Mesoporous Organosilica with Amidoxime Groups for CO₂ Sorption

Incorporation of basic species such as amine-containing groups into porous materials is a well-established strategy for achieving high uptake of acidic molecules such as CO₂. This work reports a successful use of the aforementioned strategy for the development of ordered mesoporous organosilica (OMO) with amidoxime groups for CO₂ sorption. These materials were prepared by two-step process involving: (1) synthesis of OMO with cyanopropyl groups by co-condensation of (3-cyanopropyl)­triethoxysilane and tetraethylorthosilicate in the presence of Pluronic P123 triblock copolymer under acidic conditions, and (2) conversion of cyanopropyl groups into amidoxime upon treatment with hydroxylamine hydrochloride under suitable conditions. The resulting series of amidoxime-containing OMO was prepared and used for CO₂ sorption at low (25 °C) and elevated (60, 120 °C) temperatures. These sorbents exhibited relatively high adsorption capacity at ambient conditions (25 °C, 1 atm) and remarkable high sorption uptake (∼3 mmol/g) at 60 and 120 °C. This high CO₂ uptake at elevated temperatures by amidoxime-containing OMO sorbent makes it a noticeable material for CO₂ capture

Mesoporous Alumina with Amidoxime Groups for CO₂ Sorption at Ambient and Elevated Temperatures

Development of various mesostructures with introduced basic species such as amine groups represents a viable strategy for enhancing adsorption of acidic molecules such as CO₂. To follow this strategy, mesoporous alumina-based materials with incorporated amidoxime functionality were prepared by evaporation induced self-assembly of commercial boehmite nanoparticles as an alumina precursor, (3-cyanopropyl)­triethoxysilane as an organosilica precursor, and Pluronic P123 triblock copolymer as a soft template under acidic conditions. In the next synthesis step, the resulting mesoporous materials with cyanopropyl groups were subjected to hydrothermal reaction with hydroxylamine hydrochloride at slightly basic conditions and 80 °C to convert cyanopropyl groups to amidoxime functionalities. The latter sorbents showed fairly high CO₂ uptake at ambient conditions (25 °C, 1.2 atm) and remarkably high sorption capacity (3.84 mmol/g) at 120 °C. Good thermal and chemical stabilities of these materials combined with high CO₂ uptake at elevated temperatures make them of potential interest for sorption of acidic gaseous molecules such as CO₂

Adsorption of Lead Ions from Aqueous Phase on Mesoporous Silica with P‑Containing Pendant Groups

Mesoporous silica materials with hydroxyphosphatoethyl pendant groups (POH-MS) were obtained by a two-step process: (1) block copolymer Pluronic P123-templated synthesis of mesoporous silica with diethylphosphatoethyl groups (DP-MS) by co-condensation of diethylphosphatoethyl triethoxysilane (DPTS) and tetraethylorthosilicate (TEOS) under acidic conditions and (2) conversion of diethylphosphatoethyl into hydroxyphosphatoethyl groups upon suitable treatment with concentrated hydrochloric acid. The DP-MS samples obtained by using up to 20% of DPTS featured hexagonally ordered mesopores, narrow pore size distribution and high specific surface area. Conversion of DP-MS to mesoporous silica with hydroxyphosphatoethyl groups (POH-MS) resulted in the enlargement of the specific surface area, total porosity, and microporosity. High affinity of hydroxyphosphatoethyl groups toward lead ions (Pb²⁺) makes the POH-MS materials attractive sorbents for lead ions, which is reflected by high lead uptake reaching 272 mg of Pb²⁺ per gram of POH-MS. This study shows that the simple and effective co-condensation strategy assures high loading of P-containing groups showing high affinity toward lead ions, which is of great importance for removal of highly toxic lead ions from contaminated water

Selective Ion Exchange Governed by the Irving–Williams Series in K₂Zn₃[Fe(CN)₆]₂ Nanoparticles: Toward a Designer Prodrug for Wilson’s Disease

The principle of the Irving–Williams series is applied to the design of a novel prodrug based on K₂Zn₃[Fe­(CN)₆]₂ nanoparticles (ZnPB NPs) for Wilson’s disease (WD), a rare but fatal genetic disorder characterized by the accumulation of excess copper in the liver and other vital organs. The predetermined ion-exchange reaction rather than chelation between ZnPB NPs and copper ions leads to high selectivity of such NPs for copper in the presence of the other endogenous metal ions. Furthermore, ZnPB NPs are highly water-dispersible and noncytotoxic and can be readily internalized by cells to target intracellular copper ions for selective copper detoxification, suggesting their potential application as a new-generation treatment for WD