Cobalt Ferrite Nanoparticle Intercalated Carbon Nanotubes for a Nanomagnetic Ultrasensitive Sensor for Cr-VI in Water
Tassew Mekuria, Syed Khalid, Kathryn L. Krycka, Markus Bleuel, Himanshu Verma, Haiping Hong, Shashi P. Karna, Dereje Seifu
Nanocomposites of cobalt ferrite (CFO) magnetic nanoparticles intercalated on carbon nanotubes (CNTs) are evaluated as a nanomagnetic ultrasensitive sensor for the environmental toxin, hexavalent chromium (Cr-VI). Specifically, the structural and magnetic changes that accompany the infiltration of the CFO/CNTs by Cr-VI are presented. Extended x-ray absorption fine structure (EXAFS) shows that the atomic spacing within the CFO structure changes in the presence of Cr, suggesting that the Cr is incorporated into the nanoparticles. Vibrating sample magnetometry (VSM) reveals that CFO/CNTs composite infiltrated with Cr-VI have a 71% enhancement in saturation magnetization compared with the uninfiltrated CFO/CNTs, while small-angle neutron scattering (SANS) suggests that this magnetic enhancement is not associated with the nanoparticle lengthscales, but may arise from longer-ranged clusters. Both VSM and SANS clearly demonstrate that the Cr-doped CFO/CNTs are hysteretic with a net magnetization at remanence that is about 1/3 that of saturation, while this hysteresis is absent in the undoped CFO/CNTs. These magnetic differences at either remanence or saturation are promising for the magnetic detection of Cr-VI using CFO/CNTs sensors.
, Khalid, S.
, Krycka, K.
, Bleuel, M.
, Verma, H.
, Hong, H.
, Karna, S.
and Seifu, D.
Cobalt Ferrite Nanoparticle Intercalated Carbon Nanotubes for a Nanomagnetic Ultrasensitive Sensor for Cr-VI in Water, AIP Advances, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930504
(Accessed December 5, 2023)