Transport In Carbon Nanotubes Research Articles

Modulation of water transport in carbon nanotubes by local charges

Carbon nanotubes (CNTs) enable extremely fast water transport that make them strong candidates for constructing artificial nanochannels and membranes. However, water transport properties in CNTs with defects along with local charges are rarely studied. In this work, with molecular dynamics simulations, it is found that water transport in CNTs can be greatly modulated by local charges at the CNT middle. The flux modulation factors show an increasing trend with CNT diameters and are slightly influenced by the axial positions of local charges and the CNT lengths. Analysis suggests that water transport is hindered by the confinement-enhanced concentration oscillations and bipolar orientations of water molecules induced by local charges. It is also interesting that the water flux of CNT (6, 6) with high local charges has a reversal behavior due to the overscreening effect. Simultaneously, ions are also impeded due to the water structuring and bipolarizations, which can improve the salt rejection of wide CNTs. In general, introducing local charges on CNT (10, 10) can reject 100% ions while maintaining a high water permeability of ∼90 L/cm2/day/Mpa in the reverse osmosis desalination. This study promotes the understanding of water transport in nanochannels with defects and guides the design of CNTs for high-performance desalination membranes.

Effects of modification groups and defects on the desalination performance of multi-walled carbon nanotube (MWNT) membranes

Like single-wall carbon nanotubes (SWNTs), multi-wall carbon nanotubes (MWNTs) have channels for selective separation of ions. Moreover, MWNTs have the advantages of simpler preparation and lower cost, potentially allowing wider applications in the desalination industry. In this study, the transport of water and ions inside two types of MWNTs, i.e., double-wall carbon nanotubes (DWNTs) and tri-wall carbon nanotubes (TWNTs) were investigated using non-equilibrium molecular dynamics simulations. Modification groups, including carbon chains of different lengths and types with hydrophilic groups like carboxylate anion (COO–), and ammonium (NH3+), were used to improve the salt rejection performance. The simulation results suggest that 100% salt rejection could be achieved by adding different modification groups to various MWNTs ranging from 13 to 20 Å. More importantly, this study demonstrates that MWNT membranes with 100% desalination have water fluxes that are 10–30% greater than that of SWNT membranes with 100% desalination, implying the greater potential of MWNTs as building blocks towards next-generation desalination membranes. Additionally, even though all real-world carbon nanotubes (CNTs) have a certain amount of defects from the production process, most previous molecular model studies of water and ions transport in CNTs assumed that CNTs were perfect and defect-free. This study shows for the first time that CNTs with defects have improved salt rejection rates than perfect carbon nanotubes, although the former have lower water fluxes than the latter.

The effects of pH, ionic strength, and natural organics on the transport properties of carbon nanotubes in saturated porous medium

Carbon Nanotubes (CNTs) are widely utilized, and their inadvertent release into the soil and ground water systems may have detrimental environmental implications. Therefore, it is critical to comprehend the effect of several environmental conditions on the fate and transport of CNTs in porous media. In previous studies, a narrow range of pH, ionic strength, and collector grain size have only been considered while evaluating the transport and retention of functionalized multiwalled carbon nanotubes (f-MWCNTs). None have highlighted the effect of environmentally relevant concentrations of natural organic matter and particle concentrations on the mobility of f-MWCNTs in porous medium. The current study aims to fill the knowledge gap by evaluating the fate and transport of f-MWCNTs at different, environmentally relevant physicochemical conditions of pH (5, 7, and 9), ionic strengths (10, 50, and 100 mM), humic acid as representative of natural organic matter (0.1, 1, and 10 mg/L) and particle concentrations (10, 25, and 50 mg/L) through saturated porous medium (quartz sand). It was noted that a wide range of pH and humic acid imparted an overall negative charge on the particles, enhancing their mobility (C/C0 > 0.8). However, transport of the f-MWCNTs was hindered in the presence of high ionic strength and particle concentrations (C/C0 < 0.1). The transport profile was mathematically simulated using a one-dimensional advection-dispersion equation (ADE) and colloidal filtration theory (CFT). Additionally, interaction energy profiles based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory were estimated to gain a better understanding of the mechanism of f-MWCNT deposition. In light of the potential environmental consequences, the impact of real-world water systems (tap, river, lake, and ground water) on the transport behaviour of f-MWCNTs was also investigated. The study considerably advances our understanding of the various physicochemical and environmental factors that can critically impact the transport of f-MWCNT in porous media, which could prove beneficial for environmental applications and risk management.

Enhancement of the mechanical and thermal transport properties of carbon nanotube yarns by boundary structure modulation

Carbon nanotubes (CNTs) exhibit extremely high nanoscopic thermal/electrical transport and mechanical properties. However, the macroscopic properties of assembled CNTs are significantly lower than those of CNTs because of the boundary structure between the CNTs. Therefore, it is crucial to understand the relationship between the nanoscopic boundary structure in CNTs and the macroscopic properties of the assembled CNTs. Previous studies have shown that the nanoscopic phonon transport and macroscopic thermal transport in CNTs are improved by Joule annealing because of the improved boundary Van-der-Waals interactions between CNTs via the graphitization of amorphous carbon. In this study, we investigate the mechanical strength and thermal/electrical transport properties of CNT yarns with and without Joule annealing at various temperatures, analyzing the phenomena occurring at the boundaries of CNTs. The obtained experimental and theoretical results connect the nanoscopic boundary interaction of CNTs in CNT yarns and the macroscopic mechanical and transport properties of CNT yarns.

Size effect in determining the water diffusion rate in carbon nanotubes

Water diffusion in nanochannels is the basis of a variety of emerging nanotechnologies. The self and transport diffusions of water in carbon nanotubes (CNTs) having different pore sizes were investigated using equilibrium (EMD) and non-equilibrium molecular dynamics (NEMD) simulations. It is found that the formation of a depletion layer near the carbon wall in which water molecules lost hydrogen bonds accounts for the transforming of the self-diffusion mode. The reduced life time of hydrogen bond networks in larger CNTs stimulates the decorrelation of single water molecule from the center of mass of fluid, leading to the enlarged deviation between the self and transport diffusions. Our simulations reveal that the friction coefficient for water transporting in the CNT is enhanced by more than 60 times when the diameter of the CNT is increased from 8.1 to 33.9 Å, leading to the transforming of the transport diffusion mode from ballistic into the Fickian mode. We show the smoothness of the CNT wall enhances the water flowrate in the CNT by orders of magnitude with respect to the value predicted by the Hagen-Poiseuille equation. However, this enhancement factor decreases from around 10,000 to 10 when the pore size of the CNT increases. We speculate that water transport in different CNTs experience different diffusion modes could be the explanation for the large discrepancies among the measured water flowrates in different studies. Our simulations also show that for the non-Fickian diffusion, the transport diffusivity calculated from EMD simulations is no longer effective in connecting the driving force and the driven flowrate.

Transport of surface-modified multi-walled carbon nanotubes in saturated porous media.

Carbon nanotubes (CNTs) are widely used and may pose potential environmental risks to soil and groundwater systems. Therefore, it is important to improve current understanding of the fate and transport of CNTs in porous media. In this study, the transport behavior of multi-walled carbon nanotubes (MWCNTs) with different surface modifications were examined in water-saturated sand columns under different pH (5 and 7) and ionic strength (0.1, 1, and 5mM) conditions. COOH-MWCNTs have the strongest mobility among the five types of MWCNTs, followed by pristine MWCNTs. NH2-MWCNTs, Cu-MWCNTs, and Fe-MWCNTs have the weaker mobility. The transport of five types of MWCNTs decreased with the increase of ionic strength, while increased with the increase of pH value. The results suggested that the transport of MWCNTs can be affected by the electrostatic attraction between the functional groups on the surface of MWCNTs and quartz sand. Moreover, the pH and ionic strength of the solution also played an important role in enhancing the transport of MWCNTs, which have great significance for evaluating the transport and fate of MWCNTs in natural environment.

Proteomic fingerprinting of protein corona formed on PEGylated multi-walled carbon nanotubes

In Nanomedicine, carbon-based nanomaterials, like Carbon Nanotubes (CNT), are considered potential candidates as drug delivery systems. In vivo adsorption of physiological proteins onto carbon nanotubes, through noncovalent interactions, forms a protein corona or bio corona, able to influence biological properties and biocompatibility of CNT. This study aimed to explore the composition of protein corona formed onto PEGylated Multi-Walled Carbon Nanotubes (MWCNT-PEG5k), after their incubation in human plasma. Plasma proteins were sequentially eluted in different conditions by using both native and denaturant buffers, useful to characterize soft and hard corona. Proteomic methods and mass spectrometry analysis have identified proteins in soft corona, involved in the regulation of immune response and in the CNT transport, and biomolecules in hard corona with a role in the maintenance of host homeostasis. These promising results have demonstrated the potential of PEGylated Multi-Walled Carbon Nanotubes as future candidates for drug delivery.

Phonon transport probed at carbon nanotube yarn/sheet boundaries by ultrafast structural dynamics

Modern integrated devices and electrical circuits have often been designed with carbon nanostructures, such as carbon nanotubes (CNTs) and graphene due to their high thermal and electrical transport properties. These transport properties are strongly correlated to their acoustic phonon and carrier dynamics. Thus, understanding the phonon and carrier dynamics of carbon nanostructures in extremely small regions will lead to their further practical applications. Here, we demonstrate ultrafast time-resolved electron diffraction and ultrafast transient spectroscopy to characterize the phonon and carrier dynamics at the boundary of quasi-one-dimensional CNTs before and after Joule annealing. The results from ultrafast time-resolved electron diffraction show that the CNTs after Joule annealing reach the phonon equilibrium state extremely fast with a timescale of 10 ps, which indicates that thermal transport in CNTs improves following Joule annealing. The methodology described in this study connects conventional macroscopic thermo- and electrodynamics to those at the nanometer scale. Realistic timescale kinetic simulations were performed to further elaborate on the phenomena that occur in CNTs during Joule annealing. The insights obtained in this study are expected to pave the way to parameterize the unexplored thermal and electrical properties of carbon materials at the nanometer scale.

Metallicity-Dependent Ultrafast Water Transport in Carbon Nanotubes.

Carbon nanotubes (CNTs) with hydrophobic and atomically smooth inner channels are promising for building ultrahigh-flux nanofluidic platforms for energy harvesting, health monitoring, and water purification. Conventional wisdom is that nanoconfinement effects determine water transport in CNTs. Here, using full-atomistic molecular dynamics simulations, it is shown that water transport behavior in CNTs strongly correlates with the electronic properties of single-walled CNTs (metallic (met) vs semiconducting (s/c)), which is as dominant as the effect of nanoconfinement. Three pairs of CNTs (i.e., (8,8)met , 10.85 Å vs (9,7)s/c , 10.88 Å; (9,8)s/c , 11.53 Å vs (10,7)met , 11.59 Å; and (9,9)met , 12.20 Å vs (10,8)s/c , 12.23 Å) are used to investigate the roles of diameter and metallicity. Specifically, the (9,8)s/c can restrict the hydrogen-bonding-mediated structuring of water and give the highest reduction in carbon-water interaction energy, providing an extraordinarily high water flux, around 250 times that of the commercial reverse osmosis membranes and approximately fourfold higher than the flux of the state-of-the-art boron nitrate nanotubes. Further, the high performance of (9,8)s/c is also reproducible when embedded in lipid bilayers as synthetic high-water flux porins. Given the increasing availability of high-purity CNTs, these findings provide valuable guides for realizing novel CNT-enhanced nanofluidic systems.

Heat transport in carbon nanotubes: Length dependence of phononic conductivity from the Boltzmann transport equation and molecular dynamics

In this article, we address lattice heat transport in single-walled carbon nanotubes (CNTs) by a quantum mechanical calculation of three-phonon scattering rates in the framework of the Boltzmann transport equation (BTE) and classical molecular dynamics (MD) simulation. Under a consistent choice of an empirical, realistic atomic interaction potential, we compare the tube length dependence of the lattice thermal conductivity (TC) at room temperature determined from an iterative solution of the BTE and from a nonequilibrium MD (NEMD) approach. Qualitatively similar trends are found in the limit of short tubes, where an extensive regime of ballistic heat transport prevailing in CNTs of lengths $L\lesssim 1\,\rm{\mu m}$ is independently confirmed. In the limit of long tubes, the BTE approach suggests a saturation of TC with tube length, whereas direct NEMD simulations of tubes extending up to $L=10\,\rm{\mu m}$ are demonstrated to be insufficient to settle the question of whether a fully diffusive heat transport regime and an intrinsic value of TC exist for CNTs. Noting that acoustic phonon lifetimes lie at the heart of a saturation of TC with tube length as per the BTE framework, we complement the quantum mechanical prediction of acoustic phonon lifetimes with an analysis of phonon modes in the framework of equilibrium MD (EMD). A normal mode analysis (NMA) with an emphasis on long wavelength acoustic modes corroborates the BTE prediction that heat transport in CNTs in the long tube limit is governed by the low attenuation rates of longitudinal and twisting phonons.

Does equilibrium or nonequilibrium molecular dynamics correctly simulate thermal transport properties of carbon nanotubes?

There has been a lot of debate on whether non-Fourier thermal conduction can be observed in quasi-one-dimensional materials such as carbon nanotubes (CNTs) and, additionally, whether the phenomenon can be found by equilibrium or nonequilibrium molecular dynamics (EMD or NEMD) simulations. In fact, so far EMD and NEMD simulations have revealed disparities of thermal transport in CNTs, ranging from purely diffusive behavior, to diffusive-ballistic transition, and to non-Fourier thermal conduction. By carefully examining the roles of interfacial thermal resistances and applied temperature differences in NEMD simulations, we show that the two effects often yield spurious results. After removing the unwanted effects that have been overlooked by previous works, we find that most EMD and NEMD simulations on CNTs consistently display diffusive thermal conduction for length (L) g 200 nm. The finding is further supported by the disappearance of nonlocal thermal conduction for L g 200 nm. Our results clarify many discrepancies of previous works and point out that nonideal thermostats commonly used in EMD and NEMD simulations would give an effective contact thermal resistance that misleads data interpretations. Overall, we find EMD and NEMD simulations conducted so far disagree with the current experimental results of nondiffusive thermal conduction in CNTs.

Fluid breakup in carbon nanotubes: An explanation of ultrafast ion transport

Ultrafast ion transport in carbon nanotubes (CNTs) has been experimentally observed, but the underlying mechanism is unknown. In this work, we investigate ion transport in CNTs through molecular dynamics (MD) simulations. It is found that the flow in CNTs undergoes a transition from the passage of a continuous liquid chain to the transport of isolated ion-water clusters as the CNT length or the external electric filed strength is increased. The breakup of the liquid chain in CNTs greatly reduces the resistance caused by the hydrogen bonds of water and significantly enhances the ionic mobility, which explains the two-order-magnitude enhancement of ionic conductance in CNTs reported in the literature. A theoretical criterion for fluid breakup is proposed, which agrees well with MD results. The fluid breakup phenomenon provides new insights into enhancing ion transport in nanoconfinements.

Effects of Fe2O3 and ZnO nanoparticles on 17β-estradiol adsorption to carbon nanotubes

Diverse engineering nanoparticles (NPs) have found their way into the environment due to their extensive applications. The widespread occurrence of NPs may affect the fate of the coexisting pollutants and other types of NPs in natural waters. This study investigated the heteroadsorption of pollutants to multiple NPs in simulated water environment. Particular attention was paid to the impact of two common metal oxide (MO) NPs, Fe2O3 and ZnO, on the adsorption of 17β-estradiol (E2) to carbon nanotubes (CNTs). The results showed that the presence of Fe2O3 and ZnO significantly increased the time to reach adsorption equilibrium for the adsorption of E2 to CNTs. The adsorption amount of E2 increased with increasing Fe2O3/CNTs ratio due to the adsorption of E2 to Fe2O3. In contrast, E2 adsorption was slightly inhibited by the presence of ZnO, resulting from the blockage of the adsorption sites on CNT surface by ZnO. DLVO theory calculation exhibited that Fe2O3 were likely to first homoaggregate and then heteroaggregate with CNTs, whereas the electrostatic attraction between oppositely charged ZnO and CNTs favored their heteroaggregation in the heterogeneous systems of CNTs and ZnO. This was confirmed by the transmission electron microscopy images and the thermo-gravimetric analysis. The findings highlighted the significant effects of MO on the adsorption of organic compounds to CNTs, and also provided better understanding of the fate and transport of CNTs and organic contaminants in natural aquatic environments, where they inevitably coexist with MO.

Effects of ionic strength and temperature on the aggregation and deposition of multi-walled carbon nanotubes

The aggregation and deposition of carbon nanotubes (CNTs) determines their transport and fate in natural waters. Therefore, the aggregation kinetics of humic-acid treated multi-walled carbon nanotubes (HA-MWCNTs) was investigated by time-resolved dynamic light scattering in NaCl and CaCl2 electrolyte solutions. Increased ionic strength induced HA-MWCNT aggregation due to the less negative zeta potential and the reduced electrostatic repulsion. The critical coagulation concentration (CCC) values of HA-MWCNTs were 80mmol/L in NaCl and 1.3mmol/L in CaCl2 electrolyte, showing that Ca2+ causes more serious aggregation than Na+. The aggregation behavior of HA-MWCNTs was consistent with Derjaguin–Landau–Verwey–Overbeek theory. The deposition kinetics of HA-MWCNTs was measured by the optical absorbance at 800nm. The critical deposition concentrations for HA-MWCNT in NaCl and CaCl2 solutions were close to the CCC values, therefore the rate of deposition cannot be increased by changing the ionic strength in the diffusion-limited aggregation regime. The deposition process was correlated to the aggregation since larger aggregates increased gravitational deposition and decreased random Brownian diffusion. HA-MWCNTs hydrodynamic diameters were evaluated at 5, 15 and 25°C. Higher temperature caused faster aggregation due to the reduced electrostatic repulsion and increased random Brownian motion and collision frequency. HA-MWCNTs aggregate faster at higher temperature in either NaCl or CaCl2 electrolyte due to the decreased electrostatic repulsion and increased random Brownian motion. Our results suggest that CNT aggregation and deposition are two correlated processes governed by the electrolyte, and CNT transport is favored at low ionic strength and low temperature.

Empirical transport model of strained CNT transistors used for sensor applications

We present an empirical model for the nearballistic transport in carbon nanotube (CNT) transistors used as strain sensors. This model describes the intrinsic effect of strain on the transport in CNTs by taking into account phonon scattering and thermally activated charge carriers. As this model relies on a semiempirical description of the electronic bands, different levels of electronic structure calculations can be used as input. The results show that the electronic structure of strained single-walled CNTs with a radius larger than 0.7nm can be described by a fully analytical model in the sensing regime. For CNTs with smaller diameter, parameterized data from electronic structure calculations can be used for the model. Depending on the type of CNTs, the conductance can vary by several orders of magnitude when strain is applied, which is consistent with the current literature. Further, we demonstrate the tuning of the sensor by an external gate which allows shifting the signal amplitude and the strain sensitivity. These parameters have to be balanced to get good sensing properties. Due to its basically analytical nature, the transport model can be formulated as a compact model for circuit simulations.

Transport of sodium dodecylbenzene sulfonate (SDBS)-dispersed carbon nanotubes and enhanced mobility of tetrabromobisphenol A (TBBPA) in saturated porous media

Abstract Understanding the transport behavior of carbon nanotubes (CNTs) in porous media is essential in determining their environmental impact, especially on the fate and mobility of organic contaminants. The transport of sodium dodecylbenzenesulfonate (SDBS)-dispersed CNTs and their effects on the mobility of tetrabromobisphenol A (TBBPA) in saturated glass bead-packed columns were investigated. The behavior of single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs) were compared. A simulation was carried out using a model based on convection–dispersion equation. The results showed that MWNTs was more mobile than SWNTs under the same solution conditions through porous media. CNTs transport was controlled by surface attachment and physical straining. CNTs in the feed significantly enhanced TBBPA mobility and acted as TBBPA carriers in the column. Adsorption-desorption experiments indicated that the enhanced mobility came from the irreversible adsorption and slow desorption kinetics of CNT-associated TBBPA. The modified model was in good agreement with the transport data of CNTs in different solutions with the coefficient of determination (R2) higher than 0.93. This work demonstrates that CNTs significantly enhance the mobility of TBBPA, and this effect should be considered when assessing the fate and risk of CNTs in the environment.

Anomalous Ionic Conductance in Carbon Nanotube Nanochannels

Simulations and experimental studies have reported an unusually high ionic conductance in carbon nanotube (CNT) nanochannels. The origin of this phenomenon is, however, poorly-understood: literature reports often disagree in the magnitude of the different transport mode contributions to the measured ionic current and even in what ions are actually carrying the current; moreover, results obtained with single pore measurements differ frequently from those with membranes containing billions of open CNT channels, i.e. the average CNT behavior. Toward shedding light on these phenomena, we fabricated a novel platform having vertically-aligned sub-5nm carbon nanotubes as nanofluidic channels, the number of which can be controlled from one to billions. By employing this platform with only one or a few open CNTs, we observed giant ionic currents in CNT channels and a power-law increase of conductance with KCl concentration (G ∼ cn, n=0.1-0.4), a dependence that seems to be unique of CNT pores. To understand and quantify electro-osmotic flow in CNT pores (which has been proposed as the transport mode responsible for the giant ionic currents in CNTs), we investigated translocation of neutral molecules in a single CNT nanochannel with the resistive pulse technique. Furthermore, we used first-principle simulations to show that cation-CNT interactions may explain the origin of this electro-osmotic flow. Implications of our findings on the physics of electric-field-driven ionic and molecular transport in CNTs will be presented here.

Simulation studies on the diffusion of water solitons in carbon nanotube

Fluid transport is a very common phenomenon. Recently flow process in nanochannels has drawn much attention, since it differs quite much from that in macroscopic pipes. In particular, the motion of confined water molecules in nonpolar nanochannels has become a hotspot in nanotechnology, and also an important issue in biology and chemistry. Besides the experimental studies, computer simulations (e.g., molecular dynamics simulation) have also been proven to be a powerful tool to investigate such issues. Early simulations focused on the concurrent motion of all water molecules inside nanochannels such as carbon nanotubes (CNTs), where water molecules are evenly spaced in a single file and occasionally but collectively transport through CNTs. Recently, a new model of water transport in CNTs was presented, which indicates that water-density defects in the one-dimensional (1D) chain of water molecules can move as solitons. This is explained as a natural consequence of competition between water-water interactions and water-CNT interactions. While this new model is very appealing, the identification of soliton is not a trivial work (especially at not very low temperatures), since the density defects of water molecules might not be easily recognized from their thermal fluctuation. In this paper, a new method is developed to precisely identify the soliton by quenching the simulation conformations to their nearest neighboring local minima. Based on the new soliton identification method, we study the motion of water in single-walled armchair CNTs by all-atom molecular dynamics simulations. We investigate the motion of solitons in detail, which is observed as a standard 1D diffusion on a picosecond time scale. The simulations also show that the diffusion coefficient of solitons increases with temperature rising, and decreases with the number density of solitons increasing. These results are consistent with the postulation that there exists a weak repulsion between solitons.

Anomalously Fast Diffusion of Targeted Carbon Nanotubes in Cellular Spheroids.

Understanding transport of carbon nanotubes (CNTs) and other nanocarriers within tissues is essential for biomedical imaging and drug delivery using these carriers. Compared to traditional cell cultures in animal studies, three-dimensional tissue replicas approach the complexity of the actual organs and enable high temporal and spatial resolution of the carrier permeation. We investigated diffusional transport of CNTs in highly uniform spheroids of hepatocellular carcinoma and found that apparent diffusion coefficients of CNTs in these tissue replicas are anomalously high and comparable to diffusion rates of similarly charged molecules with molecular weights 10000× lower. Moreover, diffusivity of CNTs in tissues is enhanced after functionalization with transforming growth factor β1. This unexpected trend contradicts predictions of the Stokes-Einstein equation and previously obtained empirical dependences of diffusivity on molecular mass for permeants in gas, liquid, solid or gel. It is attributed to the planar diffusion (gliding) of CNTs along cellular membranes reducing effective dimensionality of diffusional space. These findings indicate that nanotubes and potentially similar nanostructures are capable of fast and deep permeation into the tissue, which is often difficult to realize with anticancer agents.

Transport of Surface-modified Carbon Nanotubes through a Soil Column

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, electronics and biomedical applications. Due to their accelerating production and use, CNTs constitute a potential environmental risk if they are released to soil and groundwater systems. It is therefore essential to improve the current understanding of environmental fate and transport of CNTs. The transport and retention of CNTs in both natural and artificial media have been reported in literature, but the findings widely vary and are thus not conclusive. There are a number of physical and chemical parameters responsible for variation in retention and transport. In this study, a complete procedure of selected multiwalled carbon nanotubes (MWCNTs) is presented starting from their surface modification to a complete set of laboratory column experiments at critical physical and chemical scenarios. Results indicate that the stability of the commercially available MWCNTs are critical with their attached surface functional group which can also influence the transport and retention of MWCNT through the surrounding medium.