Preparation Of Semiconductor/Polymer Fiber Composites And Its Photocatalytic Degradation Of Methylene Blue

In this paper, the main study is that the electrospun polymer mats withnano-micro size interconnected open pore structure and good photocatalyticresistance ability were prepared by high pressure electrospinning process. Thensemiconductor/polymer fiber composites were performed using polymer fibers ascarrier. The photocatalytic activity and stability of the composites were tested onphotodecolorization of methylene blue under Xe lamp simulated sunlightirradiation. The main study was divided into the following2sections:（1） Poly（vinylidene fluoride）（PVDF） fibers were prepared by electrospinning.PVDF-g-MAH fibers were prepared through maleic anhydride （MAH） grafted toPVDF electrospun fibers, which were pretreated by KOH/alcohol solution. Then,using PVDF-g-MAH fibers as carrier, Lead Sulfide（PbS） particles were uniformlyimmobilized on the surface of the PVDF-g-MAH electrospun fibers byhydrothermal methods. The effects of the solvent, concentration of alkali andconcentration of MAH were discussed on grafting rate. The results showed thatusing deionized water as solvent was in favor of keeping the morphology offibers, the higher the concentration of alkali and MAH, the higher graft yield wouldbe gained. The PbS/PVDF-g-MAH fiber composites were characterized by scanningelectron microscopy （SEM）, X-ray diffraction（XRD）, ultraviolet visible diffusereflectance spectrum（UV/VIS）, thermogravimetric analysis（TG） and the experimentof the photodegradation. The absorption spectrum of composites almost covered thewhole visible area. The experiment of photocatalytic degradation of methylene blueunder Xe lamp irradiation was also performed, the result indicated that thephotocatalytic ability of PbS/PVDF-g-MAH fiber composites were higher than thatof PbS particles, which also boasted good recycle ability and great stability.（2） The polysulphone （PSU）/styrene-maleic anhydride copolymer （SMA）fibers were prepared by electrospinning. Bismuth ions were introduced onto thesurface of polymer fiber by the coordinating of carboxyl of SMA, sulfide ions wereincorporated to react with bismuth ions under hydrothermal condition. TiO₂wasdeposited on the surface of the Bi₂S₃by the reaction of titanium ions with urea alsounder hydrothermal condition. SEM and TEM images revealed that Bi₂S₃-TiO₂heterojunction was uniformly distributed on the surface of PSU/SMA fibers. The UV/VIS showed that the Bi₂S₃-TiO₂heterojunction/polymer fiber compositespossess good visible-light response ability. The experiment of photocatalyticdegradation of methylene blue under Xe lamp irradiation was also studied, theresult showed that the degradation rate of methylene blue in Bi₂S₃-TiO₂heterojunction/polymer fiber composites system was considerably higher thanthat of Bi₂S₃-TiO₂heterojunction system, which also boasted good recycle abilityand great stability.