Preparation Of Photocatalytically Active Nonwoven Fabric And Its Photodegradation Of VOCs

Photocatalytic technology is a new technology used to remove volatile organic compounds（VOCs）in recent years,which is characterized by low reaction requirements,less secondary pollution and low energy consumption costs.Photocatalytic oxidation is a process of degrading toxic and harmful substances into harmless CO₂ and H₂O with semiconductor materials as catalysts under illumination.TiO₂ is recognized as the best photocatalytic material.It not only has excellent photocatalytic activity,but also has the advantages of non-toxicity,low cost,anti-oxidation and corrosion resistance.Some toxic and harmful air pollutants such as volatile organic compounds such as alkanes,aldehydes and ketones can be rapidly degraded into substances such as CO₂ and H₂O.However,the main disadvantage of TiO₂ is its wide band gap,that is,3.2e V,resulting in only 5%of solar energy being used for photocatalytic degradation.Besides,agglomeration of TiO₂ nanoparticles leads to reduced surface area and insufficient adsorption properties,which,together with high electron-hole pair complexation rate,further limits its performance.In order to overcome these problems,two main ways are adopted to improve it:1.Combining it with carrier removal;2.TiO₂particles were modified.Based on this idea,this paper investigates the preparation of photocatalytically active nonwoven fabric and its performance study of photodegradation of VOCs,specifically from the following three aspects:（1）TiO₂ was loaded on the PAN nonwoven fabric by a simple co-solvent swelling method,and the preoxidized TiO₂@PAN nonwoven fabric was successfully prepared by pre-oxidation treatment.The pre-oxidation treatment can effectively improve the thermal stability and light stability of TiO₂@PAN,thereby prolonging the service life of the PAN nonwoven substrate.In addition,the preoxidized TiO₂@PAN nonwovens exhibited excellent photocatalytic performance in the removal of toluene and formaldehyde.The removal efficiencies of toluene and formaldehyde reached 80%and 92%,respectively.With such a treatment method,while maintaining the catalytic activity of the catalyst to remove VOCs,it can also prolong the service life of the matrix material.（2）TiO₂/SiO₂ nanocomposite photocatalysts with different molar ratios were synthesized by a simple method,and the adsorption and catalytic properties of TiO₂/SiO₂ nanocomposite photocatalysts to ethyl acetate were explored.The optimal molar ratio is TiO₂/SiO₂=70/30,and the removal rate reaches 100%.The mechanism is mainly that SiO₂ incorporation reduces the TiO₂ band gap energy,while SiO₂ also enhances the adsorption performance of TiO₂/SiO₂nanocomposite photocatalyst for ethyl acetate with a synergistic effect and a coefficient of2.39.（3）TiO₂/SiO₂=70/30 was successfully loaded onto PEEK non-woven fabric by plasma treatment and ultrasonic loading method.The ethyl acetate removal performance of TiO₂/SiO₂=70/30 loaded PEEK nonwoven fabric was explored.Simulated sunlight irradiation for 1.5 h showed that ethyl acetate could be completely removed by TiO_2/SiO₂=70/30 loaded PEEK nonwoven fabric,which exhibited excellent removal effect with a synergistic effect and a synergistic coefficient of 3.21.In this paper,photocatalysts are combined with nonwovens to prepare textiles with photocatalytic activity,which broadens a new path for commercialization of harmful gas filtration materials.