Formic Acid Removal from Formaldehyde

Formic acid develops as a contaminant of formaldehyde solutions during manufacturing. It can be removed from formaldehyde solutions concentrated as high as 55% and at temperatures up to 65°C with DOWEX™ M-43 resins . Regeneration to the free base form is done with a suitable base.

The resin is confined in a packed bed and the formaldehyde is passed through the resin at 4 to 6 bed volumes per hour until the acid removal capacity is exhausted. At this point, the resin is washed with water to remove the formaldehyde then regenerated with 3 to 5 lbs. of NaOH (2 to 4% concentration) per cubic foot of the resin. Excess base is washed from the resin with water in preparation for another operating cycle.

DOWEX Ion Exchange Resins

Product	Description	Type	Matrix	Total Exchange Capacity* eq/l (kgr/ft3)	Available Forms
DOWEX M-43	Corrosion control with DOWEX M-43 ion exchange resin.	Weak Base Anion	Styrene-DVB, Macroporous	1.55	FB (Free Base) form