engleski

Influence of fluoride and nitrite on the ion exchange of nitrate

The treatment of waste water from fertilizer factory in Kutina is realized by ion exchange process by the use of strong acid cationic and weak basic anionic ion exchangers. Regeneration of cationic exchange resin is performed by HNO3 and anionic resin regeneration by ammonium hydroxide. In the investigation period, waste water was characterized by high content of nitrogen in ammonium form (375 mg/l N-NH4+), nitrogen in nitrate form (235 mg/l (N-NO3-), fluoride 19.59 mg/l and nitrite 0.391 mg/l. Under real conditions four types of anionic resins: DUOLITE A 374, PUROLITE A 104/2561, LEWATIT S 4428 and AMBERLITE IRA 93 SP were used. The best results were obtained with the resin LEWATIT S 4428, which exchange capacity after 18 mounths of use, was 1.01 mol/l. The resin DUOLITE A 374 already after 4 months had exchange capacity decrease by more than 50 %. It was changed after one year. The saturation condition and external regeneration had influence to physical properties as well as to ion exchange capacity of resin PUROLITE A 104/2561. In the period of 10 months the exchange capacity has decreased from 1.01 mol/l to 0.28 mol/l. The initial exchange capacity of AMBERLITE IRA 93 SP was only 0.86 mol/l and decreased after 3 months to 0.69 mol/l. The influence of fluoride and nitrite on ion exchange capacity is examined.

nitrite; fluoride; ion exchangers; exchange capacity; waste water

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