Researchers from the Institute of Oceanology at the Chinese Academy of Sciences have made significant progress in water purification with the development of a 3D printed polymer substrate coated with a photocatalytic film. Led by Professor Zhang Dun, the team successfully grew a bismuth oxyiodide (BiOI) film on the polymer substrate using a technique called successive ion layer adsorption reaction (SILAR).
The researchers observed that the substrate was fully covered with a microstructure film resembling flowers. By employing an OH-/I substitution strategy, they engineered I-defects in the BiOI film, causing a change in the substrate’s color from gloss white to various shades of yellow. This color variation resulted from the modification of the band gap caused by the iodine defect engineering film.
During the film growth process, iodine spaces were introduced into the BiOI crystals, leading to an increase in the internal electric field and electron density of the material. This enhancement improved the separation and transmission efficiency of photoinduced carriers. The iodine-defect engineered BiOI film exhibited superior properties compared to stoichiometry BiOI, including smaller grain size, higher specific surface area, electronegativity, photoelectric response, and photocatalytic activity.
The researchers proposed that Bi3+ ions initially adsorbed onto the polymers, providing active sites for film growth. Over time, the films self-assembled into a petal-like BiOI structure due to the high proportion and movement speed of I-ions.
According to Xu Xuelei, the first author of the study, the developed film demonstrated excellent photocatalytic activity and cyclic stability in degrading organic compounds and sterilizing microorganisms. This breakthrough in water purification technology holds promise for providing efficient and sustainable solutions to address water pollution challenges.
You can read the full research paper, titled “In-situ growth pH-adjusted iodine defects engineering BiOI film on 3D-printed polymer substrate for efficient organic pollutant and microorganism purification“ in the Separation and Purification Technology journal at this link.
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