The first thing to note is that color of cation resin does not affect the resin’s performance, and darker-colored resins are not impure or inferior in any way. Leading manufacturers — like Purolite — can adjust the color of the resin by adjusting the sulfonation process, (sulfonation is the step when the active sulfonic acid group is added to the polymer bead to make strong acid cation (SAC) resins).
Purolite manufactures several different color shades of popular SAC products like C100E, C100 and C100H, from pale amber to very dark brown. Regardless of the color, it will perform in line with published data. The resin is still within range of the minimum specification regarding total capacity, moisture content and resin grading.
Some clients and/or applications are best suited to a specific color. For example, the softening market prefers light-colored cation resin because iron fouling can be more readily seen on the resin by service engineers.
Companies operating regenerable mixed beds must visually ensure they achieve good SAC-SBA bed separation on backwashing and need to see the SAC-SBA resins remix well after regeneration. In these instances, a dark cation resin is preferred, which is more easily seen, versus a lighter cation resin which mixes easier with yellow-colored anion resin. A similar situation exists for double-layer (stratified) SAC and WAC beds that must always stay separated. In this case, a dark SAC next to the milk-white WAC resin is a good combination.
Macroporous strong acid cation resins can be manufactured in different colors, but there is less variation in these opaque products.
Purolite can accommodate color specifications. Please consult with your local Technical Representative or click Contact Us.