Dear all:
I made photocatalytic degradation using photocatalytic membranes with different areas. I would need to standardize them, so I was wondering if the photocatalytic activity is proportional to area..In case they had homogeneous distribution of the photocatalyst on their surface..
Thanks in advance!!
Rosa
Dear Rosa,
The efficiency of TiO2 as a photocatalyst is dependent on the initial concentration of the pollutant, the amount of light penetration to the surface of TiO2, and the duration of light irradiation. The surface area of the catalyst is a key factor in catalytic reactions.
TiO2 based photocatalysts with large surface area show high photocatalytic efficiency, and thus nano-sized TiO2 has been used in most studies. The results have shown that nano-sized TiO2 suspended in solution outperforms its bulk counterpart regardless
of the morphology.
For more information regarding this topic see the following link which contains a review article entitled " TiO2 based photocatalytic membranes: A review" by Leong et al. published in Journal of Membrane Science (2014).
file:///C:/Users/Rafik%20Karaman/Downloads/2014-JMS_TiO2%20based%20photocatalytic%20membranes%20A%20review.pdf
Hoping this will be helpful,
Rafik
Dear Rafik:
Thanks a lot for your explanation!! Yes, I am agree with all. The question is, for example, when I inmobilize titania, by sol gel for example, in a membrabe area of 4.30 cm2 , and I measure the photocatalytic degradation, should it be correct to say that in an higher area that the last, using the same conditions and supports, the degradation will be higher as well?..I think that the response is yes, but I would need to get the oppinion of scientists with huge experience in this field..For that, many, many thanks again Rafik.
Dear Rosa,
I do not know what do you mean by scientists with huge experience in the field. I am in the field of pollutants removal by membranes, however, I do not know if I can be categorized into this class.
The recent review article that I indicated in my previous answer was written by good scientists in the field and it was published in a peer reviewed journal. My previous answer was a concise summary of this review which was based on results of good scientists in the field.
If you are looking to find a mathematical equation between the efficiency of the membrane and the surface area, the answer there is no such equation. There is an optimal surface area but it does not mean linear correlation of the equation of the type Y = AX + B where y is the efficiency and X is the surface area.
Regarding your example if the optimal surface are is less than 4.3 CM2, an increase of the surface area will increase the efficiency. On the other hand if the optimal surface area is less than 4.3 CM2 increasing the surface area will not result in an increase in the efficiency.
Hoping you will be more satisfied with this clarification.
Rafik
In the field of photocatalytic water splitting photocurrents/activities are always reported in milliamperes per square centimetre of substrate, independent of the amount of photocatalyst that was loaded and independent of its morphology (and therefore independent of the amount of (photo)catalyst surface area that is actually exposed to the liquid).
Thanks Pieter..I need to study more deeply and understand this field..thanks for your explanations..
Warmest regards,
Rosa
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