Modified Halloysite Nanotubes: Nanoarchitectures for Enhancing the Capture of Oils from Vapor and Liquid Phases

Abstract

We prepared hybrid halloysite nanotubes (HNT/sodium alkanoates) in which the inner cavity of the nanoclay was selectively modified. Physicochemical studies evidenced the interactions between HNT and sodium alkanoates, ruled out clay exfoliation, quantified the amount of the loaded substance, and showed an increase of the total net negative charge, allowing us to obtain rather stable aqueous nanoclay dispersions. These dispersions were exploited as inorganic micelles to capture hydrocarbon and aromatic oils in the vapor and liquid states and were revealed to be nonfoaming but very efficient in encapsulating oils. Here, we have fabricated biocompatibile and low-cost inorganic micelles that can be exploited for industrial applications on a large scale.

Surface Improvement of Halloysite Nanotubes

“…percentage of 0.07 g and 0.10 g were separately added instead of 0.05 g of SDS, PVA, or MA. The addition of SDS facilitates the dispersion as noted in [16,34]. The mixtures produced in step IV are stirred separately for 1 h at 90 • C at speed of 500 rpm.…”

Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications

“…The peculiar surface chemistry allows the selective functionalization at the inner or outer side and the formation of a composite with hierarchical nanostructure [8,9]. Halloysite is a natural material with demonstrated low toxicity both in vitro [10] and in vivo [11].…”

Ecocompatible Halloysite/Cucurbit[8]uril Hybrid as Efficient Nanosponge for Pollutants Removal

“…The translational average diffusion of HNT/CB [8] hybrid (3.4 AE 0.2) 3 10 À13 m 2 s À1 is three times smaller than the value [32] for pristine HNTs in water (9.4 3 10 À13 m 2 s À1 ); this result is consistent with the increase of the HNT size generated by the adsorption of the organic molecule onto the external surface but also by the HNTs aggregation as a consequent effect of the CB [8] total loading. Accordingly, the adsorption of the organic molecule onto the HNT causes the increase of the z-potential value (-3.1 AE 0.2 mV) compared to the value [32] of pristine HNT (-19.4 mV).…”

“…Accordingly, the adsorption of the organic molecule onto the HNT causes the increase of the z-potential value (-3.1 AE 0.2 mV) compared to the value [32] of pristine HNT (-19.4 mV). Such an increment provides further light on the sites of CB [8] anchoring.…”

“…In fact, in case CB [8] is selectively entrapped into the lumen a more negative z-potential value is expected according to literature findings. Namely, loading of alkanoates [32] and perfluoroalkanoates [13a] into the HNT cavity enhanced the negative z-potential value and did not modify the HNT translational average diffusion. On the contrary, sodium decyltrimetylammonium bromide adsorbed onto the external negative surface allowed positive z-potential value and a reduced translational average diffusion.…”