Separation of ammonium salts from coking wastewater with nanofiltration combined with diafiltration

►Successful separation of high concentration of mixed ammonium salts. ►NF membrane showed superior salt rejections of (NH4)2S2O3 around 95.0%. ►NH4SCN permeated the NF membrane completely. ►Diafiltration maintained high average salt rejection of 93.4% for (NH4)2S2O3. ►Salt concentrations and yields of diafiltration can be predicted by calculation.