Facile photocatalyst sedimentation: Utilizing isoelectric point for immediate ​TiO2 nanoparticles separation

TiO2 photocatalysis is commonly utilized in diverse applications such as environmental waste management, biomedical and energy fields. The present study demonstrates the effect of temperature on the characteristics of TiO2... [ view full abstract ]

TiO₂ photocatalysis is commonly utilized in diverse applications such as environmental waste management, biomedical and energy fields. The present study demonstrates the effect of temperature on the characteristics of TiO₂ nanopraticles (NPs) using XRD, UV-Vis, N₂ sorpometry and TEM techniques. The optimum surface area of the photocatalyst was obtained at 60ºC.

Afterwards, rapid photodegradation of Rhodamine 6G dye (R6G) with efficiency of 92.5% at pH= 9.17 was accomplished using the optimized NPs. The main focus of this study is to establish a new avenue that can be used to separate the photocatalyst from the reaction medium after the photodegradation experiment is completed. In this study, the photocatalyst was completely detached form the reaction medium in 3 minutes without utilization of coagulant agents or magnetic NPs. This was lucratively accomplished by adjusting the pH of the medium to match the isoelectric point (pH_PZC) of the photocatalyst and annulling its surface charge, hence rapid sedimentation was observed by means of turbidimetry. This new method has proven to be simple, rapid, and applicable to all types of photocatalysts on the industrial scale.