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Environmental Science and Engineering Program Seminar - Sreekiran Raveendran Pillai & Huma Sanawar

Start Date: August 20, 2017
End Date: August 20, 2017

​​DATE: Sunday, August 20, 2017
TIME: 4:00 - 5:00 p.m.
LOCATION: Auditorium 0215 · between Buildings 4 & 5​

SPEAKER: Sreekiran Raveendran Pillai, Ph.D. Student
TITLE: Isotope effects on Hydrophobic Interactions

The hydrophobic interaction, defined as the force experienced by two hydrophobic surfaces or species across water, plays a central role in various self-assembly processes in the environment. However, despite its ubiquity, mechanistic insights into hydrophobic interactions remain elusive. For instance, effects of the rigidity of water-hydrophobe interfaces, specific adsorption of intrinsic ions at hydrophobic interfaces, and delocalization of protons in water on the empirical hydrophobic force law are unknown. Thus, on this work, we strive to clarify the effect of rigidity of water-hydrophobe interfaces by experimental investigation of hydrogen/deuterium isotope effect on hydrophobic interactions. We employed surface forces apparatus (SFA) to quantify hydrophobic interactions between molecularly-smooth mica surfaces functionalized with perfluorodecyltrichlorosilane (FDTS) in heavy water and light water. Intriguingly, we found that the hydrophobic interaction was stronger in heavy water compared to light water. As an initial step to creating a theoretical model, First principle based free energy molecular simulations has also been done to find the thermodynamic drivers for the heavy water compared to light water system. 
As a future work, we are interested in direct measurement of isotope effect of hydrophobic interaction between mica surfaces coated with cationic surfactants (CTAB). In addition, I will present the sample preparation process and one of my results.

Sreekiran Raveendran Pillai received his M.Tech in Chemical Engineering from Indian Institute of Technology (I.I.T) Bombay in 2014. He joined Interfacial Lab in WDRC during the Fall of 2015. Currently he is pursuing his PhD in the department of Environmental Engineering under the supervision of Prof Himanshu Mishra. His research interest includes surface engineering, hydrophobic interactions and interfacial engineering.


SPEAKER: Huma Sanawar, Ph.D. Student
TITLE: Applicability of short-term accelerated biofouling studies to predict long-term biofouling accumulation in membrane elements

Biofouling contributes to more than 45% of all cases with membrane fouling and it can be detrimental to membrane performance, ultimately leading to filtration process failure. Biofouling studies addressing biofouling control are mostly executed in short-term studies. It is unclear whether data collected from short-term biofouling experiments in lab-scale membrane fouling simulators (MFSs) are representative for long-term biofouling as occurring in full-scale membrane systems. This study investigated whether short-term biofouling studies accelerated by biodegradable nutrient dosage to feed water were predictive for long-term biofouling development without nutrient dosage. Since feed spacer itself also has an important effect on biofouling, this study employed six geometrically different feed spacers to evaluate the biofouling impact ranking of the six feed spacers during short-term and long-term operation. The results of this study will be presented in the seminar.​

Huma Sanawar is a PhD student in WDRC under the supervision of Professor Johannes Vrouwenvelder. She is an alumna of Limerick Institute of Technology, Ireland, and holds a BSc in Pharmaceutical and Forensic Analysis, and MSc in Analytical Chemistry. Her research focuses on preventive and curative biofouling control strategies in reverse osmosis and nanofiltration membrane systems. Recently, she has collaborated with Delft University of Technology and Evides Industriewater in The Netherlands to carry out research activities at both lab-scale and full-scale set-ups, investigating novel membrane cleaning strategies for biofilm removal.