Premium
Large‐scale oxidation of multi‐walled carbon nanotubes in fluidized bed from ozone‐containing gas mixtures
Author(s) -
Lassègue Pierre,
Noé Laure,
Dupin JeanCharles,
Monthioux Marc,
Caussat Brigitte
Publication year - 2018
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23033
Subject(s) - ozone , fluidized bed , fluidization , chemical engineering , carbon nanotube , materials science , phenol , oxygen , water vapor , chemistry , carbon fibers , organic chemistry , composite material , engineering , composite number
100 g of multi‐walled carbon nanotubes (MWCNTs) tangled in balls of 388 μm in Sauter diameter were treated per run in a pre‐industrial scale fluidized bed reactor, using ozone‐based gaseous mixtures at ambient temperature. The influence of ozone concentration and of the addition of water vapour was studied, for treatment durations between 1 h and 20 h. The process behaviour was analyzed in terms of fluidized bed pressure drop and temperature profile. The nature and amount of the grafted oxygen based functions were analyzed, as the structural modifications created. An oxidation mechanism in two steps was evidenced, showing the grafting of hydroxyl, phenol, and ether functions in a first step and then of lactone, quinone, carbonyl, and carboxylic groups. A moderate etching of the MWCNT outer walls was observed. The amount of grafted functions and of structural defects increased with treatment duration and was highly exalted by the presence of water vapour. All the results obtained showed that the oxidation was uniform on the whole powder of the bed and from the outer part to the centre of the balls, probably thanks to the high fluidization quality maintained all along the ozone treatment.