Nanoparticle filtration

In the last decade many new nanotechnology based products are developed. This causes a worldwide exponential growth of the production volume of nanoparticles (NPs). The impact of manufactured nanoparticles on living organisms is still under discussion. However, most researchers postulate that NPs have negative influence. It is obvious that after usage manufactured NPs will accumulate in the aqueous systems. Therefore, deeper knowledge and fundamental understanding of the behavior of nanoparticles in water is essential. A promising technique to remove nano-sized contaminants from water are membranes. This project focuses on the separation of noble metals, metal oxides, nonmetal oxides and carbon nanoparticles from water using membranes. Interactions between the NPs in water, interactions of the NPs with the membrane and filtration parameters are critical aspects in understanding the fouling behavior of these nanoparticles.

Colloidal chemistry and the DLVO theory are the key to understand the basic principles of NPs stability. In this PhD project fundamental research on the influence of the different parameter on the dissolution, aggregation of nanoparticles in an aqueous suspension is investigated. For instance, the presence of ions, pH variations, increased ionic strength and natural organic matter (NOM) are believed to be responsible for the aggregation of NPs.

Nowadays, not much is known about the filtration of the nanoparticles. The use of commercially available membranes in the filtration of these particles is our starting point. Membrane porosity, pore distribution, surface charge, presence of active groups and surface roughness are factors that may influence the fouling behavior and retention during the filtration of nanoparticles. Process parameters that affect membrane fouling the most are the concentration of NPs and flux. Thus, optimal filtration conditions need to be found to conduct the process in the most effective way.

Fig.1 Graphic representation of the fouling phenomenon of nanoparticles with the membrane