THE PROBLEM
1.1. Introduction
Heavy metals such as lead, zinc, copper, can often be found in industrial wastewater and their discharge to the environment poses a serious threat due to their acute toxicity to aquatic and terrestrial life which includes humans. As a result of increasing industrialization more heavy metals are continually released to the environment and this has prompted environmental engineers and scientists to think of better methods by which heavy metal-bearing wastewaters can be treated effectively and economically. The most used way of removing heavy metals in wastewater is through the use of activated carbon which is used as an adsorbent. This is due to the adsorptive properties of activated carbon(Cecen & Aktas, 2011).
Agricultural by-products represent a considerable quantity of harvested commodity crops. The use of by-products as precursors for the production of widely used adsorbents, such as activated carbons, may impart a value-added component of the overall biomass harvested. In most developing countries, the activated carbon is imported at high cost, limiting the quantities of safe drinking water available to the people (Gray, 2010, p.72).
In recent years, there has been research focusing on the use of appropriate, low cost technology for the treatment of drinking water in the developing world. Research has also been focused on the indigenous production of water treatment chemicals using locally available raw materials. Generally, the raw materials for the production of Activated Carbon are those with high carbon but low inorganic contents such as wood, lignite, peat and coal.
Activated carbons form a large and important class of porous solids, which have found a wide range of technological applications. The characteristics of activated carbon depend on the physical and