RJ Vogler's REU Experience (Summer 2018)

Week 7 consisted continuing my work in lab, attending a presentation about the GRE test, and spending some time with my fellow REU students. In lab this week, I got to begin the study of the cellulose-polyacrylic acid (PAA) membrane that I made last week.  One parameter of this membrane that I got to look at was permeability, which is an indicator of how fast substances flow through the membrane.  One interesting thing about this parameter for membranes containing PAA is that it should change as the pH of the inlet solution and membrane change.  This is because the units of PAA's repeating structure become negatively charged (rather than neutral) at higher pH values, and thus, repel each other and cause swelling of PAA that constricts the pores.  To test for this behavior in the cellulose-PAA membrane, I soaked the membrane in an acidic solution in an effort to reduce the swelling of PAA and measured the flow of a similar solution through the membrane afterwards; I...

This week consisted of working in lab, meeting with my research group, spending time with my fellow REU students, and heading home for a bit on the weekend. In lab, I got to see some cool machines in action and make a membrane out of cellulose and polyacrylic acid (PAA). One of the machines that I got to see was a scanning electron microscope (SEM). This SEM also had an energy-dispersive x-ray spectrometer (EDS), which is capable of analyzing the elements present in an SEM image of a membrane sample. During my two visits, I got to see this machine be used to study the amount of iron in a polyvinylidene fluoride-PAA membrane that I loaded with iron last week. One type of EDS analysis that was done on this membrane is mapping, which marks the locations of different elements in an SEM image. Some of the maps of a portion of my membrane that all correspond to the same SEM image are directly below. The carbon and fluorine are both part of PVDF, Iron Carbon Fluorine wh...

Week 5 of the program involved working in the lab, giving a presentation, listening to others’ presentations, taking a tour of Alltech’s headquarters, and visiting the latino festival in downtown Lexington. In lab, I got to continue my study of the increase or decrease in outlet flow rate of a membrane as I changed inlet pH. The membrane that I used was the one that I helped make out of polyvinylidene fluoride (PVDF) and polyacrylic acid (PAA) earlier in the summer. While it may seem counterintuitive to decrease the outlet flow rate of a membrane, it could come in handy in certain scenarios. For exampl e, if th is type of membrane were modified to react with certain substances that flow through it, the ability to slow down the flow through the membrane would provide it with more time to breakdown these substances. One new experiment that I got to experience in lab this week was the measurement of the surface charge of a membrane. To take this measurement, I had to prepare a small...

During week 4, I got to perform some new experiments in the lab and enjoy a lunch with others in the program. One major experiment that I got to do in lab was the addition of polyacrylic acid (PAA) to a manufactured polyvinylidene fluoride (PVDF) membrane, which if done correctly, allows the pores of the membrane to change size depending on the pH of the inlet solution and the membrane. Therefore, the amount of fluid that can flow through these membranes depends on pH. I attempted to observe this behavior by performing filtrations using the setup below and recording how long it took for a certain amount of fluid to pass through the membrane at different pHs. According to theory, the flow rate should go down as the pH increases. While I was able to observe this behavior when going from a pH of 4 to 5.5, the opposite occurred when I increased the pH from 5.5 to 9. Therefore, I will spend some time next week redoing this experiment with a different sample to see if I can ob...

Week 3 of the REU program was interesting as it involved a variety of experiences. I started off the week by attending the annual conference for the North American Membrane Society (NAMS). Also, I got to present an overview of my project to my fellow REU students towards the middle of the week and worked in the lab during the end of the week. The NAMS conference was an awesome experience. I was exposed to different applications of membranes by great scientists in the field that I am researching. One of my favorites was a membrane with enzymes on it that converted lignin, a common compound in plants, into something more valuable. Also, I was able to attend multiple presentations conducted by my lab-mates and see some of their posters to find out more about what they have been working on. Aside from presentations, NAMS included some social events, including a reception, a lunch, and a banquet. At these events, I had the opportunity to meet some students from other schools. Furthermore,...

Week two of the REU program consisted primarily of further defining my goals with others' assistance, learning how to do some different types of experiments, and attending the beginning of the annual conference for the North American Membrane Society (NAMS). After talking with my lab mentors and faculty advisors, who were a great help in the goal setting process, I learned that the project that I will work on will involve making membranes from cellulose that are capable of breaking down organic compounds and performing water separations. Also, I learned that I will compare these membranes to others made from polyvinylidene fluoride (PVDF) that have the same purpose. In lab this week, I learned how to carry out a few different types of experiments. One of these was the measurement of DI water flux, which is the outlet volume flow rate per area of membrane when a deionized water inlet is used; the other was the determination of selectivity, which involves finding out the percen...