漂浮型Ag3PO4-g-C3N4共修饰TiO2复合可见光催化材料的除藻性能

Photocatalytic inactivation of algae using floating AgPO-g-CN co-modified TiO visible-light-responsive photocatalyst

以铝盐改性的膨胀珍珠岩为漂浮载体,使用溶胶凝胶-浸渍沉积法制备漂浮型Ag3PO4、氮化碳(g-C3N4)共修饰TiO2的可见光催化材料对铜绿微囊藻进行灭活,以获得高效、低耗的藻类水华控制方法。采用X射线衍射仪(XRD)、氮气吸附比表面积及孔径孔容分析仪(BET)、傅里叶红外光谱仪(FT-IR)、X射线光电能谱仪(XPS)和紫外-可见漫反射光谱仪(UV-vis DRS)等分析方法进行了材料表征。结果表明:Ag3PO4/TiO2的摩尔比变化可对催化剂的晶型结构、比表面积和表面官能团产生影响;Ag3PO4与g-C3N4对TiO2的共修饰可提高光催化剂的可见光响应;当Ag3PO4/TiO2的理论摩尔比为0.2时,催化剂的光催化除藻效果最佳;在催化剂的投加量为2 g·L−1,藻细胞的初始浓度为2.7×106 cells·mL−1时,经8 h可见光催化后,吸附-光催化对藻细胞的去除率达到85.19%。光催化除藻过程中起主要作用的活性基团贡献率为h+>∙OH>O^-2光催化剂在重复利用3次后,对藻细胞的去除率仍可达到74.41%。同时,考察了水中腐殖酸、叶绿素、硝酸盐和六价铬离子共存对该材料光催化去除铜绿微囊藻的影响。以上研究结果可为有害藻类污染水体修复技术选择提供参考。

In this study,aluminum salt-modified expanded perlite was taken as a floating carrier,a sol-gelimpregnated deposition method was used to prepare a visible photocatalyst of floating Ag3 PO4 and carbon nitride(g-C3 N4)co-modified TiO2 to inactivate Microcystis aeruginosa,expecting to obtain an efficient,lowconsumption algae bloom control method.The synthesized photocatalysts were characterized using XRD,N2 adsorption/desorption,FT-IR spectra,XPS and UV-vis DRS.Results showed that the change of Ag3 PO4/TiO2 molar ratio had influence on the crystal structure,specific surface area and surface functional groups of the photocatalysts.The co-modification of TiO2 with Ag3 PO4 and g-C3 N4 could enhance the visible light response of the photocatalysts.When the theoretical molar ratio of Ag3 PO4/TiO2 was 0.2,as-prepared photocatalyst had the highest photocatalytic inactivation efficiency of algae.After 8 h visible light irradiation,85.19%of algae with an initial concentration of 2.7×106 cells·mL^-1 could be removed at the photocatalyst dosage of 2 g·L^-1.In the photocatalytic process for algae inactivation,the contribution rate of active groups playing main role was h+>?OH>?O 2-,and the removal rate of algae could reach to 74.41%for the photocatalyst after three successive cycles.The effects of humic acid,chlorophyll,nitrate and hexavalent chromium on the removal of Microcystis aeruginosa were also investigated.The above research results can provide a reference for the selection of remediation technologies for harmful algae-contaminated water bodies.