Photogeneration of H2O2 in SPEEK/PVA Aqueous Polymer Solutions

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• 作者：Brian K. Little ; PaviElle Lockhart ; B. L. Slaten ; G. Mills
• 刊名：The Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：May 23, 2013
• 年：2013
• 卷：117
• 期：20
• 页码：4148-4157
• 全文大小：348K
• 年卷期：v.117,no.20(May 23, 2013)
• ISSN：1520-5215

文摘

Photolysis of air-saturated aqueous solutions containing sulphonated poly(ether etherketone) and poly(vinyl alcohol) results in the generation of hydrogen peroxide. Consumption of oxygen and H₂O₂ formation are initially concurrent processes with a quantum yield of peroxide generation of 0.02 in stirred or unstirred solutions within the range of 7 鈮?pH 鈮?9. The results are rationalized in terms of O₂ reduction by photogenerated 伪-hydroxy radicals of the polymeric ketone in competition with radical鈥搑adical processes that consume the macromolecular reducing agents. Generation of H₂O₂ is controlled by the photochemical transformation that produces the polymer radicals, which is most efficient in neutral and slightly alkaline solutions. Quenching of the excited state of the polyketone by both H₃O⁺ and OH^{鈥?/sup> affect the yields of the reducing macromolecular radicals and of H₂O₂. Deprotonation of the 伪-hydroxy polymeric radicals at pH > 9 accelerate their decay and contribute to suppressing the peroxide yields in basic solutions. Maxima in [H₂O₂] are observed when illuminations are performed with static systems, where O₂ reduction is faster than diffusion of oxygen into the solutions. Under such conditions H₂O₂ can compete with O₂ for the reducing radicals resulting in a consumption of the peroxide.}