Cirillo, Andrea Iginio (2022) A microfluidic approach for membrane separation processes: investigation of fouling and its prevention strategies. [Tesi di dottorato]

Anteprima

Testo Cirillo_AndreaIginio_XXXV.pdf Download (6MB) | Anteprima

Abstract

By meeting the principles of sustainability which characterize contemporary process intensification strategies, membrane technologies are gradually replacing conventional energy-intensive separation techniques and reactive processes. One of the most important applications of membrane technologies is represented by separation operations based on pressure and concentration differences, e.g., membrane filtration and osmotic processes, where higher product concentration and purity are achieved by exploiting the ability of membranes to regulate the permeation rate of species through the pores. However, a critical issue undermines the performance of membrane processes, that is the progressive decrease of permeate flux due to fouling. Despite all the research efforts so far, fouling still represents an unsolved problem. The complex interplay of physical and chemical mechanisms governing its evolution is indeed yet to be fully unraveled and the role played by foulants’ properties or operating conditions is an area of active research. An interesting approach to fouling investigation concerns the use of microfluidic systems in which low amounts of fluid are processed in channels whose diameter can reach a few micrometers. Indeed, flux decline is governed by events occurring at small time and spatial scales, the latter comparable to pore dimensions. Studying fouling in micro-sized geometries would therefore allow gaining key insights regarding the interactions between foulants and the membrane surface and how these affect the deposition processes. In this work, the main concepts of microfluidics applied to the study of fouling in membrane processes were reviewed in detail, with particular attention to novel investigation techniques involving microfluidic devices. A microfluidic approach was then employed for the experimental studies. Firstly, the effects of different pumping systems on fouling dynamics of a Bovine Serum Albumin (BSA) solution were investigated by means of an originally microfluidic filtration module characterized by a modular design. Fouling mitigation strategies were the main area of interest of the following part of the work. Specific attention was given to membrane functionalization techniques, such as antifouling coatings and nanostructure modification aimed to enhance membrane hydrophilicity and hinder foulants’ deposition. Finally, given their potential as a possible solution to alleviate the issue of water sustainability, osmotic processes and the influence of process parameters on water recovery were studied.

Downloads

Actions (login required)

Modifica documento