环糊精对Fe(Ⅲ)引发双酚A光降解的影响

环糊精口α-CD、β-CD和γ-CD能分别与双酚A形成1:1主-客体包结物.在250W金属卤化物灯(λ≥365 nm)光照下,研究了在Fe(Ⅲ)-OH配合物体系中,不同环糊精对双酚A光降解的影响.结果表明,β-CD能较大地促进双酚A的光降解,α-CD次之,而γ-CD对双酚A的光降解存在一定的抑制;并且CDs浓度的变化对双酚A光降解的初始速率有明显的影响.双酚A光降解的初始速率随着β-CD和α-CD浓度增大而增加,当β-CD=60μmol/L时达到最大,然后随着浓度增大而降低,而BPA的光降解初始速率随γ-CD浓度的增加总的趋势是减小的.通过计算机软件Gaussian98,采用PM3方法模拟了环糊精与双酚A的包结行为,进一步说明3种环糊精与双酚A形成主-客体包结物对光降解的影响.

Influence of cyclodextrins on the photodegradation of bisphenol A induced by Fe(III)

Cyclodextrins (CDs) can form a host/guest inclusion complex with bisphenol A(BPA). Under a 250 W metal halide lamp (lambda > or = 365 nm), the effects of different cyclodextrins to oxidation of endocrine disrupter BPA in the Fe(III)-hydroxyl complexes system were investigated. In the presence of alpha- cyclodextrin or beta-cyclodextrin (alpha-CD or beta-CD), the photodegradation efficiency of BPA can be enhanced, but gamma-cyclodextrin (gamma-CD) showed inhibitive effect on the photodegradation efficiency. The initial degradation rate of BPA firstly increased with increasing concentration of beta-CD and alpha-CD from 0 to 60 micromol L(-1), and the maximum rate was reached at the beta-CD concentration of 60 micromol L(-1), and then decreased. But the initial degradation rate of BPA decreased with increasing concentration of gamma-CD. Furthermore, the structures of BPA, CDs and BPA/CDs were optimized used the PM3 method in Gaussian98 software package. The results showed that BPA partly entered the cavity of CDs, which formed different super-molecular host-guest complexes, and resulted in the different photodegradation rates of BPA under UV-vis irradiation.