Acid-treated carbon nanotubes and their effects on mortar strength

Elkashef, Mohamed; Wang, K.; Abou‐Zeid, Mohamed Nagib

doi:10.1007/s11709-015-0325-7

Cited by 32 publications

(10 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…UV-Vis analyses were performed using a UV-5100S digital spectrophotometer. The CNT aqueous dispersions were diluted in deionized in the proportion of 1:100 [26] with magnetic stirring for 5 min, to keep the absorbance values in the range of 0.1-2 in the entire wavelength range similar to the interval adopted by Attal et al [27]. In aqueous solutions, the characteristic absorption of CNT occurs at 253 nm [28].…”

Section: Aqueous Cnt Dispersions Production and Characterizationmentioning

confidence: 99%

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

et al. 2021

View full text Add to dashboard Cite

The functionalization process usually increases the localized defects of carbon nanotubes (CNT). Thus, the ultrasonication parameters used for dispersing non-functionalized CNT should be carefully evaluated to verify if they are adequate in dispersing functionalized CNT. Although ultrasonication is widely used for non-functionalized CNT, the effect of this dispersing process of functionalized CNT has not been thoroughly investigated. Thus, this work investigated the effect of ultrasonication on functionalized CNT + superplasticizer (SP) aqueous dispersions by ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Furthermore, Portland cement pastes with additions of 0.05% and 0.1% CNT by cement weight and ultrasonication amplitudes of 0%, 50% and 80% were evaluated through rheometry, isothermal calorimetry, compressive strength at 1, 7 and 28 days, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). FTIR results from CNT + SP dispersions indicated that ultrasonication may negatively affect SP molecules and CNT graphene structure. The increase in CNT content and amplitude of ultrasonication gradually increased the static and dynamic yield stress of paste but did not significantly affect its hydration kinetics. Compressive strength results indicated that the optimum CNT content was 0.05% by cement weight, which increased the strength of composite by up to 15.8% compared with the plain paste. CNT ultrasonication neither increases the degree of hydration of cement nor the mechanical performance of composite when compared with mixes containing unsonicated CNT. Overall, ultrasonication of functionalized CNT is not efficient in improving the fresh and hardened performance of cementitious composites.

show abstract

Section: Aqueous Cnt Dispersions Production and Characterizationmentioning

confidence: 99%

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Although CNT incorporated PVA membranes have been researched in PV process [24,[42][43][44], the CNTs used were usually derived from acid oxidation under heating. That made the influence of the CNT functional groups unclear due to the complex composition (-OH, -COOH and -C=O) [45,46]. The PVA matrix has variable types (crosslinked or uncrosslinked), which calls for comparison to guide rational membrane design.…”

Section: Introductionmentioning

confidence: 99%

Understanding the transport enhancement of poly (vinyl alcohol) based hybrid membranes with dispersed nanochannels for pervaporation application

Yang

Xie

Doherty

et al. 2020

Journal of Membrane Science

View full text Add to dashboard Cite

“…For NiCo-LDH-150, the crystal plane diffraction peaks at 11.4°, 22.8°, 34.1°, and 60.5° can be classified as (003), (006), (012), and (110) planes according to the LDH standard card (JCPDS 40-0216). The strong diffraction peak at 26.1° in the XRD pattern can be assigned to the (002) facet of CNTs [ 38 ]. As expected, all of the XRD patterns for NiCo-LDH@CNTs- z % samples match well with those reflections of NiCo-LDH-150 and CNTs, proving that NiCo-LDH was successfully grown on CNTs through the ZIF template.…”

Section: Resultsmentioning

confidence: 99%

ZIF-67-Derived NiCo-Layered Double Hydroxide@Carbon Nanotube Architectures with Hollow Nanocage Structures as Enhanced Electrocatalysts for Ethanol Oxidation Reaction

et al. 2023

Molecules

View full text Add to dashboard Cite

The rational design of efficient Earth-abundant electrocatalysts for the ethanol oxidation reaction (EOR) is the key to developing direct ethanol fuel cells (DEFCs). Among these, the smart structure is highly demanded for highly efficient and stable non-precious electrocatalysts based on transition metals (such as Ni, Co, and Fe). In this work, high-performance NiCo-layered double hydroxide@carbon nanotube (NiCo-LDH@CNT) architectures with hollow nanocage structures as electrocatalysts for EOR were prepared via sacrificial ZIF-67 templates on CNTs. Comprehensive structural characterizations revealed that the as-synthesized NiCo-LDH@CNTs architecture displayed 3D hollow nanocages of NiCo-LDH and abundant interfacial structure between NiCo-LDH and CNTs, which could not only completely expose active sites by increasing the surface area but also facilitate the electron transfer during the electrocatalytic process, thus, improving EOR activity. Benefiting from the 3D hollow nanocages and interfacial structure fabricated by the sacrificial ZIF-67-templated method, the NiCo-LDH@CNTs-2.5% architecture exhibited enhanced electrocatalytic activity for ethanol oxidation compared to single-component NiCo-LDH, where the peak current density was 11.5 mA·cm-2, and the jf/jb value representing the resistance to catalyst poisoning was 1.72 in an alkaline environment. These results provide a new perspective on the fabrication of non-precious metal electrocatalysts for EOR in DEFCs.

show abstract

Acid-treated carbon nanotubes and their effects on mortar strength

Cited by 32 publications

References 21 publications

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Understanding the transport enhancement of poly (vinyl alcohol) based hybrid membranes with dispersed nanochannels for pervaporation application

ZIF-67-Derived NiCo-Layered Double Hydroxide@Carbon Nanotube Architectures with Hollow Nanocage Structures as Enhanced Electrocatalysts for Ethanol Oxidation Reaction

Contact Info

Product

Resources

About