My last week in El Paso was a bit hectic to say the least. Interestingly enough, the CDI was creating a more salinated solution rather than the expected desalination, and the system wasn’t getting anywhere near to producing drinkable water. First, we tried rinsing the electrodes for an extended period of time in case of super saturation, which appeared to work at first, but the electrodes still wouldn’t remove a sufficient amount of ions or dump them quickly enough. Then, we switched the carbon electrodes with a new set just in case we were nearing the end of the electrodes’ lifespan, but the result was more or less the same. Next, we tried both increasing and decreasing the concentration of the feed salt solution, trying to make the conductivity peaks more distinct, but that also didn’t seem to have much effect. At the suggestion of Dr. Walker, we tried to test the system for the presence of a short circuit, which could explain the electrode’s lack of absorption; however, this proved to be much more difficult than expected because of the presence of water in the system. Before leaving on Friday, we tried to use air to push any remaining water out of the system in order to accurately test for a short circuit, but we couldn’t be sure that the system was completely dry. All we knew was that when a meter was connected, it indicated that our system was short circuiting.
On Thursday, I took a mini-road trip with a two other interns in the lab up the Rio Grande River, collecting water samples for one of the intern’s summer project. I’d only ever seen the Rio Grande down by the most southern tip of Texas, so it was interesting to travel to New Mexico and see how different it was. We went up to Elephant Butte and then made our way back down to El Paso, stopping about 13 times at different points of the river, some of which were not as accessible as others..
It was definitely tough leaving on such an indefinite note, even more so because it felt as if our project had just begun. I’m sure that I’ll keep in touch with Seye over the next couple of months and I’m excited to hear about his progress in the system’s automation and his growth in understanding about capacitive deionization in general, but I’m sad that I cannot fully accompany him on that journey. I never could have imagined that El Paso would be so dear to me at the end of this internship. Saying goodbye was difficult, but I know that just means that I was lucky enough to have a meaningful experience in which I had the opportunity to meet a whole group of wonderful, intelligent people that give me a reason to come back one day.
After much blood, sweat, and tears, I’m proud to announce that we finally fully set up the CDI system (of course, it leaked the first time we ran water through it, which took a couple tries to figure out). We ran about 1 volt through the system and successfully reduced the conductivity for about 5 minutes, at which point we assumed that the electrode became saturated and could no longer desalinate the solution. Then we reversed the polarity of the carbon electrodes to dump the collected ions into a concentrate stream, which took a while most likely due to the significant amount of collected ions. We are still trying to figure out the quirks of the system, but the future looks promising; however, it’s all a bit bittersweet, since the project feels like it’s just beginning.
On another note, LabVIEW coding has not been going so well. After extensively reading different manuals and trying my best to figure out the new language, I discovered that the program is relatively easy to use and navigate…if it’s set up correctly. Focus had been shifted mainly toward acquiring materials to complete the CDI system, so once I could direct my attention more fully to learning the software, I quickly ran into quite a few problems while actually trying to write a code connecting different instruments to the computer. Fortunately, Dr. Walker was able to clear most everything up once back from his trip delivering water filters to those in need in Ecuador. However, we ultimately discovered that the LabVIEW software would not measure data due to an installation error, which we are currently still trying to figure out so that we can finally get the ball rolling on this automation.
As my time here comes to an end, I can’t help but feel saddened by the eventual goodbye to this wonderful place and the people that have truly made this entire experience worthwhile.
This week I functionalized reduced graphene oxide (rGO) with iron nanoparticles. I used water and ethanol to clean the functionalized rGO and then I dried the sample with the rotary evaporator. A graduate student ran IR, TGA, and BET for this sample as well as two others. I gave Jose the samples early in the week, but I have not heard back from him (and there is always a high demand for characterization tests). Although I have already made GO with two approaches, we are trying another synthesis procedure, which is a slight modification of the original procedure. I have about a liter of GO in solvent that needs to be dried, but this will take quite some time.
I have continued to help Luz, another NEWT student. I prepared two different zeolitic imidazolate frameworks (ZIFs): ZIF-9 and ZIF-11. Each of the ZIFs has to be heated in an oven for a couple days at specified conditions for crystal formation. Next week, I will be able to collect and isolate the crystals. Luz’s project is similar to mine, but graphene oxide will be functionalized with ZIFs and APTES in addition to the magnetic nanoparticles. The idea is to take advantage of ZIF’s porous properties and ability to adsorb contaminants. For the last week, I will continue to work on my project and summarize key findings. I plan to finish strong and wish the best to my fellow NEWT interns as well.
Seven weeks, two projects, one city, and great friends. My time spent here at Rice has been a great experience.
Last week I finished with my mechanical portion of my project. As I previously posted we were having issues with the module itself as I said it was “cracking under pressure, LITERALLY”. After the epoxy dried we tested immediately, it was going strong for the first few minutes and no pressure was building. Once the module was filled with water that we started to see the window bulging out, and when we started messing with the flow rates we heard some cracking. We continued to run the module when the first crack developed and a minute or two later another area of the module started spiting out water. At this point are current module is not fixable, however we have learned from the mistakes that were made here and have developed a few idea to fix these problems as we fabricate a new one.
This next week, I am finishing up my computational modeling, and even teaching one of my mentor the program so he can take over once I leave. At this point my number show that higher flux is produced when a flow rate is higher and when the feed side is at a higher temperature and is coated with carbon black. Right now I am running constant data only changing the flow channels. This number is important because it will be use as reference for the new module. It should take me a day or two too finish it and I should be at that point officially done.
Other than my research here, the rest of my time here was used to make great friends and visit great areas of Houston. Allowing us to research at different universities has allowed me to get out of my comfort area as well as make impeccable connections. I am however ready to go back home to see my family, then back to phoenix to see my friends to tell them about my seven week trip.
Last week we start wrapping up the results from all of the experiments. Collecting the data, and arranging it in an organize way. creating graphs for our results, checking the photographs from the different microscopes, and planing the last experiments. This past week I learned to how to synthesize some of the nano-materials that are use in the laboratory to conjugate to the phages. I also conjugate my phages to different materials and test them in a bacteria library. Only one more week and the program will be over. I have a mixture of feelings between wanting to go back and see my family, and not wanting to leave Rice to continue with the research.
I have been learning Chinese for 6 months now, and I have really enjoyed improving my Chinese since I’ve been in Tempe. I have met a couple really nice Chinese students who have been very helpful and willing to help me. Initially, I foresaw myself spending all my spare time practicing Chinese, but another language began to vie for position. The language of Iran, Persian/Farsi. Two of my lab partner speak the language and it sounded nice to my ear. After that, I asked them to teach me a few words. They were so excited by how well I caught on, I could not get enough of it.
Learning languages, both Chinese and Persian; being able to talk to my Chinese and Persian friends in their native language has been one of the elements of my time in Tempe that has made it so enjoyable. I have been told by my Chinese friend, that I have a Chinese spirit over Indian food, and my Iranian friend told me I have Persian spirit as well. I look forward to discovering my other latent spirits.
A major part of the fun I have had is due to fellow REU students. Me and 3 other REU students went up to Sedona for July 4th week. We had a great time hiking, swimming, eating, and just hanging out. Being in Sedona was like being in another world. The energy there was so different. Everyone there had a common goal; explore and have a good time. I only met energetic and friendly people while I was there. That and the beautiful scenery made the trip amazing. The highlight had to be the sunset hike. I don’t have the pictures of it bc my battery was completely gone, but it was beautiful.
For July 4th, me and REU students also went to see fireworks. It was fun walking to Tempe Town lake, and seeing everyone fired up. July 4th in Tempe is like none other. Considering how many people typically leave Tempe in the summer, the streets were still full, and so was the sky.
The first batch of graphene oxide(GO) is complete, the lyophilization was a success. The first batch that has been completed used the Hoffman synthesis method. Close behind is the Staudenmaier method. Based on appearance the Hoffman samples look fine. However, we will not have a concrete analysis of the material until further characterization is done. First, is SEM. This will give us a size distribution of the GO sheets.
Apart from producing and characterizing GO, I have also done analysis on silver coated cellulose membrane. Measuring the surface charge and contact angles for varying silver concentration. I obtained data for 1mM and 6mM Ag coated cellulose membranes. Unfortunately, I accidentally damaged the 3 mM Ag coated cellulose membranes which rendered erratic results.
Next is running SEM for Hoffman GO, then lyophilizing the Staudenmaier GO.
This past week was a hard week. Frustration is a thing that all scientist must learn to cope with, and this week I had a taste of it. The experiments we performed, did not showed the expected results, therefore they had to be repeated many times. Dealing with not having the expected results, thinking of ways to fix it, and trying to stay motivated, was not easy. This was my hardest week until now. Nevertheless, not everything was lost, because we were able to get good images from the microscope, of the phage conjugated with the materials. The plans now, are to start the writing portion of my project and bring together all the results from the previous experiments, and the new experiments.
My head is spinning, two weeks left and i’m using every hour to my advantage.
Bright side, our mechanical skid is finally fully functioning!!! Last week we finished the fabrication of the skid and attached all the equipment on. The skid looks amazing so far my pride in my time being here. However, there was one thing that is giving us troubles and that is the module itself. The module is the heart of the skid, its where the water is distilled and it starting to crack under pressure, LITERALLY! We are having a hard time fixing the problem because we don’t now where the pressure is coming from, it should be a zero pressure system. The window is bulging out a bit so that means there is quite a bit of pressure that is building up. Right now our main goal is to fix the crack and hole from which it is leaking. We will then assess the problem by taking one of the temperature sensors out to leave a small hole where the pressure can alleviate itself. We are using epoxy to give it a sturdy fix and is expected to dry hopefully tomorrow. If everything goes well then we can hopefully get a week in of real time testing before I have to go.
As for my computational model, it is going good. I have been running data left and right. The use of the numbers have already proven that when the feed side of the module has a high flow rate as well as a high temperature we will produce more flux. It has also been able to show that the use of Nanoparticles (aka carbon particles) are beneficial to the module to the system as well because it also produces higher flux. The goal right know is to run data that test different channel length in which the water flows to see which is more efficient. Based on what produces the best flux, those measurements will go into making a newer and better module for the future.