Air-water interfacial fluidic sonolysis in superhydrophobic silicon-nanowire-embedded system for fast water treatment

Abstract

The widespread presence of organic pollutants in water resources poses potentially grave health and environment problems. Oxidation processes, which involve in situ generation of reactive oxidant species, are widely employed to treat and remove the pollutants. The conventional advanced oxidation processes (AOPs) typically utilize energy sources and/or additives including catalysts, but the treatment time is still too long. Here, we devise a novel fluidic sonolysis system with a superhydrophobic Si nanowire structured channel, providing an air-water interfacial cavitation for efficient generation of OH· that is promoted by the structure itself without any additional energy inputs or additives. The system removes various organic pollutants including 4-chlorophenol, bisphenol A, carbamazepine and propranolol completely within 12 min, as opposed to hours needed by other AOPs. These results substantiate the promise of the air-water interfacial fluidic sonolysis system for fast and continuous-flow water treatment.