Browsing by Author "Gomes, Maria Carolina Sérgi"
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- Biodiesel production from residual cooking oils and its purification by adsorption processes based on adsorbents of natural originPublication . Garção, Maria Isabella Lima; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Ribeiro, António E.; Brito, PauloTotal global energy consumption has increased significantly in recent decades, and nowadays the main sources of world energy are oil, coal and natural gas. In addition to environmental concerns, the limited availability of fossil fuels has increased the interest in exploring alternative energy sources. In this quest, biofuel is a promising renewable energy source with low carbon emissions, also, it can be produced from a variety of resources, including waste cooking oil (WCO). Biodiesel is renewable, biodegradable, non-toxic, sulfur-free and free of aromatic carcinogens
- Biodiesel production from residual cooking oils and its purification through adsorption processes using activated carbon prepared from cork wastePublication . Garção, Maria Isabella Lima; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.; Gomes, Maria Carolina SérgiBiodiesel is a renewable fuel that can be produced from waste cooking oil mainly through transesterification. However, from its production results a contaminant called glycerol, which must be removed. Wet washing is the most common method for biodiesel purification, but it has several drawbacks, including high costs and the generation of large amounts of aqueous effluent. This study proposes using activated carbon obtained from industrial cork waste in adsorption as an alternative method for glycerol removal. This approach could potentially reduce the environmental impact and cost of producing biodiesel, while also providing an alternative for the valorization of industrial cork waste. The highest value of removal of 89% of glycerol occurred with a cork chemically activated carbon with KOH at a load of 2%wt at 25°C for 6 hours of contact. After the biodiesel washing using adsorption process, the remaining glycerol content was 0.016%wt, below the maximum value of 0.02%wt specified by the EN14214:2012 standard.
- Biodiesel production from residual cooking oils and purification by adsorption processes based on adsorbents of natural originPublication . Garção, Maria Isabella Lima; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Ribeiro, António E.; Brito, PauloTotal global energy consumption has increased significantly in recent decades. International Energy Agency predicts that from 2012 to 2040, and also the International Energy Agency (IEA), by 2030, the world's demand for energy will increase by 50%. Nowadays, the main sources of energy supply in the world are oil, coal and natural gas. In addition to the environmental problems, the supply of fossil fuels is limited, which makes many researchers increasingly interested in exploring alternative energy sources [1]. In this pursuit, biofuels are promising renewable energy sources with lower carbon emissions, besides the possibility of being made from a variety of resources, including residues such as waste cooking oil (WCO), oily sludge from factories, and discarded animal fats [2]. In contrast to petroleum-derived diesel, biodiesel is renewable, biodegradable, non-toxic, sulphur-free and aromatic carcinogen-free [3]. The cost of biodiesel is now 10% to 50% higher than petroleum diesel. A more possible way to increase biodiesel production is to use WCO as a feedstock, which is 25% to 40% of the price of edible oil. This way, WCO gets a better destination than its discard [3]. Biodiesel is produced through transesterification/esterification which are reactions that convert oils or free fatty acids into alkyl esters. Through transesterification, the triglycerides react with small chain alcohol in order to obtain methyl or ethyl esters of fatty acids and glycerol. The process occurs in three reversible and consecutive reactions, which produce molecules of diglycerides and monoglycerides as intermediates [4]. The properties of biodiesel will depend on the feedstock used in its production, and it should be similar to petroleum diesel in order to be functional in motors without any changes. All parameters, such as cetane number, fatty acid methyl esters content, density, and acid value, are defined by standards and vary depending on the location. For example, in Europe, they are defined by the European Biodiesel Standard EN 14214, whose last version was published in 2008. It is set to specify characteristics that define the behaviour of biodiesel combustion in an engine and also the methods that have to be used to determine those parameters
- Cork waste-based adsorbents for glycerol removal from biodiesel: a sustainable alternative to wet washingPublication . Garção, Maria Isabella Lima; Milani, Eduardo Candido; Camilo, Gabriel Lamino; Diaz De Tuesta, Jose L.; Gomes, Maria Carolina Sérgi; Ribeiro, António E.; Queiroz, Ana; Brito, PauloThis work aims to use activated carbon from industrial cork waste as a novel method for glycerol removal from crude biodiesel produced using waste cooking oil, combining two residues to obtain both high-quality biodiesel and highly adsorbent activated carbon. The study first optimizes the biodiesel production conditions, achieving the highest ester yield at 30 degrees C, with a 1:9 oil-to-ethanol molar ratio, 1 wt.% NaOH catalyst, and a reaction time of 1 h. Additionally, activated carbons were prepared and characterized from cork waste, showing significantly higher BET surface areas than the raw material. The most promising cork-based materials were then applied to optimize glycerol removal from crude biodiesel through adsorption. A preliminary study identified milled raw cork and its KOH-activated carbon (SBET = 2057 m2/g) as the most effective. Kinetic and equilibrium studies demonstrated that optimal glycerol removal was achieved after 6 h at 25 degrees C using 2 wt.% of KOH-activated cork-based adsorbent, resulting in 88% glycerol removal and a final glycerol content of 0.017 wt.%. These findings demonstrate that cork waste-derived activated carbon is highly effective for biodiesel purification, successfully meeting the quality specifications required by European Standard EN 14214:2012+A2:2019 and offering an innovative solution for waste valorization and sustainable fuel production.
- Evaluation and kinetic study of alkaline ionic liquid for biodiesel production through transesterification of sunflower oilPublication . Lima, Ana Carolina Coelho; Hachemane, Khadidja; Ribeiro, António E.; Queiroz, Ana; Gomes, Maria Carolina Sérgi; Brito, PauloBiodiesel production is performed in the industry by alkaline transesterification of oils with a low amount of free fatty acids. In order to reduce the disposal of conventional catalysts used industrially, ionic liquids (ILs) have been studied to be applied as catalysts in transesterification since they can be recovered and reused in subsequent reaction cycles. In this work, the ionic liquid choline hydroxide (ChOH) was successfully applied as a catalyst for the transesterification reaction of triacylglycerols present in sunflower oil with methanol. A kinetic modeling study under the specific conditions of 2 wt% catalyst dosage, 1:10 oil/methanol molar ratio, for 0–120 min at 35–65 ℃ was conducted, and liquid–liquid extraction with water/butanol was evaluated as a process to recover the IL. A 95.0% ester yield content was achieved in this work for a short reaction time (30 min). Furthermore, the results of the kinetic study demonstrated that a first-order model was the best fit for the reaction with a rate constant (k) estimated as 0.1182 min 1 and activation energy (Ea) of 13.64 kJ/mol. For the tested conditions, the complete recovery of the IL using liquid–liquid extraction did not occur since it is noted the presence of ChOH in both phases.
- Purification of biodiesel using a natural based adsorbent in a packed-bed columnPublication . Smolich, Camilla Groxko; Guimarães, Miriam D.; Fabian, João Vitor; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.In Europe, the Renewable Energy Directiva stimulates the development of renewable energy sources to reduce greenhouse gas emissions by at least 55% by the year 2030 and to become aclimate-neutral continent by 2050 [1]. Biodiesel presents advantages over diesel fuel in terms of sulfur content, biodegradability, flash point, no aromatic content, higher cetane number and miscibility in petroleum diesel in any ratio [2]. The most used feedstock is high quality vegetable oil, but the use of waste cooking oil adds to the global reduction of residue, lower costs, and competes less for vegetable oils against the food industry [3]. This biofuel is obtained through transesterification, and glycerol is formed as a coproduct. lts presence can cause damage to motors so it must be removed until its final concentration is lower than 0.02wt%. The most used method is wet washing, but the downside is the great amount of water used and long periods of time are needed to separate biodiesel from its contaminants through decantation [4]. A promising altemative is dry washing method through adsorption using biomass activated carbon. For a more practica! application, packed columns are frequently used in large scale adsorption processes. lt is one of the most efficient configurations for treating great volumes of effluent and adsorption-desorption cycles [5]. For this study, crude biodiesel was produced through transesterification from a waste cooking oil sample, using ethanol and a basic catalyst (NaOH). Afterwards the biodiesel produced was characterized in terms of glycerol content. In parallel, activated carbon materials were obtained from olive pits by physical activation at 800°C. The adsorbent materials performance for glycerol removal from crude biodiesel is assessed using a continuous system based on a packed-bed column according to the following parameters: fluid rate, removal capacity, pressure drop and adsorbent recovery.
- Review of biodiesel production using various feedstocks and its purification through several methodologies, with a specific emphasis on dry washingPublication . Camilo, Gabriel L.; Queiroz, Ana; Ribeiro, António E.; Gomes, Maria Carolina Sérgi; Brito, PauloRenewable biomass fuels are gaining attention as a cleaner energy alternative to fossil-based resources. Biodiesel, derived from biological sources, is particularly attractive due to its renewable and ecological benefits. Researchers are actively exploring various methodologies to convert biomass into gaseous and liquid fuels, similar to petroleum products. To optimize production and accommodate different feedstock sources, biodiesel production through different routes is becoming popular. The purification of biodiesel is an important step, and current methods involving water usage are being replaced with more sustainable alternatives. Adsorption and ion exchange, known as dry washing methods, are widely used for biodiesel purification worldwide. These processes use an adsorbent to selectively remove impurities from the liquid phase, offering advantages such as easy integration, shorter purification time, reduced water consumption, and minimal effluent generation. This review focuses on biodiesel production and purification methods, highlighting the advantages of adsorption over traditional wet washing methods.
- Síntese e avaliação de um líquido iónico alcalino na produção de biodieselPublication . Lima, Ana Carolina Coelho; Queiroz, Ana; Ribeiro, António E.; Gomes, Maria Carolina Sérgi; Brito, PauloBiodiesel is an attractive biofuel to overcome energy depletion from fossil fuels since it has similar properties to diesel and exhibit biodegradability, non-toxicity and low carbon content. Currently, the production of biodiesel is done by the conversion of edible oils containing triglycerides through a transesterification reaction. However, concerns related to first-generation biodiesel such as the high cost of these oils, the competition with food markets, and the possibility of soil degradation made the use of waste oils in biodiesel production a possibility. These oils are considered a promising alternative in biodiesel synthesis, due to their low cost, high availability and arise as possible alternatives to overcome the disadvantages of the traditional production processes. Therefore, this study focuses on the research of producing biodiesel in a more sustainable way, i.e., the production of biodiesel from waste oils and the application of an ionic liquid (IL) as catalyst. The interest in IL is related to their near-zero vapor pressure and other properties such as their low volatility, high thermal and chemical stability, solvent properties and the possibility to be recovered and reused in new reaction cycles. In this research, the bis-(3-methyl-1-imidazolium)-ethylene dihydroxide (IMC2OH) IL was synthesized and characterized, showing good catalytic character for the transesterification of sunflower oil samples. Thus, the IL will be applied in the transesterification of waste cooking oils, and the effects of different reaction conditions on the preparation of biodiesel, such as reaction time, reaction temperature, alcohol/oil molar ratio and catalyst dosage, will be assessed.
- Study of biodiesel production from waste cooking oil by ethyl transesterification and its purification using adsorption processesPublication . Camilo, Gabriel L.; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Ribeiro, António E.; Brito, PauloIn the year 2020, global biodiesel production reached 46.45 million tons, with biodiesel from waste cooking oils (WCO) constituting approximately 10% of this total, with Europe accounting for approximately 33% and Brazil 12% of global production [1]. The cost of conventional biodiesel production is higher than the production of diesel from petroleum, since it is produced mainly from high quality virgin oils, it is estimated that 70 to 80% of the total cost of biodiesel production is associated with the cost of the raw materials [2]. With this perspective, biodiesel production from WCO has become an economic opportunity and an environmental strategy to help address global renewable energy challenges and contribute to a sustainable society [3]. Oil with hours of frying at high temperatures results in the loss of its edible properties and nutritional value, the disposal of used cooking oil remains an issue due to its environmental and human health threats [4]. In this scenario, the collection and destination of these oils for the production of a value-added and environmentally friendly biofuel presents itself as an opportunity to be investigated. Adsorption and ion exchange are the most commonly used affinity separation processes in biodiesel purification worldwide, these methods are also known as dry washing methods. In these processes, an appropriate adsorbent is used to selectively remove certain impurities from the liquid phase onto its surface. Dry cleaning offers several advantages, including simple integration into an existing plant, shorter purification time, lower water consumption and lower effluent generation
- Study of biodiesel production from waste cooking oil by ethyl transesterification and its purification using adsorption processesPublication . Camilo, Gabriel L.; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Ribeiro, António E.; Brito, PauloIn recent years, a collective effort is made in search of alternative forms of energy through renewable and more friendly to the environment sources, currently, about 80% of the world consumption of energy comes from fossil fuels. The environmental problems associated with the use of these non-renewable fuels include air pollution and global warming, moreover, the uncertain price of a barrel of oil in the current economy also causes economic problems in its dependence. Thus, due to these problems in the dependence on fossil fuels for industry, transport and domestic purposes, research on alternative energy sources has become ever more common [1]. In this scenario, biodiesel presents itself as a renewable fuel, environmentally friendly and with similar characteristics to common diesel. According to [2] in 2020, global biodiesel production reached 46.45 million tons, with biodiesel from waste cooking oils (WCO) constituting approximately 10% of this total, with Europe accounting for approximately 33% and Brazil 12% of global production. The cost of conventional biodiesel production is higher than the production of diesel from petroleum, since it is produced mainly from high quality virgin oils, it is estimated that 70 to 80% of the total cost of biodiesel production is associated with the cost of their raw materials [3]. With this perspective, biodiesel production from WCO has become an economic opportunity and an environmental strategy to help address global renewable energy challenges and contribute to a sustainable society [4]. Oil with hours of frying at high temperatures results in the loss of its edible properties and nutritional value, the disposal of used cooking oil remains an issue due to its environmental and human health threats, countries are now imposing penalties and restrictions on the disposal of this cooking waste in drainage systems and/or natural water bodies [5]. In this scenario, the collection and destination of these oils for the production of a value-added and environmentally friendly biofuel presents itself as an opportunity to be investigated