Well, as I have written several ideas in a very old posts, such as UF fractionation, TiO2 coating, photocatalysis effect to molecular weight distribution including gel filtration chromatography, now I want to summarize what I have done and brief result.
Membrane Theses
Gel Filtration Chromatography: protein fractionation
Well known as GFC, this is usually used to fractionate protein. It is based on molecular size, when larger particles will eluete first, followed by smaller molecule. In my experiment, I will employ this to fractionate humic substance. There are several points from which the method in using this GFC. GFC is included in Size Exclusion Chromatography. Size exclusion chromatography (SEC) is a chromatographic method in which particles are separated based on their size. When an aqueous solution is used to transport the sample through the column the technique is known as gel filtration chromatography.
Further Effect of Photocatalysis toward organic particles size distribution
I have mentioned several information on my post about the effect of photocatalysis process to particle size distribution. Now in this post, I would like to a little bit further explain it more as I am really courious about this.
Photocatalysis effect for organic particle distribution
In this post, I would like to focus the effect of photocatalysis, in this case represented by Titanium dioxide and UV irradiation for organic particle distribution, which is natural organic matter, represented by Dissolved Organic Carbon, humical acid. I would like to know which organic particle size in responsible for fouling of TiO2-UV membrane.
Planning ahead: theses
Right, I am trying to list here what I am planning to do within short time:
At the moment, I am cleaning my all membranes after TiO2-UV batch: 1 kD, 15 and 50 kD, two pieces for each.
TiO2 coating procedures
There are various methods available to coat TiO2 onto the surface of the membrane. I will explain briefly some of them, and the method I used.
Ion assisted deposition
This method was used for coating on super-hydrophobic porous teflon membrane. The author stated that the coating of TiO2 by the chemical wet process such as a sol-gel method is very difficult. The method involved acceleration voltage, temperature, and oxygen. Heated at 523 K.
TiO2-UV batch for UF fractionation
The result of my experiment employing TiO2-UV was not satisfying. In terms of flux, TiO2-UV membrane showed severe decline after 30, 60, and around 90 minutes. Not only that, the rejection of membrane coated by TiO2 under UV exposure was lower than naked membrane. This probably due to smaller molecule as a result of the breaking caused by photocatalysis process. After certain minutes, it is possible that TiO2-UV react with the HA, braking bonds within HA molecules, the molecules become smaller, thus it will penetrate the pore of TiO2-UV, so the DOC will be much higher than naked membrane. How about flux? my logic says if the rejection is lower, so the flux should be better as flux and rejection usually work on the opposite way. If the flux better, usually rejection worse, vice versa.
TiO2-UV performance
First stage of experiment has been accomplished. The result was not satisfying. I used 50, 15 and 1 kD. In terms of flux and accumulated flux, TiO2-UV displayed lower result compare to just naked membrane. Although for 50 kD and 15 kD initial flux were higher than naked membrane, but after around 30-100 minutes, they showed severe decline for flux. This also applied for 1 kD TiO2-UV membrane. I do not think that permeability plays a big role on this, since the permeability of all membranes were similar, there were not significant difference. This also proves that TiO2 does not affect the structure of the membrane.
Abstract for Scientific Paper
Yesterday I was requested to join Internation Symposium held in Taiwan. One of the requirement to join is to submit abstract before due date which is next week. While I am writing my own abstract, I think it is good idea to put something here about how to write abstract.
Complete the first task
So, basically what I am going to do is to complete first target within this month. I hope I can accomplish it ontime. It has already been posted before about the performance in terms of flux, rejection of several membrane pore size, 50 kD and 15 kD. Now, I will try to use 1 kD and to repeat 15 kD which the last data seems invalid.