Effect of Enhanced Thermal Stability of Alumina Support Layer on Growth of Vertically Aligned Single-Walled Carbon Nanotubes and Their Application in Nanofiltration Membranes

Abstract

We investigate the thermal stability of alumina supporting layers sputtered at different conditions and its effect on the growth of aligned single-walled carbon nanotube arrays. Radio frequency magnetron sputtering of alumina under oxygen–argon atmosphere produces a Si-rich alumina alloy film on a silicon substrate. Atomic force microscopy on the annealed catalysts reveals that Si-rich alumina films are more stable than alumina layers with low Si content at the elevated temperatures at which the growth of single-walled carbon nanotubes is initiated. The enhanced thermal stability of the Si-rich alumina layer results in a narrower (< 2.2 nm) diameter distribution of the single-walled carbon nanotubes. Thanks to the smaller diameters of their nanotube pores, membranes fabricated with vertically aligned nanotubes grown on the stable layers display improved ion selectivity.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2585-3) contains supplementary material, which is available to authorized users.

Next-Generation Multifunctional Carbon–Metal Nanohybrids for Energy and Environmental Applications

“…Besides the strong influence of particle size, shape, morphology, dimensionality, and MLC discussed earlier, the ), nanofiltration (CNTs−Al 175 and RGO−UiO-66 176 ), microfiltration (GO− Al 2 O 3 177 ), capacitive deionization (CNTs−MnO x 178 and GO−Ag−Cu 179 ), electrochemical deionization (RGO− FePO 4 180 ), membrane distillation (RGO−Bi 2 WO 6 181 ), and organic solvent nanofiltration (GO−ZIF-8 182 ). For example, the RGO@Fe 3 O 4 nanofiltration membranes present high water permeance (∼300 L/m 2 /h/bar) and dye (Rhodamine B and bisphenol A) and ion (CuSO 4 , CdSO 4 , MnSO 4 , and CoSO 4 ) rejection by utilizing the expanded interlayer spacings and nanochannels between the ordered laminar RGO layers due to uniform loading of Fe 3 O 4 NPs (Figure 5).…”

“…Membrane-based water treatment and desalination technologies are popular treatment options in many parts of the world. − CNMs (CNTs and GFNs) have been extensively used to modify membranes and impart mechanical strength, improve water permeability and flux (e.g., aligned CNTs), enable tunability of hydrophobicity, introduce selectivity and antifouling capability, and deliver flexibility toward functionalization. ,− Recently, CNTs– and GFNs–CMNHs have shown great potential in various membrane technologies including reverse osmosis (CNTs–TiO 2 , GO–Ag, and GO–Fe), forward osmosis (CNTs–SiO 2 -polyvinylidene fluoride and GO–Ag), ultrafiltration (CNTs–Al and GO–TiO 2 ), nanofiltration (CNTs–Al and RGO–UiO-66), microfiltration (GO–Al 2 O 3 ), capacitive deionization (CNTs–MnO x and GO–Ag–Cu), electrochemical deionization (RGO–FePO 4 ), membrane distillation (RGO–Bi 2 WO 6 ), and organic solvent nanofiltration (GO–ZIF-8). For example, the RGO@Fe 3 O 4 nanofiltration membranes present high water permeance (∼300 L/m 2 /h/bar) and dye (Rhodamine B and bisphenol A) and ion (CuSO 4 , CdSO 4 , MnSO 4 , and CoSO 4 ) rejection by utilizing the expanded interlayer spacings and nanochannels between the ordered laminar RGO layers due to uniform loading of Fe 3 O 4 NPs (Figure ).…”

Novel Research on CuONPs/MWCNTs Effect on the Properties of Na-Bentonite Water Based Drilling Muds with Experimental Study

“…Synthesis of multi-walled carbon nanotubes (MWCNTs).-MWCNTs were synthesized by the CVD method, 41 which is based on the thermal decomposition of the hydrocarbon vapor passing through the tubular reactor in which the metal catalyst is placed at high temperature (2000 °C). The CVD reactor (Fig.…”

Synthesis and Characterization of SiO2NPs/MWCNTs Nanocomposite and Effect on the Properties of Na-Bentonite Water Based Drilling Fluids: Experimental Investigation

“…Graphite is then fed into the furnace in the form of steam and carbon accumulation on metal nanoparticles is achieved as a result of catalytic decomposition under 2000 °C temperature and 100 torr pressure. 26 Production of SiO 2 nanoparticle.-A suspension of 1.0 M silicon dioxide in NaOH in 0.5 M (1:1) (v/v) was prepared and then calcined at 100 °C for 30 min. This suspension was then stirred at 80 °C for 3 h. After the filtration process of the obtained residue, washing with distilled water was carried out and drying for approximately 24 h, SiO 2 NPs was produced.…”

“…Finally, the steam dispersion was fed to the furnace, subjected to thermal degradation under 2000 °C temperature, 100 torr pressure and carbon nanotube+nanoparticle accumulation was provided. 26 Preparation and analysis of water based drilling muds (WBDM).-500 g of water, 32.25 g of bentonite and 14.25 g of barite were mixed with a high speed mixer for 15 min and waterbased drilling muds were prepared. Then SiO 2 NPs/MWCNTs was added to the drilling muds separately at the ratios of 0.001, 0.005 and 0.01 (% w/v) and thoroughly homogenized by mixing.…”