Preparation And Antifouling Property Of Bismuth Oxyiodide-based Composite Materials

Traditional coatings which rely on the release of toxic substances to meet anti-fouling requirements have become increasingly harmful to the marine ecological environment.The development of environmentally friendly antifouling materials:fouling self-release coatings,bionic coatings,etc.have become a research focus.However,it is difficult to achieve long-term and effective anti-fouling simply relying on the physical properties or chemical composition of the coating itself.Therefore,to overcome the shortcomings of traditional coatings and existing research coatings,photocatalytic technology was introduced into the field of antifouling,and a series of bismuth iodide-based catalysts were designed and synthesized:Bi5O7I flower-shaped microspheres,Bi5O7I/Ag,Bi/Bi5O7I,Cs Pb Br3/Bi4O5I2 and Bi OI/Mo Se2.And the above-mentioned materials were loaded on the fluorinated polymer matrix to prepare Bi5O7I/zwitterionic fluorinated acrylic polymer composite coating（Bi5O7I/ZFP）,Ag/Bi5O7I/zwitterionic fluorinated acrylic polymer composite coating（ABZFP）,Bi/Bi5O7I/acrylic fluoroboron composite coating（BBFP）,Cs Pb Br3/Bi4O5I2/fluorinated zwitterionic polyurethane composite film（CBFZP）and Bi OI/Mo Se2/PVDF composite film（PMB）,respectively.The surface morphology,anti-fouling performance and photocatalytic mechanism were studied.The specific research contents are as follows:Bi5O7I flower-like microspheres were prepared by the oil bath-calcination method,which was compounded with zwitterionic fluorinated acrylic polymer（ZFP）synthesized by free radical polymerization to prepare a series of Bi5O7I//ZFP coatings.The study found that the flower-shaped Bi5O7I microspheres have excellent ultraviolet light response and slight visible light response,and the addition of ZFP can promote the separation of electron-hole pairs.The quality loss of Bi₅O₇I/ZFP composite coating ranged from-0.06 to 0.04 wt.%.Bi₅O₇I/ZFP-2prepared by adding 7.5 g of dimethylaminoethyl methacrylate and 22.5 g of dodecafluoroheptyl methacrylate has the best antifouling effect.The 14-day anti-diatom attachment test shows that it has less attached diatoms.The antibacterial rates against Escherichia coli and Staphylococcus aureus(10⁶ cfu·m L^-1)in 24 h are 99.09%and 99.66%,respectively.Bi5O7I/ZFP antifouling paint is prepared with Bi5O7I as antifouling agent,ZFP as resin matrix,and adding pigments,fillers and solvents,etc.After hanging the board in the Bohai Sea for 6 months,there are only a small amount of sediment on the surface,and no large-scale biofouling.To further improve the antifouling performance of the coating,silver nanoparticles were light-deposited on Bi5O7I flower-shaped microspheres by photodeposition and combined with ZFP to prepare a series of ABZFP coatings.The light absorption range and charge separation efficiency of Bi5O7I can be effectively improved by depositing 5 wt.%of Ag nanoparticles（18 nm）.After immersion in artificial seawater for 30 days,the mass loss rate of the ABZFP composite coating was below 0.0025 wt.%,indicating its good stability.And the growth rate of diatoms containing ABZFP coating is between 3.15～3.25×10^-3 d^-1,which is not much different from the blank sample,and has no inhibitory effect on the growth of diatoms.ABZFP-1 has the best antifouling performance,and the anti-diatom adhesion rate is 97.43%in 30 days.The antibacterial rates against Escherichia coli and Staphylococcus aureus(10⁶cfu·m L^-1)at 12 h are 99.62%and 99.78%,respectively.Compared with the previous chapter under the same conditions,the antibacterial rate has increased by 19%.Using Bi5O7I/Ag instead of Bi5O7I to prepare ABZFP antifouling paint.The surface of ABZFP antifouling paint is smooth and clean,no large biofouling is found,except a small amount of sediment,after hanging the board in Dalian waters for 6 months.To increase the possibility of large-scale coating production,Bi/Bi5O7I photocatalyst was synthesized with Bi instead of the noble metal Ag,then combined with acrylic fluoroboron self-polishing polymer（AFBP）synthesized by free radical polymerization to prepare BBFP composite coating.Studies have shown that the addition of Bi/Bi5O7I photocatalyst changes the surface wettability and hydrolysis rate of AFBP,and eliminates the impact of small molecular compounds released by the hydrolysis of AFBP side chains on marine organisms.BBFP composite coating has no obvious toxicity to algae,its TOC removal rate is over 85%,and after self-cleaning,it mineralizes small organic molecules into carbon dioxide and water.BBFP-5 composite coating has the best anti-fouling effect.The anti-diatom adhesion rate is98.32%for 20 days,and the antibacterial rate against Escherichia coli and Staphylococcus aureus(10⁶ cfu·m L^-1)is 98.24%and 98.61%in 24 hours.The antifouling paint prepared with Bi/Bi5O7I as the antifouling agent,AFBP as the resin,and adding pigments and fillers.After6 months of hanging the board in the Bohai Sea,there is no biofouling attached except for a little sediment.To meet the needs of marine equipment for marking or anti-counterfeiting and anti-fouling effect,the perovskite Cs Pb Br3 nanocrystals synthesized by thermal injection method,composite Bi4O5I2 nanotubes prepared by solvothermal method,and combined with fluorine-containing zwitterionic polyurethane（FZPU）to prepare the CBFZP composite film.The results show that the CBFZP composite film can be converted to 515 nm green PL fluorescence under excitation at 365 nm wavelength,and it can emit light stably for a long time in air and water environments.CBFZP composite film has good mechanical properties,its ultimate tensile stress reaches 17.30 MPa,and has no effect on the growth of diatoms.In addition to meeting the needs of luminescence,CBFZP also has excellent anti-fouling effects.The anti-diatom adhesion rate of 20 days reaches 97.51%,and the antibacterial rate of Escherichia coli and Staphylococcus aureus(10⁷ cfu·m L^-1)can reach 98.86%and 99.02%at visible light for 24 h.To solve the problem of membrane materials being affected by biofouling in the marine field,hollow Mo Se2 nanospheres were prepared by solvothermal method,which formed a heterojunction structure with defective Bi OI nanosheets,and added them to PVDF to prepare PMB photocatalytic composite membrane.Studies have shown that the PMB composite membrane can generate heat under light,and the surface temperature of the material can reach110^°C in 5 minutes,the temperature of the immersed aqueous solution can reach 59.2^°C,and the water evaporation rate is as high as 1.43 kg·m^-2·h^-1,and the stability of PMB composite membrane is good.The PMB5 composite membrane has good antifouling properties,and the anti-diatom adhesion rate is 98.83%within 15 days.Compared with PVDF,the antibacterial rates of Escherichia coli and Staphylococcus aureus(10⁷ cfu·m L^-1)reached 98.50%and 99.10%in the 24 h antibacterial cycle.And·O2^-plays a major role in the photocatalytic antifouling process,h⁺takes the second place,and·OH has the least effect on the photocatalytic antifouling performance.