Application Of Silica Nanoparticles In Structured Colored Fabrics And Refractory Organics

Silica（SiO₂）is a natural compound found widely in water,plants,animals,and the inside of the earth’s crust.It plays an important role in many fields due to its excellent physical and chemical properties.Therefore,this article uses SiO₂ nanoparticles as the substrate for the preparation of structured color cotton fabrics,and aims to apply the bionic structure coloring technology in the traditional printing and dyeing industry;secondly,atomic layer deposition（ALD）technology is used to modify SiO₂ nanoparticles to prepare for use as difficult Catalyst for degradation of organics.The main research of this article is as follows:（1）SiO₂ nanoparticles with a particle size range of 250-580 nm were successfully prepared by the stober method,and the effects of different reactant concentrations on the particle size were investigated,and the optimal spin coating conditions were investigated by the spin coating method.SEM,EDS,FTIR,XRD,etc.were used to analyze the micro-morphology and structural composition of SiO₂ nanoparticles.The results show that the synthesized SiO₂ nanoparticles are amorphous.With the increase of NH₃?H₂O concentration,the particle size of SiO₂ nanoparticles increases first and then decreases when the concentration of NH₃?H₂O reaches 3.25 mol/L.As the TEOS concentration changes,the particle size of SiO₂ nanoparticles also increases first and then decreases,and reaches the maximum when the TEOS concentration is 0.33 mol/L.At the same time,through the investigation of the spin coating conditions on the silicon wafer,it is concluded that the self-assembling effect is the best when the concentration of the SiO₂ colloid solution is 1.0 wt.% and the spin coating rate is 1000 rpm.（2）Using the prepared SiO₂ nanoparticles,constructing a structural color on the surface of the cotton fabric through a layer-by-layer electrostatic self-assembling method,and successfully preparing structural-colored cotton fabrics with different colors and different color depths.The SEM,EDS,UV-Vis,K/S value,TG,etc.were used to analyze the color and performance of the structured color cotton fabric.The results show that the color depth of the obtained cotton fabrics becomes darker as the number of cycles of the layer-by-layer electrostatic self-assembling method increases.The use of SiO₂ nanoparticles of different particle sizes can produce different color structured cotton fabrics.The mechanism is due to the difference in particle size of SiO₂ nanoparticles,which results in the formation of different periodic structure differences.In each self-assembling cycle,the amount of SiO₂ nanoparticles loaded on the surface of the cotton fabric was approximately 6.8 × 10^-7mg/cm².The structured color cotton fabric prepared by this method is not only simple in preparation process and has no pollution to the environment,and the prepared structured color cotton fabric has excellent color fastness to washing and rubbing.（3）Nano-TiO₂ was deposited on the surface of SiO₂ nanoparticles by ALD technology to prepare core-shell SiO₂@TiO₂-n（n is the number of ALD cycles）to catalyze 17-βestradiol under visible light.The structure and catalytic performance of SiO₂@TiO₂-n catalyst were determined by HRTEM,UV-Vis,XPS,XRD,BET,etc.The results show that the thickness of the TiO₂ shell is linear with the number of ALD cycles,and the average thickness is 7 nm / 1000 cycles.The minimum band gap width of SiO₂@TiO₂-n catalyst is 2.87 eV（SiO2@TiO2-1000）,which is 0.85 eV compared with the band gap width of SiO₂ nanoparticles of 3.72 eV.The band gap of all SiO₂@TiO₂-n catalysts is lower than that of commercial P25.The degradation rate of SiO₂ nanoparticles is 0.00274 min-1,and the catalytic rate of SiO₂@TiO₂-n after modification is increased with the increase of n value,and the degradation rate of SiO₂@TiO₂-4000 is as high as 0.0179 min^-1.The catalytic degradation of E2 by all SiO₂@TiO₂-n catalysts complies with pseudo-second-order kinetics.After 6 repeated photocatalytic experiments,the removal rate of E2 was still as high as 91.3%.The main mechanism of SiO₂@TiO₂-n degradation of E2 is ?OH.E2 is first activated,and then the activated E2 is attacked further,thereby completely and effectively degrading E2.