Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/24327

TitleContinuous-flow precipitation of hydroxyapatite in ultrasonic microsystems
Author(s)Castro, Filipa
Kuhn, Simon
Jensen, Klavs
Ferreira, António
Rocha, Fernando
Vicente, A. A.
Teixeira, J. A.
KeywordsMicrofluidics
Ultrasound
Nanoparticles
Hydroxyapatite
Aggregation
Issue date2013
PublisherElsevier
JournalChemical Engineering Journal
Abstract(s)This paper describes the continuous-flow precipitation of hydroxyapatite Ca5(PO4)3OH (HAp) in two ultrasonic microreactors using diluted aqueous solutions of calcium and phosphate at 37 °C. Precipitation of HAp was first carried out in a tubular microreactor immersed in an ultrasonic bath, where single-phase (laminar) flow and segmented gas-liquid flow were both evaluated. The single-phase flow study was then conducted in a novel microfluidic device developed at MIT. It consists of a Teflon stack microreactor with an integrated piezoelectric element (Teflon microreactor), thereby allowing the direct transmission of ultrasound to the reactor. Both microsystems produce single-phased calcium-deficient carbonated HAp under near-physiological conditions of temperature and pH. In addition, particle aggregation and primary particle size were significantly reduced in the segmented-flow tubular microreactor and in the Teflon microreactor. The as-prepared particles mostly consisted of rod-like shape nanoparticles with dimensions below 100 nm in length and around 20 nm in width. Further, the microreactors used yielded HAp particles with improved characteristics text was removed, namely higher crystallinity and less carbonate contamination, when compared to the HAp particles produced in a stirred tank batch reactor.
TypeArticle
URIhttp://hdl.handle.net/1822/24327
DOI10.1016/j.cej.2012.11.014
ISSN1385-8947
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CEB - Publicações em Revistas/Séries Internacionais / Publications in International Journals/Series

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