Integrating life cycle assessment and characterisation techniques: A case study of biodiesel production utilising waste Prunus Armeniaca seeds (PAS) and a novel catalyst

Biobased heterogeneous renewable catalysts: Production technologies, innovations, biodiesel applications and circular bioeconomy

The growing population and waste biomass accumulation are leading to increased environmental pollution and climate change. Waste biomass comprising of nutrient rich components has promising potential to produce value-added products for sustainable environmental solutions. This review explores the critical role of bio-based heterogeneous catalysts in enabling sustainable waste biomass utilization. In industrial chemical transformations, over 95% involve catalysts, with more than 90% being heterogeneous systems, prized for their robustness, ease of product separation, and reusability. Bio-based heterogeneous catalysts address the pressing need for sustainable waste biomass management, allowing the conversion of diverse waste biomasses into biodiesel as valuable products. Research on these catalysts, particularly for biodiesel production, has shown yields exceeding 90% with enhanced catalyst reusability. This surge in research is evident from the increasing number of published articles, notably in 2022 and 2023, highlighting growing interest and importance in the scientific community. The synthesis of these catalysts is examined, including novel approaches and techniques to enhance their efficiency, selectivity, and stability. The challenges with their feasible solutions of heterogeneous catalysts in catalyst-based processes are addressed. Altogether, this review underscores the immense potential of bio-based heterogeneous catalysts in sustainable waste biomass utilization, aligning with resource efficiency and environmental conservation goals while offering distinct insights and perspectives on the latest innovations in the field.

Valorization of non-edible fruit seeds into valuable products: A sustainable approach towards circular bioeconomy

Global imperatives have recently shown a paradigm shift in the prevailing resource utilization model from a linear approach to a circular bioeconomy. The primary goal of the circular bioeconomy model is to minimize waste by effective re-usage of organic waste and efficient nutrient recycling. In essence, circular bioeconomy integrates the fundamental concept of circular economy, which strives to offer sustainable goods and services by leveraging biological resources and processes. Notably, the circular bioeconomy differs from conventional waste recycling by prioritizing the safeguarding and restoration of production ecosystems, focusing on harnessing renewable biological resources and their associated waste streams to produce value-added products like food, animal feed, and bioenergy. Amidst these sustainability efforts, fruit seeds are getting considerable attention, which were previously overlooked and commonly discarded but were known to comprise diverse chemicals with significant industrial applications, not limited to cosmetics and pharmaceutical industries. While, polyphenols in these seeds offer extensive health benefits, the inadequate conversion of fruit waste into valuable products poses substantial environmental challenges and resource wastage. This review aims to comprehend the known information about the application of non-edible fruit seeds for synthesising metallic nanoparticles, carbon dots, biochar, biosorbent, and biodiesel. Further, this review sheds light on the potential use of these seeds as functional foods and feed ingredients; it also comprehends the safety aspects associated with their utilization. Overall, this review aims to provide a roadmap for harnessing the potential of non-edible fruit seeds by adhering to the principles of a sustainable circular bioeconomy.

Biodiesel production from Sisymbrium irio as a potential novel biomass waste feedstock using homemade titania catalyst

Biomass waste streams are a possible feedstock for a range of eco-friendly products and a crucial alternative energy source for achieving carbon neutrality; therefore, the efficient management of biomass waste has taken on a greater significance in recent years. Due to its well-comparable physic-chemical properties with fossil diesel, biodiesel is a potential substitute for fossil fuel. This study aimed to synthesize biodiesel from the widely available non-edible seed oil of Sisymbrium irio L. (a member of the Brassicaceae family) via a transesterification procedure over a homemade TiO2 catalyst. At 1:16 oil to methanol ratio, 93% biodiesel yield was obtained over 20 mg catalyst at 60 °C and 60 min. The ASTM methods were used to analyze the fuel properties. The quantitative and qualitative analysis was performed by FT-IR, GC-MS, and NMR spectroscopy. GC-MS study confirms 16 different types of fatty acids of methyl esters. FT-IR analysis showed important peaks that confirm the successful occurrence of biodiesel. 1H-NMR and 13C-NMR showed important peaks for converting triglycerides into corresponding FAMEs. The acid value (0.42 mg KOH/mg/kg), flash point (106 °C), and water content (0.034) of biodiesel are below the specified limit of ASTM D6751 whereas kinetic viscosity (3.72 mm2/s), density (0.874 kg/L), cloud point (- 4.3 °C) and pour point (- 9.6 °C) and high heating value (41.62 MJ/kg) fall within the specified range of ASTM D6751 test limit. The Unsaturation degree and oxidative stability of biodiesel are above ASTM D6751 test limit. The physic-chemical properties of the SIB confirm that it is eco-friendly fuel and a competitive source for manufacturing biodiesel on a commercial scale. Furthermore, the SIB is engine friendly and has good fuel efficacy.

Biodiesel production from date seed oil using hydroxyapatite-derived catalyst from waste camel bone

Biodiesel is considered to be more friendly to the environment than petroleum-based fuels, cheaper and capable for producing greener energy which contributed positively in boosting bio-economy. A new non-edible feedstock utilized from date seed oil was analyzed for the synthesis of eco-friendly biodiesel using newly novel hydroxyapatite heterogeneous catalysts, obtaining from waste camel bones prepared from dried camel bone followed calcination under different temperature. This catalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM). Results showed that hydroxyapatite catalyst pore size reduced with increasing the calcination temperature. Optimize biodiesel yield (89 wt%) was achieved through the process of transesterification with optimum reaction conditions of 4 wt% catalyst, oil to ethanol molar ratio of 1:7 and temperature 75 °C for 3 h reaction time. The production of FAME was confirmed by using gas chromatography-mass spectroscopy (GC-MS). Fuel properties of fatty acid ethyl ester complied with ASTM D 6751 which indicated that it would be an appropriate alternative form of fuel. As a result, using biodiesel made from waste and untamed resources to develop and implement a more sustainable and environmentally friendly energy strategy is commendable. The acceptance and implementation of the green energy method may result in favorable environmental effects, which in turn may lead to better societal and economic growth for biodiesel industry at a larger scale.

Valorization of neem seeds biomass to biofuel via non-catalytic and catalytic pyrolysis process: Investigation of catalytic activity of Co-Mo/Al2O3 and Ni-Mo/Al2O3 for biofuel production

Biofuel production from neem seeds have been evaluated via non-catalytic and catalytic pyrolysis process. Co-Mo/Al₂O₃ and Ni-Mo/Al₂O₃ industrial catalysts have been applied in upgrading process of pyrolysis oil to biofuel. The catalytic activity test revealed that these catalysts succeeded in converting fatty acids content of pyrolysis oil into low oxygen content compounds such as alcohols, alkanes, cyclic compounds, and esters via deoxygenation route. Enhancement of temperature and catalyst loading lead to increase of bio-gas production yield, significantly. The highest yield of pyrolysis oil (60.2%) was obtained at 450 °C, heating rate of 40 °C.min^-1 via non-catalytic pyrolysis. Using 40% catalyst loading of Ni-Mo/Al₂O₃, the content of alcohol, cyclic and alkane compounds in the bio-oil were reached 12.65%, 21.74% and 15%, respectively. The highest selectivity using 40% catalyst loading of Co-Mo/Al₂O₃ catalyst at 450 °C was related to fatty acids (62.5%), esters (18.2%) and alkanes (6.25). It is inferred that the addition of Ni to Mo causes more progress of decarbonylation and decarboxylation reactions, and the addition of Co to Mo generates more ester compounds. Sensitivity analysis indicated that the effect of Ni-Mo/Al₂O₃ catalyst through catalytic pyrolysis process was more severe than Co-Mo/Al₂O₃ catalyst.

Life cycle assessment of biodiesel production by using impregnated magnetic biochar derived from waste palm kernel shell

Biodiesel is renewable, biodegradable, biocompatible (non-toxic) and environmentally friendly, which emits less pollution than traditional fossil-based diesel, making it the most promising and ideal option. However, biodiesel is facing many current issues, mostly related to the utilisation of homogeneous catalytic technology, and this circumstance obstructs its potential development and advancement. Therefore, new pathways for biodiesel production need to be explored, and the aforementioned issues need to be addressed. Recently, a study was conducted on the impregnated magnetic biochar derived from a waste palm kernel shell (PKS) catalyst that can replace conventional catalysts due to its reusability property. Nevertheless, the environmental impacts of impregnated magnetic biochar derived from waste PKS catalyst for biodiesel production are yet to be studied. This study focuses on the evaluation of the life cycle assessment (LCA) of palm-based cooking oil for biodiesel production catalysed by impregnated magnetic biochar derived from waste PKS. Simapro was used in this study to evaluate the impact assessment methodologies. Case 1 (6.64 × 10² Pt) has contributed less to environmental impacts than Case 2 (1.83 × 10³ Pt). This indicates purchasing refined palm oil for biodiesel production may reduce environmental impacts by 64% compared to producing biodiesel from raw fruit bunches. In the midpoint assessment, the transesterification process was identified as the hotspot and marine aquatic ecotoxicity as the highest impact category with a value of 1.00 × 10⁶ kg 1,4-DB eq for 1 tonne of biodiesel produced. The endpoint results showed that Case 1 revealed the greatest impact on the transesterification process, with cumulative damage of 461 Pt. Scenario without processing the raw palm fruit bunches to obtained palm oil was better than Case 2. Further research should be conducted on life cycle cost and sensitivity analysis to evaluate the economic feasibility and promote sustainable biodiesel production.