Effect of Rhizoclonium grande-derived Saturated Fatty Acid Ethyl Esters on the Properties of Jatropha curcas Biodiesel Blends
J. M. Kahindo *
Department of Chemistry and Biological Sciences, Technical University of Mombasa (TUM), Mombasa, Kenya.
C. Sumesh
Department of Chemistry, Kenyatta University, Kenya.
R. Musau
Department of Chemistry, Kenyatta University, Kenya.
J. O. Odalo
Department of Chemistry and Biological Sciences, Technical University of Mombasa (TUM), Mombasa, Kenya.
T. Thoruwa
Department of Physics and Technology, Pwani University, Kenya.
*Author to whom correspondence should be addressed.
Abstract
Background: Although algal biodiesel has gained increasing attention as a renewable alternative, the role of algal-derived saturated fatty acid ethyl esters, especially from underexplored species such as Rhizoclonium grande in modifying the properties of commonly accepted biodiesel blends, remains less understood.
Aims: The effect of Rhizoclonium grande saturated fatty acid ethyl esters on physicochemical and fuel properties of Jatropha curcas biofuel was assessed.
Methodology: The study was conducted at the Technical University of Mombasa, Jomo Kenyatta University of Agriculture and Technology, Government Chemist, and Kenya Pipeline Laboratories in Mombasa, Kenya. A randomised block design with three blocks was employed, using Rhizoclonium grande and Jatropha curcas oils, their ethyl esters, and various blends. Probability and purposeful sampling methods were used to select samples, and each sample from a block was subjected to several treatments with three replications per treatment. Algae were collected from Shimoni in Kwale, Shelly beach, Jamvi la Wageni in Likoni and English Point in Mombasa to obtain algae oil. J. curcas seeds were collected from Shimba Hills, Kwale. Transesterification of J. curcas and Rhizoclonium grande oil was carried out separately, followed by GC-MS characterisation of the ethyl esters. Ethyl esters from J. curcas oils (JOFAEE) were blended with algae oil FAEE (5-25%) to obtain JAB1-JAB5. Physicochemical and fuel properties of JAB were assessed. Statistical analysis was done using STATA/SE 13.0 at 95% confidence level (P<0.05), two-tailed.
Results: Rhizoclonium grande produced 6.72 - 10.46 % v/w oil. From GC-MS analysis, the algae oil fatty acid esters contained pentadecanoic acid ethyl ester, dodecanoic acid ethyl ester, tetradecanoic acid ethyl ester and hexadecanoic acid ethyl ester. There was an observed significant difference in calorific value (P=0.03), kinematic viscosity (P=0.001), pour point (P=0.001) and cloud point (P=0.001) between JO FAEE and JAB samples, attributed to the presence of algae oil saturated FAEE. The JAB showed no significant difference in fuel properties with standard biodiesel B100 (P>0.05).
Conclusion: From the findings, the physicochemical and fuel properties of biofuel from J. curcas can be improved by the use of saturated FAEE from R. grande. This additive enables reliable engine performance and efficient combustion without any modification. Unlike common synthetic additives, R. grande esters are sustainable, renewable and quite compatible with infrastructure in existence. The approach is environmentally friendly, cost-effective, and reduces the need for other stabilisers, which simplifies storage and handling. Generally, this blend provides a scalable, practical strategy leveraging sustainable energy production for the advancement of biodiesel performance.
Keywords: Miscibility, biofuel blend, physicochemical properties, fuel properties