First-principles calculations of nickel, cadmium, and lead adsorption on a single-walled (10,0) carbon nanotube (original) (raw)
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Applied Surface Science, 2013
Absorption of Pb on a zigzag (10, 0) carbon nanotube (CNT) surface, pure and functionalized with carboxyl ( COOH) and hydroxyl ( OH) groups was investigated using the density functional theory. Binding energy calculations were performed and indicated that adsorption of the Pb metal on the surface of the three nanotubes were stable, through a chemisorption. Therefore, CNTs are a feasible active material for filters that retain such metal. After Pb adsorption, the CNT and COOH-CNT conductivity changed, from semiconductor to half-metallic for CNT and from semiconductor to metallic for COOH-CNT, which can serve as a signal for Pb sensor. In all three cases adsorption produced a change in nanotube magnetism, which can also serve as a sensitive signal for chemical sensors. After adsorption of Pb, the changes in binding energy, charge transfer, conductance and magnetism may lead to the different response in the CNTs-based sensors. Thus, it is expected that these results could provide helpful information for the design and fabrication of the Pb sensing devices.
Adsorption of heavy metal ions with carbon nanotubes
Separation and Purification Technology, 2007
Carbon nanotubes (CNTs) were employed as adsorbent to study the adsorption characteristics of some divalent metal ions (Cu, Co, Cd, Zn, Mn, Pb). The effect of solution conditions such as pH and metal ions concentration was investigated. At pH 9 the affinity order of the metal ions towards CNTs is Cu(II) > Pb(II) > Co(II) > Zn(II) > Mn(II). The Freundlich adsorption model agrees well with experimental data. Our results suggest that CNTs have good potential application in environmental protection.
Materials Chemistry and Physics, 2018
In current article, we investigated adsorption properties of Nickel (Ni), Copper (Cu), Cadmium (Cd) and silver (Ag) heavy metal atoms with zinc oxide (ZnO) nanotube and ZnO-graphene like structures sheet using Ab-initio based density functional theory (DFT) calculations. At first, both nanostructures were optimized and then most stable configuration, adsorption energy and equilibrium distance of each heavy metal with nanostructures were computed via DFT and the results were compared with each other. Our obtained results reveal that ZnO-nanotube had a better adsorbing behavior comparing to ZnO-graphene sheet case by case due to lower equilibrium distance and higher adsorption energy. This nanostructure created a strong binding with Ni, Cu and Ag but adsorption energy for Cd was clearly lower than others. Also only Ni and Cu could have a chemisorption adsorption with ZnO-graphene sheet and others showed a nearly weak physisorption adsorption with this nanostructure. The maximum adsorption energy for both ZnO-nanostructures occurred for nickel which were about-3.45 eV and-2.19 eV respectively .The minimum adsorption energy for ZnO nanotube occurred with Cd (-1.3 eV) while for ZnO-graphene sheet it occurred with Zn (-0.15 eV). In almost all items equilibrium distance decreased with increasing in adsorption energy. Moreover we generated density of state (DOS) diagrams to investigate the electrical properties of studied structures.
Applied Physics Letters, 2009
Adsorption geometries and binding affinities of metal nanoparticles onto carbon nanotubes ͑CNTs͒ are investigated through density-functional-theory calculations. Clusters of 13 metal atoms are used as models for metal nanoparticles. Palladium, platinum, and titanium particles strongly chemisorb to the CNT surface. Unlike the cases of atomic adsorptions the aluminum particle has the weakest binding affinity with the CNT. Aluminum or gold nanoparticles accumulated on the CNT develop the triangular bonding network of the metal surfaces in which the metal-carbon bond is not favored. This suggests that the CNT-Al interface is likely to have many voids and thus susceptible to oxidation damages.
Lead Adsorption on Carbon Nanotubes
Chemical Physics …, 2002
Carbon nanotubes (CTNs) show exceptional adsorption capability and high adsorption efficiency for lead removal from water. The adsorption is significantly influenced by the pH value of the solution and the nanotube surface status, which can be controlled by their treatment processing. The adsorption isotherms are well described by both Langmuir and Freundlich models. Our results suggest that CNTs can be good Pb 2þ adsorbers and have great potential applications in environmental protection.
Adsorption of Cadmium (II) From Aqueous Solution by Surface Oxidized Carbon Nanotubes
Carbon, 2003
Carbon nanotubes (CNTs) were oxidized with H O , KMnO and HNO. Their physicochemical properties were 2 2 4 3 investigated by BET N adsorption, laser particle examination, Boehm's titration, zeta potential measurement and 2 cadmium(II) adsorption. The experimental results suggest that cadmium(II) adsorption capacities for three kinds of oxidized CNTs increase due to the functional groups introduced by oxidation compared with the as-grown CNTs. The cadmium(II) 21 21 adsorption capacity of the as-grown CNTs is only 1.1 mg g , while it reaches 2.6, 5.1 and 11.0 mg g for the H O , 2 2 21 HNO and KMnO oxidized CNTs, respectively, at the cadmium(II) equilibrium concentration of 4 mg l. Adsorption of 3 4 cadmium(II) by CNTs was strongly pH-dependent and the increase of adsorption capacities for HNO and KMnO oxidized 3 4 CNTs is more obvious than that of the as-grown and H O oxidized CNTs at lower pH regions. The experiments of CNT 2 2 dosage effect on the cadmium(II) adsorption show that the adsorption capacity for KMnO oxidized CNTs has a sharper 4 increase at the CNT dosage from 0.03 to 0.08 g per 100 ml than the as-grown, H O and HNO oxidized CNTs and its 2 2 3 removal efficiency almost reaches 100% at CNT dosage of 0.08 g per 100 ml. Analysis revealed that the KMnO oxidized 4 CNTs hosted manganese residuals, and these surely contributed to cadmium sorption to a yet-undefined extent.
The journal of physical chemistry. A, 2015
The adsorption behaviors of heavy metal ions Cd(2+), Cu(2+), Pb(2+), and Hg(2+), in aqueous media using functionalized single-walled carbon nanotube (SWCNT) with functional groups -COO(-), -OH, and -CONH2 are studied using molecular dynamics (MD) simulations. The results show that adsorption capacity is improved significantly using surface modification of SWCNT with carboxyl, hydroxyl, and amide functional groups. In addition, the adsorption capacity is found to increase with increasing metal-ion concentration. It is observed that the CNT-COO(-) surface effectively adsorbs over 150-230% more metal ions than the bare CNT surface. On the contrary, -OH and -CONH2 are relatively weak functional groups where excess metal-ion adsorption compared to the bare CNT is in the range 10-47%. The structural properties, self-diffusion coefficients, and adsorption isotherms of the metal ions are computed and analyzed in detail. Moreover, the potential of mean force (PMF) is computed to understand t...
Energetics and Electronic Structures of Individual Atoms Adsorbed on Carbon Nanotubes
The Journal of Physical Chemistry B, 2004
The adsorption of individual atoms on the semiconducting and metallic single-walled carbon nanotubes (SWNT) has been investigated by using the first principles pseudopotential plane wave method within density functional theory. The stable adsorption geometries and binding energies have been determined for a large number of foreign atoms ranging from alkali and simple metals to the transition metals and group IV elements. We have found that the character of the bonding and associated physical properties strongly depends on the type of adsorbed atoms, in particular, on their valence electron structure. Our results indicate that the properties of SWNTs can be modified by the adsorbed foreign atoms. Although the atoms of good conducting metals, such as Zn, Cu, Ag, and Au, form very weak bonds, transition-metal atoms such as Ti, Sc, Nb, and Ta and group IV elements C and Si are adsorbed with a relatively high binding energy. Owing to the curvature effect, these binding energies are larger than the binding energies of the same atoms on the graphite surface. We have showed that the adatom carbon can form strong and directional bonds between two SWNTs. These connects can be used to produce nanotube networks or grids. Most of the adsorbed transition-metal atoms excluding Ni, Pd, and Pt have a magnetic ground state with a significant magnetic moment. Our results suggest that carbon nanotubes can be functionalized in different ways by their coverage with different atoms, showing interesting applications such as 1D nanomagnets or nanoconductors, conducting connects, and so forth.
Results in Physics, 2019
Interactions between transition metal atoms, nickel, titanium, palladium and gold and (3,3), (4,2), (6,0) and (5,1) carbon nanotubes were studied using first principles calculations. The Fermi energy levels of the carbon nanotubes studied were found to increase during interactions with the transition metal atoms. Amongst the four metals, gold atom was found to have an enhanced interaction with the nanotubes transforming from semiconducting to a conducting tube. Titanium was also found to show similar characteristics to gold only when the atom was placed in the middle of the carbon nanotubes. Nickel and palladium atoms interactions did not affect much the electronic properties of the carbon nanotubes, with some slight changes in the electronic properties at some specific sites of the nanotubes. It is proposed from this study that, the carbon nanotube-metal interactions could be used as a guide to shed light on the electronic properties of such materials which could become promising engineering materials and revolutionize the electronic industry.
International Journal of Environmental Science and Technology, 2012
Multi-walled carbon nanotubes were used successfully for the removal of Copper(II), Lead(II), Cadmium(II), and Zinc(II) from aqueous solution. The results showed that the % adsorption increased by raising the solution temperature due to the endothermic nature of the adsorption process. The kinetics of Cadmium(II), Lead(II), Copper(II), and Zinc(II) adsorption on Multi-walled carbon nanotubes were analyzed using the fraction power function model, Lagergren pseudo-first-order, pseudo-second-order, and Elovich models, and the results showed that the adsorption of heavy metal ions was a pseudo-second-order process, and the adsorption capacity increased with increasing solution temperature. The binding of the metal ions by the carbon nanotubes was evaluated from the adsorption capacities and was found to follow the following order: Copper(II) [ Lead(II) [ Zinc(II) [ Cadmium(II). The thermodynamics parameters were calculated, and the results showed that the values of the free energies were negative for all metals ions, which indicated the spontaneity of the adsorption process, and this spontaneity increased by raising the solution temperature. The change in entropy values were positives, indicating the increase in randomness due to the physical adsorption of heavy metal ions from the aqueous solution to the carbon nanotubes' surface. Although the enthalpy values were positive for all metal ions, the free energies were negative, and the adsorption was spontaneous, which indicates that the heavy metal adsorption of Multiwalled carbon nanotubes was an entropy-driving process.