Solid Acid Catalysts for Biodiesel Production

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Biomass Catalysis".

Deadline for manuscript submissions: closed (31 January 2022) | Viewed by 31043

Special Issue Editors


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Guest Editor
School of Chemical and Process Engineering, University of Leeds, West Yorkshire, Leeds LS2 9JT, UK
Interests: particle characterization; powder flow; particulate solid processing and manufacturing; distinct element method (DEM) coupled with computational fluid dynamics (CFD)
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Guest Editor
School of Chemical and Process Engineering, University of Leeds, West Yorkshire, Leeds LS2 9JT, UK
Interests: catalysis; particle science; nanomaterials; additive manufacturing; green chemistry; wastewater purification and desalination

Special Issue Information

Dear Colleagues,

In view of ever-increasing global energy demands and our commitments to reduce greenhouse emissions, the exploitation of renewable energy recourses has been attracting significant attention. Biofuels are in particular promising sources of low carbon energy which could potentially replace a good majority of fossil fuels. Nevertheless, food security and production cost implications are the major challenges for the commercialisation in this field. While many feedstock sources could have potential for low carbon fuel productions, used and non-edible based feedstocks offer low cost options to overcome the abovementioned challengers. For instance, an enormous amount of waste cooking oil is produced worldwide which could be used as a cheap source of feedstock for the production of biodiesel. However, it should be noted that high level of free fatty acids, moisture and other impurities hinder the transesterification reaction of triglycerides for the biodiesel production in conventional processes using homogenous catalysts. Extensive studies of heterogeneous catalysis for this purpose revealed that care must be taken with the design of active sites and pore architectures.

The use of solid acid catalysts and process intensification are the core themes in this field, and there has been significant effort in the past few decades to design suitable solid acid catalysts which are (i) tolerant to impurities, (ii) highly active (superacidity), (iii) highly stable (robust), (iv) able to facilitate low temperature reactions and (v) easily separable and reusable for continuous operations. This Special Issue is aimed at collating the state-of-the-art of the progress in this field from world-leading academics as well as industrial scientists and researchers.

Prof. Dr. Ali Hassanpour
Dr. Jabbar Gardy
Guest Editors

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Keywords

  • waste cooking oil
  • biodiesel
  • free fatty acids
  • non-edible biomass
  • fatty acid methyl ester
  • solid acid catalysts
  • heterogeneous catalysts
  • transesterification
  • esterification

Published Papers (4 papers)

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Research

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19 pages, 4222 KiB  
Article
Modelling and Optimisation of the Sol-Gel Conditions for Synthesis of Semi-Hexagonal Titania-Based Nano-Catalyst for Esterification Reaction
by Hamed Nayebzadeh, Abbas Rohani, Aliakbar Sistani, Ali Hassanpour and Jabbar Gardy
Catalysts 2022, 12(2), 239; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12020239 - 20 Feb 2022
Cited by 1 | Viewed by 2002
Abstract
Design and fabrication of a catalyst with the highest activity can be achieved by optimising the synthesis conditions. In this study, the sol-gel synthesis conditions of citric acid concentration, gelling temperature, complex time, and calcination temperature were studied for the preparation of a [...] Read more.
Design and fabrication of a catalyst with the highest activity can be achieved by optimising the synthesis conditions. In this study, the sol-gel synthesis conditions of citric acid concentration, gelling temperature, complex time, and calcination temperature were studied for the preparation of a novel semi-hexagonal calcium/titania-zirconia nano-catalyst used in the esterification reaction. After synthesis of around 24 samples at various conditions, their activity was tested in the esterification reaction and the results were analysed by multi-layer perceptron (MLP) and support vector machine (SVM) models. Both models predicted the actual data with high coefficients of determination, and indicated that the calcination temperature has the most influence on the activity of the prepared semi-hexagonal calcium/titania-zirconia nano-catalyst for the esterification reaction. Moreover, the genetic algorithm (GA) was utilised for optimising the preparation conditions based on the SVM model, due to its higher generalisation capability for prediction. The prepared nano-catalysts under the optimum conditions of 1.42 acid ratio, gelling temperature of 72 °C, complex time of 2.65 h, and calcination temperature of 487 °C showed good crystalline structure and metal–metal and metal–oxygen cation bonding. Finally, the fabricated catalyst had a high surface area (276.5 m2/g) with 3.5 nm pore diameter and almost uniform particle size (80–110 nm) distribution, leading to a high conversion of 97.6% in the esterification reaction, with good catalytic stability up to five times. Full article
(This article belongs to the Special Issue Solid Acid Catalysts for Biodiesel Production)
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16 pages, 2695 KiB  
Article
Truncated Prosequence of Rhizopus oryzae Lipase: Key Factor for Production Improvement and Biocatalyst Stability
by Josu López-Fernández, Juan J. Barrero, M. Dolors Benaiges and Francisco Valero
Catalysts 2019, 9(11), 961; https://0-doi-org.brum.beds.ac.uk/10.3390/catal9110961 - 15 Nov 2019
Cited by 10 | Viewed by 4165
Abstract
Recombinant Rhizopus oryzae lipase (mature sequence, rROL) was modified by adding to its N-terminal 28 additional amino acids from the C-terminal of the prosequence (proROL) to obtain a biocatalyst more suitable for the biodiesel industry. Both enzymes were expressed in Pichia pastoris and [...] Read more.
Recombinant Rhizopus oryzae lipase (mature sequence, rROL) was modified by adding to its N-terminal 28 additional amino acids from the C-terminal of the prosequence (proROL) to obtain a biocatalyst more suitable for the biodiesel industry. Both enzymes were expressed in Pichia pastoris and compared in terms of production bioprocess parameters, biochemical properties, and stability. Growth kinetics, production, and yields were better for proROL harboring strain than rROL one in batch cultures. When different fed-batch strategies were applied, lipase production and volumetric productivity of proROL-strain were always higher (5.4 and 4.4-fold, respectively) in the best case. rROL and proROL enzymatic activity was dependent on ionic strength and peaked in 200 mM Tris-HCl buffer. The optimum temperature and pH for rROL were influenced by ionic strength, but those for proROL were not. The presence of these amino acids altered lipase substrate specificity and increased proROL stability when different temperature, pH, and methanol/ethanol concentrations were employed. The 28 amino acids were found to be preferably removed by proteases, leading to the transformation of proROL into rROL. Nevertheless, the truncated prosequence enhanced Rhizopus oryzae lipase heterologous production and stability, making it more appropriate as industrial biocatalyst. Full article
(This article belongs to the Special Issue Solid Acid Catalysts for Biodiesel Production)
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Review

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23 pages, 41826 KiB  
Review
The Role of Sulfated Materials for Biodiesel Production from Cheap Raw Materials
by Brandon Lowe, Jabbar Gardy and Ali Hassanpour
Catalysts 2022, 12(2), 223; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12020223 - 16 Feb 2022
Cited by 11 | Viewed by 3272
Abstract
There is an urgent need to reduce global greenhouse gas emissions, yet to date the decarbonization of the transportation industry has been slow and of particular difficulty. While fossil fuel replacements such as biodiesel may aid the transition to a less polluting society, [...] Read more.
There is an urgent need to reduce global greenhouse gas emissions, yet to date the decarbonization of the transportation industry has been slow and of particular difficulty. While fossil fuel replacements such as biodiesel may aid the transition to a less polluting society, production at the industrial scales required is currently heavily dependent on chemical catalysis. Conventional two-step homogenous routes require the challenging separation of catalyst from the obtained product; however, heterogenous solid catalysts bring new considerations such as material stability, surface area, porosity, deactivation effects, and reduced reactivities under mild conditions. Nanomaterials present an attractive solution, offering the high reactivity of homogenous catalysts without complex recyclability issues. Slightly less reactive, acidic sulfated nanomaterials may also demonstrate greater stability to feedstock impurity, extending lifetime and improved versatility to a range of starting feeds. There remains, however, much work to be done in demonstrating the full-scale feasibility of such catalysts. This review explores recent developments over time in acidic sulfated nanocatalysis for biodiesel production, with particular focus on metal oxides, magnetic nanoparticles, silica-supported nanomaterials, and acidic carbon nanocatalysts. Included are various summaries of current progress in the literature, as well as recommendations for future research. Full article
(This article belongs to the Special Issue Solid Acid Catalysts for Biodiesel Production)
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20 pages, 1889 KiB  
Review
Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides
by Katja Vasić, Gordana Hojnik Podrepšek, Željko Knez and Maja Leitgeb
Catalysts 2020, 10(2), 237; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10020237 - 17 Feb 2020
Cited by 76 | Viewed by 20338
Abstract
The development of solid acid catalysts, especially based on metal oxides and different magnetic nanoparticles, gained much awareness recently as a result of the development of different nano-based materials. Solid acid catalysts based on metal oxides are promising for the (trans)esterification reactions of [...] Read more.
The development of solid acid catalysts, especially based on metal oxides and different magnetic nanoparticles, gained much awareness recently as a result of the development of different nano-based materials. Solid acid catalysts based on metal oxides are promising for the (trans)esterification reactions of different oils and waste materials for biodiesel production. This review gives a brief overview of recent developments in various solid acid catalysts based on different metal oxides, such as zirconia, zinc, titanium, iron, tungsten, and magnetic materials, where the catalysts are optimized for various reaction parameters, such as the amount of catalyst, molar ratio of oil to alcohol, reaction time, and temperature. Furthermore, yields and conversions for biodiesel production are compared. Such metal-oxide-based solid acid catalysts provide more sustainable, green, and easy-separation synthesis routes with high catalytic activity and reusability than traditionally used catalysts. Full article
(This article belongs to the Special Issue Solid Acid Catalysts for Biodiesel Production)
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