基于TiO2/石墨烯的光催化材料降解腐殖酸

Degradation of Humic Acid by TiO2/Graphene Photocatalytic Materials

针对水热法制备的氮掺杂TiO2/还原氧化石墨烯纳米颗粒(NTG)分离回收性及稳定性差的问题,采用电化学法制备了氮掺杂TiO2纳米管/还原氧化石墨烯复合膜(ENTG),并通过场发射扫描电镜(FESEM)等表征其特性。结果表明,ENTG中纳米管阵列的管径约为167 nm、管长约为6μm,TiO2晶型为锐钛矿相,氮以间隙掺杂形式进入TiO2晶格。不同光催化剂(TiO2纳米管TNT、氮掺杂TiO2纳米管N/TNT、NTG、ENTG)对腐殖酸(HA)的去除效果表明,当HA浓度较低时,4种光催化剂去除HA的过程均符合准一级动力学模型;无论在紫外光区还是可见光区,ENTG的光催化性能均优于其他3种催化剂,且在可见光区去除HA的效果更好。另外,光催化重复试验结果表明,ENTG分离回收方便且催化稳定性较好,在饮用水处理领域具有较大的应用潜能。

To solve the problems of difficult to recycle and poor stability of nitrogen-doped TiO2/reduced graphene oxide nanoparticles(NTG) via hydrothermal method,nitrogen-doped TiO2 nanotubes/reduced graphene oxide composite film(ENTG) was prepared by electrochemical method,and the properties of the material were characterized by FESEM,XRD and XPS. The diameter of TiO2 nanotube(TNT) in ENTG was approximately 167 nm,and its length was about 6 μm. The crystal form of TiO2 was anatase,and nitrogen entered the TiO2 lattice in the form of interstitial doping. The photodegradation of humic acid(HA) by different catalysts(TNT,N/TNT,NTG and ENTG) was explored. When HA concentration was low,the degradation processes of HA by the four photocatalysts all conformed to the quasi-first-order kinetic model. No matter in ultraviolet region or visible region,ENTG exhibited better photocatalytic performance than the other three catalysts,and the removal performance of HA in the visible region was better. Furthermore,the photocatalytic degradation repetitive test indicated that the separation and recovery of ENTG were convenient and the catalytic stability was good. ENTG is a promising photocatalyst in the field of drinking water treatment.