PFOAを分解するナノ粒子の設計を化学エンジニアが微調整 Chemical engineers fine-tune design of PFOA-destroying nanoparticles
2022-07-25 ライス大学
窒化ホウ素と二酸化チタンの複合体を作り、それぞれの触媒の優れた特徴を併せ持たせることにした。この新しい研究では、UV-Aを利用した複合体は、通常の二酸化チタン光触媒に比べて約15倍速くPFOAを破壊することが示された。
光電流応答測定などのデータ解析により、半導体複合材料がUV-Aエネルギーを利用して、水中のPFOA分子を分解する仕組みが明らかになった。自然光の下でペットボトルを使った屋外実験では、窒化ホウ素-酸化チタン複合体は、脱イオン水中のPFOAを3時間以内に約99％分解できることがわかった。一方、海水では約9時間かかった。
＜関連情報＞
- https://news.rice.edu/news/2022/rice-improves-catalyst-destroys-forever-chemicals-sunlight
- https://www.sciencedirect.com/science/article/abs/pii/S1385894722032223
酸化チタンによる窒化ホウ素光触媒のパーフルオロオクタン酸の分解性能向上 Titanium oxide improves boron nitride photocatalytic degradation of perfluorooctanoic acid
Lijie Duan,Bo Wang,Kimberly N.Heck,Chelsea A.Clark,Jinshan Wei,Minghao Wang,Jordin Metz,Gang Wu,Ah-Lim Tsai,Sujin Guo,Jacob Arredondo,Aditya D.Mohite,Thomas P.Senftle,Paul Westerhoff,Pedro Alvarez,Xianghua Wen,onghui Song,Michael S.Wong
Chemical Engineering Journal Available online :22 June 2022
DOI:https://doi.org/10.1016/j.cej.2022.137735
Highlights
- •BN/TiO2 composite was synthesized through simple calcination of nontoxic powders.
- •BN/TiO2 is a type II heterojunction with improved charge carrier separation.
- •Under UV-C, BN/TiO2 degraded short-chain PFOA intermediates faster than BN and TiO2.
- •Under UV-A, BN/TiO2 degraded PFOA faster than TiO2, while BN was inactive.
Abstract
Boron nitride (BN) has the newly-found property of degrading recalcitrant polyfluoroalkyl substances (PFAS) under ultraviolet C (UV-C, 254 nm) irradiation. It is ineffective at longer wavelengths, though. In this study, we report the simple calcination of BN and UV-A active titanium oxide (TiO2) creates a BN/TiO2 composite that is more photocatalytically active than BN or TiO2 under UV-A for perfluorooctanoic acid (PFOA). Under UV-A, BN/TiO2 degraded PFOA ∼ 15 × faster than TiO2, while BN was inactive. Band diagram analysis and photocurrent response measurements indicated that BN/TiO2 is a type-II heterojunction semiconductor, facilitating charge carrier separation. Additional experiments confirmed the importance of photogenerated holes for degrading PFOA. Outdoor experimentation under natural sunlight found BN/TiO2 to degrade PFOA in deionized water and salt-containing water with a half-life of 1.7 h and 4.5 h, respectively. These identified photocatalytic properties of BN/TiO2 highlight the potential for the light-driven destruction of other PFAS.
