scholarly journals Adsorption of Gold(I) and Gold(III) Using Multiwalled Carbon Nanotubes

2018 ◽  
Vol 8 (11) ◽  
pp. 2264 ◽  
Author(s):  
Francisco Alguacil
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Aqueous Media ◽  
Precious Metals ◽  
Order Kinetic ◽  
Chloride Medium ◽  
Multiwalled Carbon ◽  
Ph Values ◽  
Diffusion Controlled ◽  
Order Kinetic Model

Carbon nanotubes are materials that have been investigated for diverse applications including the adsorption of metals. However, scarce literature has described their behavior in the case of the adsorption of precious metals. Thus, this work reports the efficient adsorption of gold from cyanide or chloride media on multiwalled carbon nanotubes (MWCNTs). In a cyanide medium, gold was adsorbed from alkaline pH values decreasing the adsorption as the pH values were increased to more acidic values. In a chloride medium, the MWCNTs were able to load the precious metal and an increased HCl concentration (0.1–10 M), in the aqueous solution, had no effect on the gold uptake onto the nanotubes. From both aqueous media, the metal adsorption was well represented by the pseudo-second order kinetic model. In the cyanide medium, the film-diffusion controlled process best fitted the rate law governing the adsorption of gold onto the nanotubes, whereas in the chloride medium, the adsorption of the metal onto the nanotubes is best represented, both at 20 °C and 60 °C, by the particle-diffusion controlled process. With respect to the elution step, in cyanide medium gold loaded onto the nanotubes can be eluted with acidic thiourea solutions, whereas in the chloride medium, and due to that the adsorption process involved the precipitation of zero valent gold onto the multiwalled carbon nanotubes, the elution has been considered as a leaching step with aqua regia. From the eluates, dissolved gold can be conveniently precipitated as zero valent gold nanoparticles.

scholarly journals On the Active Adsorption of Chromium(III) from Alkaline Solutions Using Multiwalled Carbon Nanotubes

2019 ◽  
Vol 10 (1) ◽  
pp. 36 ◽  
Author(s):  
Francisco José Alguacil ◽  
Félix A. López
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Multiwalled Carbon Nanotubes ◽  
Alkaline Media ◽  
Alkaline Solutions ◽  
Order Kinetic ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Equilibrium Data ◽  
Order Kinetic Model

The present investigation deals with the adsorption of chromium(III) from alkaline media, as representative of highly-caustic component solutions of nuclear tank wastes, using multiwalled carbon nanotubes. The adsorption of Cr(III) has been studied under various experimental conditions, i.e., stirring speed of the aqueous solution, initial metal and adsorbent concentrations, NaOH concentration in the aqueous solution, and temperature. The rate law indicated that chromium adsorption is well represented by the particle diffusion model, whereas the adsorption process fits with the pseudo-second order kinetic model within an exothermic setting. Equilibrium data fit to the Langmuir type-2 equilibrium isotherm in a spontaneous process. Chromium(III) can be eluted from metal-loaded nanotubes using acidic solutions, from which fine chromium(III) oxide pigment can ultimately be yielded.

scholarly journals Evaluation of La (III) and Ce(III) Adsorption from Aqueous Solution Using Carbon Nanotubes Adsorbent

2020 ◽  
Author(s):  
Irene García Díaz ◽  
Francisco J. Alguacil ◽  
Esther Escudero ◽  
Félix A. López
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Carbon Nanomaterials ◽  
Raw Materials ◽  
Technological Development ◽  
Order Kinetic ◽  
Multiwalled Carbon ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
The 1960S

Since the 1960s Rare earths (REs) applications gradually have expanded to everyday life. REs have great strategic importance in industrial and technological development, so it is expected an increase in their demand. Among the REs the European Commission considered Cerium and Lanthanum as critical raw materials. This research article studies the adsorption of Ce and La onto two carbon nanomaterials, multiwalled carbon nanotubes (MWCNT) and carboxylic functionalized multiwalled carbon nanotubes (MWCNT_ox). The latter has slightly more affinity for REs than MWCNT. The recovery percentage for Ce were 89 and 98% and in the case of for La were 99 and 92% using 0.8 g of MWCNT and 0.2 g of MWCNT_ox respectively. The adsorption process fits a pseudo second-order kinetic model and the Langmuir isotherm best represented the metal uptake.

Solubilization, characterization, and protein coupling analysis to multiwalled carbon nanotubes

2020 ◽  
pp. 095400832095803
Author(s):  
Juliane Glória ◽  
Walter Brito ◽  
Ariamna Gandarilla ◽  
Duniesky Larrude ◽  
Jacqueline Carlos ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Aqueous Media ◽  
Chemical Properties ◽  
Electron Microscopic ◽  
Multiwalled Carbon ◽  
Physical And Chemical ◽  
The Impact ◽  
Microscopic Techniques ◽  
And Chemical Properties

Since their discovery, carbon nanotubes were used for numerous applications in the most diverse knowledge areas. However, the lack of solubility of these molecules in aqueous media compromises their beneficial properties for certain applications. Several methods to solubilize carbon nanotubes are described, however, depending on the intended application, the impact that the solubilization has on the physical and chemical properties needs to be considered. In the present study, a simple methodology is described that utilizes polyvinylpyrrolidone combined with sonication and centrifugation to solubilize multiwalled carbon nanotubes. Proteins were coupled to the surface of the solubilized products and characterized using various spectroscopic and electron microscopic techniques, evaluating the characteristics and integrity of the nanoparticle after the process. It was successfully demonstrated that nanotubes can be solubilized through a simple technique, without compromising their chemical characteristics, which makes them suitable materials for use in biomedical applications, due to their biocompatibility and lack of toxicity, among others.

scholarly journals Efficient removal of Malachite Green from aqueous solution by adsorption on carbon nanotubes modified with ZnFe2O4 nanoparticles

2019 ◽  
Vol 84 (7) ◽  
pp. 701-712 ◽  
Author(s):  
Abkenar Dehghan ◽  
Morassa Hassannezhad ◽  
Morteza Hosseini ◽  
Mohammad Ganjali
Keyword(s):  
Carbon Nanotubes ◽  
Malachite Green ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Aqueous Media ◽  
Multiwall Carbon Nanotubes ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model

In this study, multiwall carbon nanotubes modified with spinel zinc ferrite nanoparticle (ZnFe2O4/MWCNTs) were used as a solid phase adsorbent for the removal of Malachite Green (MG) from aqueous media. The synthesized nanocomposite was characterized by different methods, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Batch adsorption experiments to determine the optimal adsorption conditions and different factors that influence the adsorption efficiency (i.e., pH, amount of adsorbent, contact time, and the initial concentration of MG) were also evaluated and optimized. The data were satisfactorily fitted to the Langmuir model and a maximum adsorption capacity of 116.2 mg g-1 was obtained at a pH of 7.5. In addition, adsorption kinetics studies were performed. The adsorption of the model dye (MG) was found to reach equilibrium after 60 min, following a pseudo-second-order kinetic model. Furthermore, an external magnetic field could easily separate the nanoparticles from water with a high separation efficiency.

scholarly journals Enhanced Heavy Metal Removal from Acid Mine Drainage Wastewater Using Double-Oxidized Multiwalled Carbon Nanotubes

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 111 ◽  
Author(s):  
Carolina Rodríguez ◽  
Eduardo Leiva
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Heavy Metal ◽  
Multiwalled Carbon Nanotubes ◽  
Sorption Capacity ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Order Kinetic ◽  
Multiwalled Carbon ◽  
Oxidized Multiwalled Carbon Nanotubes

Due to the unique properties of carbon nanotubes (CNTs), they have attracted great research attention as an emergent technology in many applications including water and wastewater treatment. However, raw CNTs have few functional groups, which limits their use in heavy metal removal. Nevertheless, their removal properties can be improved by oxidation processes that modify its surface. In this study, we assessed the capacity of oxidized and double-oxidized multiwalled carbon nanotubes (MWCNTs) to remove heavy metals ions from acidic solutions. The MWCNTs were tested for copper (Cu), manganese (Mn), and zinc (Zn) removal, which showed an increment of 79%, 78%, and 48%, respectively, with double-oxidized MWCNTs compared to oxidized MWCNTs. Moreover, the increase in pH improved the sorption capacity for all the tested metals, which indicates that the sorption potential is strongly dependent on the pH. The kinetic adsorption process for three metals can be described well with a pseudo-second-order kinetic model. Additionally, in multimetallic waters, the sorption capacity decreases due to the competition between metals, and it was more evident in the removal of Zn, while Cu was less affected. Besides, XPS analysis showed an increase in oxygen-containing groups on the MWCNTs surface after oxidation. Finally, these analyses showed that the chemical interactions between heavy metals and oxygen-containing groups are the main removal mechanism. Overall, these results contribute to a better understanding of the potential use of CNTs for water treatment.

On the diffusion-controlled growth of multiwalled carbon nanotubes

2005 ◽  
Vol 97 (11) ◽  
pp. 114301 ◽  
Author(s):  
K. Bartsch ◽  
K. Biedermann ◽  
T. Gemming ◽  
A. Leonhardt
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Controlled Growth ◽  
Multiwalled Carbon ◽  
Diffusion Controlled

scholarly journals Characterization of Betulinic Acid-Multiwalled Carbon Nanotubes Modified with Hydrophilic Biopolymer for Improved Biocompatibility on NIH/3T3 Cell Line

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1362
Author(s):  
Julia Meihua Tan ◽  
Saifullah Bullo ◽  
Sharida Fakurazi ◽  
Mohd Zobir Hussein
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Betulinic Acid ◽  
Electrostatic Interactions ◽  
Aqueous Media ◽  
Mouse Fibroblast ◽  
Tween 20 ◽  
Multiwalled Carbon ◽  
Cell Viability Assay ◽  
Embryonic Mouse

The biocompatibility of carbon nanotubes (CNT) is fairly a challenging task for their applications in nanomedicine. Therefore, the objective of this research was to formulate four types of highly biocompatible betulinic acid-loaded biopolymer nanocomposites, namely chitosan-multiwalled carbon nanotubes (MWBA-CS), polyethylene glycol-multiwalled carbon nanotubes (MWBA-PG), Tween 20-multiwalled carbon nanotubes (MWBA-T2) and Tween 80-multiwalled carbon nanotubes (MWBA-T8). The physico-chemical properties of the modified nanocomposites were determined by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and Raman spectroscopy, while the surface morphology of the resulting nanocomposites was studied using field emission scanning electron microscopy (FESEM). All data revealed that the external surface of MWBA nanocomposites was successfully coated with the respective polymer molecules through hydrophobic and electrostatic interactions with improved thermal profiles. The cell viability assay, which was performed on cultured normal embryonic mouse fibroblast cells, confirmed their excellent biocompatibility in phosphate-buffered saline aqueous media. Overall, our findings herein suggest that the synthesized biopolymer-coated MWBA nanocomposites are promising nanomaterials for drug delivery applications as they enhance the solubility and dispersibility of CNT with significantly reduced cytotoxic effect, especially in normal cells.

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