Nanoparticle enhanced biodiesel blends: Recent insights and developments

Nanoparticle-enhanced biodiesel blends present a promising alternative to conventional fuels by significantly improving combustion efficiency, emission control, and fuel stability. This review examines the integration of various nanoparticles, including titanium dioxide (TiO 2 ), copper oxide (CuO), and aluminum oxide (Al 2 O 3 ), which have demonstrated notable improvements in brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and reductions in emissions of carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM). Non-metallic nanoparticles, such as graphene oxide and carbon nanotubes (CNTs), further enhance engine performance by improving thermal conductivity and fuel atomization. The use of hybrid nanoparticle blends, such as TiO 2 –CuO, capitalizes on synergistic effects to achieve superior combustion characteristics and enhanced emission control. Additionally, emerging materials like cerium oxide (CeO 2 ) and calcium oxide (CaO) have shown potential for improving oxidative stability and addressing combustion inefficiencies in biodiesel blends. This study investigates the effects of incorporating these nanoparticles into biodiesel, focusing on their impact on BTE, emission reduction, and overall fuel efficiency. The study also compares the BTE improvements and emission reductions achieved by different nanoparticles and hybrid blends, with a particular emphasis on the synergistic benefits of combining multiple nanoparticle types. The main findings indicate that nanoparticle-enhanced biodiesel blends significantly improve BTE, with Fe 3 O 4 nanoparticles leading to a 3.16 %–4.89 % increase, TiO 2 nanoparticles improving BTE by 5.2 % in a B100T50 blend, and Al 2 O 3 nanoparticles yielding a 9.83 % improvement in a B30 blend. The most significant improvement was observed with CeO 2 nanoparticles, achieving a 14.59 % increase in BTE in a B10 blend. Furthermore, hybrid nanoparticle blends such as ferric chloride-graphene showed a remarkable 33.26 % improvement, surpassing individual nanoparticle effects. The catalytic effects of RuO 2 , TiO 2 , and CuO nanoparticles contributed to reduced ignition delay, improved fuel-air mixing, and more efficient combustion, resulting in lower brake-specific fuel consumption (BSFC) and reduced emissions (CO, HC, and NO x ). The addition of graphene and MWCNTs in B20 blends further enhanced BTE and engine performance, demonstrating their versatility in improving fuel efficiency under varying engine loads. However, challenges persist, including nanoparticle agglomeration, production costs, scalability limitations, and environmental concerns regarding nanoparticle lifecycle and disposal.Future directions emphasize developing hybrid nanoparticles to enhance performance, optimizing nanoparticle concentrations, and standardizing integration methods for consistent quality. Advanced modeling approaches, such as machine learning, can expedite formulation and scalability.