施氏矿物和有机酸共存体系中孔雀石绿的多相光催化降解

Heterogeneous photocatalytic degradation of malachite green in the presence of schwertmannite and organic acids

通过氧化亚铁硫杆菌对硫酸亚铁的作用获得施氏矿物,并研究其在有机酸(草酸、柠檬酸和酒石酸)的协同作用下光催化降解孔雀石绿的影响因素及其作用机制。结果表明:避光条件下施氏矿物对孔雀石绿存在微弱的吸附作用;紫外光照射下,单独施氏矿物对孔雀石绿的降解有催化作用,在有机酸的协同下,催化降解效率得到进一步提高。相同试验条件下,不同有机酸对施氏矿物光催化降解孔雀石绿效率从大到小依次为:草酸、柠檬酸、酒石酸。同时提出了有机酸协同施氏矿物光催化降解孔雀石绿的可能机制为:有机酸吸附于矿物表面,并形成高光活性的Fe(Ⅲ)-有机酸配合物,进而释放出具有强氧化能力的羟基自由基(.OH),最终导致孔雀石绿降解。

Schwertmannite was synthesized through an oxidation of FeSO4 by Acidithiobacillus ferrooxidans and the photocatalytic degradation of malachite green in the presence of schwertmannite and organic acids（oxalic acid,citric acid,tartaric acid）was investigated.The results showed that a weak adsorption of malachite green by schwertmannite was observed in dark.Under UV irradiation,the degradation of malachite green was markedly enhanced by schwertmannite alone,and it could be further accelerated when organic acids were introduced into the reaction system.Under the same experimental conditions,the schwertmannite photocatalytic degradation of malachite green assisted by organic acids was in the order：oxalic acid,citric acid,tartaric acid.The mechanism of malachite green in this study was proposed.First,organic acids were adsorbed onto schwertmannite and Fe（Ⅲ）-organic acid complexes with a high photo-activity were formed.Then,UV irradiation led to the yield of·OH responsible for the decomposition of malachite green.