The performances of a visible light active structured photocatalyst in the oxidation of arsenite to arsenate in aqueous solution were investigated. In particular, the photocatalytic active phase was Cu-doped ZnO, while polystyrene (PS) pellets were used as support. The Cu-doped ZnO photocatalyst was immobilized on polystyrene pellets surface by “solvent casting method” and characterized by different techniques. The photocatalytic tests were performed in a floating bed reactor using a visible LEDs strip as light source. The complete As(III) oxidation was achieved after 120 min of visible irradiation at a Cu-doped ZnO loading on polystyrene pellets equal to 5 wt%. Furthermore, the optimized photocatalyst was reused for several cycles without any substantial decrease of photocatalytic performances. In order to determine which reactive species plays a more significant role in the oxidation of As(III), the effects of different radical scavengers were tested. The results evidenced that OH and O₂⁻ seem not to be the main oxidant for the direct As(III) oxidation, whereas the oxidation mechanism of As(III) using Cu-doped ZnO structure photocatalyst seems to be related to the h⁺ holes generated under visible light irradiation.

研究了可见光活性结构光催化剂在水溶液中将砷氧化为砷的性能。特别地，光催化活性相是掺杂Cu的ZnO，而聚苯乙烯（PS）颗粒用作载体。通过“溶剂浇铸法”将掺杂Cu的ZnO光催化剂固定在聚苯乙烯颗粒表面，并通过不同的技术对其进行表征。使用可见的LED条作为光源，在浮床反应器中进行光催化测试。在铜掺杂的ZnO上负载等于5 wt％的聚苯乙烯颗粒的可见光照射120分钟后，完成了As（III）的完全氧化。此外，优化的光催化剂可以重复使用数个周期，而光催化性能却没有任何实质性的下降。为了确定哪种反应性物种在As（III）的氧化中起更重要的作用，测试了不同自由基清除剂的作用。结果证明和O ₂ ^-似乎不是用于直接作为（III）氧化的主要氧化剂，而作为（III）的氧化机理使用Cu掺杂的ZnO结构光催化剂似乎与为H ⁺可见光照射下产生的空穴。