Influence of powered activated carbon (PAC) pretreatment on ultrafiltration membrane flux
粉末活性炭预处理对超滤膜通量的影响

Pretreatment by adsorption of powdered activated carbon (PAC) was employed in an attempt to improve flux in ultrafiltration (UF) membrane filtration. PAC adsorption hypothetically removes the hydrophobic and hydrophilic organic fractions, which would result in enhanced flux. Four raw water samples containing different hydrophobic and hydrophilic compounds were tested. The experimental results show that in the filtration of raw water without PAC pretreatment, the flux declined rapidly. Although pretreatment with PAC could enhance flux to some extent, the rate of flux decline was not improved. Analysis of the organic compounds showed that in direct filtration of raw water the UF membrane rejected hydrophobic compounds and PAC adsorption mainly removed hydrophilic compounds. However, after PAC adsorption pretreatment, the membrane tended to reject the hydrophobic fraction. It can be concluded that the hydrophobic compounds are responsible for the flux decline and hydrophilic compounds have less effect on flux.