34th Annual British Zeolite Association Conference location:Edinburgh, UK date:11-13 April 2011
High concentrations of heavy metals are presented in many industrial wastewater streams, tailing ponds, contaminated groundwater, etc. The levels are often toxic to the human body and have an adverse effect on the ecosystem. Removal of these harmful substances from the water streams before they are discharged into the environment is essential. Methods such as precipitation, ion-exchange, membrane technology and adsorption have been employed to reduce the level of heavy metals; however, the economical competitiveness and user friendliness of these methods are important factors to stimulate industry to apply the technology. Therefore, development of low cost adsorbents that are capable of removing multi-contaminants is of interest.
Municipal solid waste incineration (MSWI) residues contain oxides of silicon and aluminium, and have intrinsic basicity. They are suitable for the synthesis of zeolitic substances that could be used as sorbents. The objective is to use a waste-to-product valorization concept to minimize the production and disposal costs. Synthetic zeolites have large specific surface area, high adsorption capacity and good cation exchange capability that help to reduce heavy metal concentration in aqueous media.
This study investigates the zeolite-like materials synthesized by hydrothermal method from MSWI residues. The sorbents synthesized are tested for sorption performance of aqueous species of contaminants (As, Cd, Zn, and Pb). Fig. 1 shows adsorption results of a simulated multi-contaminant solution obtained by addition of synthesized zeolitic material. To maximize the utilization of the incineration process residues, the adsorption capacity of sorbent material synthesized using intrinsic waste residue alkalinity will be compared with sorbent material synthesized using conventional hydrothermal method.