Afraa Abusalih – Seminar/Ph.D. Thesis Defense – Tuesday, June 20, 2017 at 10:00 A.M.

JSNN – Afraa Abusalih – Ph.D. Thesis Defense/Tuesday Seminar

Candidate: Afraa Abusalih

Advisor and Committee Chair: Shyam Aravamudhan, Ph.D.

Department: Nanoengineering

Date: Tuesday, June 20, 2017

Time: 10:00 A.M. – 12:00 P.M.

Location: JSNN Auditorium

2907 E. Gate City Blvd., Greensboro, NC 27401

Title: “Development of an Off-chip Methodology for Detection and Measurement of Carbon Nanotubes in Wastewaters.”


The overarching objective of this work is to develop an in-line wastewater detection and measurement system for carbon nanotubes. Towards this long-term objective, specifically in this work, we have developed an off-line separation method for carbon nanotubes, followed by Raman spectroscopic method to quantify the amount of carbon nanotubes in the separated sample. With the advances in nanotechnology, the concentration of carbon nanotubes in industrial wastewater is and will be increasing in future. The United States Environmental Protection Agency (USEPA) has initiated regulation for nanomaterials including for carbon nanotubes under the Toxic Substance Control Act (TSCA). Studies have shown that carbon nanotubes under certain conditions may be toxic to aquatic life and human health. The methodology developed in this work include the off-chip coupling of two very delicate analytical techniques, namely size exclusion chromatography (SEC) and Raman spectroscopy. CNTs were successfully separated form C60 fullerenes with elusion times of 30 minutes and 3 hours for the fullerenes and CNTs respectively. A calibration curve was developed for Raman spectra for seven different types of CNTs using regression analysis, the curves had acceptable R2 values, which indicate high confidence in the equations deduced by regression analysis. The separated samples were confirmed as the fullerenes followed by the CNTs using Raman spectroscopy. After confirmation of the beginning time for CNTs elusion, SEM was used to confirm that CNTs are the only solids contained in the samples. The future work will include development of a microsystem that combines the two techniques in an on-chip format.