valentina biagioni

Dottoressa di ricerca

ciclo: XXXV


supervisore: Prof. Stefano Cerbelli

Titolo della tesi: On the effective transport approach at the microfluidic scale and its applications for size-based separations of nanometric particles

In this thesis, transport of diluted solutions and suspensions in microfluidic separation devices is investigated through Brenner macrotransport theory and Lagrangian-stochastic approach. These methods have been employed to analyze the interaction between convection and diffusion, aiming at increasing the performance of two separation techniques, namely Open Tubular Liquid Chromatography (OTLC) and Hydrodynamic chromatography (HDC), the first used to separate molecular solutes embedded in a homogeneous (single-phase) solution, the second targeting the size-based separation of particle suspensions. In both cases, the separation performance depends on the ratio between the selectivity and the analyte dispersion bandwidths. Both techniques are affected by the Taylor-Aris effect, an undesired phenomenon that impacts on any pressure-driven micro-separation processes causing the increase of species dispersion, especially when high flow rates are enforced. In the case of OTLC, the efficiency improvement is achieved through the reduction of Taylor-Aris dispersion obtained by triggering transversal vortices alongside the pressure driven axial flow. Different convective transport conditions are investigated, where the flow kinematics ranges from helical to chaotic streamlines. As regards the improvement of HDC columns, two alternative approaches have been considered. In the first, the performance enhancement is obtained by boosting the column selectivity. This is achieved through an altogether new separation mechanism, which has been termed Browian sieving, which makes use of a multichannel geometry combined with a size-based sieve. Improvement of the efficiency up to a thirtyfold factor above standard HDC has been demonstrated. As an alternative separation-enhancement strategy, electroosmotically driven cross-sectional vortices have been investigated. In this case, 50 fold enhancement factors have been theoretically predicted. The results discussed in this thesis should therefore motivate new lines of experimental research in novel microfluidics-assisted channel geometries that could be applied to both liquid chro- matography and hydrodynamic chromatography.

Produzione scientifica

  • 11573/1676781 - 2023 - Fractionation of a three-particle mixture by Brownian sieving hydrodynamic chromatography (01a Articolo in rivista)
    BIAGIONI, VALENTINA; VENDITTI, CLAUDIA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1304930 - 2019 - On the three-dimensional structure of the flow through deterministic lateral displacement devices and Its effects on particle separation (01a Articolo in rivista)
    BIAGIONI, VALENTINA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1289885 - 2019 - Numbering-up strategies for microfluidics-assisted water treatment processes. Deterministic lateral displacement for the removal of bacteria and parasites as a case study (01a Articolo in rivista)
    MURMURA, MARIA ANNA; BIAGIONI, VALENTINA; CERBELLI, STEFANO
  • 11573/1440835 - 2020 - Combining electrostatic, hindrance and diffusive effects for predicting particle transport and separation efficiency in deterministic lateral displacement microfluidic devices (01a Articolo in rivista)
    BIAGIONI, VALENTINA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1559823 - 2021 - Brownian sieving effect for boosting the performance of microcapillary hydrodynamic chromatography. Proof of concept (01a Articolo in rivista)
    BIAGIONI, VALENTINA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1584997 - 2021 - Brownian sieving enhancement of microcapillary hydrodynamic chromatography. Analysis of the separation performance based on Brenner's macro-transport theory (01a Articolo in rivista)
    BIAGIONI, VALENTINA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1660535 - 2022 - Shape-enhanced open-channel hydrodynamic chromatography (01a Articolo in rivista)
    BIAGIONI, VALENTINA; CERBELLI, STEFANO
  • 11573/1658839 - 2022 - 50-Fold reduction of separation time in open-channel hydrodynamic chromatography via lateral vortices (01a Articolo in rivista)
    BIAGIONI, VALENTINA; CERBELLI, STEFANO
  • 11573/1669508 - 2022 - Estimate of the height of molten metal reactors for methane cracking (01a Articolo in rivista)
    BORGOGNA, ALESSIA; BIAGIONI, VALENTINA; MURMURA, MARIA ANNA; ANNESINI, MARIA CRISTINA; CERBELLI, STEFANO
  • 11573/1658368 - 2022 - Impact of transversal vortices on the performance of open-tubular liquid chromatography (01a Articolo in rivista)
    VENDITTI, CLAUDIA; BIAGIONI, VALENTINA; ADROVER, ALESSANDRA; CERBELLI, STEFANO
  • 11573/1658825 - 2022 - Taming Taylor-Aris dispersion through chaotic advection (01a Articolo in rivista)
    BIAGIONI, VALENTINA; VENDITTI, CLAUDIA; ADROVER, ALESSANDRA; GIONA, MASSIMILIANO; CERBELLI, STEFANO

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