Production of biodiesel from palm fatty acid distillate using sulfonated-glucose solid acid catalyst: Characterization and optimization

Glycerol-Based Retrievable Heterogeneous Catalysts for Single-Pot Esterification of Palm Fatty Acid Distillate to Biodiesel

The by-product of the previous transesterification, glycerol was utilised as an acid catalyst precursor for biodiesel production. The crude glycerol was treated through the sulfonation method with sulfuric acid and chlorosulfonic acid in a reflux batch reactor giving solid glycerol-SO₃H and glycerol-ClSO₃H, respectively. The synthesised acidic glycerol catalysts were characterised by various analytical techniques such as thermalgravimetric analyser (TGA), infrared spectroscopy, surface properties adsorption-desorption by nitrogen gas, ammonia-temperature programmed desorption (NH₃-TPD), X-ray diffraction spectroscopy (XRD), elemental composition analysis by energy dispersive spectrometer (EDX) and surface micrographic morphologies by field emission electron microscope (FESEM). Both glycerol-SO₃H and glycerol-ClSO₃H samples exhibited mesoporous structures with a low surface area of 8.85 mm²/g and 4.71 mm²/g, respectively, supported by the microscopic image of blockage pores. However, the acidity strength for both catalysts was recorded at 3.43 mmol/g and 3.96 mmol/g, which is sufficient for catalysing PFAD biodiesel at the highest yield. The catalytic esterification was optimised at 96.7% and 98.2% with 3 wt.% of catalyst loading, 18:1 of methanol-PFAD molar ratio, 120 °C, and 4 h of reaction. Catalyst reusability was sustained up to 3 reaction cycles due to catalyst deactivation, and the insight investigation of spent catalysts was also performed.

Managing the hazardous waste cooking oil by conversion into bioenergy through the application of waste-derived green catalysts: A review

Waste cooking oil (WCO) is a hazardous waste generated at staggering values globally. WCO disposal into various ecosystems, including soil and water, could result in severe environmental consequences. On the other hand, mismanagement of this hazardous waste could also be translated into the loss of resources given its energy content. Hence, finding cost-effective and eco-friendly alternative pathways for simultaneous management and valorization of WCO, such as conversion into biodiesel, has been widely sought. Due to its low toxicity, high biodegradability, renewability, and the possibility of direct use in diesel engines, biodiesel is a promising alternative to mineral diesel. However, the conventional homogeneous or heterogeneous catalysts used in the biodiesel production process, i.e., transesterification, are generally toxic and derived from non-renewable resources. Therefore, to boost the sustainability features of the process, the development of catalysts derived from renewable waste-oriented resources is of significant importance. In light of the above, the present work aims to review and critically discuss the hazardous WCO application for bioenergy production. Moreover, various waste-oriented catalysts used to valorize this waste are presented and discussed.

Biodiesel Synthesis from High Free-Fatty-Acid Chicken Fat using a Scrap-Tire Derived Solid Acid Catalyst and KOH

A heterogeneous solid acid catalyst was synthesized using tire polymer waste (TPW) for the esterification of waste chicken fat (CF) enriched with fatty acids. The TPW was carbonized and functionalized with concentrated sulfuric acid under various sulfonation conditions to obtain a sulfonated tire polymer char (TPC-SO₃H) catalyst. The TPC-SO₃H catalyst was further characterized via acid-base titration (to ascertain the total concentration of acid), X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), and Brunauer-Emmett-Teller (BET) analysis. The esterification reaction conditions of extracted chicken fat with methanol and the viability of catalyst reuse were also investigated. The composition of the free fatty acid (FFA) decreased to below 1% under optimum reaction conditions of 5% TPC-SO₃H catalyst, the methanol-to-CF molar-ratio of 15:1, and a reaction time of 120 min at 70 °C. The catalyst preserved its conversion efficiency above 90%, even after three cycles. The results demonstrate that the catalyst is applicable and efficient in the esterification of raw materials containing various fatty acid compositions since different carbonized materials have distinct abilities to combine acid groups. Furthermore, after de-acidification of CF-FFA by the as-prepared TPC-SO₃H catalyst, the neutral CF was transesterified completely to biodiesel and characterized via Fourier Transform Infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (¹H NMR) spectroscopy and physicochemical analysis. This work unveils a promising technique for utilizing tire waste generated in large quantities for the development of a novel heterogeneous acid catalyst for biodiesel production.

Production and Evaluation of Fractionated Tamarind Seed Oil Methyl Esters as a New Source of Biodiesel

Biodiesel has attracted considerable interest as an alternative biofuel due to its many advantages over conventional petroleum diesel such as inherent lubricity, low toxicity, renewable raw materials, biodegradability, superior flash point, and low carbon footprint. However, high production costs, poor low temperature operability, variability of fuel quality from different feedstocks, and low storage stability negatively impact more widespread adoption. In order to reduce production costs, inexpensive inedible oilseed alternatives are needed for biodiesel production. This study utilized inedible tamarind (Tamarind indica) seed oil as an alternative biodiesel feedstock, which contained linoleic (31.8%), oleic (17.1%), and lauric (12.0%) acids as the primary fatty acids. A simple and cost-effective high vacuum fractional distillation (HVFD) methodology was used to separate the oil into three fractions (F1, F2, and F3). Subsequent transesterification utilizing basic, acidic, and enzymatic catalysis produced biodiesel of consistent quality and overcame the problem of low temperature biodiesel performance. The most desirable biodiesel with regard to low temperature operability was produced from fractions F2 and F3, which were enriched in unsaturated fatty acids relative to tamarind seed oil. Other properties such as density and cetane number were within the limits specified in the American and European biodiesel standards.

Development of Microwave-Assisted Sulfonated Glucose Catalyst for Biodiesel Production from Palm Fatty Acid Distillate (PFAD)

Microwave-heating method for catalyst preparation has been utilized recently due to its shorter operation time compared to the conventional method. Glucose, a renewable carbon source can be partially carbonized and sulfonated via microwave heating which could result in highly potential heterogeneous carbon-based acid catalyst. In this study, the impacts of the carbonization and sulfonation parameters during the catalyst preparation were investigated. Catalysts prepared were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Brunauer-Emmet-Teller (BET), and Temperature Programmed Desorption–Ammonia (TPD-NH3). Analysis of the carbonization screening process discovered that the best incomplete carbonized glucose (ICG) prepared was at 20 minutes, 20 g of D(+)-glucose with medium microwave power level (400W) which exhibited the highest percentage yield (91.41%) of fatty acid methyl ester (FAME). The total surface area and acid site density obtained were 16.94 m2/g and 25.65 mmol/g, respectively. Regeneration test was further carried out and succeeded to achieve 6 cycles. The highest turnover frequency (TOF) of the sulfonated catalyst was methyl palmitate, 25.214´10−3 s−1 compared to other component of the methyl ester. Kinetic study was developed throughout the esterification process and activation energy from the forward and reverse reaction was 3.36 kJ/mol and 11.96 kJ/mol, respectively. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

An Efficient Catalyst Prepared from Residual Kaolin for the Esterification of Distillate from the Deodorization of Palm Oil

The distillate from the deodorization of palm oil (DDPO) is an agro-industrial residue, approximately 84% of which consists of free fatty acids (FFAs), which can be used for the production of fatty acid ethyl esters (FAEE). A catalyst (10HPMo/AlSiM) obtained from a waste material, Amazon flint kaolin, was applied in the esterification of the DDPO, reaching a conversion index of 94%, capable of maintaining satisfactory activity (>75%) after four consecutive cycles. Flint kaolin is therefore proven to be an efficient option in the search for new heterogeneous low-cost catalysts obtained from industrial by-products, contributing to the reduction of environmental impact and adding value to widely available wastes that would otherwise be discarded directly into the environment. Based on the catalytic results, esterification of DDPO using 10HPMo/AlSiM can be a cheaper alternative for the production of sustainable fuels.

A Two-Step SO3H/ICG Catalyst Synthesis for Biodiesel Production: Optimization of Sulfonation Step via Microwave Irradiation

Conventional heating, a common method used for heterogeneous solid acid catalyst synthesis unknowingly consumes massive time and energy. In this study, acid catalyst was prepared through sulfonation process of incomplete carbonized glucose (ICG) via microwave-assisted technique to shorten the heating time and energy consumption. Optimization of the sulfonation process of ICG via microwave-assisted was carried out. Four-factor-three-level central composite design (CCD) was used to develop the design of experiments (DOE). Interaction between two factors was evaluated to determine the optimum process conditions. A quadratic model was proposed for prediction of biodiesel yield (Y) from palm fatty acid distillate (PFAD) and its conversion (C). The application of DOE successfully optimized the operating conditions for the two-step SO3H/ICG catalyst synthesis to be used for the esterification process. The optimized conditions of the best performing SO3H/ICG with maximum Y and C were at 7.5 minutes of reaction time, 159.5 mL of H2SO4 used, 671 rpm of stirring rate as well as 413.64 watt of power level. At these optimum conditions the predicted yield percentage and conversion percentage were 94.01% and 91.89%, respectively, which experimentally verified the accuracy of the model. The utilization of sulfonated glucose solid acid catalyst via microwave-assisted in biodiesel production has great potential towards sustainable and green method of synthesizing catalyst for biodiesel. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Development of Heterogeneous Alkali Methoxide Catalyst from Fly Ash and Limestone

This study is aimed to use fly ash and limestone as raw materials for preparing alkali methoxide heterogeneous catalysts for transesterification of palm oil into biodiesel. The heterogeneous catalyst was synthesized from fly ash and limestone through wet and dry methods and calcined within 1073–1273 K. X-ray diffraction and scanning electron microscopy analyses indicated the well-dispersed presence of the Ca(OCH3)2 crystal over the fly ash and limestone framework, which was mixed using wet method and calcined at 1073 K (W-800). Results showed that W-800 exhibited larger surface area and more uniform active sites than the other catalysts. About 88.6 % of biodiesel was produced from commercial palm oil with W-800 as the catalyst. The product possesses physicochemical characteristics, such as density, kinematic viscosity and free fatty acid content, which satisfy the international biodiesel standard. The catalyst was used for biodiesel production for four cycles, and the biodiesel yield was maintained up to 91.87 % from the initial value.

Palm Biochar-Based Sulphated Zirconium (Zr-AC-HSO3) Catalyst for Methyl Ester Production from Palm Fatty Acid Distillate

A palm waste kernel shell biomass was converted into bio-based sulphonated activated carbon and further used for preparation of a sulphated zirconium-doped activated catalyst (Zr-AC-HSO3) by wet impregnation method. The structural, physicochemical, morphological, textural, and thermal characteristics of the synthesized Zr-AC-HSO3 catalyst were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, temperature-programmed desorption of ammonia (TPD-NH3), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The catalytic activity of the 20 wt% Zr-AC-HSO3 catalyst was further evaluated for esterification of palm fatty acid distillate (PFAD). This study achieved a maximum fatty acid methyl ester (FAME) yield of 94.3% and free fatty acid (FFA) conversion of 96.1% via the esterification over 20 wt% Zr-AC-HSO3 using 3 wt% catalyst concentration, 15:1 methanol:PFAD molar ratio at 75 °C for 3 h. The experiments to test for reusability showed that the spent catalyst was stable for five successive reaction cycles, with a FFA conversion of 80% in the fifth cycle, without additional treatment. The critical fuel features of the synthesized PFAD methyl ester were determined and were within the range of EN14214 and ASTM D6751 standards.

Optimization Models Type Box-Behnken in the Obtaining of Biodiesel from Waste Frying Oil using a Large-acidity Carbonaceous Catalyst

The trans-esterification and esterification of waste vegetable oil mainly under sub-critical temperature of methanol in the presence of sulfonated char were achieved. The carbonaceous materials were analyzed by means of various physical and chemical techniques such as Raman spectroscopy, X-ray diffractometry, temperature programmed desorption and X-ray photoelectrons spectroscopy. The carbon-based large-acidity catalyst showed good chemical and thermal properties and a high performance in the production of methyl esters from waste vegetable oil, which was easily separated from the liquid mixture. A temperature of 210°C, reaction time of 20 min and a catalyst amount of 0.03 g were the optimal experimental conditions for the trans-esterification of the vegetable oil with methanol giving a conversion to triglycerides of 96.5% according to the response surface methodology. The design of experiments type Box-Behnken was successfully applied to study effects of the parameters in the production of biodiesel and it presented optimal conditions for maximum performance with values near to those experimentally found. The catalyst was recovered from the final mixture by filtration and reused without regeneration showing a catalytic activity stable up to 4 or more reaction cycles.

Application of biochar-based catalysts in biomass upgrading: a review

The application of biochars as versatile catalysts and/or catalyst supports for biomass upgrading is systematically overviewed.