Ultrafiltration membrane fouling performance by mixtures with micromolecular and macromolecular organics

Abstract

Ultrafiltration membrane fouling caused by mixtures of micromolecules (humic acid, HA) and macromolecules (sodium alginate, SA) was studied in a comprehensive manner. The fouling behavior can be divided into two apparent parts according to the HA/SA composition. One part with lower SA composition behaved similarly to HA alone, with the fouling mechanism determined by the standard pore blocking and intermediate pore blocking, while the other part with higher SA composition behaved similarly to SA alone, with the fouling mechanism dominated by the cake filtration. Through the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach, the calculation of the interaction energy showed a significant negative correlation between the total interaction energy and the normalized fouling resistance. Conformably, the results showed that the HA/SA mixture with the dissolved organic carbon mass ratio of 1 : 1 which had the lowest interaction energy barrier exhibited the most severe flux decline.