Organic-inorganic hybrid composites for removal of heavy metal ions from water

Organic-inorganic hybrid materials with excellent heavy metal ions chelating properties were prepared by covalent bonding of vinyl-terminated polyamidoamine (PAA) onto aminated silica particles. Two series of polyamidoamine grafted silica, differing in the PAA chemical structure, were synthesized and their heavy metal ions chelating properties were investigated. Column adsorption procedure for Cu, Zn and Ni in aqueous solution was successfully established Moreover, the adsorption behaviour of the materials was evaluated in different ionic strength solutions as well as in the distilled and natural water. Organic-inorganic hybrid materials exhibited good chelating properties and selectivity for metal ions. The hybrid columns exhibited excellent eluting and regenerating property using diluted hydrochloric acid solution as eluent. The hybrid materials containing more carboxy groups possessed superior adsorption ability, reusability and stability which can be repeated to use 20 cycles with recoveries not less than 95%.