Photocatalytic Hydrogels with a High Transmission Polymer Network for Pollutant Remediation

Abstract

Efficient heterogeneous and metal-free photocatalysts have recently been targeted as reusable materials for pollutant remediation. However, poor light penetration into photocatalytic materials currently limits modern photocatalytic systems due to uneven performance across the photocatalytic material and inefficient light usage. Here, we present a classical photocatalytic polymer hydrogel composed of a high transmittance polymer network and small conjugated photocatalytic moieties. Radical copolymerization of a photocatalytically active benzothiadiazole acrylamide monomer with water-compatible N,N-dimethylacrylamide produced a photocatalytic hydrogel where only the photocatalytic moiety absorbs visible light. The photocatalytic hydrogel network enables easy partitioning of pollutants into the gel network, where they are photocatalytically degraded. The versatility and reusability of the photocatalytic material were demonstrated for degradation of both inorganic metal and organic contaminants, including N-(phosphonomethyl)glycine (glyphosate), the most commonly used herbicide. Furthermore, the potential of this material was explored in large-scale experiments, where glyphosate could be readily photodegraded at a half liter scale.