废旧涤纶基活性炭负载g-C_(3)N_(4)光催化剂的制备及其对亚甲基蓝的光催化降解

Preparation of waste polyester-based activated carbon loaded g-C_(3)N_(4)photocatalyst and its photocatalytic degradation of methylene blue

以废旧涤纶为原料,通过ZnCl_(2)活化的方法制备了废旧涤纶基活性炭(WPT-AC),而后以制备的WPT-AC和三聚氰胺为原料,通过直接热聚合法制备了废旧涤纶基活性炭负载石墨相氮化碳光催化剂(WPT-AC/g-C_(3)N_(4)),通过X射线衍射(XRD)、红外光谱(FTIR)、透射电镜(TEM)、紫外可见漫反射光谱(UV-vis DRS)、瞬态荧光光谱(PL)、电化学交流阻抗谱(EIS)等方法对WPT-AC/g-C_(3)N_(4)光催化剂的晶型、基团、形貌和光化学性质进行了表征,以亚甲基蓝(MB)为模拟染料溶液,研究了WPT-AC/g-C_(3)N_(4)光催化剂的暗吸附性能、光催化性能,并对光催化剂的稳定性进行了研究。结果表明:WPT-AC的掺杂抑制了g-C_(3)N_(4)的层状堆叠,增加了活性位点的数量,二者π-π共轭体系的叠加提高了其对可见光的响应强度,抑制了光电子-空穴的复合,提高了其光催化活性;可见光照射2 h,0.1 g质量分数5%的WPT-AC/g-C_(3)N_(4)光催化剂对100 mL质量浓度为35 mg/L的MB染料溶液的暗吸附量为13.51 mg/g,MB染料溶液的光催化降级率达到了98%,WPT-AC/g-C_(3)N_(4)光催化剂循环使用5次后仍具有良好的稳定性。

Waste polyester-based activated carbon(WPT-AC)was prepared by ZnCl_(2)activation with waste polyester as raw material,and graphite carbon nitride photocatalyst(WPT-AC/g-C_(3)N_(4))was prepared by direct thermal polymerization with prepared WPT-AC and melamine as raw materials.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),transmission electron microscopy(TEM),UV-vis diffuse reflectance spectroscopy(UV-vis DRS),transient fluorescence spectroscopy(PL)and electrochemical impedance spectroscopy(EIS)were used to characterize the crystal structure,groups,morphology and photochemical properties of WPT-AC/g-C_(3)N_(4)photocatalyst.The dark adsorption and photocatalytic properties of WPT-AC/g-C_(3)N_(4)photocatalyst were studied by using methylene blue(MB)as simulated dye solution,and the stability of the photocatalyst was studied.The results show that the doping of WPT-AC inhibits the layered stacking of g-C_(3)N_(4)and increases the number of active sites.The superposition of the twoπ-πconjugated systems improves its response to visible light,inhibits the recombination of photoelectron-hole and improves its photocatalytic activity.Under visible light irradiation for 2 h,the dark adsorption capacity of 0.1 g 5%WPT-AC/g-C_(3)N_(4)photocatalyst for 100 mL MB dye solution with 35 mg/L concentration was 13.51 mg/g,the photocatalytic degradation rate of MB dye solution reached 98%.WPT-AC/g-C_(3)N_(4)photocatalyst still has good stability after five cycles.