Vol.:(0123456789) 1 3 Chemistry Africa (2019) 2:507–515 https://doi.org/10.1007/s42250-019-00071-0 ORIGINAL ARTICLE Optimization of Binary Mixtures of Biodiesel and Fossil Diesel for Clean Energy Combustion Bornes C. Mosonik 1  · Joshua K. Kibet 1  · Silas M. Ngari 1 Received: 7 February 2019 / Accepted: 24 May 2019 / Published online: 31 May 2019 © The Tunisian Chemical Society and Springer Nature Switzerland AG 2019 Abstract There is an urgent interest initiated to develop clean energy resources with the aim of reducing exposure to environmental pollutants and explore model fuels that can hasten the achievement of clean energy combustion. This work investigates vari- ous ratios of biodiesel and commercial diesel in order to propose model binary fuels for clean energy combustion. Accord- ingly, diesel blends of ratios 1:1, 3:2 and 2:3 were each pyrolyzed at a contact time of 5 s in a quartz reactor at 1 atmosphere pressure. A model temperature of 500 °C was explored in these experiments. The charcoal content for pure fossil diesel was compared with the binary diesel residue. Gas-phase molecular components were determined using Gas chromatography (GC) coupled to a mass selective detector (MSD). Elemental composition of thermal char was determined using Smart Elemental Analyzer. Radical intensities for the three types of char (biochar, bio-fossil char, and fossil char) were measured using an X-band electron paramagnetic resonance spectrometer. It was noted that at a ratio of 2:3 (Biodiesel: Fossil diesel), harmful molecular products reduced signifcantly, 76–99%. Elemental analysis data indicated that the carbon content from commer- cial diesel was very high (≈ 70.61%) as compared to approximately 53% for biodiesel-fossil diesel mixture in the same ratio 2:3. Interestingly, the free radical content was reduced by nearly 50% in favour of the biodiesel/fossil diesel mixture. These results are encouraging and suggest that a better optimized fuel mixture has been found for better clean energy combustion. Keywords Clean energy combustion · Elemental composition · Diesel blends · Thermal char 1 Introduction One of the mounting challenges facing the twenty-frst cen- tury is energy security, environmental pollution and public health complications including asthma, carcinogens, and acid rains. Renewable energies are considered the possible solutions to most of these challenges. Therefore, thorough research is of essence to gain insight on new energy tech- nologies with the primary focus of maintaining secure and renewable energy resources for sustainable development, better public health care and improved economies. The increase in fuel demand, depletion of fossil fuels reserves with exponential increase in population and economic growth is the precursor that has precipitated the search for alternative energy resources [1]. Furthermore, the toxic nature associated with exhaust emissions from vehicles fueled by fossil diesel has enhanced the search for alterna- tive fuels such as biodiesel and diesel blends (binary and ternary fuels from biodiesel and fossil diesel). A number of studies have reported the impact of blending fossil die- sel and biodiesel fuel on engine performance and emission characteristics that may have serious environmental bearing on human health and other ecosystems [2–10]. Conventionally, pyrolysis is the thermal degradation of biomass in absence or limited supply of oxygen [11] to form enormous pyrolysis reaction products (benzene and its derivatives, furans and dioxins) and particulate emis- sions considered harmful to human health and natural eco- systems [12]. Secondary oxidation products may include aldehydes, ketones, low molecular acids and volatile organic compounds, resulting in the increase of acidity as the degradation progresses [13]. The by-products of pyrol- ysis also include an array of particulate matter such as * Joshua K. Kibet jkibet@egerton.ac.ke Bornes C. Mosonik borenes2000@gmail.com Silas M. Ngari msngari@yahoo.com 1 Department of Chemistry, Egerton University, PO Box 536 -20115, Egerton, Kenya