Dissolved humic acid (disHA) is effective for dispersing and suspending multi-walled carbon nanotubes (MWCNTs), but the subsequent impact on the fate and risk of MWCNTs and their interaction with contaminants are unknown. We observed that the adsorption of rigid, aromatic moieties-rich disHA onto MWCNTs was lower than the flexible, aliphatic components-rich disHA, but the former was better at dispersing MWCNTs due to stronger steric hindrance. Adsorption coefficients of sulfamethoxazole on disHA-suspended MWCNTs were up to two orders of magnitude higher than aggregated MWCNTs. More importantly, we provided the first evidence in aqueous phase of the significantly increased surface area of disHA-suspended MWCNTs relative to the aggregated ones using 1H NMR relaxometry. This work emphasizes that in comparison to aggregated MWCNTs, the suspended ones have amply exposed surface area and thus have greater environmental impacts.

Dispersion and increased adsorption of multi-walled carbon nanotubes by dissolved humic acid

247th National Meeting (2014)

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