A Triazine Membrane for Sustainable Acquisition of Au(III) from Wastewater

The recovery of Au(III) from solution using adsorbents in the form of granules or powders is challenging due to issues such as instability during the recovery process or mass loss caused by small particle size. This study introduces a PEI-TCT/PVDF composite membrane designed to intercept and capture Au(III) in wastewater. Experimental results demonstrated that the PEI-TCT/PVDF membrane exhibits a broad pH range (1-8) and a high retention efficiency for Au(III) of 97.8%, with a maximum adsorption capacity of 294.5 mg/g. The mechanism of Au(III) adsorption on the PEI-TCT/PVDF membrane was mainly through electrostatic adsorption, which caused AuCl4- to aggregate on the surface of the membrane and gradually reduced to Au0 and Au+. Furthermore, the membrane can be entirely regenerated within 20 min and maintains its performance in subsequent adsorption cycles. This study highlights the potential of PEI-TCT/PVDF membranes for the recovery of precious Au(III).

Studying the Degradation of Three Polymers under Different Chlorine Concentrations and Exposure Times

Due to chlorine's ability to kill bacteria and fungi through a chemical reaction, chlorine solutions are commonly used to clean and disinfect numerous public facilities, although these actions are also dependent to the equipment present in those facilities. Accordingly, the interest in studying its effect when in contact with different materials is obvious. This study was carried out through accelerated degradation tests and various analysis methods (optical microscope, scanning electron microscope, and tensile tests). The objective was to observe the wear presented by three polymeric materials, polyvinyl chloride (PVC), high-density polyethylene (HDPE), and polypropylene (PP), when exposed to chlorine's action in swimming pools and drinking water treatment plants. The resulting effect depends on the chlorine content and the type of contact between the chemical agent and the material. The aim was to select the material less likely to be affected by chlorine through tests and analyses, allowing a longer component life. The use of certain more resistant polymeric materials can drastically reduce maintenance, reducing fundamental factors such as costs, the downtime of municipal facilities, and also the risk to public health. It was concluded that PVC has the most stable behaviour overall when in contact with chlorine solutions.

Synthesis of bottlebrush polymers based on poly(N-sulfonyl aziridine) macromonomers

We synthesized bottlebrush polymers with polyaziridine brushes and a polynorbornene backbone by a grafting-through approach. The polyaziridine macromonomer aggregates in solution, but these aggregates disperse over the course of the polymerization.

Tributylphosphine-catalyzed aziridine-based cycloaddition polymerization toward thiacyclic polymers

Cycloaddition polymerization of bis(N-sulfonyl aziridine)s with diisocyanates in the presence of tributylphosphine allows the facile synthesis of poly(thiazolidin-2-imine)s.

Catalyst-free aziridine-based step-growth polymerization: a facile approach to optically active poly(sulfonamide amine)s and poly(sulfonamide dithiocarbamate)s

Step-growth polymerization of chiral bis(N-sulfonyl aziridine)s with diamines or bis(dialkyldithiocarbamate) in the absence of a catalyst allows the facile synthesis of optically active polysulfonamide derivatives.

Organocatalytic sequential ring-opening polymerization of cyclic ester/epoxide and N-sulfonyl aziridine: metal-free and easy access to block copolymers

Sequential ring-opening polymerization of ε-caprolactone (ε-CL)/propylene oxide (PO) and N-sulfonyl aziridine switched by tosyl isocyanate (TSI) allows the metal-free synthesis of polysulfonamide-based copolymers.