Experimental Study on the Humic Acid Removal by Means of Coagulation - Ultrafiltration

Experiment was made on the humic acid removal and the membrane fouling by means of ultrafiltration with and without coagulation pretreatment. The results show that use of coagulation ahead of ultrafiltration for pretreatment of humic acid results in a rise in removal rate of DOC and UV 254 from 28% and 40% to 53% and 78% respectively. In the meantime, it is shown by high performance liquid chromatographic (HPLC) analysis that the coagulation - ultrafiltration process has significant improvement of removal rate of organic matters with molecular weight 6 000 u. The optimal pH value for coagulation - ultrafiltration process is 7, and sweeping coagulation can make small molecular organic matter agglomerated into micro flocs, which results in the reduction of membrane pore fouling and makes the ultrafiltration kept at high permeation flux.