1.1 BACKGROUND OF STUDY
Palm kernel oil (PKO) is black viscous oil extracted from the kernel of oil palm. In its raw form it contains impurities such as organic pigments, oxidation metals, trace metals and traces of soap. For PKO to be used effectively, in most industrial processes, these impurities in it have to be extensively removed, thus making bleaching inevitable (Young, 1982; Macrae, 1993; Campbell et. al, 1999). Bleaching involves a mass concentration of the colour pigment at the interface between the fluid and the bleaching agent. it is achieved as a result of intermolecular forces between molecules of solid and the substances adsorbed and is readily reversible (Richardson, Harke and Backhurst, 2002). Adsorption bleaching is the most effective form of bleaching in which various adsorbents like carbon, silica gel, activated alumina and activated clay are used. The bleaching agent should be one that will change the tint of the oil without altering the chemical properties of the oil (Purvis, 1975; Parker 1987; www.fullerseearth.com, 2005). Several bleaching agents, especially clays, have been studied in recent times for various bleaching temperatures and times. Clays that have been studied include acid, neutral and caustic activated clays (Brophy et. al 2004; Arumughan et. al 2004; Okwara and Osoka, 2006). Clays are non- renewable resources. This work studies the optimal conditions, with respect to bleaching temperatures and contact time (Malek and Farooq, 1997) for the use of periwinkle shell (a renewable resource) as an adsorbent in the bleaching of PKO.
1.2 STATEMENT OF PROBLEM
Periwinkle shell is ideal for this process because it contains calcium carbonates (a carbonaceous material), and much of the substances volatilizes on heating, leaving behind a porous structure of carbon that usually contain some hydrogen. This may, then, be activated to further open up the pores and increase total surface area. In addition, it is also passive to crude PKO.
1.3 AIM AND OBJECTIVES OF STUDY
The main aim of the research work is to examine the synthesis and characteristics of name properties from periwinkle shell for bleaching of palm kernel oil. Other specific objectives of the study are:
1. to determine the effect of temperature on the periwinkle shell ability to reduce colour in palm kernel oil
2. to investigate on the factors affecting the use of periwinkle shell for the bleaching of palm kernel oil
3. to examine both the Chemical and thermal activation of the Snail shell
4. to examine whether periwinkle shell have commercial purposes
1.4 RESEARCH QUESTIONS
The study came up with research questions so as to ascertain the above stated objectives of the study. The research questions for the study are:
1. What is the effect of temperature on the periwinkle shell ability to reduce colour in palm kernel oil?
2. What are the factors affecting the use of periwinkle shell for the bleaching of palm kernel oil?
3. What are the Chemical and thermal activation of the Snail shell?
4. Does periwinkle shell have commercial purposes?
1.5 SIGNIFICANCE OF STUDY
The study is a very important one in the sense that the study will educate chemistry students, food science and technology students on the synthesis and characteristics of name properties from periwinkle shell for bleaching of palm kernel oil. The study will serve as a repository of information to other researchers that desire to carry out similar research on the above topic. Finally the study will contribute to the body of existing literature and knowledge in this field of study and provide a basis for further research
1.6 SCOPE OF STUDY
The study will cover only on the bleaching ability of periwinkle shell on palm kernel oil. Other properties of periwinkle shell will not be discussed in this study.
1.7 DEFINITION OF TERMS
Periwinkle: The common periwinkle or winkle is a species of small edible whelk or sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles.