High-Porosity Conjugated Polyelectrolytes Synthesized via Sonogashira–Hagihara Coupling in Concentrated Emulsions: Robust Adsorptive–Photocatalytic Hydrogels for Water Pollutant Removal

TL;DR

Scientists created a new type of high-porosity hydrogel that can efficiently remove water pollutants through adsorption and light-driven reactions.

Contribution

The novel synthesis of high-porosity conjugated polyelectrolyte hydrogels via Sonogashira–Hagihara coupling in emulsions for pollutant removal.

Findings

High-porosity CPE hydrogels achieved up to 355 m²/g surface area and 25 g/g water uptake.

CPE-PH–SO3® removed 93-96% of bisphenol A through adsorption and photocatalysis.

CPE-PH–SO3® retained structural and electronic integrity during prolonged use.

Abstract

Conjugated polyelectrolyte (CPE) hydrogels uniquely combine
π-conjugation,
ionic functionality, and water compatibility in a single-polymer network.
This work reports on the design, synthesis, and application of high-porosity
CPE hydrogels obtained via the Sonogashira–Hagihara cross-coupling
reaction as a polymerization chemistry in a high internal phase emulsion
(HIPE) template. In this way, we combine the hydrophilic and π-conjugated
electronic properties of CPEs with the high porosity of polymerized
high internal phase emulsions (polyHIPEs or PHs), enabling the development
of a multifunctional polymer platform. High-porosity CPE-PHs exhibit
a surface area of up to 355 m2·g–1, excellent water uptakes of up to ∼25 g·g–1, and visible-light absorption with band edges at 720 and 610 nm
and band gaps of 2.35 and 2.47 eV for anionic CPE-PH–SO3® and cationic CPE-PH-NMe3
+, respectively.
These CPE-PHs are then used to remove the endocrine-disrupting chemical
bisphenol A (BPA) as a model water pollutant. The CPE-PH–SO3® demonstrates exceptional performance, achieving overall
removal efficiencies of 93% and 96% through synergistic adsorption
(∼71% and ∼50%, respectively) and visible light-driven
photocatalysis (∼22% and ∼46%, respectively) during
8 and 24 h experiments. These efficiencies are among the highest reported
for organic photocatalyst. In contrast, the cationic analogue CPE-PH-NMe3
+ suffers from oxidative degradation and thus limited
activity. Stability studies confirmed that CPE-PH–SO3® retains its structural and electronic integrity during prolonged
operation. These results demonstrate the potential of high-porosity
CPE-PH hydrogels as a multifunctional polymer platform that synergistically
integrates adsorption and heterogeneous photocatalysis for robust
and efficient water applications.

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