Hello everyone,
As promised, I remain true in my endeavor to keep you updated!
I would like to start off by telling you about my "first day" at the lab. Or rather, about my adventure of getting to work on that day and then expound upon the research that I have undertaken over here. Those of you who have already heard this story, you can skip it and read the other stuff.
Getting to work on the first day: Four weeks ago, on a Tuesday, I woke up to a new beginning. It was supposed to be my very first day at the lab and I was excited! I knew that from my apartment I had to take Bus#4 into centre ville and then take bus #17 out of centre ville to CEREGE, the research facility where the labs are. So, that's exactly what I did. I hopped onto bus #4, and hopped off in centre ville, crossed the street and hopped onto bus #17. I managed to find a seat before it became completely and totally filled to its holding capacity. The ride was supposed to be ~30-45 minutes long and after everyone boarded, we were on our way!
I watched as people got on and off at the various bus stops along the way... and as we neared the final destination, I noticed that there were fewer people getting on and more people getting off. Upon reaching the turn-around point where the bus turns around and goes back to centre ville, I realized that I was the only one left on the bus. There were no more stops left and I still had not reached CEREGE despite the fact that I had been anxiously watching out the windows to make sure that I wouldn't miss CEREGE and that I wouldn't miss my stop.
We reached the turn-around point and the bus driver apparently thought that the bus was empty, because he got off and had himself a nice 10 minute smoking break. He walked around, stretching his legs and then finally decided that it was time to get back on. That is when he saw that his bus wasn't quite as empty as he assumed it to be. I was still sitting on the bus quiet as a mouse and confused half-way to death!
He came up to me and asked me where I was trying to go, so I pulled out my map and pointed to where I was supposed to be. He tilted his head back and laughed (for real) telling me that I was supposed to take the other #17 bus, which comes approximately 5 min after his bus. He said that "his" bus doesn't go to CEREGE, it goes the opposite way. I had no idea that there were two #17 buses that went in opposite ways.
Anyway, so this is what he did: he dropped me off at a remote little bus station out in the middle of nowhere and told me to cross the street and go accross the "field" and that the building that I am looking for is somewhere that way. I did as I was told: crossed the street and crossed the "field".
However, this "field" turned out to be something, let me tell you! It was followed by a rocky mountain that first went up, then down, with a road down below, a fence, then a forest, then CEREGE. With my heavy backpack (that had my laptop, charger, converter, books, and map in it) on my shoulders and flimsy little ballet flats on my feet, I climbed up a mountain, then slid down its rocky other side, climbed over the fence, and got onto the only road in sight. I walked about 2 miles (sweating like crazy because I was carrying about 10 pounds in my backpack and wearing a black t-shirt that was attracting the sun like a duck on a June bug!) and came to a forest through which I could faintly see something that looked like the white CEREGE building. As the road seemed to curve away from what I presumed to be my final destination, I went straight through the brush and bramble of the forest!
Instead of the 30 minutes that it was supposed to take me to get to work, it took me 1.5 hours!! However, I made it!! Before I crawled out of that forest, I took out my hair brush, brushed my hair, picked off the thorns that attached themselves to my jeans, cleaned off my flats from the dust and removed the pebbles out of them, and walked out of that forest as if I had just stepped out of an air conditioned bus. Cool as a cucumber. I strolled into Armand's office and apologized for being late, saying that I got off at the wrong stop and had to walk a little ways. Armand is my "boss" over here and I wasn't about to tell him that I had to climb an entire mountain on my way to work. No need to give a bad first impression, especially on the first day.
So that is how I made it to the lab on my first day. It has been easier since then though because I get onto the second #17 bus which drops me off directly in front of CEREGE, eliminating the need to climb any mountains. Ironically enough, I do still walk through that "forest" from one lab to the other but I have discovered that it has paths on it, and choosing to remain civilized, I take those paths instead of tearing through the forest like a mad-woman.
Fundamental background for the research: Did you know that cement is actually more than just cement? Yes, I am talking about the cement that buildings, pavements, patios, reservoir linings etc, etc, etc are made out of. That dull, gray, hard surface that nobody ever thinks about. Or so I thought. Apparently, there is much, much more to cement than meets the eye and that is mainly the reason for why I am here: to acquaint myself with cement chemistry with the addition of nanoparticles, of course.
The chemistry of cement is very complex. Summarily, cement consists of a raw mixture of limestone (calcium carbonate) and clay (or various other materials that have almost the same overall composition and similar reactivities) that is heated to ~ 1450 degrees centigrade. Upon calefaction, some fusion occurs resulting in lumps of incombustible matter known as clinker. Calcium sulfate is then added to the clinker material in the form of gypsum and the mixture is finely crushed. This makes the cement. Sometimes there are other materials that are added during the crushing stage but it depends upon the specifications which are then based on things like chemical composition and/or physical properties.
Below is a link to a great video on how cement is made. It is approximately 5 minutes long and it originally aired on the Discovery Channel.
http://www.youtube.com/watch?v=n-Pr1KTVSXo*
* Reference: "Cement, how it is made.." YouTube. Web. 27 Jun 2010..
The clinker is primarily composed of: CaO (calcium oxide), SiO2 (silicon dioxide), some Al2O3 (aluminum oxide), some Fe2O3 (iron oxide) and also some other minor components. Clinker has four major phases (alite, belite, aluminate and ferrite) that play a very important roll in the hardening of cement. Cement hardens because of the chemical reactions that take place between these four major phases when they react with water.*
*Reference: Taylor, H.F.W. Cement Chemistry. 2nd. Heron Quay, London: Thomas Telford Publishing, 1997. 459. Print.
Sometime in the last decade, groups such as Italcementi have produced a cement that removes pollution out of the air thanks to the addition of titanium dioxide nanoparticles (TiO2 NP's). One of the most intriguing properties of TiO2 is its capability of photocatalysis. Photocatalysis is when a sufficient amount of sunlight (aka energy) is absorbed by TiO2 causing the electrons in the full valence band to be excited into the almost always empty conduction band. When this happens, the electron leaves a "hole" in the valence band that can be used as a current, flowing like a charged physical particle. This is termed the electron-hole-pair, and it generates free-radicals that have unpaired electrons/open shell configurations making them highly reactive. BUT... I'm not going to get into this right now. The important thing to know is that groups like Italcementi are incorporating nanomaterials into cements that are used in the construction of buildings, pavements, linings for reservoirs, roads, sidewalks, etc. The building that houses the headquarters of Air France's airlines at the Charles DeGaulle airport in Paris is constructed out of this very same Italcementi cement as well as The Church of the Year 2000 (aka Rome's Dives in Misericordia Church).*
* Note: For the Uky Pentecostal people reading this, did you guys know that the architect who designed our new church on Clays Mill and Brannon Crossing actually went to the Dives in Misericordia Church in Rome to draw forth some ideas for our new church? Of course most of his wonderful ideas were smashed straight into the ground by our very traditional people. No offense to absolutely anyone.
Volatile organic compounds and air pollutants, NO (nitrogen monoxide) and NO2 (nitrogen dioxide), are key players in the depletion of the ozone layer and they come from smoking cigarettes, car exhaust, etc. They are the bad guys. However, when photocatalytic TiO2 is activated by sunlight, it has the power to absorb and transform these harmful compounds through various chemical reactions into harmless compounds like NO3- (nitrate ion) which can then be washed away with water or bind to the cement making a stable compound. This is the concept that makes this cement so popular today; cement gone GREEN eliminating the pollution from the air as soon as it comes out of the source (as in a car-exhuast pipe and a TiO2 NP containing pavement).
The nanoparticles and the research: When TiO2 is added into the cement as a nanoparticle it has a greater surface area to volume ratio which ultimately means that there is more space for the reactions to occur on. As the term nano implies, these nanoparticles are extremely small and therefore a greater amount of them can be incorporated into the cement. The only known to date factual downside to this is the cost. Cement containing TiO2 as a nanoparticle costs approximately 10 times as much as normal cement. As in the majority of situations, there are the benefits and then there are the drawbacks.
There is also the question of the environmental fate of these nanoparticles. If these particles are released from the cement that is used for general construction, then what are the potential harmful effects of these particles on the environment and ultimately on human health? And that, mes amis, is what I am trying to figure out. Or, at least play a minor role in part of a larger group that is devoted to answering those questions: are nanoparticles being released from this cement into the environment and what are the environmental effects and impacts on human health?
As promised, I remain true in my endeavor to keep you updated!
I would like to start off by telling you about my "first day" at the lab. Or rather, about my adventure of getting to work on that day and then expound upon the research that I have undertaken over here. Those of you who have already heard this story, you can skip it and read the other stuff.
Getting to work on the first day: Four weeks ago, on a Tuesday, I woke up to a new beginning. It was supposed to be my very first day at the lab and I was excited! I knew that from my apartment I had to take Bus#4 into centre ville and then take bus #17 out of centre ville to CEREGE, the research facility where the labs are. So, that's exactly what I did. I hopped onto bus #4, and hopped off in centre ville, crossed the street and hopped onto bus #17. I managed to find a seat before it became completely and totally filled to its holding capacity. The ride was supposed to be ~30-45 minutes long and after everyone boarded, we were on our way!
I watched as people got on and off at the various bus stops along the way... and as we neared the final destination, I noticed that there were fewer people getting on and more people getting off. Upon reaching the turn-around point where the bus turns around and goes back to centre ville, I realized that I was the only one left on the bus. There were no more stops left and I still had not reached CEREGE despite the fact that I had been anxiously watching out the windows to make sure that I wouldn't miss CEREGE and that I wouldn't miss my stop.
We reached the turn-around point and the bus driver apparently thought that the bus was empty, because he got off and had himself a nice 10 minute smoking break. He walked around, stretching his legs and then finally decided that it was time to get back on. That is when he saw that his bus wasn't quite as empty as he assumed it to be. I was still sitting on the bus quiet as a mouse and confused half-way to death!
He came up to me and asked me where I was trying to go, so I pulled out my map and pointed to where I was supposed to be. He tilted his head back and laughed (for real) telling me that I was supposed to take the other #17 bus, which comes approximately 5 min after his bus. He said that "his" bus doesn't go to CEREGE, it goes the opposite way. I had no idea that there were two #17 buses that went in opposite ways.
Anyway, so this is what he did: he dropped me off at a remote little bus station out in the middle of nowhere and told me to cross the street and go accross the "field" and that the building that I am looking for is somewhere that way. I did as I was told: crossed the street and crossed the "field".
However, this "field" turned out to be something, let me tell you! It was followed by a rocky mountain that first went up, then down, with a road down below, a fence, then a forest, then CEREGE. With my heavy backpack (that had my laptop, charger, converter, books, and map in it) on my shoulders and flimsy little ballet flats on my feet, I climbed up a mountain, then slid down its rocky other side, climbed over the fence, and got onto the only road in sight. I walked about 2 miles (sweating like crazy because I was carrying about 10 pounds in my backpack and wearing a black t-shirt that was attracting the sun like a duck on a June bug!) and came to a forest through which I could faintly see something that looked like the white CEREGE building. As the road seemed to curve away from what I presumed to be my final destination, I went straight through the brush and bramble of the forest!
Instead of the 30 minutes that it was supposed to take me to get to work, it took me 1.5 hours!! However, I made it!! Before I crawled out of that forest, I took out my hair brush, brushed my hair, picked off the thorns that attached themselves to my jeans, cleaned off my flats from the dust and removed the pebbles out of them, and walked out of that forest as if I had just stepped out of an air conditioned bus. Cool as a cucumber. I strolled into Armand's office and apologized for being late, saying that I got off at the wrong stop and had to walk a little ways. Armand is my "boss" over here and I wasn't about to tell him that I had to climb an entire mountain on my way to work. No need to give a bad first impression, especially on the first day.
So that is how I made it to the lab on my first day. It has been easier since then though because I get onto the second #17 bus which drops me off directly in front of CEREGE, eliminating the need to climb any mountains. Ironically enough, I do still walk through that "forest" from one lab to the other but I have discovered that it has paths on it, and choosing to remain civilized, I take those paths instead of tearing through the forest like a mad-woman.
Fundamental background for the research: Did you know that cement is actually more than just cement? Yes, I am talking about the cement that buildings, pavements, patios, reservoir linings etc, etc, etc are made out of. That dull, gray, hard surface that nobody ever thinks about. Or so I thought. Apparently, there is much, much more to cement than meets the eye and that is mainly the reason for why I am here: to acquaint myself with cement chemistry with the addition of nanoparticles, of course.
The chemistry of cement is very complex. Summarily, cement consists of a raw mixture of limestone (calcium carbonate) and clay (or various other materials that have almost the same overall composition and similar reactivities) that is heated to ~ 1450 degrees centigrade. Upon calefaction, some fusion occurs resulting in lumps of incombustible matter known as clinker. Calcium sulfate is then added to the clinker material in the form of gypsum and the mixture is finely crushed. This makes the cement. Sometimes there are other materials that are added during the crushing stage but it depends upon the specifications which are then based on things like chemical composition and/or physical properties.
Below is a link to a great video on how cement is made. It is approximately 5 minutes long and it originally aired on the Discovery Channel.
http://www.youtube.com/watch?v=n-Pr1KTVSXo*
* Reference: "Cement, how it is made.." YouTube. Web. 27 Jun 2010.
The clinker is primarily composed of: CaO (calcium oxide), SiO2 (silicon dioxide), some Al2O3 (aluminum oxide), some Fe2O3 (iron oxide) and also some other minor components. Clinker has four major phases (alite, belite, aluminate and ferrite) that play a very important roll in the hardening of cement. Cement hardens because of the chemical reactions that take place between these four major phases when they react with water.*
*Reference: Taylor, H.F.W. Cement Chemistry. 2nd. Heron Quay, London: Thomas Telford Publishing, 1997. 459. Print.
Sometime in the last decade, groups such as Italcementi have produced a cement that removes pollution out of the air thanks to the addition of titanium dioxide nanoparticles (TiO2 NP's). One of the most intriguing properties of TiO2 is its capability of photocatalysis. Photocatalysis is when a sufficient amount of sunlight (aka energy) is absorbed by TiO2 causing the electrons in the full valence band to be excited into the almost always empty conduction band. When this happens, the electron leaves a "hole" in the valence band that can be used as a current, flowing like a charged physical particle. This is termed the electron-hole-pair, and it generates free-radicals that have unpaired electrons/open shell configurations making them highly reactive. BUT... I'm not going to get into this right now. The important thing to know is that groups like Italcementi are incorporating nanomaterials into cements that are used in the construction of buildings, pavements, linings for reservoirs, roads, sidewalks, etc. The building that houses the headquarters of Air France's airlines at the Charles DeGaulle airport in Paris is constructed out of this very same Italcementi cement as well as The Church of the Year 2000 (aka Rome's Dives in Misericordia Church).*
* Note: For the Uky Pentecostal people reading this, did you guys know that the architect who designed our new church on Clays Mill and Brannon Crossing actually went to the Dives in Misericordia Church in Rome to draw forth some ideas for our new church? Of course most of his wonderful ideas were smashed straight into the ground by our very traditional people. No offense to absolutely anyone.
Volatile organic compounds and air pollutants, NO (nitrogen monoxide) and NO2 (nitrogen dioxide), are key players in the depletion of the ozone layer and they come from smoking cigarettes, car exhaust, etc. They are the bad guys. However, when photocatalytic TiO2 is activated by sunlight, it has the power to absorb and transform these harmful compounds through various chemical reactions into harmless compounds like NO3- (nitrate ion) which can then be washed away with water or bind to the cement making a stable compound. This is the concept that makes this cement so popular today; cement gone GREEN eliminating the pollution from the air as soon as it comes out of the source (as in a car-exhuast pipe and a TiO2 NP containing pavement).
The nanoparticles and the research: When TiO2 is added into the cement as a nanoparticle it has a greater surface area to volume ratio which ultimately means that there is more space for the reactions to occur on. As the term nano implies, these nanoparticles are extremely small and therefore a greater amount of them can be incorporated into the cement. The only known to date factual downside to this is the cost. Cement containing TiO2 as a nanoparticle costs approximately 10 times as much as normal cement. As in the majority of situations, there are the benefits and then there are the drawbacks.
There is also the question of the environmental fate of these nanoparticles. If these particles are released from the cement that is used for general construction, then what are the potential harmful effects of these particles on the environment and ultimately on human health? And that, mes amis, is what I am trying to figure out. Or, at least play a minor role in part of a larger group that is devoted to answering those questions: are nanoparticles being released from this cement into the environment and what are the environmental effects and impacts on human health?
In order to answer this question, I am working with cement samples that come specifically from the Italcementi group. The cement samples that I have contain TiO2 NP's and although I cannot reveal the amount of TiO2 in them, I can say that I am in the process of "leaching out" the nanoparticles. In other words, attempting to wash out the nanoparticles out of the cements under simulated conditions which mimic real conditions of aging, rain, wind, weathering on the cement over time. The ultimate goal is to identify, characterize and quantify the nanoparticles that have been leached out of the cement IF they actually do come out of the cement. This brings up an interesting topic of discussion, if the nanoparticles do come out of the cement then we want to know how soon they come out and are they bound to other compounds. Do the pollution-minimizing benefits of the use of nanoparticles in cement outweigh the drawbacks?
Conclusion: There are so many questions and so few answers. However, we can be sure of one thing: with the rate at which nanomaterials are being incorporated into various different products ranging from sports-wear pants and sunscreens to cements and paints, then there will inevitably be a release of these nanomaterials into the environment that we live in.
How many years will pass before we see the effects of these nanomaterials in our environment? Will they be harmful to humans? What are the consequences? What can we do today to make a better tomorrow? There are many questions and to find all of the answers, massive amounts of research needs to be done. We must remember, though, that the answers begin with the questions.
"The scientist is not a person who gives the right answers, he's one who asks the right questions."
Claude Lévi-Strauss, Le Cru et le cuit, 1964
Nanotechnology is a fairly new area in science and it brings along with it both benefits as well as many new challenges. Quite frankly, we create problems and then we turn around and try to solve them; this is what makes the world spin around!!
Conclusion: There are so many questions and so few answers. However, we can be sure of one thing: with the rate at which nanomaterials are being incorporated into various different products ranging from sports-wear pants and sunscreens to cements and paints, then there will inevitably be a release of these nanomaterials into the environment that we live in.
How many years will pass before we see the effects of these nanomaterials in our environment? Will they be harmful to humans? What are the consequences? What can we do today to make a better tomorrow? There are many questions and to find all of the answers, massive amounts of research needs to be done. We must remember, though, that the answers begin with the questions.
"The scientist is not a person who gives the right answers, he's one who asks the right questions."
Claude Lévi-Strauss, Le Cru et le cuit, 1964
Nanotechnology is a fairly new area in science and it brings along with it both benefits as well as many new challenges. Quite frankly, we create problems and then we turn around and try to solve them; this is what makes the world spin around!!
This is a picture that I took of one type of experiment that I am running. These two contraptions are called Soxhlets and they are used for extraction purposes. The concept is extremely simple and I will explain it as simply as possible without too many details. There is a sample of cement in the big chamber on the right (the one on the elevated white hotplate) and as the water flows over this sample it carries away everything that comes out of the cement (in this specific experiment, we are seeing if the TiO2 NP's will dislodge from the cement). This leachate, or, run-off from the cement, flows through the tubes then through an overflow (really hard to see in the picture) and then into the glass extraction balloon that is sitting in the other hotplate. When heated, some of the water evaporates and goes up the brown duck-taped tube (the distillation path) and then condenses back into water as it travels through the cooled water condenser which is the horizontal glass tube at the very top. This water then drips back into the chamber where the sample is and the process starts all over again. Every day for the first two weeks, I have been taking a sample out of the extraction balloon to do ICP analysis on. ICP stands for Inductively Coupled Plasma analysis and it is a way to determine the concentration of metals, or in our case, the concentration of the TiO2 NP's.
I shall conclude here as this post is way too long and jam-packed with informatin on cement chemistry. Have a great and wonderful new week and I will be writing about the city of Avignon in my next post. Talk to you all soon,
Oksana
