Surface Of Carbon Nanotubes Research Articles

Construction of highly hydrophilic PAN-co-IA/CNTs@TA composite membrane with large flux and high retention for purification of dye wastewater

The rising pollution caused by dye industrial wastewater has led to irreversible destruction of the environment and human health. Hence, there is an urgent need to construct hydrophilic separation membranes possessing high flux and retention to be used in water treatment. To solve this problem, polyacrylonitrile-co-itaconic acid (PAN-co-IA) copolymer was prepared as matrix, tannic acid (TA) encapsulated carbon nanotubes (CNTs) named as CNTs@TA was used as nano-modifier to design the PAN-co-IA/CNTs@TA composite flat membrane by the non-solvent-induced phase separation technique. The copolymerization of IA improved the hydrophilicity of PAN, in addition, the hydrogen bonding formation between IA and TA on the surface of CNTs ensured the stable existence of CNTs@TA particles in the composite membrane. At the same time, the π-π bonds between TA and CNTs avoided the loss of TA during the wastewater separation process. The introduction of IA, TA, and CNTs endowed the PAN-co-IA/CNTs@TA composite membrane with excellent hydrophilicity and double-layer finger pore structure, which achieved its high pure water flux of 3102.63 Lm-2h-1. What's more, the PAN-co-IA/CNTs@TA composite membrane behaved large flux (>1600 Lm-2h-1) and high retention (>97 %) for various cationic dye wastewater based on the electrostatic adsorption mechanism. In addition, the high hydrophilicity and the reinforcing effect of CNTs endowed PAN-co-IA/CNTs@TA membrane with excellent cycling stability. Therefore, this research provides a simple and convenient dye wastewater purification strategy with promising application prospects.

Stability Analysis of the Rapid Heating Multilayer Structure Mold by the Contact Error and Thickness of Layers

Rapid heating of the mold surface is necessary for the high-gloss, high-productivity injection molding process. A rapid heating mold system that uses a carbon nanotube (CNT) as a heating element was investigated because of its structure. For CNT web film to be utilized in the injection molding process, heating must be applied inside the mold. That can cause poor contact at the contact area between the mold and the CNT heating element, leading to local temperature deviation and resistance changes that reduce the heating stability of the CNT surface element. Additionally, the multilayer structure of the CNT web film can cause heat-transfer performance variations due to the different layer thicknesses. To address these issues, an adjustable flush was constructed at the contact area between the electrode inside the mold and the insulator to analyze the heating behavior of the CNT heating element as a function of dimensional deviation. The thermal durability of the CNT web film was also evaluated by analyzing the Raman spectra and measuring resistance changes caused by local overheating. The film can withstand high temperatures, with a flush limit value of 0.3 mm. An optimization analysis was conducted to determine the ideal thicknesses of the multilayer CNT web film, insulator, and electrical insulator. Optimal layer thicknesses were found to be 10 μm, 5 mm, and 0.5 mm, respectively. The main variables of the rapid heating mold required for application to the injection process were identified and reflected in the mold design to suggest directions for commercialization.

Fabrication of CNT/cobalt hexacyanoferrate core/shell nanostructured for boosting the removal of crystal violet from water

Carbon nanotubes (CNTs) are highly promising materials for the adsorption of dyes from water. Recently, there has been a growing interest in Prussian blue-type coordination polymers due to their inexpensive nature, chemical stability, and simple synthesis using non-toxic metals that are prevalent in the earth. The results present a straightforward technique for effectively altering the surface of CNT using cobalt-iron-based prussian blue (CoFe-PB). The procedure led to a significant increase in the removal of crystal violet (CV) from water relative to the bare CNTs. The maximum removal efficiency (about 93 %) of CV dye was obtained at pH 6 with fast saturation time (15 min). The use of the coating approach yields a core–shell structure consisting of CNT as the core and a CoFe-PB shell. The CoFe-PB shell, with a thickness of 10–15 nm, forms a highly conformal coating that completely covers the CNT. The high conformance of the coating is considered an essential characteristic for its strong adsorption performance. The method demonstrates the significant potential of prussian blue-type materials, when appropriately coated, as very effective adsorbent materials.

Correlation Measurements for Carbon Nanotubes with Quantum Defects.

Single-photon sources are essential building blocks for the development of photonic quantum technology. Regarding potential practical application, an on-demand electrically driven quantum-light emitter on a chip is notably crucial for photonic integrated circuits. Here, we propose functionalized single-walled carbon nanotube field-effect transistors as a promising solid-state quantum-light source by demonstrating photon antibunching behavior via electrical excitation. The sp3 quantum defects were formed on the surface of (7, 5) carbon nanotubes by 3,5-dichlorophenyl functionalization, and individual carbon nanotubes were wired to graphene electrode pairs. Filtered electroluminescent defect-state emission at 77 K was coupled into a Hanbury Brown and Twiss experiment setup, and single-photon emission was observed by performing second-order correlation function measurements. We discuss the dependence of the intensity correlation measurement on electrical power and emission wavelength, highlighting the challenges of performing such measurements while simultaneously analyzing acquired data. Our results indicate a route toward room-temperature electrically triggered single-photon emission.

Molecular-scale mechanics of a crystalline polyethylene interface formed by projection of carbon nanotube structures

The semicrystalline nature of polymer chains induced by the intrusion of carbon nanotubes (CNTs) is a decisive factor in understanding the properties of interfacial regions. Herein, the structural and mechanical behavior of polyethylene (PE) formed around CNT surfaces were determined using a combination of classical molecular dynamics simulations and subcontinuum-scale analysis. The results suggest that inserting CNTs into the polymer domain forces the PE chains to align along the longitudinal axis of the CNTs. The interface functions as a nucleating agent, and the area occupied by the crystalline phase propagates radially as PE chains are stacked over long distances. The crystalline PE, grown with CNT as the central axis, exhibits extreme mechanical anisotropy, particularly for normal and shear deformations in the transverse direction. Therefore, this study provides an important theoretical guideline for understanding polymeric semi-crystals around CNTs.

Electrocatalytic urea synthesis from CO2 and nitrate co-reduction on natural vitamin B12 coupled carbon nanotubes

The synthesis of urea from CO2 and nitrate co-electrolysis is highly attractive for the sustainable production of nitrogen-containing fertilizers such as urea. However, this process requires electrocatalysts that are not only highly active but also selective. In this study, we present a remarkable approach wherein Vitamin B12 is immobilized on the surface of carbon nanotubes to catalyze the co-electroreduction to urea under ambient conditions. This unique hybrid system, incorporating a naturally abundant molecular catalyst, exhibits exceptional selectivity and maintains a constant current density in CO2-saturated 0.1 M KNO3. Remarkably, we achieved a Faradaic efficiency (FE) of 26.04% at −0.5 V versus the reversible hydrogen electrode (RHE), resulting in a production yield of 164.04 μg h−1 mg−1 and an impressive turnover number (TON) reaching up to 830.53 while demonstrating excellent stability and durability over a period of 50 hours. Our experimental findings are further supported by density functional theory (DFT) studies that shed light on the influence exerted by the covalently attached and redox-active benzimidazole unit within Vitamin B12 molecule itself when immobilized onto conductive surfaces like carbon nanotubes. This work represents an unprecedented example where naturally abundant vitamin has been successfully immobilized on a conductive surface for achieving highly efficient electroproduction of urea.

Effect of thiol-modified carbon nanotubes on curing, mechanical, and thermophysical properties of poly(ethylene trisulfide)

Herein, we performed grafting of thiol groups to the surface of multi-walled carbon nanotubes. Then, using them (CNTS), zinc oxide (ZnO), ethylene dichloride, and sodium trisulfide (Na2S3), poly(ethylene trisulfide) (PETS) nanocomposites were synthesized via in situ polymerization. After that, the samples were cured at 170°C using a rheometer. The structural characteristics of CNTS were identified by Fourier transform infrared (FTIR), Raman spectroscopies, and X-ray diffraction (XRD). The PETS characteristics were investigated by FT-IR, Raman, X-ray diffraction (XRD), and proton nuclear magnetic resonance (1H NMR). Also, the samples were studied using scanning electron microscopy (SEM), Shore A, tensile tests, and differential scanning calorimetry (DSC). The results showed that CNTS has a significant effect on the curing time of the nanocomposites, so that the curing time decreases with increasing CNTS content. Moreover, the nanocomposites had improved mechanical properties, indicating that they are more resistant to deformation and fracture. In addition, after the curing process, the melting temperature (Tm ) was not observed, and by increasing CNTS in composites, the glass transition temperature (Tg ) occurs at higher temperatures. Furthermore, the hardness of the samples showed a slight increase with higher CNTS content.

In Situ Growth Strategy to Construct "Four-In-One" Separators with Functionalized Polyphosphazene Coatings for Safe and Stable Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are facing many challenges, such as the inadequate conductivity of sulfur, the shuttle effect caused by lithium polysulfide (LiPSs), lithium dendrites, and the flammability, which have hindered their commercial applications. Herein, a "four-in-one" functionalized coating is fabricated on the surface of polypropylene (PP) separator by using a novel flame-retardant namely InC-HCTB to meet these challenges. InC-HCTB is obtained by cultivating polyphosphazene on the surface of carbon nanotubes with an in situ growth strategy. First, this unique architecture fosters an enhanced conductive network, bolstering the bidirectional enhancement of both ionic and electronic conductivities. Furthermore, InC-HCTB effectively inhibits the shuttle effect of LiPSs. LSBs exhibit a remarkable capacity of 1170.7mAhg-1 at 0.2C, and the capacity degradation is a mere 0.0436% over 800 cycles at 1C. Third, InC-HCTB coating serves as an ion migration network, hindering the growth of lithium dendrites. More importantly, InC-HCTB exhibits notable flame retardancy. The radical trapping action in the gas phase and the protective effect of the shielded char layer in the condensed phase are simulated and verified. This facile in situ growth strategy constructs a "four-in-one" functional separator coating, rendering InC-HCTB a promising additive for the large-scale production of safe and stable LSBs.

Debundling and reorganization of CNT networks under high temperature treatment

Highly purified and uniformly distributed carbon nanotube (CNT) network is one of the key issues for developing advanced nanocomposites. However, the challenge for mitigation of the aggregation of CNT bundles during the CNT film fabrication still remained. In this work, debundling and reorganization of CNT bundles have been realized simultaneously by using a high-temperature thermal treatment. The debundling of large CNT bundles into small ones started after they were heat treated under 1400 °C and uniformly distributed CNT networks with small bundles were obtained after heat treated under 1800 °C. The tensile strength of the CNT film significantly increased by about 64% compared to the pristine film. Microstructural observations showed that the iron nanoparticles started to evaporate at 1400 °C and were completely removed at 1800 °C. Hollow amorphous carbon shells wrapped on the nanoparticles were left inside the CNT networks after the removal of the iron nanoparticles. Interestingly, these amorphous carbon shells act as carbon source for the deposition of a carbon layer on the CNT surface when the heat treatment temperature was up to 2000 °C, and they were completely consumed after being treated at 2800 °C. The microstructural evolution process of CNT bundles during heat treatment suggests the simple high-temperature treatment strategy could be applied for fabrication of highly purified CNT networks with well-distributed small bundles, enabling the development of advanced multifunctional nanocomposites in the near future.

Redox-active cerium-based metal–organic layers coordinated on carbon nanotubes as materials for supercapacitors

In this work, the redox-active, two-dimensional (2D), and highly dispersible metal–organic layers (MOLs) constructed from hexa-cerium(IV) clusters, CeBTB (BTB = 1,3,5-benzenetribenzoate), were directly coordinated onto the surface of carboxylic acid-functionalized multi-walled carbon nanotubes (CNTs) by utilizing a post-synthetically grafting approach. Nanocomposites with various MOL-to-CNT ratios can be synthesized. Crystallinity, porosity, morphology, electrical conductivity, and electrochemical behaviors of CeBTB and all nanocomposites as well as the chemical interaction between CeBTB and CNT in the composite are investigated. Thin films of materials with the same mass loading are then fabricated for measuring their capacitive performances in neutral aqueous solutions of Na2SO4. With the electrical conductivity provided by carbon nanotubes and the redox activity of CeBTB between Ce(IV) and Ce(III), the optimal CeBTB-CNT nanocomposite can show a better capacitive performance compared to the pristine CeBTB, pristine CNT, and the physical mixture of both of them with the same MOL-to-CNT ratio. With such a simple post-synthetically grafting approach that can precisely control the ratio between the 2D MOLs and CNTs, the findings here open opportunities for designing numerous composites composed of MOLs and nanocarbons with tunable conductivity, redox activity, and functionality, which are potential candidates for a range of applications.

Viscoelasticity of a carbon nanotube-laden air-water interface.

The viscoelasticity of a carbon nanotube (CNT)-laden air-water interface was characterized using two different experimental methods. The first experimental method used a Langmuir-Pockels (LP) trough coupled with a pair of oscillating barriers. The second method is termed the Bicone-Trough (BT) method, where a LP trough was custom-built and fit onto a rheometer equipped with a bicone fixture to standardize the preparation and conditioning of a particle-laden interface especially at high particle coverages. The performance of both methods was evaluated by performing Fast Fourier Transform (FFT) analysis to calculate the signal-to-noise ratios (SNR). Overall, the rheometer-based BT method offered better strain control and considerably higher SNRs compared to the Oscillatory Barriers (OB) method that oscillated barriers with relatively limited positional and speed control. For a CNT surface coverage of 165mg/m2 and a frequency of 100mHz, the interfacial shear modulus obtained from the OB method increased from 39 to 57mN/m as the normal strain amplitude increased from 1 to 3%. No linear viscoelastic regime was experimentally observed for a normal strain as small as 0.5%. In the BT method, a linear regime was observed below a shear strain of 0.1%. The interfacial shear modulus decreased significantly from 96 to 2mN/m as the shear strain amplitude increased from 0.025 to 10%.

Facile and Nondestructive Transformation of Intrinsic Hydrophobic Behavior of a Carbon Nanotubes Sheet to Hydrophilic.

It is imperative to induce hydrophilicity in intrinsically hydrophobic carbon nanotubes (CNTs) without losing their superior properties for applications that specifically deal with aqueous media. A method for transforming a CNTs sheet from hydrophobic to hydrophilic by treatment with N-methyl-2-pyrrolidone (NMP) is explored. The NMP-treated CNT sheets are assessed based on complementing characterization, and it is concluded that the binding of NMP to a CNTs surface is through noncovalent interaction without the incorporation of defects in CNTs. The induced hydrophilicity in the CNTs sheet is stable for water exposure over a longer duration while it displays a semireversible nature upon heat treatment. The mechanical and electrical properties of the NMP-treated CNTs sheet revealed enhancement in the tensile strength from 221 to 421 MPa while maintaining a good electrical conductivity of ∼1.22 × 104 S/m because of the improved interfacial properties. The hydrophilic CNTs exhibited excellent adsorption capacity for methylene blue dye. The NMP-treated CNTs sheets demonstrated their suitability in flexible hybrid supercapacitor (FHSC) devices with improved electrochemical performance with enhancement in the capacitance from 5.4 to 7.6 F/g and a decrease in the equivalent series resistance from 53 to 34 Ω compared to pristine CNTs-based devices. These solid-state FHSC devices displayed excellent cyclic charge-discharge performance along with robust behavior over thousands of bending cycles without significant performance degradation. The excellent dye removal capability and superior electrochemical performance of the NMP-treated CNTs sheet is a consequence of their improved interface with aqueous media, which is governed by the hydrophilic nature of the CNTs sheet.

Polymer Nanocomposites Based on Nanosized Substituted Ferrites (NiZn)1-xMnxFe2O4 on the Surface of Carbon Nanotubes for Effective Interaction with High-Frequency EM Radiation.

To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)1-xMnxFe2O4 (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)1-xMnxFe2O4/CNT system was from 0.05 to 0.07 vol. fractions. The dielectric and magnetic characteristics of both pristine (NiZn)1-xMnxFe2O4 ferrites and (NiZn)1-xMnxFe2O4/CNT composite systems were studied. The introduction of (NiZn)1-xMnxFe2O4/CNT composites into the amorphous epoxy matrix allows to tailor absorbing properties at the high-frequency by effectively shifting the maximum peak values of the absorption and reflection coefficient to a region of lower frequencies (20-30 GHz). The microwave adsorption properties of (NiZn)1-xMnxFe2O4/0.07CNT-ER (x = 0.5) systems showed that the maximum absorption bandwidth with reflection loss below -10 dB is about 11 GHz.

Magnetic dummy-template molecularly imprinted polymer with an ultrathin shell for selective enrichment of geosmin in water sample

A dummy-template molecularly imprinted polymer (DMIP) based on magnetic carbon nanotubes was synthesized. The eluted polymers with an improved ultrasound assisted/oscillating (magnetic separation) method were successfully employed for the adsorption and separation of geosmin (GSM), an odorous compound in eutrophic waterbodies. The properties of the obtained composite materials were evaluated through a series of morphological and physicochemical characterization. The results showed that a thin and uniform imprinted shell (∼10–15 nm) effectively coated the surface of magnetic carbon nanotubes, exhibiting good adsorption efficiency and magnetic functionality. The binding performance and selectivity of Mag-MWCNTs @DMIPs as adsorbents for GSM were evaluated and compared with non-imprinted polymers. The maximum adsorption capacity of polymers for GSM, as determined by the Langmuir model, is 18.71 mg g−1, which adsorption equilibrium reached in approximately 45 min. The adsorption thermodynamic parameters ΔG shown that the adsorption process was spontaneous. Selectivity and regeneration experiment further demonstrated the ability of Mag-MWCNTs @DMIPs to selectively separate trace GSM from complex matrices. The polymer obtained in this study can be used as an adsorbent for magnetic dispersion solid-phase extraction to preconcentration of trace GSM in natural water, facilitating the measurement of GSM.

Seamless Integration of Rapid Separation and Ultrasensitive Detection for Complex Biological Samples Using Multistage Annular Functionalized Carbon Nanotube Arrays.

Efficient separation, enrichment, and detection of bacteria in diverse media are pivotal for identifying bacterial diseases and their transmission pathways. However, conventional bacterial detection methods that split the separation and detection steps are plagued by prolonged processing times. Herein, a multistage annular functionalized carbon nanotube array device designed for the seamless integration of complex biological sample separation and multimarker detection is introduced. This device resorts to the supersmooth fluidity of the liquid sample in the carbon nanotubes interstice through rotation assistance, achieving the ability to quickly separate impurities and capture biomarkers (1mL sample cost time of 2.5 s). Fluid dynamics simulations show that the reduction of near-surface hydrodynamic resistance drives the capture of bacteria and related biomarkers on the functionalized surface of carbon nanotube in sufficient time. When further assembled as an even detection device, it exhibited fast detection (<30min), robust linear correlation (101-107 colony-forming units [CFU] mL-1, R2 = 0.997), ultrasensitivity (limit of detection = 1.7 CFU mL-1), and multitarget detection (Staphylococcus aureus, extracellular vesicles, and enterotoxin proteins). Collectively, the material and system offer an expanded platform for real-time diagnostics, enabling integrated rapid separation and detection of various disease biomarkers.

Influence of the Quantum Capacitance on Electrolyte Conductivity through Carbon Nanotubes.

In recent experiments, unprecedentedly large values for the conductivity of electrolytes through carbon nanotubes (CNTs) have been measured, possibly owing to flow slip and a high pore surface charge density whose origin remains debated. Here, we model the coupling between the CNT quantum capacitance and the classical electrolyte-filled pore one and study how electrolyte transport is modulated when a gate voltage is applied to the CNT. Our work shows that under certain conditions the quantum capacitance is lower than the pore one due to the finite quasi-1D CNT electronic density of states and therefore controls the CNT surface charge density that dictates the confined electrolyte conductivity. The dependence of the computed surface charge and conductivity on reservoir salt concentration and gate voltage is thus intimately related to the electronic properties of the CNT. This approach provides key insight into why metallic CNTs have larger experimentally measured conductivities than semiconducting ones.

Determination of Escherichia coli Ligase Activity by Carbon Nanotube Fluorescence Anisotropy

The characterization of nucleic acid ligase activity is of great significance for the study of physiological processes. In the present work, a new method for the detection of E. coli DNA ligase is designed based on the non-covalent interaction of carbon nanotubes with dyes and ssDNA and DNA ligation reactions. When no E. coli DNA ligase is present, the ssDNA probe and dye SG I adsorb to the surface of carbon nanotubes. After centrifugation, the carbon nanotubes with DNA and dye SG I have larger molecular weights, resulting in higher fluorescence anisotropy. When E. coli DNA ligase is present, a double-stranded structure is formed, with SG I embedded in the groove of the DNA double strand. Due to the weak interaction between the DNA double-strand structure and the carbon nanotubes, after centrifugation, the supernatant does not contain the carbon nanotubes, resulting in lower fluorescence anisotropy. The feasibility of the assay was confirmed by optimizing the conditions. This method improves the accuracy of the detection with a relative error within 1%. The increase of fluorescence anisotropy in samples is small compared with in the buffer solution. Therefore, the system has good selectivity and is suitable for the characterization of enzyme activity in biological samples. Moreover, the method does not require the labeling of fluorescent molecules or a special design of nucleic acid sequences, which avoids complex probe modification.

Protein Deceleration and Sequencing Using Si3N4-CNT Hybrid Nanopores.

Protein sequencing is crucial for understanding the complex mechanisms driving biological functions and is of utmost importance in molecular diagnostics and medication development. Nanopores have become an effective tool for single molecule sensing, however, the weak charge and non-uniform charge distribution of protein make capturing and sensing very challenging, which poses a significant obstacle to the development of nanopore-based protein sequencing. In this study, to facilitate capturing of the unfolded protein, highly charged peptide was employed in our simulations, we found that the velocity of unfolded peptide translocating through a hybrid nanopore composed of silicon nitride membrane and carbon nanotube is much slower compared to bare silicon nitride nanopore, it is due to the significant interaction between amino acids and the surface of carbon nanotube. Moreover, by introducing variations in the charge states at the boundaries of carbon nanotube nanopores, the competition and combination of the electrophoretic and electroosmotic flows through the nanopores could be controlled, we then successfully regulated the translocation velocity of unfolded proteins through the hybrid nanopores. The proposed hybrid nanopore effectively retards the translocation velocity of protein through it, facilitates the acquisition of ample information for accurate amino acid identification.

Voltammetric determination of hemagglutinin using triazolotriazine derivatives as agents for the biomolecule recognition

An original approach for rapid voltammetric determination of the hemagglutinin (HA) protein using original new triazoloazine-based compounds as agents of biomolecule recognition was developed. A pronounced redox activity of original molecules was established; a possible mechanism of electrochemical conversion was proposed. The peak current of the nitro group electroreduction was chosen as an analytical signal. An efficient method for immobilizing the molecules on the surface of carbon nanotubes using thiol-ene and thiol-ine reactions with the radical initiator azobisisobutyronitrile has been proposed. The binding constants of the “compound-hemagglutinin” interaction were determined experimentally without and with external potential and calculated by the molecular modeling method. Compound 2-methylthio-6-nitro-7-oxo-4-propylene-1,2,4-triazolo-4,7-dihydro[5,1-c]-1,2,4-triazine(1a) showed the best characteristics of selective binding to the biotarget. A dependence of the analytical signal on the concentration of hemagglutinin in probe I* = -(13.1 ± 0.5) lgC + (93±2) was obtained in the range 10−7–10−3 M, the limit of detection calculated by the 3-sigma criteria was 7.0 10−8 M. The proposed approach has been successfully tested on saliva model solutions and anti-influenza vaccines.

A molecular dynamics study for the extraction of cesium from aqueous solutions in the presence of functionalized carbon nanotube

ABSTRACT Molecular dynamics (MD) simulation was conducted to obtain the interfacial behavior of cesium (Cs+) extraction by functionalized carbon nanotubes (CNTs). The present study explores the extraction mechanism of Cs+ with functional groups such as OCH(CH3)2, and CONH2-based CNTs. The results display that adsorption capacity is improved significantly using a surface modification of a single-walled carbon nanotube (SWCNT) with isopropoxide and amide functional groups. The studies investigate the separation of Cs+ in the presence of functionalized CNTs from the ionic liquid (IL) – water biphasic systems. It has been found that CNT with OCH(CH3)2 functional group is highly efficient for Cs+ extraction as compared to the CONH2 group and bare CNT. The higher interaction energy between Cs+ and CNT with OCH(CH3)2 functional group (˗84.41 kcal/mol) was observed at the interface when compared with bare CNT (˗4.34 kcal/mol). In general, the order of Cs+ ion adsorption capacity on the CNT surface is CNT – OCH(CH3)2 > CNT – CONH2 > bare CNT. The current study offers quantitative data and insights into the extraction of metal ions with functionalized CNTs, which may be highly helpful for future technological exploration of the many nano-adsorbent-based investigations.