Ti-FAC复合光催化剂的水热-溶胶浸渍法制备及其对水中亚甲基蓝的光催化降解研究

Preparation of Ti-FAC Composite Photocatalyst by Hydrothermal-sol Impregnation Method and Its Photocatalytic Degradation of Methylene Blue in Aqueous Solution

水热-溶胶浸渍法制备可磁分离复合光催化剂分两步进行:首先,水热法将锰锌铁氧体负载于活性炭(AC)上制得软磁性活性炭(FAC),然后钛溶胶浸渍FAC,煅烧后形成软磁性复合光催化剂Ti-FAC。以亚甲基蓝为目标降解物考察了制备参数对其光催化降解率的影响,并使用XRD、SEM和VSM对其晶体结构、形貌和磁性能进行了表征。结果表明:锰锌铁氧体负载量为AC质量的1/8,钛溶胶浸渍两次,在500℃煅烧后所得复合光催化剂光催化活性最高。此复合催化剂上锰锌铁氧体为尖晶石结构,并有轻微烧结;TiO2纳米颗粒为锐钛矿相,均匀分散于AC上或者锰锌铁氧体上。该复合光催化剂具有很好的软磁性和稳定性,在循环使用过程中可采用外加磁场进行固液分离,并经6次循环使用后仍保持较高的光催化降解率。

Composite photocatalysts,enable to be separated from water by external magnetic field,were prepared by hydrothermal-sol impregnation method,which was composed of two steps： Firstly,Mn-Zn ferrite was loaded on activated carbon（AC） by hydrothermal reaction to form soft magnetic activated carbon（FAC）.Then,FAC was impregnated in titanium sol,and soft magnetic composite photocatalysts Ti-FAC were produced after calcination.Effects of preparation parameters on the photodegradation of methylene blue（MB） were investigated and the crystalline structure,morphology and magnetic properties of the photocatalysts were characterized by XRD,SEM and VSM.The results show that the photocatalyst Ti2-F（1/8）AC has the highest photocatalytic actvity,for which Mn-Zn ferrite is one-eighth of AC in quality,titanium sol impregnating FAC for twice followed by calcination at 500 ℃.Mn-Zn ferrite maintains cubic spinel structure with little aggregation in the composite catalyst.TiO2 nanoparticles with anatase phase homogeneously distribute either on AC or on Mn-Zn ferrite particles which supported on AC.The sample shows excellent soft magnetic properties and high stability,feasible to be completely recovered by an external magnetic field and keeping high photodegradation efficiency after 6 reuse cycles.