Complete removal of 4-fluorophenol using a novel optical fiber photocatalysis–biodegradation–ion-adsorption system

To effectively remove 4-fluorophenol from water, a novel optical fiber photocatalysis–biodegradation–ion-adsorption reactor, which is composed of photocatalytic optical fibers, algal–bacterial biofilm, and ion-adsorption functionalized glass fiber cloth, was developed. The photocatalytic optical fibers, i.e., polymeric carbon nitride and lanthanum-doped TiO 2 coated photocatalytic optical hollow fibers (POHFs), were located in the middle-layer of the reactor. POHFs have good ultraviolet–visible–near-infrared light absorption and photocurrent conversion capability and can rapidly oxidize 4-fluorophenol into biodegradable products. The S. obliquus biofilm was located on the top layer of the reactor and enriched by phototrophs ( Limnothrix and Gemmatimonas ) and heterotrophs ( Blastomonas and Roseococcus ), which continuously consume the photocatalytic products to accumulate biomass and provide dissolved oxygen through photosynthesis to generate advanced oxidation groups. The fluoride ion (F – ) absorption material, which is composed of amyloid fibril/ZrO 2 /activated carbon nanoparticles, was coated on the glass fiber cloth. The prepared fiber cloth was located on the bottom layer of the reactor and has good F adsorption (the adsorption rate approaches 27.8 μM/L), which enables it to effectively remove the F − in water to avoid F − poisoning of the biofilm. The results showed that the developed fiber reactor can perform complete and rapid removal of 4-fluorophenol (for 160 mL, 0.44 mM 4-FP, totally removed in 20 h) and increase biomass production (increase up to 18.0 mg/day). Hence, it provides a smart method for the effective removal and conversion of 4-fluorophenol in water.