Treatment of thermomechanical pulp mill white water with organically tailored synthetic zeolites.

APPLICATION: Organically tailored synthetic zeolites can be used to remove dissolved and colloidal substances (DCS) from white water in thermomechanical pulping.

Is it technically feasible to use organically tailored synthetic zeolites to remove dissolved and colloidal substances (DCS) from synthetic process water? When synthetic process water was treated with 20 g/L untailored synthetic zeolites, 19-45% of dehydroabietic acid (DHA) was removed. However, treatment with C15/C17-tailored synthetic zeolites removed 100% of DHA. DHA removal was affected by tailoring the length of the cation chain (optimum C15 or higher), the pH (improved removal at lower pH), the treatment time (minimum contact time of 3 min), and the mineral dose. Mineral doses of TDTMA-tailored synthetic zeolite as low as 5 g/L removed 90% of the DHA from synthetic process water, and complete DHA removal was obtained at doses of 10 g/L and higher. Treatment of white waters (pH 7.25) using TDTMA-tailored zeolites at 1 g/L mineral dose resulted in 51% reduction of resin and fatty acids (RFA), 10% removal of soluble biochemical and chemical oxygen demands, 85% removal of acute toxicity, and 24% uptake of sterols. Higher mineral doses resulted in more complete removals of the compounds of concern: RFA (100%), soluble biochemical oxygen demand (SBO[D.sub.5]) (36%), soluble chemical oxygen demand (SCOD) (38%), acute toxicity (91%), and sterols (100%). View this paper online at http://www.tappi.org/index.asp?pid=28648

Christophorous Budi Kurniawan and Sheldon J.B. Duff are with the UBC Dept. of Chemical and Biological Engineering. 2216 Main Mall, Vacouver. BC V6T 1Z4. Email Duff at [e-mail].