碳酸氢根和碳酸根离子对水溶液中 Rhodamine B 的声化学降解的影响。
Influence of bicarbonate and carbonate ions on sonochemical degradation of Rhodamine B in aqueous phase.
机构信息
Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, University of Annaba, P.O. Box 12, 23000 Annaba, Algeria.
出版信息
J Hazard Mater. 2010 Mar 15;175(1-3):593-9. doi: 10.1016/j.jhazmat.2009.10.046. Epub 2009 Oct 20.
The influence of bicarbonate and carbonate ions on sonolytic degradation of cationic dye, Rhodamine B (RhB), in water was investigated. As a consequence of ultrasonic cavitation that generates .OH radicals, carbonate radicals were secondary products of water sonochemistry when it contains dissolved bicarbonate or carbonate ions. The results clearly demonstrated the significant intensification of sonolytic destruction of RhB in the presence of bicarbonate and carbonate, especially at lower dye concentrations. Degradation intensification occurs because carbonate radicals sonochemically formed undergo radical-radical recombination at a lesser extent than hydroxyl radicals. The generated carbonate radicals are likely able to migrate far from the cavitation bubbles towards the solution bulk and are suitable for degradation of an organic dye such as RhB. Therefore, at low dye concentrations, carbonate radical presents a more selective reactivity towards RhB molecules than hydroxyl radical. In the presence of bicarbonate, degradation rate reached a maximum at 3 g L(-1) bicarbonate, but subsequent addition retards the destruction process. In RhB solutions containing carbonate, the oxidation rate gradually increased with increasing carbonate concentration up to 10 g L(-1) and slightly decreased afterward. Carbonate radicals sonochemically generated are suitable for total removal of COD of sonicated RhB solutions.
研究了碳酸氢根和碳酸根离子对水中阳离子染料罗丹明 B(RhB)超声降解的影响。由于超声空化会产生.OH 自由基,因此当水中含有溶解的碳酸氢根或碳酸根时,它们是水超声化学的次级产物。结果清楚地表明,在存在碳酸氢根和碳酸根的情况下,RhB 的超声降解得到了显著强化,尤其是在较低的染料浓度下。强化降解的发生是因为碳酸根自由基在超声化学条件下形成的自由基-自由基复合程度比羟基自由基低。生成的碳酸根自由基很可能能够从空化泡中迁移到溶液主体中,并适合降解像 RhB 这样的有机染料。因此,在低染料浓度下,碳酸根自由基对 RhB 分子的选择性反应性比羟基自由基更强。在碳酸氢盐存在下,降解速率在 3 g L(-1) 碳酸氢盐时达到最大值,但随后的添加会减缓破坏过程。在含有碳酸根的 RhB 溶液中,氧化速率随着碳酸根浓度的增加逐渐增加,最高可达 10 g L(-1),随后略有下降。超声化学生成的碳酸根自由基适合于完全去除超声处理后的 RhB 溶液的 COD。