Fig. 1: Concept of an autonomous buoyancy-driven shuttle (BDS) gel for the degradation of microplastics.
From: A self-regulating shuttle for autonomous seek and destroy of microplastics from wastewater
It consists of thermoresponsive pNIPAM cross-linked with nanoporous organosilica particles (NOPs). a At the seabed (cold), the collapsed hybrid hydrogel begins to swell and adsorb microplastics. Simultaneously, due to increased accessibility during swelling, the drive unit produces oxygen from D-glucose. b The oxygen formed is captured in the pores of the NOPs. Once a critical amount of oxygen has been generated, the hydrogel begins to ascend due to buoyancy caused by the oxygen. c Two light-induced effects occur at the water’s surface. Firstly, the photocatalyst (porphyrin) on the NOPs generates ROS, which decomposes the collected microplastics (center), and secondly, the gel heats up due to its black color. d The introduced heat energy causes the BDS gel to collapse and the accumulated oxygen to escape. The gel descends, and the next cycle starts.
