Colloidal Stabilization of Sodium Dilauraminocystine for Selective Nanoparticle–Nanoparticle Interactions: Their Screening and Extraction by Iron Oxide Magnetic Nanoparticles

Abstract

Nanoparticle−nanoparticle (NP−NP) interactions between Au and Ag NPs were studied by using sodium dilauraminocystine (SDLC)-and Gemini surfactant-stabilized NPs to demonstrate the unique NP surface adsorption behavior of SDLC in controlling and mimicking such interactions in complex mixtures. They were significantly affected by the spacer as well as the polymeric nature of the head group of Gemini surfactants. A longer spacer impeded while a polymeric head group facilitated the interactions. The Au−Ag NPs interactions in an aqueous phase were also controlled by placing surface-active magnetic NPs at an aqueous−air interface, which interacted with either or both kinds of interacting NPs in an aqueous phase and reduced their ability to interact with each other. On the other hand, water-soluble zwitterionic magnetic NPs proved to be excellent extractants of both Au and Ag NPs from the aqueous phase. Extraction efficiency depended on the strength of interactions between the water-soluble magnetic NPs and aqueous-solubilized Au and/or Ag NPs.

Extraction of Bionanomaterials from the Aqueous Bulk by Using Surface Active and Water-Soluble Magnetic Nanoparticles

“…DPS stabilized magnetic NPs are not surface active and do not adsorb at the aqueous–air interface. Rather they are aqueous bulk soluble and hence remove protein conjugated Au NPs by directly incorporating in the aqueous bulk through NP–NP interactions Figure a shows typical UV–visible scans of a titration of DPS stabilized magnetic NPs against a zein conjugated Au NPs suspension.…”

“…Rather they are aqueous bulk soluble and hence remove protein conjugated Au NPs by directly incorporating in the aqueous bulk through NP−NP interactions. 25 Figure 3a shows typical UV−visible scans of a titration of DPS stabilized magnetic NPs against a zein conjugated Au NPs suspension. It drives an instant extraction of zein conjugated Au NPs with the result that the absorbance of Au NPs shows a rapid decrease until almost all Au NPs are extracted from the aqueous bulk.…”

Photo-oxidative Decolorization of Brilliant Blue with AgNPs as an Activator in the Presence of K2S2O8 and NaBH4

“…Kaur et al also observed the color change of AgNPs and AuNPs after the addition of Fe 2 O 3 NPs. 27 These NPs have strong complex-forming efficiency with Fe 2 O 3 NPs.…”

“…For example, Kaur and her co-workers reported the extraction of gold and silver nanoparticles from the aqueous phase by using water-soluble iron oxide nanoparticles and suggested that the degree of extraction depends on the strength of interactions between the AuNPs and AgNPs with Fe 2 O 3 NPs. 27 Pal and his co-workers reported the degradation of aromatic nitro phenols by using AgNPs as a catalyst in the presence of NaBH 4 . 28 Ghaedi and his coworkers prepared various mono-, bi-, and tri-metallic nanoparticles (palladium, silver, bismuth−silver, copper−zinc− nickel, and nickel−cobalt−alumina) that were used as an adsorbent for the removal of Congo red.…”

“…It is also used as a source of hydrogen to the reduction of metal ions and oxidative discoloration of various toxic nonbiodegradable organic dyes and other compounds in the presence of metal NPs. − The surface of NPs plays a significant role (electron relay effect) during the transfer of hydrogen from NaBH 4 to the oxidizing agent. For example, Kaur and her co-workers reported the extraction of gold and silver nanoparticles from the aqueous phase by using water-soluble iron oxide nanoparticles and suggested that the degree of extraction depends on the strength of interactions between the AuNPs and AgNPs with Fe 2 O 3 NPs . Pal and his co-workers reported the degradation of aromatic nitro phenols by using AgNPs as a catalyst in the presence of NaBH 4 .…”