscosity reduction degree. The experimental results showed that surfactants lead to the in-depth destructive hydrogenation of the high-molecular components of heavy oil such as resins and asphaltenes. However, the content of light fractions increased. According to the results of the elemental analysis, the surfactants assist in the hydrodesulphurization of heavy oil. Overall, the physical and chemical consequences of hydrothermal upgrading in the presence of surfactants led to the irreversible viscosity reduction of heavy oil.

A fabrication technique for paper-based analytical devices via two-sided patterning with thermal-transfer printer and laminator

In this study, we propose a novel technique for fabricating paper-based analytical devices (PADs) using a wax-based thermal-transfer printer and a thermal laminator, which allows prototyping and roll-to-roll mass production of PADs without utilizing widely used conventional wax printers. This fabrication scheme involves two-sided patterning to form hydrophobic barriers and an ink ribbon that contains sufficient wax content to form hydrophobic barriers without undesirable components or additives. First, a thermal-transfer printer forms positive patterns on the ink ribbon for the front and back sides of the device design. Subsequently, a laminator performs the two-sided thermal transfer of the patterns from the ink ribbon to a paper substrate and the thermal formation of hydrophobic barriers for channels. The hydrophobicity of the prepared ink is similar to that of ink used in wax printers and exhibits excellent stability in organic solvents and surfactants. Hydrophobic barriers and channels were successfully formed using various paper substrates typically used for PADs. The two-sided scheme allows the formation of 3D channels, including vertical paths in a single paper substrate. The utility of the proposed fabrication technique was demonstrated using a dip-type 3D PAD for sensing glucose.

Spontaneous Imbibition Oil Recovery by Natural Surfactant/Nanofluid: An Experimental and Theoretical Study.

Organic surfactants have been utilized with different nanoparticles in enhanced oil recovery (EOR) operations due to the synergic mechanisms of nanofluid stabilization, wettability alteration, and oil-water interfacial tension reduction. However, investment and environmental issues are the main concerns to make the operation more practical. The present study introduces a natural and cost-effective surfactant named Azarboo for modifying the surface traits of silica nanoparticles for more efficient EOR. Surface-modified nanoparticles were synthesized by conjugating negatively charged Azarboo surfactant on positively charged amino-treated silica nanoparticles. The effect of the hybrid application of the natural surfactant and amine-modified silica nanoparticles was investigated by analysis of wettability alteration. Amine-surfactant-functionalized silica nanoparticles were found to be more effective than typical nanoparticles. Amott cell experiments showed maximum imbibition oil recovery after nine days of treatment with amine-surfactant-modified nanoparticles and fifteen days of treatment with amine-modified nanoparticles. This finding confirmed the superior potential of amine-surfactant-modified silica nanoparticles compared to amine-modified silica nanoparticles. Modeling showed that amine surfactant-treated SiO2 could change wettability from strongly oil-wet to almost strongly water-wet. In the case of amine-treated silica nanoparticles, a strongly water-wet condition was not achieved. Oil displacement experiments confirmed the better performance of amine-surfactant-treated SiO2 nanoparticles compared to amine-treated SiO2 by improving oil recovery by 15%. Overall, a synergistic effect between Azarboo surfactant and amine-modified silica nanoparticles led to wettability alteration and higher oil recovery.