Scalable development of photocatalysis-mediated aquatic habitat restoration devices based on TiO₂/graphene/BiVO₄ and the application in black-odorous river treatment

A novel concept of photocatalysis-mediated aquatic habitat restoration materials (PMAHRM) has been introduced in this study. The primary objective of development lies in enhancing the aquatic habitat, indirectly fostering favorable living conditions for aquatic organisms and fostering their growth. TiO₂/Graphene/BiVO₄ (TGB), serving as a PMAHRM, was constructed through a hydrothermal process. The absorption wavelength extends to 504 nm. Furthermore, a PMAHRM device with a dual-function area structure based on TGB and in-situ microorganisms immobilized separately has been designed. Both sections were seamlessly integrated through the use of conductive fibers. The device demonstrates a RhB removal rate of 85.70 % under visible light. During the nearly six-month field trial for the restoration of a black-odorous river, the scalable developed TGB devices, in conjunction with Myriophyllum verticillatum, were employed to achieve comprehensive restoration outcomes. The results showed significant decreases in NH₃-N, TP, and COD concentrations by 85.96 %, 77.78 % and 73.53 %. The transparent index rising 3.3 times. TN, TP, and OM concentrations of sediment decreased by 10.64 %, 9.60 % and 34.08 % respectively. The enhancement of habitat quality led to various positive biological responses. The Shannon-Wiener biodiversity index increased for plankton and zoobenthos. Furthermore, the density of Cyanophyta decreased by 57.33 %, and the emergence of a substantial population of Chlorophyta and Bacillariophyta contributed to a balance algal facies. Additionally, the average density of zooplankton increased fivefold, while the density of zoobenthos decreased slightly. PMAHRM devices, utilizing newly developed TGB materials, played a pivotal role in aquatic habitat restoration, thereby fostering the sustainable development of aquatic ecosystems.