Electro-ceramic self-cleaning membranes for biofouling control and prevention in water treatment

Membrane fouling is a major drawback in membrane-based separation processes. In this work, periodic electrolytic membrane cleaning was used for the first time on ceramic-based electrically conductive membranes made from nano-zeolite and carbon nanostructures (CNS). Highly conductive nano zeolite/CNS, hydrophilic microfiltration membranes were fabricated through vacuum filtration, with PVDF as a binder for improved mechanical strength. Membrane cross-section revealed a uniform nano-zeolite distribution within the CNS. The membrane was subjected to periodic electrolysis during the filtration of yeast and sodium alginate (SA) as model foulants. High flux recoveries were obtained, with flux increasing to 95% and 90% for yeast and SA after the first cycle compared to without electrolysis. Subsequent increase in flux was observed thereafter each cleaning cycle reducing the concentration boundary layer. The composite membrane possessed high electrical conductivity and good electrocatalytic behavior for hydrogen evolution, which enabled membrane surface cleaning through the generation of hydrogen bubbles which led to the sweeping away of the foulant layer during the electrocatalytic cleaning between each filtration cycle. The membrane also showed good anti-microbial properties with low bacterial proliferation for both gram-positive and gram-negative bacteria. These electro-ceramic self-cleaning membranes hold immense potential in several types of separation processes where ceramic membranes are a choice of material, and where bio-fouling is a predominant factor for flux decline.