Welcome to the official blog of the NEWT REU internship program, where students from Rice, Arizona State University, University of Texas El Paso, and Yale, will share their experiences and stories from their summer internship sessions. Students will be working on water-related projects with mentors in university labs throughout the United States and in the University of Malawi Polytechnic in Blantyre, Malawi. Click here to learn more about the NEWT Center and here to learn more about the NEWT Program’s education activities.
Till Next Time, El Paso!
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.
Week of July 11-16 Part Two
Building began Friday, with cutting of the metal. We are still on schedule, and should be done with building by mid-next week. Once the frame is welded together, we will be able to conduct testing as to its effectiveness compared to the flocculator in the lab.
This weekend we planned a trip to go hiking in Zomba, on the mountain. The president has a residence on the mountain, and it was very scenic driving up as many old houses and trees were along the road. Apparently, Zomba used to be the old capital of Malawi and thus has a more historical feel to it compared to Blantyre. Once higher up on the mountain, we saw many people selling raspberries, which was exciting. We ended up filling a one-gallon zip lock bag with them before leaving. Once on the hike, I got very confused all of a sudden, as I started to smell pine trees and see pine needles all over the ground, as if I were back in New England. Our guide told us that these trees were imported and grown for the lumber industry. It was certainly a strange landscape, seeing pine trees in the sub-tropics and raised the question of how common a practice it has become to import foreign trees for logging. Next week, we should be able to finish building our apparatus and maybe even go out for a water collection.
Week of July 11-16 Part One
Now that a design has been decided upon, we put together a shopping list. We wanted to use both easily sourced materials as well as inexpensive ones. We thought scrap metals would be the best material for this and we went to the market. To gather all the materials, both for the framework and for the stirring apparatus, we spent about three afternoons at the market. On Wednesday, we met with Dr. Mkandawire, who said we were on the right track. Despite earlier discouragements that building would be a misguided project, she believed that we should still put forth efforts to devise a treatment system even if it might fail in the field because it would all be part of the learning process.
On Thursday, we had a scheduled trip to the Blantyre Water Board’s collection and treatment facility at Walkers Ferry. We hoped that by visiting the municipal water treatment system, we would have a better understanding of how water treatment works in general and what the standards are for the Southern Region of Malawi. A four-stage process—extraction, sedimentation (several sub-stages), filtration, and finally chlorination—was used to supply over 90% of the required water to Blantyre. A set of pumps, tanks, gages, as well as a large contact tank to store the chlorinated water before being pumped to Blantyre, proved the complexity of water treatment. Our system hopes to combine sedimentation and treatment into one bucket, filtration as a step between the two buckets, and then clean water in the bottom bucket.
Nearing the End
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.
Rinse, Repeat… Research
Same old, same new. Right now, it’s just repetition of what I’m familiar with and what I’m still unfamiliar with. I’ve got the hang of running the RO system and using the goniometer to measure contact angles, but I’m still learning how ATRP (remember atom transfer radical polymerization?) works. It’s a lot of chemistry and science at a molecular level because initiators, buffers, attachments of copolymers, etc. are involved. In case you don’t remember from my last report, it is one of the most commonly employed techniques for the development of new materials due to the ability to control molecular weight and polymer structure throughout the process.
We decided to reduce the salinity concentration of the feed water for the RO system because the first modified membrane’s permeability was negatively affected by the polydopamine phase (which acts as the initiator) and therefore it’s flux was low relative to the commercial BW30 membranes. Lowering the salinity allows us to better characterize the surface, especially since the concentration will be at a saturation index of less than one (because at an index of greater than one, crystallization is going to occur regardless of the surface chemistry of the membrane). The concentration at the membrane surface also has to be taken into account because it is always greater than the concentration of the feed. There was a reduced appearance of scaling on the membrane surface after 48 hours in the RO system, but, again, the flux was lower at the same pressures and cross flow as the commercial membranes. Just to give you an idea, the commercial membrane produced a flux of approximately 1.7 mL/min at 350 psi while it took a pressure of about 400 psi to reach the same flux with the modified membrane.
There is a lot of room for error throughout the ATRP procedure, so non-homogeneity is expected, but a lack of uniform coverage of the membrane surface with the copolymers is an issue when it comes to reducing scaling. We were measuring contact angles the other day and the first strip of the newly modified membrane was giving us very low angles with drops of water, which is exactly what we wanted because it indicates that the surface is more hydrophilic. Then, we tried another strip of a membrane from the same modified batch and the angles were almost twice as large. When the membrane was examined more closely, there was a varying level of dullness on the surface, which could be evidence that the modifications are not taking place throughout the entire surface evenly.
This week has been a race against time, with my work ending this Friday and Humberto’s conference taking place a week later. We’re hoping that by performing more ATRP on membranes and having a better handle on the process and consistency of modification, we can gather more agreeable data on the effects of ATRP on scaling. My next post will detail the end of my research here at Yale, and hopefully I’ll have conclusive results by then. Wish me luck!
Last Experiment
As the monsoon season approaches Arizona toward the end of the month, my stay here at ASU begins to end. Conducting three experiments back to back, today I see my last experiments as ASU. All that is left for this set of data is analysis and interpretation. Throughout the week I will be working on a final report and constructing an abstract for future conferences I will attend. This has provided a challenge to be to consolidate everything I have learned in the past month into concise report. Determining the material to add to the report seems like the most difficult task for me to do as well as proper documentation from the several reports and articles I have read.
Several events are being planned this week by both my adviser and roommate. I have my final presentation in ASU this Friday where there is expected to be a larger crowd than normal for my departure. My roommate is planning a get together with some of his friends on Tuesday where I will be cooking fish using one of my Dad’s famous recipes. At the get together everyone will be bringing their own dish to our dorm and have fun. This Wednesday, my mentor, Dr. Bi, and some of my colleagues are going to watch a movie in the istb4 building about space travel and what mankind has accomplished and discovered thus far.
As a conclusion, I look forward to what this week holds for me. In between all of the work and other activities, I am certain I will enjoy my last few days here in Arizona.
Finish Strong
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
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.
Later Alligators,
Evelyn
Final steps
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.
Chinese and Persian Spirit
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.
