Background: TiO₂ nanoparticles possess adsorption capacity and photocatalytic activity, and are thus fitted for removal of dyes from water. However, TiO₂ nanoparticles are difficult to separate from the bulk solution due to high loss. Moreover, TiO₂ can only use light with a wavelength of less than 387.5 nm, so the utilization efficiency of solar energy is very low. The present work prepared Fe₃O₄@C@TiO₂-AgBr-Ag composites to overcome the shortcomings of TiO₂.

Objective: Adsorptive and photocatalytic performance of nano-magnetic materials Fe₃O₄@C@TiO₂- AgBr-Ag.

Methods: Fe₃O₄@C@TiO₂ and Fe₃O₄@C@TiO₂-AgBr-Ag magnetic nanocomposites were prepared by the sol-gel method. Their structure was characterized. Performances of Fe₃O₄@C@TiO₂ and Fe₃O₄@C@TiO₂-AgBr-Ag for removing Rh B were thoroughly investigated and compared. Langmuir– Hinshelwood kinetic model was applied to analyze the heterogeneous processes of adsorption and photodegradation.

Results: Removal experiments were carried out with Rhodamine B as the subject. The effects of contacting time, pH, subject concentration, and doses of photocatalyst on the removal performance were studied. The removal of Rh B by Fe₃O₄@C@TiO₂ and Fe₃O₄@C@TiO₂-AgBr-Ag involved both adsorption and photodegradation, and the photocatalytic activity of Fe₃O₄@C@TiO₂-AgBr-Ag was much higher than that of Fe₃O₄@C@TiO₂. The optimum removal conditions were determined. Under the optimal conditions, the removal rate of Rhodamine B with Fe₃O₄@C@TiO₂ was 77.8%, and the removal rate of Rhodamine B with Fe₃O₄@C@TiO₂- AgBr-Ag was 87.3%.

Conclusion: The coupling of the nanostructured metal Ag to the outer surface of TiO₂ could effectively increase photocatalytic efficiency under visible light. The photocatalysts could be separated from bulk solutions by using a magnet and be easily recycled. The removal reaction kinetics fitted with the first-order model.

背景：TiO ₂纳米粒子具有吸附能力和光催化活性，因此适合从水中去除染料。然而，由于高损失，TiO ₂纳米颗粒难以从本体溶液中分离。而且，TiO ₂只能利用波长小于387.5nm的光，所以太阳能的利用效率很低。目前的工作制备了 Fe ₃ O ₄ @C@TiO ₂ -AgBr-Ag 复合材料，以克服 TiO ₂的缺点。

目的：纳米磁性材料Fe ₃ O ₄ @C@TiO ₂ - AgBr-Ag的吸附和光催化性能。

方法：采用溶胶-凝胶法制备Fe ₃ O ₄ @C@TiO ₂和Fe ₃ O ₄ @C@TiO ₂ -AgBr-Ag磁性纳米复合材料。它们的结构被表征。对Fe ₃ O ₄ @C@TiO ₂和Fe ₃ O ₄ @C@TiO ₂ -AgBr-Ag去除Rh B的性能进行了深入研究和比较。Langmuir-Hinshelwood 动力学模型用于分析吸附和光降解的非均相过程。

结果：以罗丹明B为对象进行去除实验。研究了接触时间、pH、对象浓度和光催化剂剂量对去除性能的影响。Fe ₃ O ₄ @C@TiO ₂和Fe ₃ O ₄ @C@TiO ₂ -AgBr-Ag对Rh B的去除涉及吸附和光降解，以及Fe ₃ O ₄ @C@TiO ₂ -的光催化活性AgBr-Ag 远高于 Fe ₃ O ₄ @C@TiO ₂。确定了最佳去除条件。在最佳条件下，罗丹明B对Fe的去除率₃ O ₄ @C@TiO ₂为77.8%，罗丹明B与Fe ₃ O ₄ @C@TiO ₂ - AgBr-Ag的去除率为87.3%。

结论：纳米结构金属Ag与TiO ₂外表面的偶联可有效提高可见光下的光催化效率。光催化剂可以通过使用磁铁从本体溶液中分离出来，并且很容易回收利用。去除反应动力学符合一级模型。