混凝对正渗透过程中抗生素去除特性及膜污染的影响

为探明混凝预处理对正渗透去除抗生素的影响以及混凝对后续膜处理的影响，选用PAC、FeCl₃、Al₂(SO₄)₃对正渗透原料液进行混凝预处理，考察了混凝预处理对正渗透水通量、NaCl返混通量、抗生素截留率及膜污染的影响。结果表明：混凝预处理对正渗透过程中膜污染程度的影响由原料液中HA残留量以及Zeta电位共同决定；经混凝预处理后，原料液中腐殖酸残留量越多，正渗透过程中所形成的滤饼层越厚，原料液Zeta电位绝对值越低，形成的滤饼层越密实。滤饼层的形态影响正渗透的浓差极化作用，进而影响正渗透的运行特性及抗生素的截留效果，同时决定了膜清洗的难易程度。

Effect of coagulation on antibiotic removal efficiency and membrane fouling during forward osmosis

To determine the effects of coagulation pretreatment on the removal of antibiotics by forward osmosis the subsequent membrane treatment, PAC, FeCl3 and Al2(SO4)3 were used to conduct coagulation pretreatment. The effects of coagulation pretreatment on water flux, NaCl reverse flux, antibiotic rejection and membrane fouling during forward osmosis were investigated. The results showed that both HA residues in raw material liquor and zeta potential determined the effect of coagulation pretreatment on membrane fouling level. After coagulation pretreatment, the more residual HA led to the thicker filter cake layer, and the lower absolute value of Zeta potential resulted in the denser filter cake layer. The morphology of the filter cake layer affected the concentration polarization of the forward osmosis, and further affected operating characteristics of forward osmosis and antibiotic rejection, then determined the ease of membrane cleaning.