| The environmental contamination has led to the deterioration of quality of water and air.An exposure to contaminated indoor air may result in sick building syndrome such as headache and fatigue.Formaldehyde is one of the most common volatile organic compounds(VOCs),which is the number one killer of human health and great harmful to human beings.Not only that,it is easy to breed bacteria in humid indoor areas and cause microbial contamination,which could infection lead to body infection.The deterioration of air quality is the main cause of respiratory diseases.The quality of air quality is closely related to human health.Photocatalytic technology has great potential for pollution control.Semiconductor photocatalytic materials are considered as excellent materials for environmental pollution treatment because they can degrade pollutants directly by cheap light energy with simple operation,mild conditions and low energy consumption.Titanium dioxide(TiO2)is one of the most attractive semiconductor materials due to its low cost,stability,and high photocatalytical activity.However,applications of TiO2 are largely limited due to inherent drawbacks such as a wide band gap(3.20 eV)and fast recombination of photogenerated electron-hole.It only can be excited by ultraviolet light(about 3-5%of total sunlight).Therefore,TiO2 should be modified to broaden the photoabsorption region and improve photo-quantum efficiency.In this paper,nano-titanium dioxide was modified by dye sensitization and semiconductor composite method.Combining white TiO2 with ?-Fe2O3,copper perchlorophthalocyanine(CuPcCCl6),and copper phthalocyanine(CuPc)respectively,three kinds of photocatalysts with different colors were prepared(i.e.,Fe2O3/TiO2,CuPc/TiO2 and CuPcCl16/TiO2).Then as-prepared nanocomposites were successfully immobilized on the sheath-core composite polyester(LMPET)fibers and got Fe2O3/TiO2@LMPET,CuPcCl16/TiO2@LMPET and CuPc/TiO2@LMPET.At the same time,it makes up for the shortcomings of powder catalyst,such as difficult to fix in water,easy to disperse in air,difficult to recycle and reuse,and even easy to cause secondary pollution.The presence of catalyst fabric expands its application in environmental pollution treatment.The results of TEM,SEM and FTIR showed that Fe2O3,CuPcCl16 and CuPc were successfully combined with TiO2,and the powder catalysts were evenly distributed on the surface of LMPET fibers.Ultraviolet-visible spectra displayed both powder and fabrics catalysts exhibited a redshift in the absorption edge and strong absorption in the visible light range,which improves the utilization efficiency of sunlight.Significantly,the composite catalysts were not only immobilized on the surface of the LMPET fiber,but also endowed it with higher solar light utilization efficiency compared with TiO2@LMPET.Compared with TiO2-based white fabric,the prepared colored catalytic fabrics have remarkable performance in photocatalytic degradation of formaldehyde(HCHO),a pollutant in water and indoor air according to performance test.In addition,the study on the antimicrobial activity of fabrics showed that the antimicrobial effect of fabrics against Escherichia coli and Staphylococcus aureus could reach 90%under LED lamp illumination.Furthermore,they could be recycled or reused without any appreciable decrease in reaction rates.The enhancement in the photocatalytic activity of colored fabric is attributed to a broadening in the photo-absorption region and to a decrease in the recombination of electron-hole pairs.In the photocatalytical process,an increase in photocurrent response suggests increase in charge separation.Additionally,·OH as the major reactive species which oxidizes formaldehyde into water and carbon dioxide in photocatalytical activity of colored fabrics is confirmed by electron paramagnetic resonance technique.Furthermore,the photocatalytic fabrics have a promising future in virtue of the mild operation conditions required for their use,low cost and suitability to extensive production,which could be widely applied in the fields of indoor environmental control. |
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