Equipment Set-Up

While a 25 mm diameter glass column with a sintered glass bottom is ideal for conducting initial trials, a plastic column is suitable to create a basic test system. The recommended height of the column is 1200 mm. This will allow enough headspace for expansion if necessary. Configure the column with a rubber stopper at each end, with a glass tube running through the system (see Figure 1). Nylon cloth or screen should be placed over the surface of each stopper to retain the resin in the bed. Fill the column to a depth of 15–25 mm with small diameter glass beads (3 mm diameter) or sand to help distribute the fluid and hold the resin above the bottom of the column, preventing it from blocking the outlet.

If the column does not have a valve connection to control the flow rate at the exit end of the column, rubber tubing with a screw clamp assembly can be used as an on/off valve.

Depending on the laboratory set-up, additional equipment may include a funnel, tubing, a pump, cotton or glass wool, and a graduated cylinder. Depending on the trial, the column can be fed either by gravity or a peristaltic or diaphragm pump.  If gravity feed is used, arrange the pipework from the column in a “U” shape so that it rises to a level above the top of the bed, keeping the resin flooded at all times.

Whether gravity or pumped systems are used, it is essential to have regenerant and demineralized water solutions prepared and ready for use before the trial and regeneration processes begin.