Return to site



· Volume III Issue I


Scientific studies in coming up to renewable sources of fuel has become a high demand all over the world due to depletion of fossils. Biofuel is processed or obtained from plants and animals or living matter, that’s where its name was derived. This creates an idea of using alternative fuels as replacement due to the loss. Its importance was given emphasis because of its large scope of application, especially in driving mechanical operations, be in whatever field like agriculture, domestic, commercial and transport sectors, and also the fact of the continuous rise in fuels cost and their eventual vanishment, (Alamu et al., 2007). Thus, this makes fossil fuel a vital component to carry the processes to its dependents and being a renewable source, it is now gaining much attention all over the world.

The mushrooming of different biofuel plants around the globe is ultimately based from the needed source. This supports in providing alternative and massive production of fuel as demand in some various ways. Negros Occidental which has now became part of an autonomous region (Negros Island Region) last year, initiated its major step in seeking to become a biofuel center source in the said region. The operation of San Carlos Bioethanol Plant in Northern Negros Occidental materializes the production of biofuel from sugarcane, since majority of its agricultural land is planted with sugarcane. Jathropha (kasla) plants also considered by localities because it was found out by many researches to produce biodiesel out from the oil extracted from the plants. According to Demirbas (2005), the use of vegetable oils and their derivatives was found to be one of the reasonable solutions. However, the utilization of vegetables oils posted a lot of issues due to certain properties like its acid composition, viscosity and free fatty acid content. The analyses among oils received a deeper study as an effective ingredient in the transesterification of biodiesel. It has been chosen as an alternative fuel because it shows positive study results on its emission, flash point, lubrication, and high cetane number, besides from the fact that it is renewable by nature (Kouzu, et al, 2007).

There are several studies conducted about transesterification of vegetable oils or animal fats in converting into biodiesel. The process is being characterized by the conversion of triglycerides into diglycerides, monoglycerides and glycerol. At each change of conversion, one mole of ester formed (Diaz, Ferraz, and Almeida, 2008). In the biodiesel production, an emphasis to the type and nature of catalysts from a different kind of oil is intensively done for transesterification. Pugnet, et al (2010) and Demirbas (2009), categorized catalysts that are commonly used for biodiesel production into several types: homogenous catalysts (sodium hydroxide, potassium hydroxide, sulfuric acid, etc.), and heterogenous catalysts (cation-exchange resin, hydrotalcites, etc.), and enzymes (Chromabacteriumviscosum, Candida rugosa, and Porcine pancreas). Heterogeneous catalysts have been developed and studied in biodiesel production because it displays good points in terms of its reaction to low temperature and pressure, shows fast reaction on various raw materials and many other practical grounds (Serio, et al, 2007). 

On the other hand, homogenous catalysts are less desirable to use because of some drawbacks along with the enzymes. These include, they easily dissolved in methanol, relatively difficult to synthesize, susceptible to humidity and are more expensive. For acid catalysts, higher molar ratio of methanol to oil should be used, and it requires longer reaction time (Noiroj, 2009; Gao, 2010; and Ngamcharussrivichai, 2008). Since then, the development of a new system using heterogeneous catalysts from organic materials began to rise in the making of biodiesel.

In the present study, the researchers focused on brown mussel (Perna perna) or “tahong” as called in the locale of the study or  are common to tropical and subtropical regions usually found in rocky shores. This is an economically important mussel, a bivalve mollusk belonging to the family Mytilidae. It is usually 90 mm. long although it can reach sizes of up to 120 mm, brownish in color or appearance and its identifying characteristic is the divided posterior retractor mussel scar ( Apart from being candidate for commercial cultivation, the meat of P.perna can be utilized as animal feed or as an alternative food for human consumption, while the shells are discarded as waste. 

The utilization of P. perna shells as alternative raw materials in the production of heterogeneous catalysts for biodiesel is expected to raise its economic value and helps to overcome the waste problems. Shells can be considered as potential solid catalyst for biodiesel yield because it contains CaCO3 (calcium carbonate) which can be converted into CaO (calcium oxide) during its synthesis- calcination (Refaat, 2011). Yoosuk, et al (2010) and Viriya et al (2010), described CaO as heterogeneous catalyst which is better to use because it offers practical grounds in terms of price and offers good chemical standing on its alkalinity and solubility compare to that of KOH (potassium hydroxide)/ NaOH (sodium hydroxide), and also the ease of handling.

The research aimed in developing a new type of heterogeneous catalyst for biodiesel production derived from P. perna shells. The capability of the catalyst from the brown mussel shells were tested on the transesterification of canola oil into the biodiesel yield. The process parameters of making biodiesel such as: (a) characteristics of CaO solid particles derived from P.perna shells in terms of CaO concentration(% w/w), pH level and settling time; (b) which of the concentration of catalyst and methanol to oil will provide better yield of biodiesel; (c) characteristics and properties of produced biodiesel in the study and compare to standard values; (d) significant effect of the molar ratios of methanol to oil in biodiesel produced; (e) significant effect of various catalyst concentrations (% w/w) in yielding biodiesel; and (f) significant interaction of molar ratios of methanol to oil and catalyst concentrations in producing biodiesel; were also studied.

The researchers assumed that there were no significant effects and interactions among the studied parameters. In other words, all the treatments applied were of the same effect in a laboratory scale production of biodiesel.

see PDF attachment for more information