Preparation of Buoyant Adsorbent for the Removal of Heavy Metal Ions in Rainwater Runoff: Characteristics of Manganese – Dioxide – Coated Polypropylene Granules

Abstract

For the treatment of contaminated rainwater runoff, the synthesis of manganese dioxide and its coating onto buoyant polypropylene granule was done with accompanying adsorption experiments. Results showed 35-45 m oxide coating was stable under severe hydrodynamic conditions, had 37 mg of Mn attached per gram of granules, moreover, consisted of mixed birnessite and cryptomelane forms of manganese dioxide. Adsorption capacity of each gram of media was 4.9, 3.9, 0.98, 0.75 mg of Pb , Cu , Cd , and Zn , fitting well to the Freundlich adsorption model. Manganese-dioxide-coated polypropylene granules had favorable engineering advantages and excellent adsorptive properties, being challenging alternative to other practically-oriented in situ or centralized rainwater treatment media.