N-TiO_(2)/聚丙烯复合熔喷非织造材料的制备及其光催化性能

Preparation and photocatalytic properties of N-TiO_(2)/polypropylene melt-blown nonwovens

为制备具有光催化功能的聚丙烯(PP)熔喷非织造材料,首先通过溶胶-凝胶法制备氮掺杂二氧化钛(N-TiO_(2))光催化剂,然后采用超声浸渍的方法将N-TiO_(2)均匀负载在PP熔喷非织造材料表面得到N-TiO_(2)/PP复合熔喷材料,并对其结构和性能进行表征和分析,通过自由基捕获实验确定光催化机制。结果表明:N掺杂量为1%的N-TiO_(2)的颗粒大小均匀,粒径约为10 nm,在30 min暗吸附和90 min光照条件下,其光催化降解亚甲基蓝(MB)的效率最佳,达到98%;将该N-TiO_(2)负载在PP熔喷非织造材料表面后,可包裹在PP纤维表面,当负载量超过30 mg后出现团聚现象;负载量为30 mg的N-TiO_(2)/PP复合熔喷材料的光催化降解性能最优,在30 min暗吸附和90 min光照条件下,对亚甲基蓝(MB)的降解效率达到98%;在光激发下N-TiO_(2)会产生超氧自由基和羟基自由基,二者共同降解MB。

Objective Titanium dioxide(TiO_(2))has non-toxicity,low cost,and high photocatalytic activity.However,the photocatalytic ability of TiO_(2)itself cannot reach the application level,and the powdered TiO_(2)is difficult to recycle and reuse.Thus,it is difficult for TiO_(2)to be practically applied in industrial fields.Polypropylene(PP)melt-blown nonwoven material with good chemical stability,low price,and simple manufacturing process has been widely used in air filtration,medical protection,and other fields.However,its single function limits its application.This research aims to improve photocatalytic ability and to tackle the recycling of TiO_(2)by doping N with TiO_(2)and then loading N-TiO_(2)nanoparticles on the surface of PP melt-blown nonwovens.Method N-TiO_(2)photocatalyst was first prepared by sol-gel method,and the optimal doping amount of N was determined by studying the surface morphology,microstructure,chemical structure,and photocatalytic performance of N-TiO_(2).The N-TiO_(2)photocatalyst with the best performance was loaded on the surface of PP melt-blown nonwovens by ultrasonic impregnation method.The surface morphology,chemical composition and structure,and photocatalytic properties of N-TiO_(2)/PP composite melt-blown nonwovens with different N-TiO_(2)loading concentrations were studied.The photocatalytic mechanism of N-TiO_(2)/PP composite melt-blown materials for organic dyestuff was verified and analyzed by free radical capture experiments.Results The particle size of N-TiO_(2)reached about 10 nm.N-TiO_(2)with N doping amount of 1%was found to have the best photocatalytic performance for MB.After loading the optimal N-TiO_(2)on the surface of PP melt-blown nonwovens,N-TiO_(2)were found uniformly wrapped on the surface of PP fibers.The agglomeration of N-TiO_(2)on the surface of PP fibers occurs when the loading amount of N-TiO_(2)exceeds 30 mg.Compared with PP melt-blown materials,the water contact angle of N-TiO_(2)/PP composite melt-blown materials was significantly reduced,and the thermal stability was also improved.When the N-TiO_(2)loading amount is 30 mg,the photocatalytic degradation rate of N-TiO_(2)/PP composite melt-blown material for MB reached 98%under the conditions of 30 min dark adsorption and 90 min photocatalysis.After trapping superoxide radicals(·O-2)and hydroxyl radicals(·OH),the photocatalytic MB degradation efficiency of N-TiO_(2)with 1%N doping were decreased by 22%and 23%,respectively.After being first used for the MB photocatalytic degradation,the crystalline structure and morphology of N-TiO_(2)/PP composite melt-blown nonwovens remained the same.After the fourth MB photocatalytic degradation,the photocatalytic degradation efficiency of the composite melt-blown material for MB was about 58%.Conclusion Low N doping amount can effectively improve the photocatalytic performance of TiO_(2).N-TiO_(2)/PP composite melt-blown material has proved to effectively degrade methylene blue dye.The composite melt-blown material has good stability and is recyclable.The research provides reference for expanding the application of PP melt-blown materials in the water treatment industry.