SEMINAR: Removal of Toxic Heavy Metal Cations from FGD Wastewater Using Functionalized Silica

Vadim V. Guliants Chemical and Environmental Engineering University of Cincinnati
When Mar 10, 2017
from 01:00 PM to 02:00 PM
Where Ernst Hall, Room 310
Contact Name
Contact Phone (502) 852-6347
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Abstract:

Flue-gas desulfurization (FGD) process employed by electric power generation utilities produces wastewater containing significant levels of soluble heavy metal ions that are being regulated to parts-per-billion (ppb) levels due to their toxicity. In order to address this issue, the removal of several heavy metal ions was investigated by employing high-surface area amorphous silica grafted with sulfur-containing functional groups, which have been shown to have high affinity towards heavy metal ions. These adsorbents were tested for the removal of single component as well as multiple component heavy metal ions.

The silica support was grafted with 3-mercaptopropyltrimethoxysilane and 2-mercaptobenzothiazole. Thermogravimetric analysis (TGA) and potentiometric mass titrations (PMT) were performed on functionalized silica to determine surface loadings and the point of zero charge (PZC), respectively. The removal of Hg2+ at high concentration (10,000 µg/L) in different matrices was investigated. The effect of FGD matrix ions (Ca2+, Mg2+, Na+, SO42-, Cl-, NO3-) on the removal efficiency of Hg2+ was also investigated. Simultaneous removal of Hg2+ along with the several other heavy metal cations has been studied at concentrations in the ppb range relevant for the FGD wastewater (Cu2+, Cd2+, Hg2+, Tl+, Pb2+, Ni2+, Zn2+). 99% of Hg2+ was removed using these adsorbents for both Hg2+ concentration ranges, while other heavy metal cations were also captured very selectively. Preliminary regeneration studies of spent adsorbents were performed using dilute HCl indicating limited regeneration and suggesting their disposal without regeneration.

About the Speaker:

Vadim V. Guliants
Professor Guliants received a PhD degree in chemistry from Princeton University, and after 4 years of industrial R&D experience at Praxair, Inc., joined the Department of Chemical Engineering at the University of Cincinnati in 1999.  He is a recipient of the King Carl XVI Gustaf’s Professorship in Environmental Science, Uppsala University, Sweden (2010), NSF CAREER Award (2002), and Soros Scholarship at Oxford University (1990). His research has been supported by the NSF, DOE/BES, US Department of the Interior, DOD, NASA, the Ohio Coal Development Office, and industry. He published over 120 peer-reviewed publications and 8 patents.