Challenges of vertically aligned carbon nanotubes production and application

Carbon nanotubes (CNTs) have play a dominant role in nanotechnology research for over 20 years due to their exceptional properties. Different solid catalytic substrates can be used to produce vertically aligned carbon nanotubes (VACNTs); however it is important that this structure can be achieved mainly on conductive substrates. It is important that further application of this structure is preferable on conductive substrates. The conditions under which the catalytic layer is prepared and synthesized also have major impact on the structure and properties of the resulting vertically aligned carbon nanotubes. Environmental protection and green chemistry are highly discussed topics nowadays. Therefore, the development of energyefficient, sustainable technological solutions is also receiving increasing attention in vertically aligned carbon nanotubes research. Thus, the progress in this direction will be briefly review in this work

Production of CNT forests by a simple layer building method on a conductive substrate

The carbon nanotubes (CNTs) play an important role in nanotechnology research today because the CNT have outstanding properties. Many substrates can be used to fabricate carbon nanotube forests (CNT forests); however, it is important that the desired structure is achieved on a conductive substrate, and for these reasons, carbon nanotube forests have been synthetized on a titanium substrate in this research. Environmental protection is highly discussed nowadays, therefore it is necessary to be able to produce CNT forests with less energy investment and costeffectively. For these reasons, we used dip-coating method, which is a simple process and without heat-treatments step to save energy in achieving the forest structure. Therefore, this research uses a dip-coating method to form a catalyst layer on the surface of the substrate, and to investigate the effect of heat-treatment of the substrate to produce CNT forests directly on the titanium substrate

A simple method to build catalyst layers for the synthesis of vertically aligned carbon nanotubes

Nowadays, environmental protection and sustainability are getting more and more attention. Thus, our aim was to develop a cost and energy efficient catalyst layer building method for the synthesis of carbon nanotube forests. A simple spray coating method was used to develop a catalyst layer on the surface of the titanium substrates. Then vertically aligned carbon nanotubes (VACNTs) were synthesized directly on the substrate via catalytic chemical vapor deposition (CCVD) method. During our research, the effect of catalyst layer deposition parameters on the structure of CNTs was investigated and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy

A Simple and Scalable Method for the Preparation of Magnetite/Graphene Oxide Nanocomposites under Mild Conditions

Nanostructured composite dispersions containing magnetic nanoparticles (MNPs) and graphene oxide (GO) lamellae have been prepared by a simple and easily scalable room temperature procedure. We show that, owing to the enormous surface area and negative surface charge developed in aqueous GO suspensions, large amounts of positively charged MNPs can be electrostatically attached to the layered host. This procedure is superior to many previous synthesis pathways because it exploits the charge-regulated adhesion of naked MNPs to GO resulting in the formation of stable and uniform nanocomposite materials in a wide composition range without any preliminary functionalization steps or harsh conditions that may lead to chemical degradation of the graphene-based nanosheets

Development and Investigation of Photoactive WO3 Nanowire-Based Hybrid Membranes

Novel hybrid structures have attracted attention in several instances of scientific research and different technological applications in this decade due to their novel characteristics and wide range of applicability. Hybrid membranes with multiple components (three or more) are also increasingly used in water purification applications, and their ease of handling and reusability make them a promising candidate for the degradation of organic pollutants by photocatalysis. In this study, the preparation and characterization of tungsten trioxide nanowire (WO3 NW)-based hybrid membrane structures are reported. Furthermore, the adsorption properties and photocatalytic efficiency of the as-prepared membranes against methylene blue (MB) organic dye under UV irradiation is also presented. Characterization techniques, such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray powder diffraction (XRD) are performed to study the morphology and surface of the as-prepared hybrid membranes. The removal efficiency of the hybrid membranes against MB is 77% in a 120 min decomposition reaction. The enhanced value can be attributed to the hybrid structure of the membrane that enhances not only the adsorption capability, but also the photocatalytic performance. Based on the results obtained, it is hoped that hybrid membrane technology could be a promising candidate for future photocatalysis-based water treatment applications

Preparation and Photocatalytic Performance of TiO2 Nanowire-Based Self-Supported Hybrid Membranes

Nowadays, the use of hybrid structures and multi-component materials is gaining ground in the fields of environmental protection, water treatment and removal of organic pollutants. This study describes promising, cheap and photoactive self-supported hybrid membranes as a possible solution for wastewater treatment applications. In the course of this research work, the photocatalytic performance of titania nanowire (TiO(2) NW)-based hybrid membranes in the adsorption and degradation of methylene blue (MB) under UV irradiation was investigated. Characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffractometry (XRD) were used to study the morphology and surface of the as-prepared hybrid membranes. We tested the photocatalytic efficiency of the as-prepared membranes in decomposing methylene blue (MB) under UV light irradiation. The hybrid membranes achieved the removal of MB with a degradation efficiency of 90% in 60 min. The high efficiency can be attributed to the presence of binary components in the membrane that enhanced both the adsorption capability and the photocatalytic ability of the membranes. The results obtained suggest that multicomponent hybrid membranes could be promising candidates for future photocatalysis-based water treatment technologies that also take into account the principles of circular economy

Widespread applicability of bacterial cellulose-ZnO-MWCNT hybrid membranes

The novel photoactive membranes have grabbed the attention in the field of environmental protection by employing wastewater treatments and the removal of microorganisms or organic pollutants from wastewater. Here we present a promising self-supported photoactive hybrid membrane for future antimicrobial and water treatment applications. In this study, the efficiency of bacterial cellulose (BC) - zinc oxide (ZnO) - multi walled carbon nanotube (MWCNT) hybrid membranes in the adsorption and photocatalytic degradation of methylene blue (MB) under UV radiation and the removal of Escherichia coli (E. coli) was investigated. It was found that the photocatalytic efficiency is strongly dependent on both the preparation method and the amount of ZnO-MWCNT additives loaded into the hybrid membranes. The characterization of BC-ZnO-MWCNT membranes was done using scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and X-ray micro computed tomography (μCT) to study the morphological and porosity aspect of the prepared-membranes. The promising results of this study could provide a new pathway in the field of photocatalysed-based water treatment technology by the application of hybrid membranes