Study On The Catalytic Properties Of Fe-Pillared Bentonite And Mechanism Of UV-Fenton Degradation Of Dye

Heterogeneous photo-Fenton process is one of the most promising technologies for organic wastewater treatment. At present, a key problem of this technology development and its industrial application is to develope ideal catalyst, extend the range of pH values for Fenton-type oxidation, increase the catalytic activity of heterogeneous catalyst and lower the cost of treatment. And selection of catalyst supports is the most important during the preparation of novel heterogeneous catalyst. Bentonite is one of ideal catalyst supports because of its large surface area, high adsorption capacity and low cost. In this dissertation, the catalytic activities of Fe-pillared bentonite (pillared with hydroxyl-Fe-polycation, α-Fe₂O₃ and α-FeOOH) in UV-Fenton system were investigated in an aim to increase the discolouration and mineralization efficiency of Orange II (a model compound of azo-dye). And the catalytic process, mechanism as well as regulation of hydroxyl-Fe-pillared bentonite were studied in detail. The main original conclusions of the work are drawn as following parts.1. A novel UV-Fenton catalyst, hydroxyl-Fe-pillared bentonite, was developed. This catalyst exhibited a high catalytic activity and good long-term stability in multiple runs in the discolouration and mineralization of Orange II. Furthermore, the catalyst could exhibite high catalytic activity in a wide range of pH values (3.0 ～ 9.0). For example, almost 100% color removal and 82% TOC removal of 0.2 mM Orange II could be obtained within 60 min even if the initial pH of solution was as high as 9.0.2. A possible catalytic mechanism of hydroxyl-Fe-pillared bentonite was proposed. It was found that the homogeneous UV-Fenton process was the dominant reaction in the degradation of Orange II. The catalyst acted as not only heterogeneous catalyst for heterogeneous UV-Fenton process but also source and sink of iron ions...