Adsorption and Its Applications: Using Zinc Adsorption on Water Hyacinth to Elaborate the Kinetics and Thermodynamics of Adsorption

Abstract

Adsorption is a technique for removing adsorbate from the liquid or gas phase using adsorbents. The adsorbent is solid while the adsorbate can either be dissolved in liquid or gas. Adsorption has attracted the attention of many researchers because of its wide applicability in water and air purification, environment friendly, effectiveness, and ease to design as compared with the other methods. Activated carbon has been used as an effective adsorbent. However, its application is limited since it’s expensive. This has necessitated research interest in other materials that are safe and economical instead of commercial activated carbon. Some of the materials that have been successfully tested include sawdust, silica gel, zeolites, clay minerals and oxides, nanomaterial, agricultural by-products, biological waste, ion exchange resins and water hyacinth, etc. Although some of these materials are effective, they are not readily available. The kinetics of adsorption is done through testing the adsorption data against standard kinetic models and the model with the best line of fit, based on the values of coefficient of determination (R2) is selected. The adsorption process is described using isotherms such as Freundlich and Langmuir. This chapter sheds more light on adsorption, the most common adsorbents, kinetic models, isotherms, and adsorption applicability.

Removal of Ni(II) and Cu(II) in Aqueous Solutions Using Treated Water Hyacinth (Eichhornia crassipes) as Bioadsorbent

“…In underdeveloped countries, the treatment of effluents containing heavy metals before discharge into the sewer is often inadequate [3][4][5]. Heavy metals are non-biodegradable, exhibit high mobility in aquatic systems, and are soluble in water, which allows them to be adsorbed in cells and accumulate in the tissues of organisms, causing serious damage to the composition of blood and the respiratory and nervous systems [2,[4][5][6][7]. Among the heavy metals that cause the most concern are Ni, Cu, and Co, which are used in electroplating, paint, fertilizers, tanning, metallurgy, etc.…”

“…Due to this hypertoxicity of heavy metals, removal methods have been developed such as those that use physical barriers (reverse osmosis membranes), electrochemical processes (electrolytic extraction and electrodialysis), chemical precipitation, ion exchange, and other techniques [2,3,7,9], which are effective but turn out to have high costs for infrastructure and control and require too much energy [1][2][3]5,6,9]. Adsorption is a costeffective and efficient method used to remove pollutants such as dyes (methylene blue, methyl orange, phenol red) and heavy metals such as Cr, Ni, Pb, Cd, Cu, Zn, and Fe, among others [2][3][4][5][10][11][12].…”