【作者】 张静；

【导师】 何作利；

【作者基本信息】 山东大学 ， 环境科学与工程， 2023， 硕士

【摘要】 光催化技术是一种利用太阳能进行环境净化和能源转化的技术,具有能耗低、无二次污染、效率高的优点,目前已经得到了广泛而深入的研究。纳米光催化剂在水处理过程中存在易团聚失活、难分离回收、稳定性差的问题,严重限制光催化技术在环境污染治理方面的应用。因此,对纳米光催化剂进行有效固载,成为一大研究热点。本论文聚焦于利用湿法纺丝技术实现二氧化钛(TiO2)与有机聚合物——聚氨酯(TPU)的复合,成功开发具有光催化性能的新型TiO2/TPU复合纤维。本研究有效地解决了光催化剂与水介质分离的问题和回收的问题,并提高了光催化剂的循环稳定性。首先,选择了商品化TiO2(P25)作为光催化剂,通过湿法纺丝技术制备了 P25/TPU复合纤维,研究了 P25的加入量对复合纤维的结构和机械性能的影响,并对其纤维织物的光催化活性及稳定性进行了深入研究。其次,采用静电纺丝技术合成了 TiO2纳米纤维(TNF),结合湿法纺丝技术制备了高强度、高TiO2含量的TNF/TPU复合纤维,并探究了 TNF/TPU的机械性能、光催化活性和循环稳定性。主要研究结论如下:(1)采用湿法纺丝技术制备了 P25/TPU复合纤维。P25/TPU复合纤维具有良好的机械性能,1-5 P25/TPU复合纤维的断裂应力为13.35 MPa,断裂伸长率为347.94%。P25/TPU复合纤维具有中空多孔结构,为光催化反应提供丰富的活性位点。通过光催化降解实验和光催化产氢实验评估了 P25/TPU复合纤维的光催化活性和稳定性。1-5P25/TPU复合纤维因TiO2含量最高具有最佳的光催化降解、产氢活性,5 ppm罗丹明B(RhB)溶液光照240 min后的降解率可达99%以上,光催化产氢效率为96.74 μmol·g-1·h-1。同时,1-5P25/TPU复合纤维在循环实验中保持了良好的稳定性。(2)通过静电纺丝法,成功制备了具有高长径比的TiO2纳米纤维(TNF)。500℃煅烧后,TNF表面光滑,直径分布较为集中,为锐钛矿相和金红石相的混晶结构,TNF的比表面积为32.780 m2/g。选取RhB、甲基橙(MO)、4-氯酚(4-CP)和磺胺二甲基嘧啶(SMZ)四种典型污染物,评价了 TNF的光催化降解性能。TNF对RhB有良好的吸附能力和光催化降解能力,光照150 min后可以将RhB完全去除。TNF对另外三种污染物几乎没有吸附作用,TNF对MO、4-CP和SMZ的降解效果较差。(3)采用湿法纺丝技术成功制备了TNF/TPU复合纤维。TNF粉末含量较高时,TNF/TPU复合纤维仍能保持良好的机械强度。拉伸力学性能实验表明,TNF/TPU复合纤维的断裂应力和断裂伸长率显著优于纯TPU纤维。1-2TNF/TPU复合纤维因光催化剂含量较高而具有最佳的光催化活性,在反应210min后,对5 ppm RhB的降解率将近99%。同时TNF/TPU复合纤维在循环实验中保持了良好的稳定性。另外,在降解高浓度的RhB溶液时,TNF/TPU复合纤维比TNF粉末的降解活性更高。总之,本研究利用湿法纺丝技术成功制备了具有光催化性能的TiO2/TPU复合纤维,解决了TiO2在液相体系中的分离回收问题,为推动光催化技术解决环境污染问题提供了理论依据和技术支持。更多还原

【Abstract】 Photocatalytic technology utilizes solar energy for environmental purification and energy conversion,with the advantages of low energy consumption,no secondary pollution,and high efficiency.Currently,it has been widely and deeply researched.However,nano photocatalysts have problems with easy agglomeration and deactivation,difficult separation and recovery,and poor stability in water treatment,which seriously limit the application of photocatalytic technology in environmental pollution treatment.Therefore,effective immobilization of nano photocatalysts has become a significant research area.This thesis uses wet spinning technology to achieve the composite of titanium oxide(TiO2)and organic polymer-polyurethane(TPU)and successfully develop TiO2/TPU composite fibers with photocatalytic properties.This study effectively solves the problem of separation and recovery of photocatalysts from aqueous media and improves the circulation stability of the photocatalysts.Firstly,commercial TiO2(P25)was selected as the photocatalyst to prepare P25/TPU composite fibers through wet spinning technology.The effects of P25 addition on the structural and mechanical properties of the composite fibers were investigated.Furthermore,the photocatalytic activity and stability of the fiber fabrics were studied.Secondly,TiO2 nanofibers(TNF)were synthesized using electrospinning technology.Then the TNF/TPU composite fibers with h igh mechanical strength and high TiO2 content were prepared using wet spinning technology.The mechanical properties,photocatalytic activity,and cyclic stability of TNF/TPU composite fibers were investigated.The main research conclusions are as follows:(1)P25/TPU composite fibers were prepared by wet spinning technology.P25/TPU composite fibers had good mechanical properties.The tensile strength of 1-5 P25/TPU composite fiber was 13.35 MPa,and the tensile strain was 347.94%.P25/TPU composite fibers had a hollow and porous structure,providing rich active sites for photocatalytic reactions.The.photocatalytic activity and stability of P25/TPU composite fibers were evaluated through photocatalytic degradation experiments and photocatalytic hydrogen production experiments.The 1-5 P25/TPU composite fiber had the best photocatalytic degradation and hydrogen production activity due to the highest TiO2 content.After 240 minutes of irradiation,the 5 ppm Rhodamine B(RhB)solution degradation rate could reach over 99%,and the photocatalytic hydrogen production efficiency was 96.74%μ mol·g-1·h-1.At the same time,the 1-5 P25/TPU composite fiber maintained good stability in the cyclic experiment.(2)TiO2 nanofibers(TNF)with a high aspect ratio were successfully prepared by electrospinning method.After calcination at 500℃,the TNF had a smooth surface with a relatively concentrated diameter distribution.And the TNF had a mixed crystal structure of anatase and rutile phases.The specific surface area of TNF was 32.780 m2/g.Furthermore.four typical pollutants,RhB,methyl orange(MO),4-chlorophenol(4-CP),and sulfamethazine(SMZ),were selected to evaluate the photocatalytic degradation performance of TNF.TNF had good adsorption and photocatalytic degradation capabilities for RhB,and RhB could be completely removed after 150 minutes of illumination.TNF had almost no adsorption effect on the other three pollutants,and its degradation effect on MO,4-CP,and SMZ was poor.(3)TNF/TPU composite fibers were successfully prepared using wet spinning technology.When the content of TNF powder was high,the TNF/TPU composite fibers could still maintain good mechanical strength.The tensile mechanical property experiments showed that the tensile strength and strain of TNF/TPU composite fibers were significantly superior to pure TPU fibers.1-2 TNF/TPU composite fiber had the best photocatalytic activity due to the high photocatalysts content.After 210 minutes of reaction,the degradation rate of 5 ppm RhB was nearly 99%.At the same time,TNF/TPU composite fibers maintained good stability in the cyclic experiment.In addition,TNF/TPU composite fibers had higher degradation activity than TNF powder in degrading high-concentration RhB solution.In summary,this study successfully prepared a novel TiO2/TPU composite fiber with photocatalytic property using wet spinning technology,which solved the separation and recovery of TiO2 in the liquid phase system.What’s more,the study provided the theoretical basis and technical support for promoting photocatalytic technology to solve environmental pollution issues.更多还原