Gravity-assisted distillation on a chip: fabrication, characterization, and applications
Gabriela Furlan Giordanoa,b, Luis Carlos Silveira Vieiraa, Angelo Luiz Gobbia, Lauro Tatsuo Kubotab, Renato Sousa Limaa,b,∗
aLaboratorio Nacional de Nanotecnologia (LNNano), Centro Nacional de Pesquisa Em Energia e Materiais (CNPEM), Campinas, Sao Paulo, 13083-970, Brazil
bInstituto de Quimica, Universidade Estadual de Campinas (UNICAMP), Campinas, Sao Paulo, 13083-970, Brazil
ABSTRACT: Distillation is widely used in industrial processes and laboratories for sample pre-treatment. The conventional apparatus of flash distillation is composed of heating source, distilling flask, condenser, and receiving flask. As disadvantages, this method shows manual and laborious analyses with high consumption of chemicals. Inthis paper, all these limitations were addressed by developing a fully integrated microscale distiller in agreement with the apparatus of conventional flash distillation. The main challenge facing the distillation miniaturization is the phase separation since surface forces take over from the gravity in microscale channels. Otherwise, our chip had ability to perform gravity-assisted distillations because of the somewhat large dimensions of the distillation chamber (roughly 900μL) that was obtained by 3D-printing. The functional distillation unitswere integrated into a single device composed of polydimethylsiloxane (PDMS). Its fabrication was cost-effective and simple by avoiding the use of cleanroom and bonding step. In addition to user-friendly analysis and low consumption of chemicals, the method requires cost-effective instrumentation, namely, voltage supply and analytical balance. Furthermore, the so called distillation-on-a-chip (DOC) eliminates the use of membranes and electrodes (usually employed in microfluidic desalinations reported in the literature), thus avoiding drawbacks such as liquid leakage, membrane fouling, and electrode passivation. The DOC promoted desalinationsat harsh salinity (NaCl 600.0 mmol L−1) with high throughput and salt removal efficiency (roughly 99%).
Besides, the method was used for determination of ethanol in alcoholic beverages to show the potential of the approach toward quantitative purposes.
This article was published in Analytica Chimica Acta (Elsevier, DOI: 10.1016/j.aca.2018.05.028). Such project has been conducted in Laboratório de Microfabricação (LMF, LNNano).