This study aims to investigate the influence of varying hydrogen flow rates on the tribological properties of graphene-coated piston rings developed via chemical vapor deposition (CVD) with oil palm fiber as precursor. Graphene was derived from oil palm fiber and polystyrene with varying Hydrogen (H2) flow rate in the CVD process i. e, 200, 400, 600 and 800 sccm and deposited on piston rings. The tribological tests were conducted using a high-frequency reciprocating rig (HFRR) according to ASTM G181 - 11 engineering standards. The load of 10N was kept constant for each test and the test was performed till 300m sliding distance was attained. Among all four hydrogen flow rates, it was observed that graphene-coated piston ring developed with 600 sccm and 800 sccm hydrogen flow rates show enhanced tribological properties when derived from 100 wt% of oil palm fiber and polystyrene respectively. The coated piston ring results were compared with non-coated commercially used piston rings and it was found that the coefficient of friction and wear rate of 600 sccm oil palm fiber based graphene coated piston ring was reduced by 20 % and 70 % respectively as compared to uncoated piston ring.

Biodiesel is an eco-friendly source of energy that is synthesized from plant or animal-based oils and fats. However, the commercial use of biodiesel is limited due to its drawbacks such as auto-oxidation and moisture absorption, leading to accelerated corrosion of the metallic parts and degradation of wear resistance. In this work, a novel amorphous metal coating was proposed to promote the wear and corrosion resistance under multigrade diesel engine oil (15W-40) diluted with 7% palm oil-based biodiesel (B30). The coating was performed using laser cladding technique at different scanning speeds (40 and 60 mm/s) and constant laser power 280 W. Microstructure investigation and X-ray diffraction confirmed amorphous structure and crystalline phase (FeCr). It was found that the wear rate was reduced for the coated specimens by about 90% compared to the uncoated samples. The corrosion rates decreased by 54.74% and 69.96% for scanning speeds 40 and 60 mm/s, respectively. Thanks to the reduced microstructural defects such as grain boundaries in the amorphous structure of the coating. These findings showed that amorphous metal coating provides promising solutions to increase the reliability of using biodiesel without the need for corrosion inhibitors which reduce the combustion efficiency.

This study examines the mechanical and tribological properties of FeCrMoCB amorphous coatings on AISI 52100 bearing steel using laser cladding (LC). Two samples with varying LC parameters were compared to uncoated polished steel. Analytical methods included scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness testing and tribological tests via a high-frequency reciprocating rig (HFRR) tribometer under both dry and lubricated conditions, were employed. Sample S1 exhibited a microhardness five times that of uncoated steel and a 95% reduction in wear volume loss under dry conditions. Under grease-lubricated, S1 showed a 20% reduction in the coefficient of friction and a 93% reduction in wear volume loss. Sample S2 also outperformed uncoated steel. These results highlight the significant benefits of FeCrMoCB coatings.

Purpose The purpose of this study is to evaluate the performance of a modified engine oil filter in biodiesel-driven internal combustion engines. Specifically, it aims to assess the filter’s effectiveness in improving engine oil properties, reducing wear and corrosion, and enhancing engine longevity. Design/methodology/approach The study investigates the impact of a modified engine oil filter on biodiesel-driven engines. The filter was designed using 3D modeling, machining and chemical modifications to enhance durability. Engine tests were conducted for 100 h, with oil samples extracted at 20-hour intervals. Physiochemical properties, including viscosity, total acid number (TAN), total base number (TBN) and wear characteristics, were analyzed. Tribological tests, including HFRR and four-ball tests, assessed friction and wear. Corrosion was examined using immersion tests, while scanning electron microscopy (SEM) analyzed surface morphology, providing comprehensive insights into filter performance. Findings The modified engine oil filter significantly improved engine oil performance. Viscosity increased by 6.2%, TAN decreased by 13.4% and TBN retention improved by 11.87%. Tribological testing revealed a 13.2% reduction in the coefficient of friction (COF) and a 32.4% decrease in wear scar diameter (WSD). Corrosion rate analysis showed a 23.07% improvement in corrosion resistance with the modified filter. SEM confirmed reduced corrosion pit formation, demonstrating that the modified filter effectively enhanced wear resistance, oil quality and engine component longevity. Research limitations/implications The scope of the study was confined to specific tribological and corrosion tests, and more comprehensive lifecycle analyses are needed. Future research could explore the scalability and economic feasibility of the modified filter, as well as its impact on various engine configurations and biodiesel blends. Practical implications By enhancing oil performance and reducing wear and corrosion, it could lead to lower maintenance costs and extended engine life. The use of this filter can benefit industries that rely on biodiesel, including transportation and agriculture, by improving fuel sustainability and reducing engine-related issues. Originality/value This study presents a novel modification to engine oil filters by incorporating a weak base inhibitor to improve biodiesel-driven engine performance. Unlike conventional filters, the modified design reduces corrosion, wear and oil degradation while enhancing filter lifespan. The findings highlight the significant impact of this innovation on the sustainability and efficiency of biodiesel use in internal combustion engines. This research provides valuable insights into optimizing biodiesel engine performance and supporting the transition to renewable energy sources. Peer review The peer review history for this article is available at: Link to website of Web Science

Sewage sludge is a residual by-product of the treatment of municipal or industrial wastewater. The aim of this study is to increase the value of dual waste to produce sustainable lubricants. By implementing esterification (at degrees C for 2 h with 1 vol% H2SO4) and transesterification processes, which were optimized using artificial neural networks (ANN), sewage sludge and waste cooking oil (WCSSO) were converted to biolubricants (WCSSME), with a model accuracy of R2 = 0.9770. Optimal parameters (Reaction time = 4.65 h, methanol-to-oil ratio = 3.66, glycol loading = 1 %, KOH = 0.64 wt%) led to predicted conversions of 96.88 % and experimental conversions of 96.14 % +/- 0.302. The biolubricant exhibited improved lubricity, with a coefficient of friction (COF) 0.04791, which was 23 % less than the commercial lubricant at 0.0622 and a wear scar diameter (WSD) of 465 mu m, 44.4 % lower than the commercial 836 mu m. In addition, it displayed stable rheological properties conforming to ISO VG 46 standards. These results confirm the utilization of sewage sludge-WCO as a sustainable feedstock for high-performance industrial biolubricant production, advancing practices of a circular economy.

Biodiesel-diesel blends are known to result in increased NOx emissions compared to diesel alone, while ethanol as a ternary fuel in diesel-biodiesel shows that the blend successfully lowers diesel fuel NOx emissions but increases BSFC consumption. Hypothetically, pentanol, when added to blends as a second alcohol, may enhance engine performance and lower NOx emissions because pentanol exhibits superior characteristics including cetane number (CN) and viscosity, which is closer to diesel, as well as a higher calorific value. Therefore, this research aims to investigate engine performance and exhaust emission diesel engine operating with dual alcohol (ethanol and pentanol) +B20 POME biodiesel blend. The experiments involved evaluating different engine loads (25%, 50%, and 75%) at a constant speed of 1800 RPM. The findings indicate that the BSFC of dual alcohol blends are higher than diesel and B20 for all tested loads, with B20E10P10 showing least increment by 6.56% and 11.18% respectively. At 75% engine load, B20E10P30 exhibits a higher BTE by 2.11% compared to Diesel. The addition of dual alcohol in the blend significantly reduces NOx emissions, especially with B20E10P30. CO₂ emissions from B20E10P30 are closer to diesel fuel and B20, being only 1.54% lower than diesel and 0.79% higher than B20 at lower engine loads. For CO emissions, B20E10P10 shows the lowest CO emissions compared to B20E10P20 and B10E10P30. The findings suggest that combining higher alcohol with lower alcohol can effectively enhance the overall performance and emission characteristics of the fuel blend, supporting the hypothesis above.

Biomass can be converted into carbon through carbonization processes (pyrolysis and hydrothermal carbonization) and activation (physical and chemical). The resulting carbon has a high potential as a supercapacitor electrode material due to its porous structure, which supports rapid ion transport. Various methods have been developed to extract or transform biomass into porous carbon. One of the newly developed nanocarbon materials is carbon nanotubes (CNTs) because they have advantages in terms of mechanical, physical, chemical, and electrical properties. This review discusses various kinds of CNT synthesis as activated carbon composites for supercapacitors. The synthesis of these CNTs can be conducted through chemical and physical methods, including arc discharge, laser vaporization, and chemical vapor deposition (CVD). This work reviews various methods of CNT synthesis and analyzes the best methods to be used as composites for supercapacitors for electric vehicles. It is concluded that CVD is the best method for synthesizing CNTs. Its main advantage is that CNTs can be used directly without purification unless the catalyst particles need to be removed. However, further experimental studies are required to find the most optimal conditions for each composite from a type of mesoporous activated carbon and CNTs in terms of preparation and performance outcome.

The shift from fossil fuels to renewable energy is a crucial strategy to achieve carbon neutrality. However, the methanol industry relies heavily on fossil fuels. Alternative feedstocks, such as biomass and plastics, still face many challenges. Biomass is hydrogen-deficient and cannot achieve a high methanol yield, while plastic gasification consumes too much energy. Accordingly, this research proposed a new method to synergistically coproduce methanol and biochar from bagasse pyrolysis and plastic waste gasification. This innovative approach was assessed using techno-economic analysis and hybrid life-cycle assessment based on sugarcane bagasse resources in Guangxi province as a case study and compared with the other four scenarios. The results indicated that the novel method exhibits huger economic and environmental benefits with a low payback period of 6.32 years and a low global warming potential of -1875.41 kg CO2-eq/t. However, the high total capital cost is the primary potential obstacle to widespread promotion. Spatial-temporal analysis shows that Chongzuo and Laibin have the most tremendous methanol production potential and economic and environmental benefits due to their high bagasse production. This study contributes to biomass utilization and plastic waste management by proposing a synergistic process and offers multiple benefits for carbon sequestration, energy security, and waste valorization.

Graphene is a 2D material with exceptional properties that surpass those of many other materials in many respects. Conventional methods of graphene synthesis heavily rely on gaseous carbon (C) precursors, primarily hydrocarbons; such as methane or ethylene; that have significantly negative effects on the environment. The global shift towards sustainability and eco-conscious practices has increased the need for graphene production methods that are sustainable. As such, multiple studies have explored alternative sources of C, particularly bio-based materials, as well as waste-to-value processes. Reusing bio-based materials as C-based precursors not only addresses the urgent need for C sources that are sustainable and environmentally friendly but effectively creates a circular economy in the materials science and technology industry. As such, this present study explores the methods of synthesising, applying, and optimising the conversion of bio-based renewable solid carbon (SC) and liquid carbon (LC) precursors derived from a diverse range of C sources; such as lignocellulosic biomass, agricultural residues, and everyday vegetable oils; into high-quality graphene. The findings emphasise the promising role of renewable SC and LC precursors in the pursuit of sustainable and environmentally responsible methods of graphene production.

These days, cutting emissions and increasing fuel efficiency are more pressing issues than ever before. Automakers have long pursued ways to make internal combustion engines more efficient, in addition to electrifying powertrains. Vegetable oil provides substantial research and production cost advantages compared to mineral and synthetic oils, making it a sustainable and economically feasible option. This article examines TMP's tribological performance in a commercial engine vehicle adapted to operate on motor power without combustion energy. The impact of spark plug installation while running is also examined. In contrast, fuel injection adjusts combustion rates during operation, which might impact the lubrication test variable. In this research, a fourball and commercial engine to evaluate the tribological performance of TMP ester, mineral oil (MO) and fully synthetic oil (FSO). The result shows that the TMP ester being the most efficient due to its low viscosity and strong film- forming properties compared to MO and FSO. Besides that, TMP ester has efficiency of 49.33% without spark plug, and 54.5% with the use of spark plug. Spark plugs has improved engine performance by creating a pressurized chamber.

Biodiesel and bio-lubricants became desirable options as alternative fuel and engine oil, respectively, to meet sustainability goals. However, their effects on the performance and longevity of engines are not wellestablished yet. The lubricity performance of engine oils is affected by oxidation and biodiesel dilution, potentially resulting in reduced efficiency and tribological characteristics. This research investigates the effect of oxidation on the physicochemical and tribological properties of aged pentaerythritol (PE) ester diluted with 0%, 1%, 5% and 10% palm oil biodiesel blend (B30) as well as 5% B30 + 0.2% antioxidant additive and compared to pure PE ester. The results showed that ageing and biodiesel dilution increased the kinematic and dynamic by 504.02-521.87% at 40 degree celsius and 148.25-154.44% at 100 degree celsius. Additionally, they significantly improved the coefficient of friction (from > 0.1 to less than 0.06) and the wear rate compared to unaged-undiluted PE ester. It was found that the antioxidant additive reduced the dynamic and kinematic viscosities which resulted in higher COF and wear rate compared to the aged and biodiesel diluted samples.

Currently, pyrolysis is the primary choice for addressing the significant problems caused by plastic waste. Temperature and catalysts are the main parameters in pyrolysis. However, using catalysts can become a serious problem when scaling up production capacity, as the process can become more complex and expensive due to the high cost of catalysts. Without a catalyst, the required pyrolysis temperature must be sufficiently high to achieve high-quality pyrolytic fuel oil. In this work, plastic grocery bag is pyrolyzed followed by distillation to produce a liquid similar to conventional fuel, called distillate plastic fuel. Non-catalyst and low-temperature pyrolysis was performed at a single temperature of 350 °C, followed by distillation at temperatures of 250 °C and 350 °C to determine the effect of distillation temperature on the chemical properties of the obtained distilled fuel. Elemental and composition analyses were conducted using the GCMS method. Results indicated that the chemical properties and composition of distilled plastic fuel are similar to diesel fuel with a heating value of approximately 43.362 to 44.364 MJ/kg.

The current study builds upon the prior research (Mulkan et al., 2023) [1], which successfully created an innovative solid catalyst from discarded jackfruit peel waste (JPW) to produce biodiesel from waste cooking oil (WCO). Expanding on this initial research, our study's primary objective is to assess the performance and emissions attributes of a diesel engine when utilizing blends of WCO biodiesel and conventional diesel fuel under full load conditions, covering engine speeds from 1200 to 2400 rpm. The results show that as engine speed increases, brake-specific fuel consumption (BSFC) decreases by an average of 16.67%-22.69%, while brake thermal efficiency (BTE) increases by 16.67%. Engine torque initially decreases and drops significantly at higher speeds, while brake power (BP) proportionally rises. Notably, substantial reductions in CO emissions (ranging from 6.11% to 48.63%) were observed at all engine speeds compared to pure diesel. However, CO2 and NO emissions generally increased, although some fuel samples demonstrated reductions. Hydrocarbon emissions decreased with higher engine speeds, while smoke opacity increased, with slight reductions observed for specific fuel samples at 1800-2400 rpm. In conclusion, blending WCO biodiesel synthesized using the JPW catalyst with pure diesel results in improved engine performance and reduced exhaust emissions.

Sustainable aviation fuels (SAFs) provide a vital pathway to reduce emissions from the growing aviation sector. Taking this inspiration, this review critically examines recent progress in the catalytic deoxygenation (DO) of triglycerides (TGs) feedstocks to produce renewable jet fuel without external hydrogen (H2) requirements. The effects of various key parameters are analysed in terms of its selectivity, efficiency and production yields. The choice of catalyst can be regarded as the most significant parameter followed by the temperature then the feedstock. This review provides an up-to-date examination of this emerging technology area and its status in overcoming barriers to viable aviation biofuel production.

Despite the economic and environmental benefits of biodiesel, it poses significant challenges, including coking on metal surface and increased wear on diesel engine injector nozzles. Therefore, this study investigates the synthesis of niobium-doped diamond-like carbon (Nb-DLC) coatings on two types of injector nozzle materials (viz. H13 steel, AISI 420 stainless steel) using the Closed-Field Unbalanced Magnetron Sputtering (CFUBMS) technique. Comprehensive characterizations, including microstructural analysis, crystal structure evaluation, hardness assessment, and tribological property assessment, were conducted. The Nb-DLC coatings demonstrated a stable friction coefficient, with values four times lower than that of the substrate materials. The present findings demonstrate significant enhancements in terms of structural composition, crystalline phase, hardness, friction coefficients, and adhesion properties due to the Nb-DLC coatings. Therefore, Nb-DLC coated materials could be the promising candidate material for biodiesel engine injector nozzle applications. This emphasizes their potential to contribute significantly to the sustainable consolidation of biodiesel within automotive engine.

Methanol is regarded as an important chemical precursor in the chemical industry and has huge potential to replace gasoline and diesel as vehicle fuel. Biomass to methanol is a sustainable and green production method, but its economic and environmental viability is contingent on production technologies and geographic context. This study proposed a carbon-negative methanol production method that integrated four modules of bagasse pyrolysis, physical activation, chemical looping, and methanol synthesis in the context of China. Three scenarios, including co-production of methanol and biochar, co-production of methanol and activated carbon, and coproduction of methanol and activated carbon with extra hydrogen, were put forward and simulated in Aspen Plus. An evaluation system was established to quantitatively assess the carbon and energy efficiencies and economic and environmental benefits of the three scenarios. The results suggested that the addition of hydrogen effectively increased the methanol yield in Scenario 3, leading to high carbon and energy efficiencies. Scenarios 1 and 2 exhibited better economic and environmental performance with low payback periods of 6.53 and 5.80 years and low global warming potentials of -1631.18 and -710.28 kg CO2-eq/t methanol. However, Scenario 3 would be economically and environmentally feasible by decreasing hydrogen production costs and implementing green hydrogen production methods in the foreseeable future. This study provides a viable approach for sustainable methanol production in China, thereby aligning with the current imperative of achieving carbon neutrality.

Biodiesel is one of the most promising alternative liquid energy carriers for use in the transport sector. Biodiesel can be produced from edible or nonedible feedstock by different processes. The ASTM D6751 and EN 14214 standards are used to evaluate biodiesel quality. Despite a vast number of research works and projects conducted on different aspects of biodiesel production and consumption, there are still important challenges to be addressed by future investigations. Past experiments have shown that biodiesel is feasible as a successful alternative fuel for the transport sector. This chapter the main areas that should be covered by future investigation: (1) sustainable production of biodiesel feedstocks to achieve a transition from first-generation biodiesel (produced from edible resources) to higher-generation biodiesels (nonedible resources, including nonedible energy crops and waste oils/fats); (2) improving the analytical techniques used for determining the physicochemical properties of biodiesel; (3) upgrading and improving the fuel properties of biodiesel using various economically and environmentally viable fuel additives; (4) conducting more sophisticated and in-depth engine analysis, including engine endurance test for new biodiesel formulations, and (5) thorough analyses of various stages of biodiesel production and consumption using advanced sustainability assessment techniques, including techno-economic analysis, life cycle assessment analysis, emergy, exergy, and the combination of these methods.