Application of atomic force microscopy for characterizing membrane biofouling in the micrometer and nanometer scales

Abstract

Despite the availability of new detection and monitoring methods, a complete understanding of biofouling is still lacking. Therefore, this study employed a combination of biofilm characterization protocols macro, micro, and nano (meter) scales to provide insight into the early stages of biofilm formation using cellulose acetate ultrafiltration membranes. Membranes were fouled during 53 hours of crossflow filtration using two distinct feed waters. Biofilm characterization techniques included flux decline, image analysis, and atomic force microscopy (AFM). The flux decline and image analysis (bulk biofilm surface area coverage) data could not be correlated with feed water characteristics. Using AFM, it was possible to provide feature height analyses on the nano‐ scale to verify distinct biofilm distribution and formation as function of feed water characteristics. These findings suggest that AFM‐based biofilm characterization may provide the details needed to distinguish variations in cell deposition on a single membrane surface and/or between varied feed waters. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 449–457, 2013

Feed substrates influence biofilm formation on reverse osmosis membranes and their cleaning efficiency

“…The surface of the virgin membrane was observed to be rough, having peak-and-valley morphology with an S q value of 50.7 nm. Previous researchers have also found polyamide membranes to be much rougher than cellulose acetate membranes (S q = 6.2-6.6 nm; Zaky et al, 2012;Fang and Duranceau, 2013). The initial microbial attachment to the membrane surface is primarily due to the membrane's surface properties, which affect the strength and speed of cell adhesion to the membrane followed by multiplication and the consumption of feed substrate nutrients (Pasmore et al, 2001;Kang et al, 2006).…”

Enhanced chlorine‐resistant and low biofouling reverse osmosis polyimide‐graphene oxide thin film nanocomposite membranes for water desalination

“…If R ku < 3, the surface has more peaks than valley. [ 53,54 ] In the same time, these peak‐valley asymmetry and flatness of membranes surface can be clearly declared from the cross‐sections of 3D AFM images. PI‐GO.06 has higher symmetry than other PI‐GO membranes, with six alternating peaks to valleys heights from 16 to 43 nm and spatial periodicities ranging of 7 μm, that could be another reason for its higher performance (higher water flux).…”

Marker-assisted breeding value estimation for mastitis resistance in Finnish Ayrshire cattle

“…Previous researchers have also found polyamide membranes to be much rougher than cellulose acetate membranes (S q = 6.2-6.6 nm; Zaky et al, 2012;Fang and Duranceau, 2013). The initial microbial attachment to the membrane surface is primarily due to the membrane's surface properties, which affect the strength and speed of cell adhesion to the membrane followed by multiplication and the consumption of feed substrate nutrients (Pasmore et al, 2001;Kang et al, 2006).…”

“…The S sk represents profile symmetry relative to mean line and helps to calculate the extent of surface texture regularity through the distribution of peaks rather than valleys on membrane. The S sk value is zero when the height distribution is symmetrical, positive when the height distribution is asymmetrical with more peaks than valleys, and negative when the valleys are prevalent and the surface is too planar (Raposo et al, 2007;Zaky et al, 2012).…”