Biofouling initiation on a microfiltration membrane related to deposition and adhesion of bacteria from the perspective of interface interactions

Abstract

Inhibition of bacteria deposition and adhesion is an effective strategy to control biofouling in membrane applications. In this study, the deposition and adhesion characteristics of individual bacteria (Pseudomonas aeruginosa) on a polyvinylidene fluoride microfiltration membrane were systematically investigated from the perspective of interface interactions. Preliminary results demonstrated that the deposition process was compatible with and dominated by the intermediate blocking model and cake filtration model However, the adhesion process analyzed by thermodynamic analysis revealed that bacteria should, in theory, not adhere to the virgin membrane, which was inconsistent with the experimental results. Further experiments and theoretical analysis suggested that organic matter in feed water, bovine serum albumin (BSA), or sodium alginate (SA) increased the adhesion capacity of the membrane by changing the properties of the membrane, and the thermodynamic relationship resulted in a reduction in the total interface interaction energy, Lewis acid–base component, and repulsive force. Therefore, biofouling can be controlled by reducing BSA-like or SA-like organics and inhibiting protein secretion by bacteria. This study furthers the understanding of the bacterial attachment process, and provides new insights into the adhesion mechanism from the perspective of interface interactions and thermodynamic analysis.