Remediation via adsorption process has been proven to be one of the best water treatment technologies globally. Many adsorbents, including agricultural wastes, have been considered for the removal of a variety of pollutants from water. However, most of the studies reported in the literature used metal concentrations below 1000 ppm. It is also known that initial metal concentrations in polluted aqueous solutions, as well as metal and adsorbent type, are some of the factors that affect metal removal. Therefore, this project examined the remediation of water contaminated by 1000 ppm of lead, zinc, copper, magnesium, and calcium ions using wood ash, sodium hydrogen phosphate (dibasic), and sodium carbonate (dibasic). Comparative analysis of the results showed the order of order of metal removal by the adsorbents as: dibasic phosphate (Ca > Cu > Pb > Zn > Mg);dibasic Carbonate (Pb ~ Ca > Zn > Cu > Mg);Wood ash (Mg > Cu > Zn > Pb > Ca). These results suggest that metal and adsorbent type as well as the inherent chemical properties of these metal cations may contribute to the varying binding affinity of the metals to the adsorbent ligand(s) and thus, affect the extent of metal removal. It is equally worthy to note that wood ash more effectively removed hardness metals (Mg and Ca) from water than the inorganic phosphate and carbonate ions.
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