Evolution towards the utilisation of functionalised carbon nanotubes as a new generation catalyst support in biodiesel production: an overview

Abstract

The conventional heterogeneous catalysts involved in biodiesel production include mixed metal oxides, alkaline metal oxides, ion-exchange resins, sulfated oxides and immobilised enzymes. Heterogeneous catalysis has emerged as the preferred alternative for biodiesel production because the products are easy to separate, the catalysts are reusable, and the process is environmentally friendly. However, this method suffers from limitations, such as mass transfer problems, high cost and low catalyst stability, that diminish its economic feasibility and low environmental impact on the entire biodiesel process. Carbon nanotubes (CNTs) appear to be a promising catalyst support for biodiesel production due to their ability to overcome the limitations faced by conventional heterogeneous catalysts. Thus, the aim of this paper is to present the current application of functionalised CNTs as catalyst support in biodiesel production, discussing issues such as the limitations encountered by conventional heterogeneous catalysts, the advantages offered by functionalised CNTs and possible methods to functionalise CNTs to serve as catalyst support in biodiesel production. In addition, the reaction parameters required for the transesterification/esterification reaction using functionalised CNTs will be discussed, including the catalyst's life time and regeneration. The challenges and future outlook on the use of functionalised CNTs in the biodiesel industry are also presented. Based on the findings presented in this review, functionalised CNTs have the potential to be a breakthrough technology in the biodiesel industry.

Enzyme Immobilized on Nanoporous Carbon Derived from Metal–Organic Framework: A New Support for Biodiesel Synthesis

“…These results are also comparable or even better than those of other supportsf or enzyme catalysts, such as SBA-15, zeolites, or polymers (Tables S2 and S3). For instance, the disordered micropores of AC contributed adequately in terms of the surface area but were limited to the adsorptiono fs mall molecules, at the same time hindering the mass-transfer kinetics for the reactants (soybean oil and ethanol) [29] despite high adsorption efficiency( ca. AC, SWCNTs, and cMIL-100(Al) have similar pore-size distributions (in the range of 2-18 nm), as shown in Ta ble S4 and Figure S16.…”

“…However,t he catalytic efficiency is mainly pore-morphologyd ependent ( Figure S17 a). For instance, the disordered micropores of AC contributed adequately in terms of the surface area but were limited to the adsorptiono fs mall molecules, at the same time hindering the mass-transfer kinetics for the reactants (soybean oil and ethanol) [29] despite high adsorption efficiency( ca. 33.4 %).…”

One-dimensional nitrogen-containing carbon nanostructures

“…The major focus of research has been the preparation, characterization, processing and application of 1-D NCNSs (Fig. 1) [17,[20][21][22][23][24][25][26][27][28][29][30][31][32].…”

Applications of Low-Temperature Plasmas

“…Heterogeneous catalysis has a rich history of facilitating energy efficient selective molecular transformations and contributes to 90 % of chemical manufacturing processes and to more than 20 % of all industrial products (Shuit et al 2013). In a post-petroleum era, catalysis will be central to overcoming the engineering and scientific barriers to economically feasible routes to alternative source of both energy and chemicals, notably bio-derived and solar-mediated via artificial photosynthesis.…”