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