Student Ph.D. Defense – Dinesh Mahalingam

Nov 07 2019 02:00 PM - Nov 07 2019 03:00 PM

​Ph.D. Dissertation Defense

Development of Graphene Oxide Based Membranes for Liquid Separations

Dinesh Mahalingam
Supervised by Prof. Suzana Nunes

Thursday, November 07, 2019
02:00 PM - 03:00 PM
Building 5 - Level 5 - Room 5209
Several attempts have been made to combine the unique characteristics of graphene oxide (GO) and commercial polymers for successfully designing and fabricating next-generation membranes in filtration and separation technologies. The first part of the work develops a high flux polyethersulfone ultrafiltration membranes, by embedding GO sheets, starting from the polymer/GO solutions in ionic liquid and N, N dimethylformamide as co-solvents and promoting the pore formation via non-solvent induced phase separation. In the second part of the work, a protic ionic liquid was introduced as a solvent to disperse GO sheets and fabricate GO liquid crystal membranes for nanofiltration. The third part addresses the stability enhancement. GO membranes frequently disintegrate in aqueous environments due to swelling. Ethylenediamine was then used as a crosslinker, and the membranes were tested for organic solvent nanofiltration. Additionally, overcoming the permeation-rejection trade-off is challenging. Hence, the fourth work involved the intercalation of silica nanoparticles to form dual-sized nanochannels. In the final work, GO membranes were fabricated on the surface of hollow fibers to overcome scalability issues, by using a feasible spray coating method for efficient nanofiltration. Overall, this study demonstrates the potential of GO in developing high-performance membranes for liquid separations relevant for industrial applications, such as wastewater treatment, food, chemical, petrochemical, and pharmaceutical processing.
Dinesh was born in India, in a small town called Ooty. After completing his post-graduation in chemistry, he worked as a project assistant in National Aerospace Laboratories, a national research and development lab in India. Following this, he went on to pursue his second master’s degree in nanotechnology and later joined as a faculty teaching chemistry. He was awarded the proficiency award in the undergraduate course for showing exemplary excellence in the academic department. Dinesh joined KAUST in Fall 2015 in the Environmental Science and Engineering (EnSE) program under the supervision of Prof. Suzana Nunes. He develops graphene oxide-based membranes for solution-based separations.