The aquatic plant water hyacinth is a powerful tool for mediating pollution from aquatic environment. PM3 semiempirical method and FTIR spectroscopy was used to predicate the mechanism of pollution control. First the plant is subjected to acetic acid 0.1 M for 19 hours. FTIR proves that the plant is cellulose like material. Furthermore, the acetylated plant is looks like cellulose acetate. The mechanism of acetylation is tested using PM3 method. CH3COOH is interacted with OH of CH2OH by two ways. The first is through H-bonding of CH3 the second is through the interaction of the H-bonding of COOH. The mechanism of divalent metal removal was such that Cd as an example is coordinated with acetylated plant either through two OH of CH2OH or through two COOH attached with CH2OH.