| In today’s society with the lack of water resources, water pollution has become a seriousenvironmental problem that must be resolved urgently. Moreover, emissions of printing anddyeing wastewater in the industrial production is one of the main cause of water pollution.Photocatalytic oxidation process with the advantages of high efficiency and energy saving canmake organic pollutants degraded completely under sunlight irradiation, and has become aresearch hotspot in environmental pollution control. However, there are often somedisadvantages for some traditional photocatalysts, such as low visible light utilization ratio andpoor stability. Therefore, development of the photocatalytic materials with visible light responseand good stability has become a key to dealing with organic pollutants in water by photocatalyticoxidation process. Graphitic C3N4possessing relatively narrow band gap, visible light responseand high photocatalytic activity is widely used in photocatalytic degradation of organicpollutants under visible light irradiation. In addition, the photocatalysts possess good stabilityand the resistance of acid, alkali and chemical corrosion，so it can be well used to treat with theprinting and dyeing wastewater comprising complicated constituents and with strong acid andalkali. However, powder catalysts are easily agglomerated in water and it is difficult to recycle,which limits its practical application in dye wastewater treatment. Hence, the supporting ofpowder catalysts has become an effective method to solve the problem. In this paper, g-C3N4wasprepared by thermal polymerization of organic precursors. The nanofibers with photocatalyticactivity under visible light irradiation were prepared by electrostatic spinning, and then thephotocatalytic performance of the nanofibers for dyes degradation under visible light irradiationwas studied.g-C3N4catalysts were synthesized by the pyrolysis of urea, and the prepared catalysts werecharacterized by FESEM, TEM, XRD, FTIR, UV-vis DRS, showing that g-C3N4possessedtypical layered platelet-like morphology and was capable of absorbing visible light. Thephotocatalytic activity was evaluated for RhB and AR1degradation under visible lightirradiation. Indicating that g-C3N4catalysts performed good photocatalytic degradation propertyfor the dyes, and exhibited the highest photocatalytic activity under acidic conditions. The addition of inorganic could inhibit the degradation of RhB, while promote the degradation ofAR1. In addition, it could be further concluded that photogenerated holes and O2-are the majoroxidation species for the system of photocatalytic degradation of dyes by g-C3N4.The prepared g-C3N4catalysts were first dispersed into PAN polymer solution by ultrasoundto prepare the spinning solution, and then g-C3N4/PAN nanofibers were prepared by electrostaticspinning. TEM was used to observe the dispersion of the catalysts, showing that the size ofg-C3N4platelets decreased and the fragments were dispersed into the polymer solution. Moreover,the g-C3N4fragments were dispersed uniformly on the nanofibers owing to the drafting ofelectrostatic spinning. Zeta potential test declared that the potential of g-C3N4/PAN nanofiberssurface is negative, leading to good absorbing for positively charged dyes, therefore the cationicdyes that has been adsorbed to nanofibers can have more chances to contact photocatalysts andwere degraded rapidly. In addition, duing to its low density and hydrophobic, g-C3N4/PANnanofibers can spread out on the water, which could reduces light loss caused by the absorptionby dyes solution. |
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