Sulfonic acid/sulfur trioxide (SO3H/SO3) functionalized two-dimensional MoS2 nanosheets for high-performance photocatalysis of organic pollutants

We report the enhanced photocatalytic activity of sulfonic acid/sulfur trioxide (SO3H/SO3) functionalized two-dimensional (2D)-MoS2 (SO3H/SO3-MoS2) nanosheets synthesized using a one-pot hydrothermal method.

De Novo Ion-Exchange Membranes Based on Nanofibers

The unique functions of nanofibers (NFs) are based on their nanoscale cross-section, high specific surface area, and high molecular orientation, and/or their confined polymer chains inside the fibers. The introduction of ion-exchange (IEX) groups on the surface and/or inside the NFs provides de novo ion-exchangers. In particular, the combination of large surface areas and ionizable groups in the IEX-NFs improves their performance through indices such as extremely rapid ion-exchange kinetics and high ion-exchange capacities. In reality, the membranes based on ion-exchange NFs exhibit superior properties such as high catalytic efficiency, high ion-exchange and adsorption capacities, and high ionic conductivities. The present review highlights the fundamental aspects of IEX-NFs (i.e., their unique size-dependent properties), scalable production methods, and the recent advancements in their applications in catalysis, separation/adsorption processes, and fuel cells, as well as the future perspectives and endeavors of NF-based IEMs.

Fabrication of a lead ion selective membrane based on a polycarbazole Sn(iv) arsenotungstate nanocomposite and its ion exchange membrane (IEM) kinetic studies

A polycarbazole-Sn(iv) arsenotungstate (Pcz-SnAT) nanocomposite cation exchanger membrane (CEM) was prepared via the casting solution technique utilizing polycarbazole-Sn(iv) arsenotungstate and PVC (polyvinyl chloride) as a binder. The synthesis of the Pcz-SnAT membrane was confirmed via various characterization methods such as EDX, SEM, TGA, XRD, and FTIR spectroscopy. This membrane having a 4.5 : 1 composition ratio of composite by PVC exhibited the most effective outcomes for swelling, thickness, porosity, and water content. Our research indicates that the present ion selective membrane electrode is selective towards Pb(ii) ions, with the detection limit ranging from 1 × 10-7 mol L-1 to 1 × 10-1 mol L-1 where 20 s is the response time and 3-7 is the working value pH. The mechanism of the Pcz SnAT ion exchange membrane was obtained by kinetic studies by utilizing the equation given by Nernst Planck at 40-80 °C. As a result, activation energy and thermodynamic studies were done. The analytical utility of this electrode is conventional by utilizing it as an electrode indicator within the potentiometric titration.

Unidimensional Approximation of the Diffuse Electrical Layer in the Inner Volume of Solid Electrolyte Grains in the Absence of Background Ions

In this paper we continue working on our theory of electrical double layers resulting exclusively from dissociation of a solid electrolyte, which we previously proposed as a medium for catalytic interaction between solid cellulose and solid acid catalysts of hydrolysis. Two theoretical unidimensional models of the inner grain volume are considered: an infinitely long cylindrical pore, and a gel electrolyte near a grain outer surface. Despite the model simplicity, the predictions for the cylindrical pore case are in semi-quantitative agreement with literature data on electroosmotic experiments, adequately explaining high proton selectivity of sulfonic membranes, and decline of such selectivity at high background acid concentration. The gel model predicts less concentrated diffuse layer in comparison to electrolytes with impenetrable skeleton (e. g., sulfonated carbons). This suggests limited suitability of gel electrolytes as catalysts if a substrate cannot diffuse into the gel bulk and the reaction is thereby spatially limited to the near-surface region, for example if a substrate is solid like aforementioned cellulose.

Sulfonated carbon derived from the residue obtained after recovery of essential oil from the leaves of Cinnamomum longepaniculatum using Brønsted acid ionic liquid, and its use in the preparation of ellagic acid and gallic acid

A Brønsted acid ionic liquid, 3-methyl-1-(4-sulfonylbutyl) imidazolium hydrogensulfate ([HO₃S(CH₂)₄mim]HSO₄), was used for the first time for the preparation of a sulfonated carbon catalyst. The catalyst was prepared from the residue obtained after recovery of the essential oil from the leaves of Cinnamomum longepaniculatum. The sulfonated carbon catalyst with an amorphous structure attained high acidic efficiency at a sulfonation temperature of 200 °C for 2 h of sulfonation time, and was characterised. SEM morphologies revealed that the carbon catalyst consisted of uniform carbon microspores. FTIR analysis, elemental analysis, and X-ray photoelectron spectroscopy revealed that the sulfonic acid group was successfully introduced on the surface of the sulfonated carbon catalyst. The result of TG analysis showed that the obtained sulfonated carbon catalyst has high thermal stability. Good acid and catalytic activity of the obtained sulfonated carbon catalyst were observed for the preparation of ellagic acid and gallic acid, which is comparable to those of diluted sulfuric acid and a sulfonated carbon catalyst that had been prepared with concentrated sulfuric acid. The excellent reusability of the sulfonated carbon catalyst was also confirmed by repeated experimental trials. In summary, the sulfonated catalyst derived from the residue obtained after recovery of essential oil from the leaves of C. longepaniculatum is an economic, eco-benign and promising substitute for traditional mineral acid catalysts for acidic catalysis in industrial applications.

A Brønsted acid ionic liquid, 3-methyl-1-(4-sulfonylbutyl) imidazolium hydrogensulfate ([HO₃S(CH₂)₄mim]HSO₄), was used for the first time for the preparation of a sulfonated carbon catalyst.