Characterization of ultrafiltration membranes fouled by quantum dots by confocal laser scanning microscopy

Use of filtration techniques to study environmental fate of engineered metallic nanoparticles: Factors affecting filter performance

“…For instance, ENPs have already been demonstrated to be released from consumer goods [3], during washing of textiles [4,14,40], and via surface run-off from coated faç ades [20,19], and have been detected in effluents from wastewater treatment plants [21,39], indicating that conventional (waste)water treatment processes might be insufficient in removing ENPs [34,41]. Therefore, increasing concern has been raised within the scientific community regarding the occurrence, behaviour, and fate of these emerging contaminants in aquatic systems [28], in particular on their removal and fractionation methodologies [42].…”

“…Filtration processes are promising options when studying ENPs, not only for retaining and removing nanoparticles from solution, but also as fractionation techniques during characterization or sample preparation prior to further analysis [22,42]. Microfiltration (MF) using 0.45 m cut-off filter membranes is commonly utilized to determine the dissolved metal fraction in e.g., surface waters or soil solutions [7,16], while 0.2 m filtration is routinely used for sterilization of for instance nutrient media [38].…”

“…On the other hand, nanoparticlemembrane interactions (e.g., sorption) or membrane fouling could lead to retention of particulates that are smaller than the filter pore size [22,41,18]. Ultrafiltration (UF) is already being extensively applied during drinking water treatment, and is anticipated to be an effective removal strategy of ENPs from drinking water sources as nanoparticles or their aggregates are often too large to pass through UF filters [27,42]. In contrast to MF, where the retention capability is basically expressed through size exclusion from a well-defined pore size of the filter membrane (>0.1 m), UF membranes are characterized by their molecular weight cut-off (MWCO), which refers to the approximate molecular weight of a compound that is retained for 90% by the filter membrane [41].…”

“…In contrast to MF, where the retention capability is basically expressed through size exclusion from a well-defined pore size of the filter membrane (>0.1 m), UF membranes are characterized by their molecular weight cut-off (MWCO), which refers to the approximate molecular weight of a compound that is retained for 90% by the filter membrane [41]. Ultrafiltration has been regularly utilized in trace metal speciation studies [33,16], or in studies involving nanoparticles [8,7,30,34,9,42], primarily to investigate removal of (nano)particulate matter from solution, to examine dissolution behaviour by differentiating between (nano)particulate and "truly" dissolved compounds, or to characterize and purify nanoparticle dispersions.…”

Nanopipet‐Based Resistive Pulse Sensing to Follow Alterations in the Size and Concentration of Nanoparticles During Membrane Filtration

“…Ideally, these separation processes need to be combined with detection techniques able to follow alterations in the size and concentration of the nanoparticles. Some nanoparticles such as plasmonic nanoparticles 1 or fluorescent nanocrystals 10 possess inherent properties that allows for both their quantitation, based on light absorbance or fluorescence, and sizing, based on spectral characteristics. More general properties of nanoparticles such as static or dynamic light scattering can be used also for their detection.…”