Recycling a nonionic aqueous-based metal-cleaning solution with a ceramic membrane: Pilot-scale evaluation

The effectiveness of a zirconium dioxide (ZrO(2)) membrane filter was evaluated for recycling a nonionic aqueous metal cleaning bath under real-world conditions. The pilot-scale study consisted of four 7- to 16-day filtration runs, Each processed a portion of the cleaning bath during immersion cleaning of aircraft engine and motor parts. The results indicated that the filter aas effective in removing contaminants such as oil and grease and suspended solids from the process solution, thus extending the life-span of the bath up to three times. The process bath, however, bad to be replenished with, surfactant additives to compensate for those removed by the filter. The fouled membrane could be effectively cleaned with its permeability fully restored for reuse.