Self-assembly and regeneration strategy for mitigation of membrane biofouling by the exploitation of enzymatic nanoparticles

Biofouling of membranes is an unresolved problem in the water industry. Numerous anti-biofouling membrane technologies have been proposed but the duration of their anti-fouling properties is short relative to the required lifetime of the membrane. The present work investigated a facile renewable anti-biofouling layer strategy whereby smart enzymatic nanomaterials are self-assembled onto a commercial membrane surface, creating a pH-triggered releasable and regenerable anti-biofouling system. The Proteinase-K-functionalized-PEGylated-silica (SPK) nanoparticles were characterized both chemically and biologically. These smart enzymatic particles demonstrated an excellent capability of against Pseudomonas fluorescens biofilms, and their activity persisted for at least 45 days in synthetic wastewater. Surface morphology and analysis of chemical compositions showed that these smart nanoparticles generated an anti-biofouling layer on the cellulose-based membrane surface through a submersion method, attributed to the strong noncovalent affinity-interactions between the particles and membrane. The SPK anti-biofouling layer stably attached to the membrane surfaces in synthetic wastewater (pH 7.4), whilst having the capacity to be released for regeneration in a pH 10 solution. Regeneration was accomplished by simple reloading of fresh particles on the membrane. Filtration tests revealed that the SPK anti-biofouling layer negligibly affected on membrane permeance while effectively mitigated membrane biofouling. Besides significant improvement in filtration fluxes, the SPK assembled membrane efficiently reduced the irreversible fouling and bacterial coverages on the membrane surface.