Article
Green & Sustainable Science & Technology
L. Bartolucci, S. Cordiner, A. Di Carlo, A. Gallifuoco, P. Mele, V. Mulone
Summary: Spent coffee grounds are a valuable biogenic waste that can be used as a source of biofuels and valuable chemicals through pyrolysis and solvent extraction processes. The study found that heavy organic bio-oil derived from coffee grounds can be used as a carbon-rich biofuel, while solvent extraction can extract xantines and p-benzoquinone, which are important chemicals for various industries. The results highlight the promising potential of solvent extraction in improving the economic viability of coffee grounds pyrolysis-based biorefineries.
Article
Food Science & Technology
Jitrawadee Meerasri, Rungsinee Sothornvit
Summary: Coffee oil derived from spent coffee grounds can be used as a substitute for butter in bakery products. When 20% of butter was replaced with coffee oil, the cookies had improved antioxidant properties and a softer texture. This study suggests that coffee oil can be a novel alternative ingredient for healthier bakery products, while also utilizing waste resources.
JOURNAL OF FOOD PROCESSING AND PRESERVATION
(2022)
Article
Agricultural Engineering
L. Bartolucci, S. Cordiner, P. Mele, V. Mulone
Summary: This study investigates the impact of lipid extraction and conversion to biodiesel on the energy yield of pyrolysis products. The results show that the pyrolysis temperature has an important impact on the energy distribution of the products. The energy contribution of biodiesel significantly improves the energy yield of the pyrolysis system.
BIOMASS & BIOENERGY
(2023)
Article
Engineering, Chemical
Rosa Colucci Cante, Isidoro Garella, Marianna Gallo, Roberto Nigro
Summary: In this study, lipids were successfully extracted from spent coffee grounds using an innovative system and the hydrofluorocarbon Norflurane as solvent. The extraction process was efficient, with oil yields and extraction times comparable to those obtained using supercritical CO2. The fatty acid profiles of the extracts revealed the presence of major components like palmitic and linoleic acids, and minor components like stearic and oleic acids.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2021)
Article
Chemistry, Multidisciplinary
Tatiane Akemi Toda, Mariana Marques Barreiro, Guilherme Barao da Cunha, Christianne Elisabete da Costa Rodrigues
Summary: This study evaluated the effectiveness of ethanol and isopropanol as solvents for oil extraction from spent coffee grounds. The partitioning of ethanol and SCGO can be described by the Langmuir equation, while the partitioning of isopropanol and SCGO showed a linear relationship. The temperature did not affect the partitioning when isopropanol was used as the solvent. Ethanol hydrate required more solvent for SCGO extraction, while isopropanol hydrate required less solvent. A solvent-to-feed ratio of at least five is needed when considering an extractor with five theoretical stages operating at 80 degrees Celsius.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Lauren I. Austen, Thomas I. J. Dugmore, Avtar S. Matharu, Glenn A. Hurst
Summary: This experiment introduces students to the valorization of byproducts by producing a biodiesel analogue from spent coffee grounds. By analyzing spectroscopic characteristics and green metrics, students apply green concepts and sustainable development goals to real-world problems, demonstrating the value of waste and the importance of reducing fossil fuel consumption.
JOURNAL OF CHEMICAL EDUCATION
(2023)
Article
Energy & Fuels
Jie Yang, Hao Chen, Haibo Niu, Josiah McNutt, Quan He
Summary: The study compared two valorization options for spent coffee grounds: oil extraction followed by hydrothermal liquefaction of defatted grounds, and direct hydrothermal liquefaction of raw grounds. The results showed that direct hydrothermal liquefaction was a more favorable valorization route.
Article
Chemistry, Multidisciplinary
Mihle Magengelele, Samkelo Malgas, Brett I. Pletschke
Summary: Spent coffee ground (SCG) is a viable source for the production of mannooligosaccharides (MOS) with prebiotic and antioxidant activities. The SCG was pretreated and hydrolyzed to produce MOS, which showed suitability for oral administration and enhanced the growth of beneficial bacteria in vitro.
Article
Food Science & Technology
Raffaele Romano, Lucia De Luca, Giulia Basile, Chiara Nitride, Fabiana Pizzolongo, Paolo Masi
Summary: This study utilized green technologies to extract bioactive compounds from spent coffee grounds (SCG) using supercritical and liquid CO2. The extracts obtained showed high yields and antioxidant activity, with high contents of polyphenols and known antioxidant and antimicrobial compounds. These extracts have potential applications in the cosmetic, pharmaceutical, and food sectors.
Article
Agricultural Engineering
Federico Battista, Luca Zuliani, Fabio Rizzioli, Salvatore Fusco, David Bolzonella
Summary: This study explored a cascade biorefinery approach to produce biodiesel, fermentable sugars, and biomethane from spent coffee grounds, rich in high-value compounds. Transesterification and glycerol pretreatment were used to achieve high product performance. However, the low content of easily degradable compounds led to the need to search for better alternatives to improve methane production.
BIORESOURCE TECHNOLOGY
(2021)
Article
Food Science & Technology
Danh C Vu, Quyen T Vu, Long Huynh, Chung-Ho Lin, Sophie Alvarez, Xuyen T Vo, Trang H D Nguyen
Summary: The study examined the fatty acids, bioactive phenolics, antioxidant and anti-aging potentials of spent coffee ground (SCG) samples obtained from coffee shops in Ho Chi Minh city, Vietnam. The results showed that SCG samples had high oil content and antioxidant properties, with promising anti-aging activity, which could open new avenues for the food and cosmeceutical industry.
INTERNATIONAL JOURNAL OF FOOD PROPERTIES
(2021)
Article
Green & Sustainable Science & Technology
Mirna Brekalo, Blanka Bilic Rajs, Krunoslav Aladic, Lidija Jakobek, Zita Seres, Sasa Krstovic, Stela Jokic, Sandra Budzaki, Ivica Strelec
Summary: This study investigated the potential of transforming spent coffee grounds into a cellulose-based enzyme immobilization carrier through a multistep extraction process. The cellulose-enriched coffee grounds obtained from this transformation process demonstrated ideal characteristics for use as a potential enzyme immobilization carrier.
Article
Green & Sustainable Science & Technology
Valentina Kafkova, Robert Kubinec, Jozef Mikulec, Miroslav Variny, Petra Ondrejickova, Ales Haz, Adriana Brisudova
Summary: With the increasing consumption of coffee beverages, a large amount of food waste-spent coffee grounds (SCG)-is generated. SCG is highly polluting due to the presence of caffeine, tannins, and polyphenols. However, it contains 15% oil on average, making it suitable for biodiesel production.
Article
Green & Sustainable Science & Technology
Georgia-Christina Mitraka, Konstantinos N. Kontogiannopoulos, Maria Batsioula, George F. Banias, Andreana N. Assimopoulou
Summary: The study aimed to exploit the potential of spent coffee grounds as a source of bioactive compounds and developed a cost-effective and environmentally friendly extraction technique. The results showed that SCG extracts have high potential for high value-added applications.
Article
Green & Sustainable Science & Technology
Nurulfarah Adilah Rosmahadi, Hemamalini Rawindran, Jun Wei Lim, Worapon Kiatkittipong, Suttichai Assabumrungrat, Vesna Najdanovic-Visak, Jiawei Wang, Boredi Silas Chidi, Chii-Dong Ho, Eman Alaaeldin Abdelfattah, Sze Mun Lam, Jin Chung Sin
Summary: One economical approach to harvesting mature microalgal biomass is through the attached growth system. This study found that spent coffee grounds can serve as a support material for Chlorella vulgaris sp. microalgae, enhancing the attached microalgal growth. Additionally, a specific photoperiod regime with a dark period cycle of 4 hours per day resulted in the maximum microalgal density, allowing the attached microalgae to strengthen their mixotrophic growth and accumulate a significant amount of lipid.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Article
Energy & Fuels
Paul Hellier, Farrukh Jamil, Ernesto Zaglis-Tyraskis, Ala'a H. Al-Muhtaseb, Lamya Al Haj, Nicos Ladommatos
Article
Energy & Fuels
Ioannis Efthymiopoulos, Paul Hellier, Nicos Ladommatos, Ben Mills-Lamptey
Article
Thermodynamics
Xinyu Wei, Paul Hellier, Frank Baganz
ENERGY CONVERSION AND MANAGEMENT
(2020)
Article
Energy & Fuels
Aydek Gokce Erman, Paul Hellier, Nicos Ladommatos
Article
Chemistry, Analytical
Hamisu Adamu Dandajeh, Nicos Ladommatos, Paul Hellier
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2020)
Article
Engineering, Environmental
Christopher C. Ogbunuzor, Paul R. Hellier, Midhat Talibi, Nicos Ladommatos
Summary: This study analyzed the formation and adsorption mechanisms of PAHs in the combustion process of diesel engines, finding that gas-phase PAHs were more abundant than soot-bound PAHs in the engine cylinder. Levels of PM and in-cylinder PAHs varied significantly during different combustion phases.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Daniel Southern, Paul Hellier, Midhat Talibi, Martin O. Leonard, Nicos Ladommatos
Summary: Biofuels have the potential to reduce carbon intensity in road transport, but their impact on engine-derived particulate toxicity compared to fossil diesel remains uncertain. This study found that biodiesel reduced particle toxicity in some cases, with differences observed between different types of biodiesels for specific biomarkers. The most significant fuel effect was on cytotoxicity, with Waste Cooking Oil Methyl Ester increasing particle cytotoxicity and Palm oil Methyl Ester decreasing it.
ATMOSPHERIC ENVIRONMENT
(2021)
Article
Chemistry, Physical
James Frost, Abdoulaye Tall, Abubakar Mahmud Sheriff, Alessandro Schonborn, Paul Hellier
Summary: Ammonia has the potential to be a solution for decarbonising transport due to its ability to act as a hydrogen carrier. Increasing the aspiration of ammonium hydroxide solution was found to prolong ignition delay, raise peak in-cylinder temperature, decrease combustion quality, and reduce particle size.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Zuhaib Ali Khan, Paul Hellier, Nicos Ladommatos
Summary: This study investigates the production of soot mass and PAHs from the pyrolysis of different alcohol fuels, revealing that primary alcohols produce higher soot mass than secondary alcohols. Additionally, the position of the hydroxyl group affects the distribution of total PAHs in the gas and particulate-bound phases within a specific temperature range.
COMBUSTION AND FLAME
(2022)
Article
Metallurgy & Metallurgical Engineering
Hamisu Adamu Dandajeh, Nicos Ladommatos, Paul Hellier
Summary: This paper investigated the effect of equalizing ignition delay in a compression ignition engine, finding that adding an ignition improver reduced soot generation. Different fuel mixtures did not significantly affect ignition delay and fuel air premixing rate.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
Article
Energy & Fuels
James Frost, Paul Hellier, Nicos Ladommatos
Summary: The study investigates the combustion performance of different furanic molecules when blended with diesel fuel. It concludes that saturated furanic molecules achieve stable combustion and reduce carbon monoxide emissions when blended with diesel at a volumetric ratio of 50:50. Biofuel combustion produces higher NOx emissions and particle number but lower particle mass compared to fossil diesel. Increasing the degree of saturation decreases the ignition delay and NOx emissions, while adding alkyl chains enhances ignition propensity. Adding an oxygenated functional group decreases particle mass but increases NOx emissions.
Article
Thermodynamics
James Frost, Paul Hellier, Nicos Ladommatos
Summary: The use of bioderived drop-in fuels is crucial in reducing fossil fuel usage. This study investigates the combustion and exhaust emissions of lactone fuels, sourced from 2nd generation biomass, in a compression ignition engine. The results show that certain lactone blends exhibit promising ignition qualities and reduce emissions, such as particle mass and nitrogen oxides, compared to unblended fossil diesel.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Green & Sustainable Science & Technology
Zuhaib Ali Khan, Paul Hellier, Nicos Ladommatos, Ahmad Almaleki
Summary: Air pollution in cities poses a threat to public health and the environment. Particulate emissions containing toxic polyaromatic hydrocarbons (PAHs) contribute to this pollution. The study investigates the decomposition of methane, ethane, and butane fuels and the subsequent formation of aromatic rings, providing insights for reducing PM formation.
Article
Environmental Sciences
Christopher Ogbunuzor, Leonie Francina Hendrina Fransen, Midhat Talibi, Zuhaib Khan, Abigail Dalzell, Adam Laycock, Daniel Southern, Aaron Eveleigh, Nicos Ladommatos, Paul Hellier, Martin Oliver Leonard
Summary: FAME biodiesel has less impact on airway epithelial toxicity compared to fossil diesel, but alters the profile of polycyclic aromatic hydrocarbons (PAHs) and increases the levels of carcinogenic PAHs. Higher blends of biodiesel result in higher levels of carcinogenic PAHs and stress response gene expression, increasing the risk of particle-associated carcinogenesis and toxicity.
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
(2023)
Article
Energy & Fuels
Ahmad Almaleki, Paul Hellier, Nicos Ladommatos, Midhat Talibi, Zuhaib Khan
Summary: This study investigates the influence of varying relative air-fuel ratios (exhaust lambda) on the knock resistance of a range of fuels with different RON values and chemical compositions. It was found that fuels with equivalent RON values have the same compression ratio at fuel rich conditions, but exhibit significant differences at stoichiometric conditions (lambda = 1). The knock resistance of paraffinic reference fuels is more sensitive to changes in exhaust lambda, especially at lambda = 1, requiring higher engine compression ratios compared to aromatic gasoline fuels to achieve equivalent knock levels.