Functionalization Of Multi-walled Carbon Nanotubes Research Articles

Hyaluronate Functionalized Multi-Wall Carbon Nanotubes Filled with Carboplatin as a Novel Drug Nanocarrier against Murine Lung Cancer Cells.

Carbon nanotubes (CNTs) have emerged in recent years as a potential option for drug delivery, due to their high functionalization capacity. Biocompatibility and selectivity using tissue-specific biomolecules can optimize the specificity, pharmacokinetics and stability of the drug. In this study, we design, develop and characterize a drug nanovector (oxCNTs-HA-CPT) conjugating oxidated multi-wall carbon nanotubes (oxCNTs) with hyaluronate (HA) and carboplatin (CPT) as a treatment in a lung cancer model in vitro. Subsequently, we exposed TC–1 and NIH/3T3 cell lines to the nanovectors and measured cell uptake, cell viability, and oxidative stress induction. The characterization of oxCNTs-HA-CPT reveals that on their surface, they have HA. On the other hand, oxCNTs-HA-CPT were endocytosed in greater proportion by tumor cells than by fibroblasts, and likewise, the cytotoxic effect was significantly higher in tumor cells. These results show the therapeutic potential that nanovectors possess; however, future studies should be carried out to determine the death pathways involved, as well as their effect on in vivo models.

Ultrasonic assisted functionalization of MWCNT and synergistic electrocatalytic effect of nano-hydroxyapatite incorporated MWCNT-chitosan scaffolds for sensing of nitrofurantoin.

In the present work, we report the fabrication of stable composite of chitosan hydrogels (CHI) on multiwalled carbon nanotubes (MWCNT) using a simple ultrasonic-assisted method. Also, rod-like hydroxyapatite nanoparticles (HA NPs) were synthesised using a hydrothermal route and were incorporated into the highly conductive MWCNT-CHI scaffolds using an ultrasonication method. The functionalization of MWCNT and preparation of HA NPs on MWCNT-CHI nanocomposite were done using the sonication over the frequency of 37 kHz with the ultrasonic power capable of 150 W (Elmasonic Easy 60H bath sonicator). The resulting hybrid HA NPs/MWCNT-CHI nanocomposites have an excellent surface area and high surface to volume ratio, which leads to the sensitive detection of nitrofurantoin than pristine MWCNT and HA NPs. The complete elemental and morphological analyses of the HA NPs/MWCNT-CHI nanocomposites were characterised by XRD, FTIR, RAMAN, FESEM, TEM, EDX, and elemental mapping techniques. Electrochemical analysis of the HA NPs/MWCNT-CHI nanocomposites was carried out by cyclic voltammetry, electrochemical impedance spectroscopy and amperometry methods. The modified glassy carbon electrode (GCE) of HA NPs/MWCNT-CHI nanocomposites exhibit the nitrofurantoin detection activity at the linear range of 0.005-982.1 µM with the detection limit of 1.3 nM. The synergistic electrocatalytic activity of HA NPs/MWCNT-CHI nanocomposites modified GCE is correlated to the sensitivity of 0.16 µAµM-1 cm-2 with excellent precision and accuracy towards the sensing of nitrofurantoin.

Functionalization of multiwalled carbon nanotubes for enzyme immobilization.

A simple strategy for enzyme immobilization onto homo- and hetero-functionalized multiwalled carbon nanotubes (MWCNTs) is described. Homo-functionalization of MWCNTs can be carried out using an amino-silane compound, i.e., 3-aminopropyl-triethoxysilane (APTES). It is an important silane coupling agent, which promotes interfacial behavior of nanomaterials. Whereas, hetero-functionalization of MWCNTs can be performed using APTES and cross-linking agent glutaraldehyde (GA). Key parameters for the immobilization of an enzyme on MWCNTs are selection of an efficient functionalizing agent, sonication of MWCNTs, enzyme load and enzyme coupling time. The optimal level of these factors is very important to obtain high specific activity and immobilization efficiency of the developed immobilized biocatalyst. Both homo- and hetero-functionalized MWCNTs can be used to develop an efficient immobilized biocatalyst having good operational stability. However, hetero-functionalized MWCNTs are more potent candidate for enzyme immobilization. The present methodology provides very efficient approach for enzyme immobilization on a versatile support to achieve high enzyme selectivity and operational stability for various industrial applications.

Characterization of functionalized multiwalled carbon nanotubes and comparison of their cellular toxicity between HEK 293 cells and zebra fish in vivo.

Carbon nanotubes (CNTs) hold tremendous potential due to their unique and modifiable properties. Their robust biological applications necessitate minimizing their cytotoxicity and increasing the solubilization. In the present manuscript, we have functionalized multiwalled carbon nanotubes (MWCNTs) using defect functionalization methodology to covalently bind carboxy and amino groups on their walls. This functionalization was reassured through fourier-transform infrared spectroscopy (FTIR), energy dispersive x-ray analysis (EDX), elemental and field emission scanning electron microscopy (FE-SEM) analysis. The observations demonstrated that addition of carboxy as well as amino groups on MWCNTs, besides enabling MWCNTs solubilization also significantly ameliorated the cytotoxicity and the oxidative stress in comparison to pristine MWCNTs. It is envisaged that changes in agglomeration of the functionalized MWCNTs and the acquired surface charge is the reason for the reduction of cytotoxicity. Zebra fish embryo model test system employed for in vivo analysis of the MWCNTs showed no significant toxicity on account of any nanoparticle tested pointing towards intrinsic mechanisms in place for deterring the damage in complex organisms. Overall, the observations besides pointing towards functionalized MWCNTs effectiveness towards weakening the toxicity of pristine MWCNTs also caution for extrapolating in vitro data to in vivo observations. The observations further lend credibility for exploiting the zebra fish as a model system for analyzing the effects of MWCNTs functionalization.

CVD Synthesis, Functionalization and CO2 Adsorption Attributes of Multiwalled Carbon Nanotubes

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.

Incorporation of F-MWCNTs into electrospun nanofibers regulates osteogenesis through stiffness and nanotopography.

Nanotopography and stiffness are major physical cues affecting cell fate. However, the current nanofiber modifications techniques are limited by their ability to control these two physical cues irrespective of each other without changing the materials' surface chemistry. For this reason, the isolated effects of topography and stiffness on osteogenic regulation in electrospun nanofibers have been studied incompletely. Here, we investigated 1. how functionalized multiwall carbon nanotubes (F-MWCNTs) loaded in Polycaprolactone (PCL) nanofibers control their physical properties and 2. whether the resulting unique structures lead to distinctive phenotypes in bone progenitor cells. Changes in material properties were measured by high-resolution electron microscopes, protein adsorption and tensile tests. The effect of the developed structures on human mesenchymal stem cell (MSC) osteogenic differentiation was determined by extensive quantification of early and late osteogenic marker genes. It was found that F-MWCNT loading was an effective method to independently control the PCL nanofiber surface nanoroughness or stiffness, depending on the applied F-MWCNT concentration. Collectively, this suggests that stiffness and topography activate distinct osteogenic signaling pathway. The current strategy can help our further understanding of the mechano-biological responses in osteoprogenitor cells, which could ultimately lead to improved design of bone substitute biomaterials.

Non-covalent and covalent immobilization of Candida antarctica lipase B on chemically modified multiwalled carbon nanotubes for a green acylation process in supercritical CO2

• Efficient immobilization of Candida antarctica B lipase on modified MWCNTs. • Enzyme loading reaching as high as 21 wt.% for non-covalent immobilization. • Active O-acylation of geraniol into geranyl acetate by CAL-B in supercritical CO 2 . • Reaction regioselectivity unchanged through immobilization. • Development of a fully green enzymatic process. Candida antarctica B lipase (CAL-B) was immobilized on purified and functionalized multiwalled carbon nanotubes (MWCNTs). Both immobilization routes, physical adsorption and covalent bonding, were investigated. MWCNT functionalization by a non-aggressive oxidation by potassium permanganate led to an interesting balance between the hydrophilic and the hydrophobic areas of the MWCNT surface; the former being responsible of the good dispersion of MWCNTs in water and the latter having a favorable affinity with CAL-B. The enzyme loadings reached were significant: around 16 wt. % and 21 wt.% for non-covalent and covalent immobilization, respectively. The enzymatic activity was studied with the reaction of O-acylation of geraniol into geranyl acetate by CAL-B in supercritical CO 2 . Even if a decay in synthesis of geranyl acetate was observed over cycling for both CAL-B@MWCNT catalysts, it was demonstrated that the regioselectivity of CAL-B was unchanged through immobilization on the MWCNT surface for both routes. Interestingly, it was shown that a fully green enzymatic process can be achieved with these prepared CAL-B@MWCNT biocatalyst. Such approach could be transferred to other support/enzyme systems for developing new eco-friendly synthesis processes.

Ultrasound-assisted Solid-liquid Trap Phase Extraction based on Functionalized Multi Wall Carbon Nanotubes for Preconcentration and Separation of Nickel in Petrochemical Waste Water

In this study, a novel sorbent based on phenylsulfonic acid functionalized multiwall carbon nanotubes (MWCNTs-Ph-SO3H) was used for preconcentration and separation of trace Ni(II) ions in petrochemical wastewater samples by ultrasound-assisted solid-liquid trap phase extraction. In this work, a mixture of MWCNTs-Ph-SO3H as a nanosorbent and ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate, IL) dispersed in acetone was rapidly injected by a syringe into 50 mL of a sample containing Ni(II). The metal was extracted by sulfonate group as (RSO3)2-Ni at optimized pH. After shaking and centrifuging, the nanoparticles of sorbent were trapped in IL phase and settled down in a conical centrifuge tube (IL/MWCNTs-Ph-SO3H). Hydrophobic IL was used to fast trap the Ni(II) loaded sorbent from the sample solution. Under the optimized conditions, the linear range (peak area), limit of detection and enrichment factor were obtained as 1.5–165 μg/L, 0.35 μg/L and 50, respectively.

Investigation of the CO2 absorption in pure water and MDEA aqueous solution including amine functionalized multi-wall carbon nano tubes

The objective of this study is investigating CO2 absorption in Amine functionalized Multiwall Carbon Nanotube (NH2_MWCNT) in pure water and Methyldiethanolamine (MDEA). A dispersant was used to disperse nanofluid solutions. Results showed that at the optimum concentration of NH2_MWCNT in pure water (0.005 wt%), the absorption capacity increased up to 26.4% at the highest pressure. Additionally, the effect of nanoparticles on aqueous solution of MDEA showed that NH2_MWCNT is more efficient at 10 wt% of MDEA and absorption capacity was increased by up to 21% at the highest pressure. It can be concluded that NH2_MWCNTs lead to many advantages such as higher absorption capacity and lower heat of reaction.

Rheological behavior of polypropylene nanocomposites with tailored polymer/multiwall carbon nanotubes interface

Maleic anhydride grafted polypropylene (MA‐g‐PP) or polypropylene (PP) was noncovalently coated onto acid functionalized multiwall carbon nanotube (f‐MWNT) through solution mixing. These coated f‐MWNTs and pristine MWNT (p‐MWNT) were melt microcompounded with neat PP to form PP/f‐MWNT and PP/p‐MWNT nanocomposites at 0.1–1 wt% MWNT concentration. Complex viscosity and tan δ (ratio of loss modulus to storage modulus) behavior of these systems were studied using dynamic frequency sweep test, while relaxation time, activation energy, and melt homogeneity were also calculated and compared. Among the three types of samples, PP/f‐MWNT masterbatch‐based nanocomposite demonstrated not only the presence of interphase but also good processability. As a consequence, increase of both the crystallization rate in the presence of shear and the melt elasticity during annealing were found only in the masterbatch‐based samples but not in the PP/p‐MWNT. The mechanism of such increased melt elasticity was attributed to the formation of the space‐spanning network, which is consistent with the Cole–Cole plot showing similar behavior to the branched polymers in the literature. This has implications in polymer processing due to suggested changes in the balance between melt strength and polymer flow. Nanocomposite rheological behavior has also been correlated with the mechanical properties. POLYM. ENG. SCI., 59:1763–1777, 2019. © 2019 Society of Plastics Engineers

Microwave dielectric properties and Targeted heating of polypropylene nano-composites containing carbon nanotubes and carbon black

The complex dielectric constants of three polypropylene (PP) composite samples were measured at microwave frequency ranges of X (8.2–12.4 GHz) and Ka band (26.5–40 GHz), and as a function of filler content. Three types of carbon filler materials – pristine multiwall carbon nanotubes (p-CNTs), functionalized multiwall carbon nanotubes (f-CNTs), and carbon black (p-CB) were investigated. Attenuation constant for each composite was calculated, based on its measured complex dielectric constant, to highlight the importance of studying frequency dependent performance of composite materials for microwave heating. Most of the reported works for polymer composite heating using microwave power, have been conducted using commercial microwave ovens operating at 2.45 GHz. The results of this investigation for the CNT-composite samples indicate the importance of frequency optimization for creating maximum heat generation. The composite samples were also irradiated using low-power microwave energy at 2.6, 10 and 28 GHz and using a thermographic camera their relative capabilities for producing heat was investigated. The heating results corroborated those of the dielectric property measurements.

Inulinase immobilization on polyethylene glycol/polypyrrole multiwall carbon nanotubes producing a catalyst with enhanced thermal and operational stability.

This paper describes the development of a simple method for mixed non-covalent and covalent bonding of partially purified inulinase on functionalized multiwall carbon nanotubes (f-MWCNTs) with polypyrrole (PPy). The pyrrole (Py) was electrochemically polymerized on MWCNTs in order to fabricate MWCNTs/PPy nanocomposite. Two multiple forms of enzyme were bound to N-H functional groups from PPy and -COO- from activated MWCNTs to yield a stable MWCNTs/PPy/PEG immobilized preparation with increased thermal stability. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to confirm functionalization of nanoparticles and immobilization of the enzyme. The immobilization yield of 85% and optimal enzyme load of 345μg protein onto MWCNTs was obtained. The optimum reaction conditions and kinetic parameters were established using the UV-Vis analytical assay. The best functional performance for prepared heterogeneous catalyst has been observed at pH 3.6 and 10, and at the temperatures of 60 and 80ºC. The half-life (t 1/2) of the immobilized inulinase at 60 and 80ºC was found to be 231 and 99min, respectively. The reusability of the immobilized formulation was evaluated based on a method in which the enzyme retained 50% of its initial activity, which occurred after the eighteenth operation cycle.

Epoxy functionalization of multiwalled carbon nanotubes for their waterborne polyurethane composite with crosslinked structure

In order to achieve covalent bond between multiwalled carbon nanotubes (MWCNTs) and waterborne polyurethane (WPU), pristine MWCNTs were first oxidized by strong acids and then underwent ring-opening reaction with epoxy resin to chemically attach epoxy moiety onto their surface. For fabrication of the MWCNTs/WPU composite, the epoxy moiety facilitates the dispersion of MWCNTs in the polymer matrix and could react with carboxylic acid or amine groups in the WPU macromolecules to form a crosslinked structure in their composite, resulting in a great improvement in their mechanical property, thermal stability, water resistance, and electrical conductivity. As the content of MWCNTs reached 1.5 wt%, the tensile strength of functionalized MWCNTs composite was improved by about 108% and the electrical conductivity was increased by six orders of magnitude compared to that of the pristine MWCNTs composite.

Investigation of photocatalytic behavior of modified ZnS:Mn/MWCNTs nanocomposite for organic pollutants effective photodegradation

In this research, zinc sulfide (ZnS) doped with manganese (Mn) is synthesized on functionalized multiwall carbon nanotubes (MWCNTs) nanocomposite by a facile co-precipitation method as the photocatalysis. Due to the excellent electrical and optical characteristics of ZnS:Mn/MWCNTs nanocomposite, it is worth to investigate its photodegradation activity. To investigate the photocatalytic degradation properties of organic pollutants, the synthesis conditions were optimized in the presence of four substances: COOH, ethylene glycol, sodium dodecyl sulfate, and polyvinyl-pyrrolidone. Surface studies of the photocatalyst, i.e., structural, morphological, optical and physical properties, were characterized by FTIR, PL, XRD, SEM, and TEM analyses. The results showed that Mn ions decreased the band gap energy of the nanocomposites and there was excellent adhesion between ZnS and MWCNTs in the synthesized composite. According to the results, MWCNTs effectively increased the photocatalytic activity of the ZnS nanoparticles by the electron-hole pair recombination of ZnS and MWCNTs, and the composites with the carboxylic functional group showed greater photocatalytic activity. In addition, the kinetic studies showed that the photocatalytic process obeyed the pseudo-first-order kinetic model. To determine the exact mathematical formula of the photocatalysis, response surface methodology was modeled by the central composite design method. Various parameters, such as the time of the treatment process and initial concentration of the pollutants were studied for a quadratic model that fit all the cases well and their mathematical models were obtained.

Effect of Synthesis Condition on the Structural Features of Ni-Ce Bimetallic Catalysts Supported on Functionalized Multi-Walled Carbon Nanotubes

In this paper, screening study in regards to preparation of functionalized multi-walled carbon nanotubes (FMWNT)-supported bi-metallic catalyst is discussed. Functional groups such as hydroxyl and carboxylic acid are introduced on multi-walled carbon nanotubes (MWCNT) surface using acid treatment method with the aid of probe-type ultrasonication. It is done by varying the concentration of nitric acid (HNO3) and sulphuric acid (H2SO4), acid volume ratio and treatment duration. Catalysts with different ratios of cerium and nickel nanoparticles which are either loaded inside or outside of MWCNT were prepared via ultrasonic-assisted co-precipitation method (NiCe/CNT). This is done to study the effect of cerium loadings. The characterization of the FMWNT and catalysts are carried out using transmission electron micrographs (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and Raman spectroscopy. The results showed that the treatment in concentrated HNO3/H2SO4 with volume ratio of 3:1 for 8 h was the most suitable condition to generate large amount of surface oxygen group with minimal defects. The observations for each used condition were discussed thoroughly. Decoration of MWCNT with different metal loadings resulted in different distribution and dispersion of metal on nanotubes surface.

Purification and functionalisation of multi-walled carbon nanotubes

Purifying and functionalising multi-walled carbon nanotubes (MWCNTs) are important processes for providing property modifications, improving handling and enhancing reactivity. The removal of impurities allows avoiding synthesis process interferences and the formation of by-products. During the process it is possible to change the MWCNT properties, e.g. providing enhanced hydrophilicity and better chemical reactivity. In this work, a two-step procedure of MWCNT functionalisation with non-oxidative and oxidative agents is presented. Firstly, hydrochloric acid was used to remove catalyst impurities, which remain after the synthesis process. Secondly, nitric acid was employed to oxidise the MWCNT surfaces and incorporate carboxylic groups onto the surface.

Comparative study on the electrosorption properties of carbon fabric, functionalized multiwall carbon nanotubes and solar-reduced graphene oxide for flow through electrode based desalination studies

Removal of salt ions using capacitive deionization (CDI) is an efficient and environmentally friendly route to fulfill the necessity of fresh water. Carbon nanomaterials are preferred as electrode material for desalination studies. However, the design of the CDI cell and the structure of electrodes also plays an important role in deciding the salt removal efficiency. Here, we have fabricated a flow-through electrode capacitive deionization (FTE-CDI) cell to study the electrosorption performances of various carbon-based materials like; carbon fabric (CF), functionalized-multiwall carbon nanotubes (F-MWCNT), and solar reduced graphene oxide (SRGO). Surface morphology and elemental composition of all the electrodes were examined using a scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was analyzed using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Specific capacitance and equivalent series resistance of about 49.91 F/g (2.18 Ω), 64.69 F/g (2.03 Ω), and 128.45 F/g (0.87 Ω) were achieved for CF, F-MWCNT, and SRGO respectively. Electrosorption capacity of 10.70, 31.22, and 37.54 mg/g was attained with the CF, F-MWCNT, and SRGO sponge electrodes respectively. The ion sorption followed the Langmuir isotherm and Pseudo-first-order kinetics. Hence, corresponds to monolayer physisorption of the salt ions on the surface of the electrodes. This work demonstrates the significance of the electro-active material, importance of an electrodes structure, and CDI cell architecture for desalination applications.

Platinum single-atom and cluster anchored on functionalized MWCNTs with ultrahigh mass efficiency for electrocatalytic hydrogen evolution

Platinum (Pt)-based heterogeneous catalysts are promising for electrocatalytic hydrogen evolution reaction (HER); considerable efforts, however, are devoted to reducing Pt usage by maximizing catalytic efficiency due to its high price and scarcity. Herein, we report Pt single-atom and cluster catalyst anchored on functionalized multiwall carbon nanotubes (Pt/f-MWCNTs) by photodeposition. The Pt/f-MWCNTs catalyst with Pt loading of 0.323 wt% exhibits exceptionally high activity and decent stability for HER in acid condition, whose mass activity is 74.7 times higher than that of state-of-the-art commercial Pt/C catalyst at an overpotential of 50 mV vs. RHE. This work paves a novel way to realize controllable synthesis of Pt-based catalysts with ultrahigh activity and long-term stability for electrocatalytic HER.

Enhanced SO2 sensing characteristics of multi-wall carbon nanotubes based mass-type sensor using two-step purification process

In this work, a room temperature gas sensor based on functional multi-wall carbon nanotubes (MWNTs) coated quartz crystal microbalance (QCM) was developed. The two-step purification process was used to remove amorphous carbon and inactivated catalyst particles, and added functional groups on the sidewall of tubes. The functional MWNTs were then dispersed in deionized water to deposit on the gold electrode of the QCM. The operative MWNTs-coated QCM sensor was tested with toxic hazardous gases such as hydrogen sulfide, hydrogen, nitrogen dioxide, carbon monoxide, and sulfur dioxide. The sensing results expose that the fabricated sensor exhibits good sensitivity with sulfur dioxide gas at room temperature. The sensitivity of the functional MWNTs based sensor presented to be superior to that of the as-grown MWNTs based sensor.

Experimental Investigation of Mechanisms in Functionalized Multiwalled Carbon Nanotube Flooding for Enhancing the Recovery From Heavy-Oil Reservoirs

Summary In the past few years, nanoparticle flooding has displayed significant potential for enhancing oil recovery. Among different nanoparticles, hydrophilic (functionalized) nanotubes have not been tested yet. Therefore, in this study, functionalized multiwalled carbon nanotubes (MWCNT) were used in three concentrations—0.01, 0.05, and 0.1 wt%—to conduct micromodel, interfacial–tension (IFT), wettability, viscosity, phase–behavior, and static–adsorption tests. In addition, constancy of nanofluids in the presence of sodium chloride (NaCl) was investigated qualitatively. Obtained results illustrated that by increasing the nanoparticle concentration from 0.01 to 0.1 wt%, nanofluid/oil IFT decreased, because MWCNT were placed between the surfaces of the oil and the nanofluid. Also, viscosity of the nanofluid improved slightly when the nanoparticle concentration increased. Moreover, contact angle was measured before and after coating with nanosuspensions, and the achieved data showed a change from oil–wet to water–wet. The resulting emulsion was a water–in–oil type; therefore, as MWCNT concentration increased, the size and number of water droplets in the oil also increased. This augmentation improved the effectiveness of the emulsion viscosity. Stability tests also provided evidence confirming that the nanofluids were stable for 10 days in concentrations of 0.01 and 0.1 wt% and in salinities of 1 and 0.5 wt%, respectively. Besides, the addition of 0.05 wt% sulfonated polymer to the nanofluids ensured their stability in higher salinities. Moreover, the results of the micromodel test revealed that by increasing the concentration of nanoparticles, sweep efficiency increased and the fingering phenomenon was reduced. In addition, the ultimate recovery of oil obtained by nanosuspension flooding in concentrations of 0.01, 0.05, and 0.1 wt% was, respectively, 12.6, 16.4, and 20% higher than that of waterflooding. Static adsorption on sandstone was found to be 0.575, 1.25, and 1.76 mg/m2 at 0.01, 0.05, and 0.1 wt%, respectively, and it reached its fixed amounts within 24 hours. Therefore, functionalized MWCNT might help increase heavy–oil recovery through mechanisms of reducing IFT, changing wettability from oil–wet to water–wet in oil–wet reservoirs, increasing viscosity (slightly), and developing a water–in–oil emulsion.