1.0 INTRODUCTION AND LITERATURE REVIEW
Water is an essential part of human nutrition, both directly as water or indirectly as a constitution of food in addition to various other applications in daily life. Water is not only essential for life, it also remains a most important vector of illness and infant mortality in many developing countries and even in technologically more advanced countries.It’s also a key parameter influencing survival and growth of micro-organisms in food and other microbial environments. In the order of importance, air, water and food are the three main necessities of life. A person can survive for about a month without food, about a week without water and less five minutes without air. The provision of an adequate supply of safe water was one of the 18 components of Primary Health Care identified by the International Conference on Primary Health Care (Edemeet al 1978).
Water of good quality is of basic importance to human physiology and man’s continued existence depends very much on its availability. An average man of (53-63kg) body weight requires about 3litres of water in liquid and food daily to keep the body healthy. (Wordlowet al 2004).This fact apparently, is why water is regarded as one of the most indispensable substances in life and like air, its most abundance. However, despite its abundance, good quality water is not readily available to man. Since the end of the last century a large amount of products, such as medicines,disinfectants, contrast media, laundry detergents, surfactants, pesticides, dyes,paints, preservatives, food additives, and personal care products, have been released by chemical and pharmaceutical industries threatening the environment and human health. Currently there is a growing awareness of the impact of these contaminants on groundwater, rivers, and lakes. Therefore the removal of emerging contaminants of concern is now as ever important in the production of safe drinking water and the environmentally responsible release of wastewater (Kummerer 2009, Zuccato et al,2007).
Adsorption is a major industrial separation technique for the purification of effluent media. It is a mass transfer operation by which a solid material can selectively remove dissolved components from an aqueous solution by attracting the dissolved solute to it’s surface. Therefore, it involves the inter phase accumulation of concentration of substances at a surface or at the inter phase (Tien,1994). This separation technique finds wide application in removal of dye from aqueous media. Specially, it finds application in textile industries where water recovery is very essential. In order to achieve and sustain this efficient recovery of desired water quality, a careful selection of adsorbent is very paramount (Keller et al,1987, Albarins and Hela,1993).
However, the array of adsorbents available in our local markets are imported from other countries; inspite of abundance of raw materials in Nigeria for the production of the required quantity of adsorbents for our local industries. This situation calls for inward looking that adds impetus to the need to produce adsorbents sourced from our local raw materials such as plantain peels, animal hairs, corn cobs, coal, and animal bones etc. (Swaraj et al, 2001,) . Several studies on the adsorption of a single component from an aqueous solution onto activated carbon and similar materials have been performed experimentally with different system. (Olafadehan and Aribike, 2001). In one of such studies, activated carbon was used to remove highly odorous p-cresol from waste water (Baker et al,1973).Adsorption tests alsoshowed that granular activated carbon removed colour and phenol completely from industrial effluent (Gould and Taylor, 1969). As a contribution towards sourcing of local adsorbents, activated clays are used. The investigation also incorporates the study of the Freundlich and Langmuir isotherms. Armed with the data from this study, a valuable assessment on the efficiency and design of adsorption units can be made.
1.1.1 BACKGROUND OF THE STUDY
The most abundant, ubiquitous, and accessible material on the earth crust is clay (Olokode,2011). (Rado,1988) observed that a great emphasis is placed on exploiting the abundant solid minerals endowments in Nigeria with a view to diversifying the economic base of the country, improving Gross Domestic Product (GDP) and industrial activity. One of these endowments with tremendous potential for economic utilization is clay. Clay deposit is spread across the six geo- political zones of the country (Adegoke,1980). Clays have their origin in natural processes, mostly complex weathering, transport, and deposition by sedimentation within geological periods (Nosbusch,1988). The abundance of the clay minerals in Nigeria supports its rich and historic traditional pottery industry that dates from the Stone Age. Archeological evidences from the ancient pottery areas of Nigeria such as Iwo-Eleru near Akure in Ondo State, Rop in Plateau state, Kagoro in Kaduna State and Afikpo in Ebonyi state proved that as far back as the late stone age, the occupants of these areas made productive used of clay for pottery (Fatunsin,1992). The composition of clayey and organic materials such as straws made into adobe brick, served as a ubiquitous building material widely used for building weather-friendly houses in the vast rural domains. Modern industrial uses of clay for ceramics and bricks now obtained in notable parts of the country including Kaduna, Northern Nigeria. Clay is simply defined as earth or soil that is plastic and tenacious when moist and that becomes permanently hard when baked or fired. It consists of a group of hydrous aluminosilicate minerals formed by the weathering of feldspathic rocks, such as granite. Individual mineral grains are microscopic in size and shaped like flakes. This makes their aggregate surface area much greater than their thickness and allows them to take up large amounts of water by adhesion, giving them plasticity and causing some varieties to swell (expandable sclay). According to Callay et al( 1977) one of the hall marks of an advanced civilization is its concern for the disposal of its society’s waste products in a safe and environmentally acceptable manner.Under the present legislation, industrial effluents may be discharge into either to the sewage system or to the natural water course provided they conform to the requirements of the appropriate statutory bodies.
To this end, huge amount of money is spent either to import appropriate technologies or materials for the treatment of these effluents. This work is intended to provide alternative liquid effluent treatment using the locally obtainable material at minimal or zero cost.