A novel composite membrane was prepared by loading multiwalled carbon nanotubes (MWCNTs) on the surface of existing aluminum oxide micro-filtration (MF) membrane using filtration-coating method. The effects of both loading dosages and dimensional sizes of MWCNTs on the surface mats structure were investigated

while the responses to the rejection performance of composite membranes were also established for improving the conventional MF process. The results showed that the effective dispersion of MWCNTs could be achieved by combining large molecular surfactant and ultrasonic technology

which was beneficial to form homogeneous carbon nanotubes mats on the surface of MF membranes. For the same type of MWCNTs

increasing MWCNTs loading dosage would have no significant effects on the pore size distribution and specific filtration resistance (rc) of carbon nanotubes mats. When the MWCNTs with low length-diameter (L/D) ratio was used

the smaller pore size on the surface mats resulted in the decrease of membranes permeability. On the contrary

a highly twining and fluffy mat structure was observed with the high L/D ratio of MWCNTs

corresponding to the lowest value of rc. In addition

the positive correlations between the rejection of composite membranes for small molecular fluvic acid and both loading dosages and specific surface area of MWCNTs were found

which was also related to the mats compactness based on the main mechanism of adsorption.