pf_01547 - Laserfiche WebLink

Home

Activated Carbon Adsorption The plating baths in electroplating and printed circuit board manufacturing shops normally become contaminated with a variety of substances. The important contaminants of concern to the proposed metals recovery system are those that adversely affect the ion exchange resins. These important contaminants include strongoxidants that may physically break down the resin, chelating agents and oils or other organics that may gradually foul the resin and various suspended solids that may foul the ion exchange column. Therefore, it is essential that these organic contaminants be removed from the waste water prior to the ion exchange treatment in order to preserve the longevity of the resins. Activated carbon performs this required step by the process of adsorption. There are three important steps in the process of adsorption of dissolved organics in the waste water by the granular activated carbon. First is the transport of the solute through a film on the surface of the activated carbon granule to the exterior surface of the carbon. The second step is the diffusion of the solute through the pores of the carbon to its interior. Finally, adsorption of the solute occurs on the interior surfaces of the pore and capillary spaces of the activated carbon. The effectiveness of adsorption by activated carbon is dependent upon a number of factors. The physical and chemical nature of the solution, the nature of the material to be adsorped, including its molecular size and polarity, the type of contacting system (carbon column for example) and its mode of operation, and the nature of the carbon itself. Activated carbon canisters would be used at the industrial shops as a prefilter to the ion exchange system. At the Facility there will be two activated carbon columns installed in series. At the Facility the main function of the carbon would be to trap suspended solids and remove organics from nickel and copper waste waters which arrive at the facility in bulk shipments. Once the carbon columns have reached their capacity they must be replaced with fresh activated carbon columns. In order to be disposed of they will first be dried and then incinerated. The ash may then be disposed of in a sanitary landfill. Since no heavy metals are adsorped by the carbon, none will be present in the ash. A-5