Anion selectivity in ion exchange reactions with surface functionalized ionosilicas

Abstract

Mesoporous imidazolium functionalized surface functionalized ionosilicas have been investigated as anion exchange materials for the adsorption of oxo-anions in aqueous media. We studied particularly pertechnetate adsorption and could show that solids bearing long chain substituted imidazolium groups are highly efficient anion exchange materials often displaying high distribution coefficients between solid and liquid phases. We observed that the distribution coefficient of pertechnetate is a function of the presence of competing anionic species. As a consequence, our experiments allowed reproducing experimentally Hofmeister's series. However, pertechnetate adsorption on the material can completely be inhibited in the presence of highly fluorinated anions such as bis(trifluoromethylsulfonyl)amide (NTf2). This behaviour indicates a particularly imidazophilic behaviour of these anions, which have a particular importance due to their use in water immiscible ionic liquids. Finally, the adsorption process has been shown to be reversible. This feature is of importance in view of the regeneration of the anion exchange material.

Pd@ionosilica as heterogeneous hydrogenation catalyst for continuous flow reductive upgrade of cinnamaldehyde

“…In a second step, we performed ion exchange with the ionosilica material A. As reported earlier, ionosilicas are efficient sorption phases for metallic anions such as perruthenate and pertechnetate . In full agreement with these studies, we observed here that ionosilicas also efficiently adsorb PdCl 4 2− anions.…”

Investigating the Interaction of Water Vapour with Aminopropyl Groups on the Surface of Mesoporous Silica Nanoparticles

“…The importance of organic-inorganic hybrid silica-based materials in many fields of chemistry and relatedareas, such as electrochemistry, [1][2][3][4][5] catalysis, [6][7][8][9][10][11][12][13][14] separation, [12,15] adsorption, [16,17] CO 2 capture [16,18,19] and nanomedicine, [20][21][22][23][24] has steadily increasedi nr ecent years. Particular attention has been focused on ordered mesoporouss ilicas (OMSs), thanks to their intrinsic large surfaceareas, ordered and tuneable pore arrays with controlled size and huge available volume for hosting, reaction and release of molecules and ease of surfacef unctionalisation.…”

Controlled synthesis and osmotic properties of ionosilica nanoparticles

“…In our previous studies, we used ionosilica nanoparticles as drug carrier vehicles for anionic drugs [32,33]. In this way, we took benefit of the unique anion exchange properties of ionosilicas [23,[34][35][36][37], combined with the possibility to efficiently control the morphology of silica hybrid materials. We observed that ionosilica nanoparticles efficiently vectorize anionic pharmaceuticals such as diclofenac, a non-steroidal anti-inflammatory drug (NSAID), or gemcitabine monophosphate, a potent anti-cancer drug.…”