Construction,Properties And Application Of Bismuth-based Visible Light Catalytic Films In Bactericidal Reactors

Biofouling is one of the major problems faced by marine engineering materials in service.It is of great practical significance to develop new,environmental and efficient antifouling materials.In recent years,Bi based nanomaterials and their composites have been proved to be promising in the field of photocatalytic antifouling due to the excellent visible light absorption and photocatalytic activity.However,in practical applications,Bi-based photocatalytic materials are mainly applied in the form of powder,powdered materials have shortcoming with complicated recovery process,which limits its further application.Therefore,it is necessary to fix Bi-based nanomaterials on substrates to improve the recyclability.Analyzing the research of predecessors,this study can expand the preparation technology and application range of Bi-based photocatalytic films by constructing the Bi-based materials on polymer to solve the bottleneck problems of the existing film construction methods,such as complex preparation process,high cost of carrier materials and limited application environment.The films on different polymers are studied to reveal the films grown mechanism.Bi-based films with different morphologies,structures and chemical compositions are synthesized by adjusting the in-situ grown temperature and time.The photocatalytic performance of the film is evaluated by degrading organic pollutants and killing microorganism.Customized 3D printing large specific surface area polymer carriers are applied to facilitate the practical application of the photocatalytic film.The details are as follows:1.Hydrothermal in-situ grown Bi-based film is constructed on polyvinyl chloride（PVC）.The in-situ grown Bi-based film is related to the hydrothermal temperature and time,but is not related to polyvinyl pyrrolidone（PVP）amount.In hydrothermal progress,the desorption of chlorine atoms on PVC causes surface charge instability and induces the adsorption of O and Bi elements to form Bi₂O_2.7and Bi₂O₃.The Bi₂O_2.7 is the precursor phase of Bi₂O₃.0.81μm of Bi₂O₃/Bi₂O_2.7 p-n scheme heterostructure film fabricated at 140 ^oC for 4 h.This is the first successful example of using polymer as supported substrate to prepare hydrothermal Bi-based film.Furthermore,by using precipitation-reduction method,plasmon resonance Ag nanoparticles on film can obviously improve the visible light absorption performance of the film.Ag/Bi₂O₃/Bi₂O_2.7 film produces·O₂^-and h⁺under the visible light irradiation.The film shows obvious degradation and inactivation activity to RhB and E.coli.2.Hydrothermal in-situ grown Bi-based film is constructed on epoxy resin（ER）and other polymer materials.It is found that Bi-based film prepared by hydrothermal method is selective to polymer substrates.The hydrothermal in-situ grown of Bi-based film has nothing to do with the surface energy of polymer,but is related to the properties of polymer functional group.In addition to PVC,Bi-based film can be constructed on ER.In-situ grown Bi based films on ER is related to hydrothermal temperature,time and PVP amount.In hydrothermal progress,the dipole interaction between the epoxy group of ER and the amino group of PVP firstly induces Bi³⁺to form the grown active sites on ER.With the amount change of Bi³⁺,O^2-and I^-,the self-assembled grown of the film is gradually induced.13μm of Bi₂O₃/BiOI Z-scheme heterostructure film is fabricated at 140 ^oC with 0.1 g of PVP（70 m L glycol and 10 m L distilled water）for 4h.The surface plasmon resonance Ag nanoparticles loaded on the film by precipitation-reduction method can obviously improve the visible light absorption performance of the film.Ag/Bi₂O₃/BiOI Z-scheme heterostructure film produces·O₂^-and·OH under visible light irradiation.The film has obvious degradation and inactivation efficiency towards TCS,RhB,E.coli and S.aureus,and also has the significant anti-adhesion effect toward Pseudoalteromonas sp.The film shows good photocatalytic activity and cycle stability.3.SILAR in-situ grown BiOI film is constructed on polymers at room temperature and abnormal pressure.The SILAR method can construct Bi-based film on various polymers and has no selectivity for polymers.In SILAR process,Bi³⁺firstly adsorbs on polymers to construct the active grown sites of the film.With the extension of time,the films gradually are self-assembled into petal-like BiOI film.High proportion and movement speed of I^-promote the in-situ grown of BiOI film along the（110）crystal plane.In the grown process of films,displacement function between OH^-and iodine atom occurs by adding NaOH to KI solution.Iodine spaces are introduced into the BiOI crystals,causing BiOI internal electric field and electron density increase and improve the photoinduced carrier separation and transmission efficiency.Iodine defects engineering BiOI exhibits smaller grain size,higher specific surface area,electronegativity,photoelectric response and photocatalytic activity than stoichiometry BiOI.The film fabricated at pH 6～9 is BiOI/I-defects engineering BiOI Z-scheme heterostructure can produce·O₂^-,·OH and h⁺,the film shows good degradation and inactivation efficiency towards RhB and E.coli.4.3D-printing technology is introduced to design the polymer substrates with large specific surface area.I-defects engineering BiOI film is fabricated on 3D-printing model-like CNT and MOF substrates at pH 6～9 by SILAR method.The photocatalytic efficiency of the film is improved by the improved light source irradiation system.The film shows good degradation and inactivation towards RhB,E.coli and S.aureus.