This paper reports the immobilization of nano-sized Er_xTi_1-xO_2-yN_y catalyst (TiO₂ modified with erbium and nitrogen) onto natural porous mineral diatomaceous earth (DE). The as-synthesized composite was designed as pellet form and used as floating photocatalyst to overcome the drawback of suspended photocatalysis system. The starting material DE for catalyst preparation originated from industrial waste of winery company. XPS, SEM, TEM, XRD and UV-Vis DRS techniques were used to study the catalyst’s morphology and physicochemical properties. The catalyst was used to mitigate micropollutant ibuprofen (IBP) from water under sunlight. At optimal conditions, about 96.4% of IBP (10 mg/L) was mitigated in 240 min using 1.0 g/L catalyst at pH=6. Moreover, when oxidant persulfate (PS, K₂S₂O₈) was introduced, it can rapidly capture the photo-induced electrons to generate sulfate radicals (·SO₄^-). These radicals then turned into hydroxyl radicals (·OH) in IBP solution. The above reaction process not only hindered the charge carrier recombination but also led to the formation of more reactive species. Both results can improve IBP mitigation efficiency. After PS was added, IBP was completed removed within 210 min. The introduction of common ions hindered IBP mitigation process. The inhibiting order of anions was: CO₃^2- > NO₃^- > Cl^-, and the order of cations was Cu²⁺ > Mg²⁺ > Ca²⁺. The quenching tests demonstrated that ·O₂^- and h⁺ were major reactive species during photo-oxidation process, before or after the addition of PS. The intermediate products of IBP were determined by HLPC-MS technique, and possible reaction pathways and mechanism were proposed. The IBP oxidation rate slightly dropped after 5 reuse tests, suggesting that the reported catalyst presented high stability and recyclability. The reported floating photocatalyst can be introduced as a promising wastewater remediation material, thanks to its excellent sunlight-driven activity, good absorbability, simple recovery, high stability, and reuse potential.

本文报道了纳米级Er _x Ti _1-x O _2-y N _y催化剂（TiO ₂用和氮改性）到天然多孔矿物硅藻土（DE）上。合成后的复合材料设计为颗粒形式，并用作漂浮光催化剂，以克服悬浮光催化系统的缺点。催化剂制备的起始原料DE来源于酒厂的工业废料。采用XPS，SEM，TEM，XRD和UV-Vis DRS技术研究了催化剂的形貌和理化性质。该催化剂用于减轻阳光下水中的微污染物布洛芬（IBP）。在最佳条件下，使用pH = 6的1.0 g / L催化剂，在240分钟内可降低约96.4％的IBP（10 mg / L）。此外，当氧化剂过硫酸盐（PS，K ₂ S ₂ O ₈）被引入，它可以迅速地捕捉光诱导的电子以生成硫酸自由基（·SO ₄ ^- ）。然后这些自由基在IBP溶液中变成羟基自由基（·OH）。上述反应过程不仅阻碍了电荷载流子的重组，而且导致了更多反应性物质的形成。两种结果都可以提高IBP缓解效率。添加PS后，IBP在210分钟内完成去除。常见离子的引入阻碍了IBP缓解过程。阴离子的抑制顺序为：CO ₃ ^2- > NO ₃ ^- >氯^- ，和阳离子的顺序为Cu ²⁺ >镁²⁺ >的Ca ²⁺。淬火测试表明·O2 ₂ ^-和H ⁺是在光氧化过程主要反应性物质之前或在加入PS的后。通过HLPC-MS技术测定了IBP的中间产物，并提出了可能的反应途径和机理。5次重复使用测试后，IBP氧化速率略有下降，表明所报道的催化剂具有较高的稳定性和可回收性。由于其优异的阳光驱动活性，良好的吸收性，简单的回收，高稳定性和可重复使用的潜力，所报道的浮动光催化剂可作为有前途的废水修复材料而引入。