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14 pages, 2474 KiB

Open AccessArticle

Lipozyme^® TL IM Biocatalyst for Castor Oil FAME and Triacetin Production by Interesterification: Activity, Stability, and Kinetics

by Alba Gómez-Calvo, M. Esther Gallardo and Miguel Ladero

Catalysts 2022, 12(12), 1673; https://doi.org/10.3390/catal12121673 - 19 Dec 2022

Cited by 3 | Viewed by 2014

Abstract

Global climate change and present geopolitical tensions call for novel, renewable, and, ideally, sustainable resources and processes that, in the end, will be integrated in the natural cycles of carbon and water, progressively replacing non-renewable feedstocks. In this context, the production of biofuels [...] Read more.

Global climate change and present geopolitical tensions call for novel, renewable, and, ideally, sustainable resources and processes that, in the end, will be integrated in the natural cycles of carbon and water, progressively replacing non-renewable feedstocks. In this context, the production of biofuels and, in consequence, of biodiesel plays a notable role. This work is focused on the production of fatty acid methyl esters (FAME) from castor oil, an abundant non-edible oil, using a sustainable technology approach based on industrial lipases and methyl acetate as a methylating reagent to reduce biocatalyst inactivation. We have selected a stable industrial enzyme preparation to determine its suitability for FAME production: Lipozyme^® TL IM (an inexpensive lipase from Thermomyces lanuginosus immobilized by agglomeration in silica gel). Several operational variables affecting the enzyme activity have been studied: methanol excess (6:1 to 13:1), temperature (from 40 to 60 °C), and enzyme concentration (10 and 30% w/w). At all temperatures and reagent ratios, we have also tested the enzyme stability for six cycles, showing its low to negligible inactivation under operational conditions. Finally, a novel multivariable kinetic model has been proposed and fitted to experimental data obtained in a wide experimental range for the first time, showing that direct and reverse in-series reactions are present. We have estimated the values of the kinetic constants and their standard errors, and goodness-of-fit parameters, observing that the kinetic model fitted very reasonably to all retrieved experimental data at the same time. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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25 pages, 2454 KiB

Open AccessFeature PaperArticle

Synthesis of Ibuprofen Monoglyceride Using Novozym^®435: Biocatalyst Activation and Stabilization in Multiphasic Systems

by Marianela Ravelo, M. Esther Gallardo, Miguel Ladero and Felix Garcia-Ochoa

Catalysts 2022, 12(12), 1531; https://doi.org/10.3390/catal12121531 - 28 Nov 2022

Cited by 4 | Viewed by 1984

Abstract

This work was focused on the enzymatic esterification of glycerol and ibuprofen at high concentrations in two triphasic systems composed of toluene+ibuprofene (apolar) and glycerol or glycerol–water (polar) liquid phases, and a solid phase with the industrial immobilized lipase B from Candida antarctica [...] Read more.

This work was focused on the enzymatic esterification of glycerol and ibuprofen at high concentrations in two triphasic systems composed of toluene+ibuprofene (apolar) and glycerol or glycerol–water (polar) liquid phases, and a solid phase with the industrial immobilized lipase B from Candida antarctica named Novozym^®435 (N435) acting as the biocatalyst. Based on a preliminary study, the concentration of the enzyme was set at 30 g·L⁻¹ and the stirring speed at 720 r.p.m to reduce external mass transfer limitations. To obtain more information on the reaction system, it was conducted at a wide range of temperatures (50 to 80 °C) and initial concentrations of ibuprofen (20–100 g·L⁻¹, that is, 97 to 483 mM). Under these experimental conditions, the external mass transfer, according to the Mears criterion (Me = 1.47–3.33·10⁻⁴ << 0.15), was fast, presenting no limitation to the system productivity, regardless of the presence of water and from 50 to 80 °C. Considering that the enzyme is immobilized in a porous ion-exchange resin, limitations due to internal mass transfer can exist, depending on the values of the effectiveness factor (η). It varied from 0.14 to 0.23 at 50 to 80 °C and 0.32–1 mm particle diameter range in the absence of water, and in the same ranges, from 0.40 to 0.66 in the presence of 7.4% w/w water in the glycerol phase. Thus, it is evident that some limitation occurs due to mass transfer inside the pores, while the presence of water in the polar phase increases the productivity 3–4 fold. During the kinetic study, several kinetic models were proposed for both triphasic reacting systems, with and without first-order biocatalyst deactivation, and their fit to all relevant experimental data led to the observation that the best kinetic model was a reversible hyperbolic model with first-order deactivation in the anhydrous reaction system and a similar model, but without deactivation, for the system with added water at zero time. This fact is in sharp contrast to the use of N435 in a water-glycerol monophasic system, where progressive dissolution of ibuprofen in the reacting media, together with a notable enzyme deactivation, is observed. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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20 pages, 3630 KiB

Open AccessArticle

A Theoretical and Experimental Study for Enzymatic Biodiesel Production from Babassu Oil (Orbignya sp.) Using Eversa Lipase

by Jeferson Yves Nunes Holanda Alexandre, Francisco Thálysson Tavares Cavalcante, Lara Matias Freitas, Alyne Prudêncio Castro, Pedro Tavares Borges, Paulo Gonçalves de Sousa Junior, Manoel Nazareno Ribeiro Filho, Ada Amelia Sanders Lopes, Aluisio Marques da Fonseca, Diego Lomonaco, Maria Alexsandra de Sousa Rios and José Cleiton Sousa dos Santos

Catalysts 2022, 12(11), 1322; https://doi.org/10.3390/catal12111322 - 27 Oct 2022

Cited by 23 | Viewed by 2508

Abstract

A theoretical and experimental study was carried out on the biocatalytic production of babassu biodiesel through enzymatic hydroesterification. The complete hydrolysis of babassu oil was carried out using a 1:1 mass solution at 40 °C for 4 h using 0.4% of lipase from [...] Read more.

A theoretical and experimental study was carried out on the biocatalytic production of babassu biodiesel through enzymatic hydroesterification. The complete hydrolysis of babassu oil was carried out using a 1:1 mass solution at 40 °C for 4 h using 0.4% of lipase from Thermomyces lanuginosus (TLL). Then, with the use of Eversa^® Transform 2.0 lipase in the esterification step, a statistical design was used, varying the temperature (25–55 °C), the molar ratio between free fatty acids (FFAs) and methanol (1:1 to 1:9), the percentage of biocatalyst (0.1% to 0.9%), and the reaction time (1–5 h) using the Taguchi method. The ideal reaction levels obtained after the statistical treatment were 5 h of reaction at 40 °C at a molar ratio of 1:5 (FFAs/methanol) using 0.9% of the biocatalyst. These optimal conditions were validated by chromatographic analysis; following the EN 14103 standard, the sample showed an ester concentration of 95.76%. A theoretical study was carried out to evaluate the stability of Eversa with FFAs. It was observed in the molecular docking results that the ligands interacted directly with the catalytic site. Through molecular dynamics studies, it was verified that there were no significant conformational changes in the studied complexes. Theoretical and experimental results show the feasibility of this process. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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27 pages, 10548 KiB

Open AccessArticle

Niobium and Zirconium Phosphates as Green and Water-Tolerant Catalysts for the Acid-Catalyzed Valorization of Bio-Based Chemicals and Real Lignocellulosic Biomasses

by Claudia Antonetti, Anna Maria Raspolli Galletti, Domenico Licursi, Sara Fulignati, Nicola Di Fidio, Federica Zanetti, Andrea Monti, Tommaso Tabanelli and Fabrizio Cavani

Catalysts 2022, 12(10), 1189; https://doi.org/10.3390/catal12101189 - 7 Oct 2022

Cited by 5 | Viewed by 2604

Abstract

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose [...] Read more.

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose and cellulose was preliminarily investigated. Then, a wide plethora of raw lignocellulosic biomasses, such as conifer wood sawdust, Jerusalem artichoke, sorghum, miscanthus, foxtail millet, hemp and Arundo donax, were valorized towards the production of water-soluble saccharides, 5-hydroxymethylfurfural (HMF), levulinic acid (LA) and furfural. The different catalytic performances of the two phosphates were explained on the basis of their acid features, total acidity, Brønsted/Lewis acid sites ratio and strength. Moreover, a better insight into their structure–acidity relationship was proposed. The different acid properties of niobium and zirconium phosphates enabled us to tune the reaction towards target products, achieving from glucose maximum HMF and LA yields of 24.4 and 24.0 mol%, respectively. Remarkably, when real Jerusalem artichoke biomass was adopted in the presence of niobium and zirconium phosphate, maximum yields of furanic compounds and cellulose-derived sugars of 12.7 and 50.0 mol%, respectively, were obtained, after only 1 h of reaction. The synthesized hydrolysates, which were found to be rich in C5 and C6 carbohydrates, can be better exploited for the cascade production of more added-value bio-products. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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15 pages, 1757 KiB

Open AccessArticle

Evaluation of Porous Honeycomb-Shaped CuO/CeO₂ Catalyst in Vapour Phase Glycerol Reforming for Sustainable Hydrogen Production

by Adrian Chun Minh Loy, Shanthi Priya Samudrala and Sankar Bhattacharya

Catalysts 2022, 12(9), 941; https://doi.org/10.3390/catal12090941 - 24 Aug 2022

Cited by 2 | Viewed by 1905

Abstract

This study presented an optimisation study of two-stage vapour-phase catalytic glycerol reforming (VPCGR) using response surface methodology (RSM) with a central composite experimental design (CCD) approach. Characterisation through Brunauer–Emmett–Teller analysis (BET), small-angle X-ray scattering (SAXS), scanning electron microscopy coupled with energy dispersive X-ray [...] Read more.

This study presented an optimisation study of two-stage vapour-phase catalytic glycerol reforming (VPCGR) using response surface methodology (RSM) with a central composite experimental design (CCD) approach. Characterisation through Brunauer–Emmett–Teller analysis (BET), small-angle X-ray scattering (SAXS), scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX), atomic force microscopy (AFM) and particle X-ray diffraction (PXRD) were carried out to understand the physiochemical activity of the honeycomb morphology CuO/CeO₂ catalyst. Notably, in this study, we achieved the desired result of glycerol conversion (94%) and H₂ production (81 vol.%) under the reaction condition of Cu species loading (10 wt.%), reaction temperature (823 K), WHSV (2 h⁻¹) and glycerol concentration (15 wt.%). From the RSM analysis, an optimum predicted model for VPCGR was obtained and further integrated into Microsoft Excel and Aspen Plus to perform an energy analysis of the VPCGR plant at a scale of 100 kg h⁻¹ of glycerol feed. As a whole, this study aimed to provide an overview of the technical operation and energy aspect for a sustainable frontier in glycerol reforming. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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19 pages, 3467 KiB

Open AccessFeature PaperArticle

One-Step Biodiesel Production from Waste Cooking Oil Using CaO Promoted Activated Carbon Catalyst from Prunus persica Seeds

by Ayesha Hameed, Salman Raza Naqvi, Umair Sikandar and Wei-Hsin Chen

Catalysts 2022, 12(6), 592; https://doi.org/10.3390/catal12060592 - 30 May 2022

Cited by 20 | Viewed by 4346

Abstract

In recent years, the scope for replacing fossil fuels has been appealing to the world, owing to limited conventional fuels, crude oil price volatility, and greenhouse gas emission concerns. In this regard, this article demonstrates the preparation of a novel solid base catalyst [...] Read more.

In recent years, the scope for replacing fossil fuels has been appealing to the world, owing to limited conventional fuels, crude oil price volatility, and greenhouse gas emission concerns. In this regard, this article demonstrates the preparation of a novel solid base catalyst for the transesterification of waste cooking oil. A calcium-loaded activated carbon catalyst was prepared through pyrolysis of peach shell followed by chemical activation with KOH and then calcium loading through the wet impregnation method. The prepared catalyst showed the best performance with 20% calcium loading and 650 °C of calcination temperature. The catalyst’s physicochemical, structural, and textural properties were examined using XRD, FTIR, SEM, EDX, and BET analysis. The catalyst showed a maximum yield of 96% at optimized conditions, i.e., 65 °C temperature, oil to methanol ratio 1:8, 5 wt% catalyst concentration, and a 160 min reaction time. Additionally, it illustrated high recyclability up to 10 cycles with negligible leaching of Ca⁺² ions. The high activity of the catalyst was due to the presence of calcium ions on the activated carbon support. Physio–chemical properties and GC-MS analysis of prepared biodiesel determined that all attributes were within the biodiesel standard tolerances set by ASTM D6751 and EN 14214. Therefore, all the innovations mentioned above concluded that catalyst generated from peach shell biochar is a promising candidate for biodiesel production, ultimately resulting in solid and liquid waste management. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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15 pages, 1737 KiB

Open AccessFeature PaperArticle

Thermal Behavior of Heavy Oil Catalytic Pyrolysis and Aquathermolysis

by Mohammed A. Khelkhal, Semen E. Lapuk, Aleksey V. Buzyurov, Nikita E. Ignashev, Elvira I. Shmeleva, Irek I. Mukhamatdinov and Alexey V. Vakhin

Catalysts 2022, 12(4), 449; https://doi.org/10.3390/catal12040449 - 18 Apr 2022

Cited by 32 | Viewed by 2875

Abstract

There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA [...] Read more.

There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA (S: saturates, A: aromatics, R: resins, A: asphaltenes) analysis has shown a significant increase in light hydrocarbon content during aquathermolysis. Moreover, the elemental analysis has indicated an increase in C and H content by almost 4% and 6%, respectively, with a significant decrease in S and O content by up to 23% in the presence of iron tallates. These results have been further confirmed by infrared spectrometry. The obtained IR data indicated that asphaltene and resin compounds transform into light hydrocarbons after aquathermolysis. On another hand, the activation energy of heavy oil pyrolysis decreased in the presence of the utilized catalyst; meanwhile, the reaction rate increased, especially in the temperature range of 200–480 °C, which may validate a significant effect of the used catalyst in real conditions. Moreover, the obtained thermodynamic data showed a decrease in the enthalpy and entropy of activation of oil pyrolysis in the presence of iron tallates. Our results are encouraging in terms of energy consumption, optimization, and process control and should be validated by a larger sample size. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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13 pages, 3064 KiB

Open AccessArticle

Ni-Cu/Al₂O₃ from Layered Double Hydroxides Hydrogenates Furfural to Alcohols

by Abdulaziz Aldureid, Francisco Medina, Gregory S. Patience and Daniel Montané

Catalysts 2022, 12(4), 390; https://doi.org/10.3390/catal12040390 - 31 Mar 2022

Cited by 7 | Viewed by 3091

Abstract

The hydrogenation of furfural is an important process in the synthesis of bio-based chemicals. Copper-based catalysts favor the hydrogenation of furfural to alcohols. Catalytic activity and stability were higher at a Ni-to-Cu atomic ratio of 1:1 and 1.5:0.5 compared to 0.5:1.5. Here, we [...] Read more.

The hydrogenation of furfural is an important process in the synthesis of bio-based chemicals. Copper-based catalysts favor the hydrogenation of furfural to alcohols. Catalytic activity and stability were higher at a Ni-to-Cu atomic ratio of 1:1 and 1.5:0.5 compared to 0.5:1.5. Here, we prepared Ni-Cu/Al₂O₃ hydrogenation catalysts derived from layered double hydroxides (LDHs). Catalysts calcined at 673 K and reduced at 773 K with nominal Ni/Cu atomic ratios y/x = 1.5/0.5, 1/1 and 0.5/1.5 were characterized by XRD, FESEM-EDX, H₂-TPR, XPS, FAA and BET. Their activity was tested at 463 K and in a 0.05 g g⁻¹ furfural solution in ethanol, and the space velocity in a packed-bed reactor (PBR) was 2.85 g_FF g_cat⁻¹ h⁻¹. In a slurry reactor (SSR) at 5 MPa H₂ and a contact time of 4 h, conversion was complete, while it varied from 91 to 99% in the PBR. Tetrahydrofurfuryl alcohol (TFA) was the main product in the SSR, with a selectivity of 32%, 63% and 56% for Ni_0.5Cu_1.5Al₁, Ni₁Cu₁Al₁ and Ni_1.5Cu_0.5Al₁, respectively. The main product in the atmospheric PBR was furfuryl alcohol (FA), with a selectivity of 57% (Ni_0.5Cu_1.5Al₁), 61% (Ni₁Cu₁Al₁) and 58% (Ni_1.5Cu_0.5Al₁). Other products included furan, methylfuran, 1-butanol and 1,2-pentanediol. Ethyl tetrahydrofurfuryl ether and difurfuryl ether were also formed via the nucleophilic addition of furfural with ethanol and furfuryl alcohol. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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13 pages, 679 KiB

Open AccessArticle

Effectiveness of Eggshells as Natural Heterogeneous Catalysts for Transesterification of Rapeseed Oil with Methanol

by Ieva Gaide, Violeta Makareviciene and Egle Sendzikiene

Catalysts 2022, 12(3), 246; https://doi.org/10.3390/catal12030246 - 22 Feb 2022

Cited by 14 | Viewed by 4861

Abstract

Heterogeneous catalysis has an advantage of easy separation of the catalyst after biodiesel is produced. CaO is known to be an efficient heterogeneous catalyst for biodiesel production. Taking into account that CaO is a key component of eggshells, the effectiveness of eggshells as [...] Read more.

Heterogeneous catalysis has an advantage of easy separation of the catalyst after biodiesel is produced. CaO is known to be an efficient heterogeneous catalyst for biodiesel production. Taking into account that CaO is a key component of eggshells, the effectiveness of eggshells as a heterogeneous catalyst for rapeseed oil transesterification with methanol was investigated and optimal conditions of biodiesel production were determined applying RSM methodology. The influence of three independent variables on ester content was analyzed and a quadratic model was created. It was determined that this model is statistically significant. The optimum transesterification conditions when eggshells are used as a heterogeneous catalyst, and the process temperature of 64 °C, were determined as: the methanol-to-oil molar ratio 10.93:1; the catalyst amount 6.80 wt%; the reaction duration 9.48 h. The ester yield of 97.79 wt% was obtained under these conditions. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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13 pages, 2863 KiB

Open AccessArticle

Bacterial Competition for the Anode Colonization under Different External Resistances in Microbial Fuel Cells

by Alexiane Godain, Naoufel Haddour, Pascal Fongarland and Timothy M. Vogel

Catalysts 2022, 12(2), 176; https://doi.org/10.3390/catal12020176 - 29 Jan 2022

Cited by 16 | Viewed by 2932

Abstract

This study investigated the effect of external resistance (R_ext) on the dynamic evolution of microbial communities in anodic biofilms of single-chamber microbial fuel cells fueled with acetate and inoculated with municipal wastewater. Anodic biofilms developed under different R_ext (0, 330 [...] Read more.

This study investigated the effect of external resistance (R_ext) on the dynamic evolution of microbial communities in anodic biofilms of single-chamber microbial fuel cells fueled with acetate and inoculated with municipal wastewater. Anodic biofilms developed under different R_ext (0, 330 and 1000 ohms, and open circuit condition) were characterized as a function of time during two weeks of growth using 16S rRNA gene sequencing, cyclic voltammetry (CV) and fluorescence microscopy. The results showed a drastic difference in power output of MFCs operated with an open circuit and those operated with R_ext from 0 to 1000 ohms. Two steps during the bacterial community development of the anodic biofilms were identified. During the first four days, nonspecific electroactive bacteria (non-specific EAB), dominated by Pseudomonas, Acinetobacter, and Comamonas, grew fast whatever the value of R_ext. During the second step, specific EAB, dominated by Geobacter and Desulfuromonas, took over and increased over time, except in open circuit MFCs. The relative abundance of specific EAB decreased with increasing R_ext. In addition, the richness and diversity of the microbial community in the anodic biofilms decreased with decreasing R_ext. These results help one to understand the bacterial competition during biofilm formation and suggest that an inhibition of the attachment of non-specific electroactive bacteria to the anode surface during the first step of biofilm formation should improve electricity production. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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17 pages, 3361 KiB

Open AccessArticle

Transesterification of Soybean Oil through Different Homogeneous Catalysts: Kinetic Study

by José María Encinar, Juan Félix González, Gloria Martínez and Sergio Nogales-Delgado

Catalysts 2022, 12(2), 146; https://doi.org/10.3390/catal12020146 - 24 Jan 2022

Cited by 9 | Viewed by 4199

Abstract

The search for alternatives to fossil fuels has been widely covered, especially in the past two decades. Thus, the role of biodiesel has been important, and its implementation in biorefineries seems feasible due to the sustainability of the process. This way, the knowledge [...] Read more.

The search for alternatives to fossil fuels has been widely covered, especially in the past two decades. Thus, the role of biodiesel has been important, and its implementation in biorefineries seems feasible due to the sustainability of the process. This way, the knowledge of kinetics is vital to design industrial facilities and to compare the efficiency of catalysts (both typical and innovative ones) during transesterification or other similar processes taking place in a biorefinery, such as biolubricant production through transesterification with superior alcohols. In this work, a thorough kinetic study of homogeneous catalysts (base catalysts, such as KOH, NaOH or CH₃OK, and acid catalysts (H₂SO₄, H₃PO₄ and p-toluenesulfonic acid, CH₃C₆H₄SO₃H)) applied to the transesterification of soybean oil was carried out to provide extensive kinetic data about this process. As a conclusion, a pseudo-first-order reaction mechanism was applied in all cases, with activation energies of 65.5–66 and 92.3 kJ·mol⁻¹ for KOH and CH₃C₆H₄SO₃H, respectively, proving the higher activation energy for acid catalysis compared to base catalysis. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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11 pages, 3458 KiB

Open AccessArticle

Comprehensive Comparison of Hetero-Homogeneous Catalysts for Fatty Acid Methyl Ester Production from Non-Edible Jatropha curcas Oil

by Khawer Khan, Noaman Ul-Haq, Wajeeh Ur Rahman, Muzaffar Ali, Umer Rashid, Anwar Ul-Haq, Farrukh Jamil, Ashfaq Ahmed, Faisal Ahmed, Bryan R. Moser and Ali Alsalme

Catalysts 2021, 11(12), 1420; https://doi.org/10.3390/catal11121420 - 23 Nov 2021

Cited by 9 | Viewed by 2544

Abstract

The synthesis of biodiesel from Jatropha curcas by transesterification is kinetically controlled. It depends on the molar ratio, reaction time, and temperature, as well as the catalyst nature and quantity. The aim of this study was to explore the transesterification of low-cost, inedible [...] Read more.

The synthesis of biodiesel from Jatropha curcas by transesterification is kinetically controlled. It depends on the molar ratio, reaction time, and temperature, as well as the catalyst nature and quantity. The aim of this study was to explore the transesterification of low-cost, inedible J. curcas seed oil utilizing both homogenous (potassium hydroxide; KOH) and heterogenous (calcium oxide; CaO) catalysis. In this effort, two steps were used. First, free fatty acids in J. curcas oil were reduced from 12.4 to less than 1 wt.% with sulfuric acid-catalyzed pretreatment. Transesterification subsequently converted the oil to biodiesel. The yield of fatty acid methyl esters was optimized by varying the reaction time, catalyst load, and methanol-to-oil molar ratio. A maximum yield of 96% was obtained from CaO nanoparticles at a reaction time of 5.5 h with 4 wt.% of the catalyst and an 18:1 methanol-to-oil molar ratio. The optimum conditions for KOH were a molar ratio of methanol to oil of 9:1, 5 wt.% of the catalyst, and a reaction time of 3.5 h, and this returned a yield of 92%. The fuel properties of the optimized biodiesel were within the limits specified in ASTM D6751, the American biodiesel standard. In addition, the 5% blends in petroleum diesel were within the ranges prescribed in ASTM D975, the American diesel fuel standard. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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15 pages, 5292 KiB

Open AccessFeature PaperArticle

The Promotor and Poison Effects of the Inorganic Elements of Kraft Lignin during Hydrotreatment over NiMoS Catalyst

by Joby Sebastian, You Wayne Cheah, Diana Bernin, Derek Creaser and Louise Olsson

Catalysts 2021, 11(8), 874; https://doi.org/10.3390/catal11080874 - 21 Jul 2021

Cited by 10 | Viewed by 2846

Abstract

One-pot deoxygenation of kraft lignin to aromatics and hydrocarbons of fuel-range quality is a promising way to improve its added value. Since most of the commercially resourced kraft lignins are impure (Na, S, K, Ca, etc., present as impurities), the effect of these [...] Read more.

One-pot deoxygenation of kraft lignin to aromatics and hydrocarbons of fuel-range quality is a promising way to improve its added value. Since most of the commercially resourced kraft lignins are impure (Na, S, K, Ca, etc., present as impurities), the effect of these impurities on the deoxygenation activity of a catalyst is critical and was scrutinized in this study using a NiMoS/Al₂O₃ catalyst. The removal of impurities from the lignin indicated that they obstructed the depolymerization. In addition, they deposited on the catalyst during depolymerization, of which the major element was the alkali metal Na which existed in kraft lignin as Na₂S and single-site ionic Na⁺. Conditional experiments have shown that at lower loadings of impurities on the catalyst, their promotor effect was prevalent, and at their higher loadings, a poisoning effect. The number of moles of impurities, their strength, and the synergism among the impurity elements on the catalyst were the major critical factors responsible for the catalyst’s deactivation. The promotor effects of deposited impurities on the catalyst, however, could counteract the negative effects of impurities on the depolymerization. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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Review

Jump to: Research

17 pages, 1734 KiB

Open AccessReview

Advances and Challenges in Biocatalysts Application for High Solid-Loading of Biomass for 2nd Generation Bio-Ethanol Production

by Reeta Rani Singhania, Anil Kumar Patel, Tirath Raj, Mei-Ling Tsai, Chiu-Wen Chen and Cheng-Di Dong

Catalysts 2022, 12(6), 615; https://doi.org/10.3390/catal12060615 - 3 Jun 2022

Cited by 22 | Viewed by 3669

Abstract

Growth in population and thereby increased industrialization to meet its requirement, has elevated significantly the demand for energy resources. Depletion of fossil fuel and environmental sustainability issues encouraged the exploration of alternative renewable eco-friendly fuel resources. Among major alternative fuels, bio-ethanol produced from [...] Read more.

Growth in population and thereby increased industrialization to meet its requirement, has elevated significantly the demand for energy resources. Depletion of fossil fuel and environmental sustainability issues encouraged the exploration of alternative renewable eco-friendly fuel resources. Among major alternative fuels, bio-ethanol produced from lignocellulosic biomass is the most popular one. Lignocellulosic biomass is the most abundant renewable resource which is ubiquitous on our planet. All the plant biomass is lignocellulosic which is composed of cellulose, hemicellulose and lignin, intricately linked to each other. Filamentous fungi are known to secrete a plethora of biomass hydrolyzing enzymes. Mostly these enzymes are inducible, hence the fungi secrete them economically which causes challenges in their hyperproduction. Biomass’s complicated structure also throws challenges for which pre-treatments of biomass are necessary to make the biomass amorphous to be accessible for the enzymes to act on it. The enzymatic hydrolysis of biomass is the most sustainable way for fermentable sugar generation to convert into ethanol. To have sufficient ethanol concentration in the broth for efficient distillation, high solid loading >20% of biomass is desirable and is the crux of the whole technology. High solid loading offers several benefits including a high concentration of sugars in broth, low equipment sizing, saving cost on infrastructure, etc. Along with the benefits, several challenges also emerged simultaneously, like issues of mass transfer, low reaction rate due to water constrains in, high inhibitor concentration, non-productive binding of enzyme lignin, etc. This article will give an insight into the challenges for cellulase action on cellulosic biomass at a high solid loading of biomass and its probable solutions. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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28 pages, 438 KiB

Open AccessFeature PaperReview

Bio-Derived Catalysts: A Current Trend of Catalysts Used in Biodiesel Production

by Hoang Chinh Nguyen, My-Linh Nguyen, Chia-Hung Su, Hwai Chyuan Ong, Horng-Yi Juan and Shao-Jung Wu

Catalysts 2021, 11(7), 812; https://doi.org/10.3390/catal11070812 - 1 Jul 2021

Cited by 32 | Viewed by 4786

Abstract

Biodiesel is a promising alternative to fossil fuels and mainly produced from oils/fat through the (trans)esterification process. To enhance the reaction efficiency and simplify the production process, various catalysts have been introduced for biodiesel synthesis. Recently, the use of bio-derived catalysts has attracted [...] Read more.

Biodiesel is a promising alternative to fossil fuels and mainly produced from oils/fat through the (trans)esterification process. To enhance the reaction efficiency and simplify the production process, various catalysts have been introduced for biodiesel synthesis. Recently, the use of bio-derived catalysts has attracted more interest due to their high catalytic activity and ecofriendly properties. These catalysts include alkali catalysts, acid catalysts, and enzymes (biocatalysts), which are (bio)synthesized from various natural sources. This review summarizes the latest findings on these bio-derived catalysts, as well as their source and catalytic activity. The advantages and disadvantages of these catalysts are also discussed. These bio-based catalysts show a promising future and can be further used as a renewable catalyst for sustainable biodiesel production. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

26 pages, 2161 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Progress on Modified Calcium Oxide Derived Waste-Shell Catalysts for Biodiesel Production

by Hui Khim Ooi, Xin Ning Koh, Hwai Chyuan Ong, Hwei Voon Lee, Mohd Sufri Mastuli, Yun Hin Taufiq-Yap, Fahad A. Alharthi, Abdulaziz Ali Alghamdi and Nurul Asikin Mijan

Catalysts 2021, 11(2), 194; https://doi.org/10.3390/catal11020194 - 2 Feb 2021

Cited by 29 | Viewed by 7009

Abstract

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous [...] Read more.

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous catalyst at an economical price has been studied widely for biodiesel production. It was noted that various types of natural waste shell are a potential calcium resource for generation of bio-based CaO, with comparable chemical characteristics, that greatly enhance the transesterification activity. However, CaO catalyzed transesterification is limited in its stability and studies have shown deterioration of catalytic reactivity when the catalyst is reused for several cycles. For this reason, different approaches are reviewed in the present study, which focuses on modification of waste-shell derived CaO based catalyst with the aim of better transesterification reactivity and high reusability of the catalyst for biodiesel production. The catalyst stability and leaching profile of the modified waste shell derived CaO is discussed. In addition, a critical discussion of the structure, composition of the waste shell, mechanism of CaO catalyzed reaction, recent progress in biodiesel reactor systems and challenges in the industrial sector are also included in this review. Full article

(This article belongs to the Special Issue Catalysts for Biofuel and Bioenergy Production)

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