I am now reading “Removal of color substances using photocatalytic oxidation for membrane filtration processes” for deeper understanding of what membrane is capable of. The study was aimed to determine the effectivity of UV/TiO2/H2O2 to remove color. So the technique can remove TOC at 38% and color 400 at 89%. The interesting fact was if the dosage of H2O2 is less than 0.016 M, then the system is accelerated, produce better TOC rejection and color removal, over-dosage (more than 0.016) declines the rejection enhancement. I only get this point, it appears that there is a break point dosage at which best removal can be achieved. However, there is no information yet the comparison between only TiO2/UV and TiO2/UV/H2O2 of the efficiency.
Membrane Theses
My International paper
Wow, it has been more than 1 month of my absence updating this blog. I am now busy to submit my paper. The paper is concentration to discuss the advantage and the plus of my ceramic membrane. So first step I want to compose for my paper is to define the benefit of using the ceramic membrane instead of organic membrane. The benefit that I would like to propose is in terms of flux. My experiments had shown that the flux decline of my ceramic membrane is less than the organic membrane. The other thing I would like to display is the process of photocatalysis, by attaching the TiO2 in the surface of the membrane. This is often called immobilization.
What is the effect of MWCO membrane towards fouling?
Right, this post is actually being made because of my other post about Between TiO2 and UV254 to contribute fouling and performance. If you look at the paragraph 2, it tells everything about the problem of the permeability. Im gonna try again to define the problem.
Well, permeability as I already mention it in another post about will TiO2 coating cause denser pore or smaller MWCO? is representing the MWCO of membrane, because permeability is an indicator of the quantity of pure water passing through the membrane. Several conclusions about permeability based on my experiments are located below.
Between TiO2 and UV254
Between TiO2 and UV254 which one contributes more towards fouling? This question that I would like to discuss in this post. The answer at this time will solely based on my own experience. From what I have before about permeability, it is important factor to be considered. Because as I said already in that post, permeability means the size, the MWCO of the membrane. Higher permeability tends to give higher flux in the short term, depending on the MWCO of the membrane. Higher permeability membranes will give more severe decline of flux, means more fouling. Lower permeability membranes in initial operation produce lower flux, but at least the fouling is not as severe as higher permeability membranes. Another advantage for lower permeability membranes is higher rejection, stable as a function of operation time.
Titanium dioxide: paper review
So I read this paper, and found something valuable there. Photocatalysis is often used for treating water organic pollutants. Titanium dioxide is usually used because it is stable and inexpensive. This paper stated that one author observed that increasing the initial pH of phenol, increases the decomposition rate, reaching max value at 3.3, then decreasing upon further increase in pH.
Recovery rate of flux membrane operation
In this post I want to know about the flux recovery rate. From the book Basic Principles of Membrane Technology
So, recovery or r is defined by Qr/Qp. My research compute the value of Qr in m3/sec, while Qp in term of gram/sec. So, assume that the density of feed water equals to 1,000 kg/m3, then I can equalize the unit. Recovery is usually used to describe the membrane performance. In practical, membrane installation is usually set to produce recovery as high as possible. On the opposite on the lab in university, where generally recovery is very low to allow complete separation.
Why TiO2 is most often used photocatalyst
This post is dedicated to answer several questions raised why TiO2 being a popular photocatalyst and thus often being used for photocatalysis and photodegradation any unwanted compounds or chemicals including microorganism, organic particles. I just found in a paper of Weimin Xi (2001), he stated that TiO2 is having considerable photocatalytic activity. Honestly I do … Read more
Fouling as membrane shortcomings
I do not care if this post will contain only a couple hundred words. I just found an interesting definition of cake formation on the membrane surface. As you probably aware, this cake formation along with pore blockage, concentration polarization have caused fouling, sort of clogging in conventional filter, which increase negative value of membrane … Read more
Does TiO2 coating form denser pore size?
Interesting question is raised because that result that what I have got. Interesting, in one side it is known that the coating of TiO2 has caused higher affinity of membrane surface. In my opinion higher affinity, more or less, means higher permeability, higher chance that more water passes the pore of membrane. But my experiment shows the opposite. I just did a simple permeability though, but I think despite of its simplicity, it offers a very powerful tool to gain some insight about what is going on after coating in terms of its ability to allow water pass through the membrane. This post is dedicated to find out is it really true that the coating of TiO2 affect the pore size of membrane surface and make it denser.
About ultrafiltration: introduction
Combine with microfiltration, ultrafiltration (UF) is a low pressure membrane. UF is usually used for potable water treatment, biological wastewater treatment and also for ultrapure water production. The latter is common method for metal or electronic industries. UF typically operates within 40-1000 kPa (5.8-145 psi) (0.4-10 bar) having molecular weight cut off (MWCO) ranging from 1 kDa to 100 kDa (kilo Dalton).
MWCO is a term used to define 90% of molecular weight of a compound can be retained by the UF. Since UF have higher pore size or MWCO than reverse osmosis (RO), it usually produce higher flux. However, since RO has denser pore size, thus the rejection is become more excellent, even a virus may be filtered out to result a high ultrapure water.