Intimately coupling photocatalysis with phenolics biodegradation and photosynthesis

We developed and demonstrated a novel intimately coupled photocatalysis and biodegradation (ICPB) system. The ICPB system was comprised of photocatalytic optical hollow-fibers (POHFs) coated with Ag-loaded GeO2 and N-doped TiO2 photocatalyst, along with a biofilm that included phototrophic and heterotrophic microorganisms. The POHFs exhibit high UV–visible photocatalytic activity to degrade phenolic compounds rapidly and stably, decrease toxicity, generate readily biodegradable products, and emit visible light for biofilm growth and O2 production by phototrophs. O2 produced by the phototrophs was transferred to the POHFs, helping generate hydroxyl free radicals for photocatalysis. The biofilm, which became enriched in Rhodococcus and Pseudomonas, maintained rapid and stable biodegradation of photocatalytic products from the phenolics. Thus, the synergism among photocatalysis, biodegradation, and photosynthesis in the novel ICPB system provided an efficient means to rapidly and sustainably degraded and mineralized high concentrations of phenolic compounds.