Preparation And Application Of PU/TiO₂ Composite Photocatalyst Materials By Layer By Layer Self Assembly

With the rapid development of industry,a large amount of industrial wastewater discharge has made environmental pollution increasingly serious.Photocatalysis technology provides us with an effective way to solve environmental problems.Among many photocatalytic materials,TiO₂ has become the most widely used semiconductor photocatalytic material due to its non-toxicity,good chemical stability,high photocatalytic activity,and low cost.However,there are still some problems in practical applications.As a powdered catalyst,TiO₂ is easy to agglomerate in solution,difficult to separate and recover,and has low recycling rate,which limits its promotion.Therefore,it is of great significance to find a suitable carrier for the study of immobilized TiO₂.In this paper,TiO₂ was prepared by hydrothermal method,and?PU/TiO₂?n composite photocatalytic material was prepared based on layer-by-layer self-assembly technology.The results of X-Ray diffraction?XRD?,Raman spectroscopy?Raman?,scanning electron microscopy?SEM?and transmission electron microscopy?TEM?showed that the prepared TiO₂ was anatase TiO₂ with good dispersion and Successful loading onto the PU,which solves the problem of difficult separation and recovery of TiO₂.The absorption properties of UV light and the MB of adsorption properties and photocatalytic degradation properties of?PU/TiO₂?n composite photocatalytic materials were studied.The results of UV-Vis Abs analysis show that as the number of assembled layers increases,the absorption of UV light,the adsorption performance of MB and the photocatalytic performance increase,?PU/TiO₂?₁₀0 has the best light absorption performance,adsorption performance and photocatalytic degradation performance.It was found that the?PU/TiO₂?₁₀0 composite photocatalytic material degraded in solution for too long,and it was easy to swell and fall off.In order to improve the stability of the composite,a negatively charged strong polyelectrolyte material sodium polystyrene sulfonate?PSS?was introduced,with a high charge density,the charge is not affected in a wide range,and the more constant charge density makes the assembled composite more stable.In order to further improve the adsorption performance and photocatalytic activity of TiO₂,a hydrothermal method was also used to prepare{201}TiO₂ with special morphology under the control of HF.The analysis showed that it is anatase TiO₂ with regular rules.The geometric shape,similar to the dandelion microsphere hierarchy,facilitates the refraction and absorption of ultraviolet light on the surface and promotes the separation of carriers.Similarly,the?PU/PSS/TiO₂?n,?PU/PSS/{201}TiO₂?n composite photocatalytic material was prepared by layer self-assembly method,which absorbs ultraviolet light,adsorbs to MB and photocatalytic degradation properties increased with the increase of the number of layers.However,for MB adsorption performance and photocatalytic degradation performance:?PU/PSS/{201}TiO₂?₁₀>?PU/PSS/TiO₂?₁₀>?PU/TiO₂?₁₀,after 6 cycles of reuse,?PU/PSS/{201}TiO₂?₁₀0 has the highest stability and photocatalytic degradation properties.The degradation effect of?PU/PSS/{201}TiO₂?₁₀0 composite photocatalytic material on metallurgical coking phenol-containing wastewater was investigated.It can exist stably in large ionic strength solution.When the initial concentration of phenol solution is 10mg/L When the temperature is 25°C,the PH is 9,and the addition amount of H₂O₂ is 0.3%,the adsorption performance and photocatalytic degradation performance of?PU/PSS/{201}TiO₂?₁₀0 composites are the best.After 6 times of repeated use,It can maintain high photocatalytic performance and stability,and has good recycling efficiency.