Gold Extracted from Wastewater as an Efficient MOF-Supported Electrocatalyst

The recovery of gold from wastewater is necessary from both environmental and economic standpoints. Metal–organic frameworks (MOFs) can serve as high-capacity and selective adsorbents, as shown in a recent work by Zhao and co-workers. Their novel three-dimension cationic framework goes further than selectively adsorbing AuCl₄⁻. It also serves as a stable platform to transform adsorbed gold into an efficient catalyst for the electrochemical reduction of CO₂. This work highlights the versatility of MOFs, which can serve as selective adsorbents and as a support for nanoparticle catalysts.     

Supramolecular Polymerization of Polymeric Nanorods Mediated by Block Copolymers

Introducing a second component is an effective way to manipulate polymerization behavior. However, this phenomenon has rarely been observed in colloidal systems, such as polymeric nanoparticles. Here, we report the supramolecular polymerization of polymeric nanorods mediated by block copolymers. Experimental observations and simulation results illustrate that block copolymers surround the polymeric nanorods and mainly concentrate around the two ends, leaving the hydrophobic side regions exposed. These polymeric nanorods connect in a side-by-side manner through hydrophobic interactions to form bundles. As polymerization progresses, the block copolymers gradually deposit onto the bundles and finally assemble into helical nanopatterns on the outermost surface, which terminates the polymerization. It is anticipated that this work could offer inspiration for a general strategy of controllable supramolecular polymerization.     

The Directional Crystallization Process of Poly (triazine imide) Single Crystals in Molten Salts

Poly (triazine imide) photocatalysts prepared via molten salt methods emerge as promising polymer semiconductors with one-step excitation capacity of overall water splitting. Unveiling the molecular conjugation, nucleation, and crystallization processes of PTI crystals is crucial for their controllable structure design. Herein, microscopy characterization was conducted at the PTI crystallization front from meso to nano scales. The heptazine-based precursor was found to depolymerize to triazine monomers within molten salts and KCl cubes precipitate as the leading cores that guide the directional stacking of PTI molecular units to form aggregated crystals. Upon this discovery, PTI crystals with improved dispersibility and enhanced photocatalytic performance were obtained by tailoring the crystallization fronts. This study advances insights into the directional assembling of PTI monomers on salt templates, placing a theoretical foundation for the ordered condensation of polymer crystals.     

Engineering the Morphologies of Block Copolymer Particles from the Confined Self-assembly within Emulsion Droplets†

Block copolymers (BCPs) can automatically assemble into various regulated nanoparticles when they are confined within the emulsion droplet because of the structural frustration of polymer chains and the soft template effect of the oil/water interface. In the past few years, great efforts have been made to regulate the morphologies of the resulting BCP particles. In this review article, various strategies for tuning oil/water interfacial properties to engineer the as-formed BCP particles were summarized. Then, the comprehensive scenarios of the applications of the resulting BCP particles were discussed. Finally, the future tendency and challenge of the self-assembly of BCPs confined in emulsion droplet were suggested.     

Xanthan or esterified xanthan/cobalt ferrite-lignin hybrid materials for methyl blue and basic fuchsine dyes removal: equilibrium,kinetic and thermodynamic studies

In this study, new adsorbents based on xanthan (XG) or esterified xanthan (XGAC) and ferrite-lignin hybrids were obtained and characterized by using the dynamic vapor sorption (DVS) method, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The porosity, swelling ratio and point of zero charge (PZC) of the adsorbents were also evaluated. Batch adsorption experiments have been performed to determine the adsorption capacity of the adsorbents for Methyl Blue (MB) and Basic Fuchsine (BF). Ferrite-Lignoboost® lignin and ferrite-organosolv lignin hybrid materials (CFLB and CFLO) presented the highest adsorption capacity for MB dye (44.73 and 37.54 mg/g), while the adsorbents based on xanthan and ferrite-lignin hybrids (XG/CFLO and XG/CFLB) retained the highest quantities of BF dye (36.23 and 33.33 mg/g). The chemical nature of the adsorption process was determined, the analyzed data being better fitted to the pseudo second order (PSO) kinetic model. The data analysis showed that the adsorption process followed Langmuir, Dubinin-Radushkevich and Jovanovi? isotherm models. All the studied adsorption processes were endothermic (ΔH^o > 0) and the positive values of the entropy (ΔS^o > 0) indicated disorder at the interface between the adsorbent and the dye solutions.