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Effect of Acid and Alcohol Network Forces within Functionalized Multiwall Carbon Nanotubes Bundles on Adsorption of Copper (II) Species
Citation:
Rosenzweig, S., G. A. Sorial, E. Sahle-Demessie, AND J. Mack. Effect of Acid and Alcohol Network Forces within Functionalized Multiwall Carbon Nanotubes Bundles on Adsorption of Copper (II) Species. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 90(2):395-402, (2013).
Impact/Purpose:
Multiwall carbon nanotubes (CNTs) have been studied for their capacity on removing copper from and as sensor. Adsorptive properties of selected their equilibrium isotherm and kinetic studies are conducted to measure and compare these effects. This study focused in understanding properties of CNT and how they affect the CNTs behavior in water. This has major implication in environmental applications of CNT as sensors and adsorbents.
Description:
Adsorption of metals on carbon nanotubes (CNTs) has important applications in sensors, membranes, and water treatment. The adsorptive capacity of multiwall CNTs for copper species in water depends on the type of functional group present on their surface. The alcohol (COOH) and acid (OH) network forces formed by van der Waals bonds within the CNT bundles can define their aggregate state and available sites for copper adsorption. Copper is attracted to different oxygen radicals on the surface and within the bundles of CNTs. The effect of initial concentration shown on isotherm curves was investigated as an impact of different network forces and the presence of impurities leached from as-received CNTs. Deprotonation of CNTs reduced the acid network forces, improved adsorption capacity, and removed the effect of initial concentration. Impurities leached from CNTs under the effect of pH were less than 1 mg/g for each metal, which was insignificant compared to copper in solution. Pristine CNTs were acid washed and purified (Ox-CNTs), improving their adsorption capacity, but the effect of initial concentration was still present. Adsorption of copper is stronger for alcohol functionalized CNTs (OH-CNTs), followed by deprotonated COOH-CNTs, as-received COOH-CNT, Ox-CNTs and finally pristine CNTs. FTIR, XPS, and Zeta potential measurements were used to identify and quantify the different surface functional groups present on CNTs. KEYWORDS: adsorption; copper; CNT; deprotonation; kinetics; nanotubes; network
