Iron Oxide Nanoparticles: Multiwall Carbon Nanotube Composite Materials for Batch or Chromatographic Biomolecule Separation

Abstract

Carbon-based materials are the spearhead of research in multiple fields of nanotechnology. Moreover, their role as stationary phase in chromatography is gaining relevance. We investigate a material consisting of multiwall carbon nanotubes (CNTs) and superparamagnetic iron oxide nanoparticles towards its use as a mixed-mode chromatography material. The idea is to immobilize the ion exchange material iron oxide on CNTs as a stable matrix for chromatography processes without a significant pressure drop. Iron oxide nanoparticles are synthesized and used to decorate the CNTs via a co-precipitation route. They bind to the walls of oxidized CNTs, thereby enabling to magnetically separate the composite material. This hybrid material is investigated with transmission electron microscopy, magnetometry, X-ray diffraction, X-ray photoelectron and Raman spectroscopy. Moreover, we determine its specific surface area and its wetting behavior. We also demonstrate its applicability as chromatography material for amino acid retention, describing the adsorption and desorption of different amino acids in a complex porous system surrounded by aqueous media. Thus, this material can be used as chromatographic matrix and as a magnetic batch adsorbent material due to the iron oxide nanoparticles. Our work contributes to current research on composite materials. Such materials are necessary for developing novel industrial applications or improving the performance of established processes.

Recyclable Ag-Au bimetallic nanoparticles supported on acid functionalized multi walled carbon nanotubes for effective catalytic applications

“…The CNT surface was treated with strong acids H 2 SO 4 and HNO 3 to increase their polarity and facilitate interactions with Ag-Au BNPs. This treatment produces surface functionalisation and even charged surface groups which act as binding sites for polar T.C-Ag-Au BNPs [30].…”

Design of 3D Carbon Nanotube Monoliths for Potential-Controlled Adsorption

“…Intending to synthesize and stabilize monoliths containing minimal quantities of additives, we compared untreated and oxidized CNT particles as raw material prior to monolith synthesis. It therefore has to be considered that oxidation can lead to structural damage and conductivity loss of CNTs [39][40][41]. Hence, particular focus was given to developing a mild oxidation protocol (30 min, 3:1 v/v 3M H 2 SO 4 to HNO 3, ratio, 80 • C).…”