Effect of hydrodynamic diameter on the sieving of waterborne carbon nanotubes by porous membranes

Gaurav S. Ajmani, Talia Abbott-Chalew, Benoit Teychene, Yifei Wang, Joseph G. Jacangelo, Haiou Huang

Research output: Contribution to journalArticlepeer-review

Abstract

Carbon nanotubes (CNTs) are rapidly influencing the development and applications of membrane technology for water treatment. Passage of CNTs through membrane pores is becoming a fundamental question to water industries, as the toxicity and environmental fate of waterborne CNTs are largely unknown. This study utilized CNTs and membranes with known properties to investigate the applicability of the Ferry-Renkin sieving equation to the rejection of CNTs by porous membranes. The results demonstrate that the hydrodynamic size of CNTs is more important than their physical dimensions for rejection. Moreover, the classical sieving equation provided reasonable predication of the experimental results. Important for water industries, current membranes used in drinking water treatment should be efficient barriers for waterborne CNTs leached from composite membranes or released from wastewater effluents. Further, process streams containing CNTs may be treated using membrane filtration for CNT recovery. However, micron-pore-size membranes used in previous studies for CNT-membrane fabrication may not be efficient in protecting CNT breakthrough. Since the hydrodynamic diameters of waterborne CNTs are usually above 150. nm, as a general rule of thumb, membranes with pore size smaller than 100. nm need to be used to ensure the safety of CNT membranes.

Original languageEnglish (US)
Pages (from-to)470-478
Number of pages9
JournalJournal of Membrane Science
Volume470
DOIs
StatePublished - Nov 15 2014

Keywords

  • Carbon nanotube
  • Composite membrane
  • Ferry-Renkin equation
  • Hydrodynamic diameter
  • Membrane sieving

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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