以木材为模板的BiVO_(4)-CdS光催化性能研究

Photocatalytic performance of BiVO_(4)-CdS based on wood templates

【目的】以木材加工固体废弃物为原料,制备具有木材仿生微纳米孔结构的BiVO_(4)-CdS复合光催化剂,旨在利用木材模板形成更多的异质结结构提高光催化材料的催化性能,拓展其在木材加工染料废水污染处理中的应用。【方法】分别采用杉木、杨木、巴沙木3种树种的木材加工固体废料为模板,通过浸渍煅烧和化学沉积两步法制备BiVO_(4)-CdS复合光催化剂,以木材染色废水中的罗丹明B(RhB)为目标降解对象,对复合光催化剂可见光下降解RhB的性能进行评价研究。【结果】3种具有木材模板仿生结构的BiVO_(4)-CdS复合光催化剂均表现出良好的吸附-光催化降解RhB的能力。密度较低的巴沙木-BiVO_(4)-CdS在达到吸附平衡后,对RhB有着高达29.26%的去除率;在120 min内可见光下对RhB的降解率为96.01%,其反应速率是无模板BiVO_(4)、BiVO_(4)-CdS的6.69倍和3.37倍。10次吸附-光催化降解循环处理后,材料的降解效率依然达到85%以上。【结论】木材模板仿生构造赋予复合光催化剂丰富的孔道结构,低密度树种木材腔壁结构有利于催化剂在浸渍煅烧处理后获得较大的比表面积、稳定的孔结构以及BiVO_(4)-CdS异质结结构形成,进而促进光催化反应过程中污染物分子的快速吸附和降解。

[Objective]BiVO_(4)-CdS composite photocatalysts with the wood biomimetic micro-nanopore structure were prepared from wood processing residues.The wood template was used to form more heterojunction structures,improve the catalytic performance of the photocatalytic material and expand the application of BiVO_(4) in the treatment of wood dye wastewater.[Method]BiVO_(4)-CdS composite photocatalysts were prepared by impregnation-calcination and chemical deposition using wood processing residues from three species of wood (fir,poplar,and balsa).[Result]All three BiVO_(4)-CdS composite photocatalysts with wood biomimetic structures exhibited good adsorption-photocatalytic degradation of RhB.The lower-density balsa-wood BiVO_(4)-CdS showed a high removal rate of RhB (29.26%) after reaching adsorption equilibrium;the degradation rate of RhB under visible light was 96.01%in 120 min,and its reaction rate was 6.69 and 3.37 times higher than that of BiVO_(4) and BiVO_(4)-CdS without a template.After ten adsorption-photocatalytic degradation cycles,the balsa-wood BiVO4-CdS still achieved a degradation efficiency of over 85%.[Conclusion]The biomimetic structure of wood gives the composite photocatalys a rich pore structure.The cavity wall structure in the low-density wood facilitates the catalyst to obtain a large specific surface area and stable pore structure after impregnation and calcination treatment.At the same time,it also promotes the formation of the BiVO4-CdS heterojunction structure,which accelerates the rapid adsorption and degradation of pollutant molecules during the photocatalytic reaction.