EAS PhD Dissertation Defense by Dipshika Das
When: Tuesday,
December 19, 2023
8:00 AM
-
9:00 AM
Where: Online
Description: EAS PhD Dissertation Defense by Dipshika Das
Date: December 19, 2023
Time: 8:00 a.m.
Topic: Enhanced Ammonium Removal and Recovery Using Alkaline Hydrothermally Treated Chabazite (CHA) Zeolite
Zoom: https://umassd.zoom.us/j/91948495335?pwd=TjFnS1N1RmIyNGV0cDVRK25rdGdVdz09
Meeting ID: 919 4849 5335
Passcode: 161289
Abstract:
Natural zeolites, as inorganic ion exchangers, exhibit a strong affinity for ammonium (NH4+), rendering them promising candidates for efficient NH4+ removal from municipal/industrial wastewater and agricultural runoff. The ability to recover NH4+ during zeolite regeneration contributes to a circular economy, significantly reducing the energy footprint associated with NH4+ generation. Alkaline hydrothermal treatment of natural zeolites enhances their ion-exchange capacity by incorporating extra-framework cations into their crystal structures. In this study, Chabazite (CHA), a natural zeolite, underwent alkaline hydrothermal treatment with varying alkali concentration, temperature, and treatment duration.
A comprehensive analytical investigation, including X-ray Powder Diffraction (XPD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and 27Al and 29Si Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR), conclusively demonstrated the conversion of CHA into analcime (ANA), a zeolite with a denser tetrahedrally coordinated atom structure.
Mesopores in a zeolite act as an entrance for larger molecules, facilitating their movement for catalytic chemical reactions. This modification enhances the ion exchange capacity of zeolite, improves mass-transfer and opens up more accessible sites in the zeolite. This study provides conclusive evidence of enhanced mesoporosity of CHA following alkaline hydrothermal treatment.
The modified zeolite exhibited twice the NH4+ removal capacity compared to the parent natural CHA. When utilized in a packed-bed configuration, the modified CHA demonstrated excellent selectivity toward NH4+ in synthetic wastewater containing competing cations. The exhausted zeolite was successfully regenerated using a brine solution, recovering 94 - 98% of the loaded NH4+, providing a nitrogen-rich source for various applications. The regenerated zeolite could be used for subsequent exhaustion cycle without any loss of performance.
Keywords: Ion-exchange, Ammonium, Chabazite, Alkaline mediated hydrothermal treatment, Selectivity, Cation Exchange Capacity, Regeneration
ADVISOR(S):
Dr. Sukalyan Sengupta, Dept of Civil & Environmental Engineering
(ssengupta@umassd.edu)
COMMITTEE MEMBERS:
Dr. Walaa Mogawer, Dept of Civil & Environmental Engineering
Dr. Jonathan Mellor, Dept of Civil & Environmental Engineering
Dr. Chen-Lu Yang, Center for Innovation & Entrepreneurship, UMass Dartmouth Dr. Sudipta Sarkar, Indian Institute of Technology, Roorkee, India
NOTE: All EAS Students are ENCOURAGED to attend.
Date: December 19, 2023
Time: 8:00 a.m.
Topic: Enhanced Ammonium Removal and Recovery Using Alkaline Hydrothermally Treated Chabazite (CHA) Zeolite
Zoom: https://umassd.zoom.us/j/91948495335?pwd=TjFnS1N1RmIyNGV0cDVRK25rdGdVdz09
Meeting ID: 919 4849 5335
Passcode: 161289
Abstract:
Natural zeolites, as inorganic ion exchangers, exhibit a strong affinity for ammonium (NH4+), rendering them promising candidates for efficient NH4+ removal from municipal/industrial wastewater and agricultural runoff. The ability to recover NH4+ during zeolite regeneration contributes to a circular economy, significantly reducing the energy footprint associated with NH4+ generation. Alkaline hydrothermal treatment of natural zeolites enhances their ion-exchange capacity by incorporating extra-framework cations into their crystal structures. In this study, Chabazite (CHA), a natural zeolite, underwent alkaline hydrothermal treatment with varying alkali concentration, temperature, and treatment duration.
A comprehensive analytical investigation, including X-ray Powder Diffraction (XPD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and 27Al and 29Si Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR), conclusively demonstrated the conversion of CHA into analcime (ANA), a zeolite with a denser tetrahedrally coordinated atom structure.
Mesopores in a zeolite act as an entrance for larger molecules, facilitating their movement for catalytic chemical reactions. This modification enhances the ion exchange capacity of zeolite, improves mass-transfer and opens up more accessible sites in the zeolite. This study provides conclusive evidence of enhanced mesoporosity of CHA following alkaline hydrothermal treatment.
The modified zeolite exhibited twice the NH4+ removal capacity compared to the parent natural CHA. When utilized in a packed-bed configuration, the modified CHA demonstrated excellent selectivity toward NH4+ in synthetic wastewater containing competing cations. The exhausted zeolite was successfully regenerated using a brine solution, recovering 94 - 98% of the loaded NH4+, providing a nitrogen-rich source for various applications. The regenerated zeolite could be used for subsequent exhaustion cycle without any loss of performance.
Keywords: Ion-exchange, Ammonium, Chabazite, Alkaline mediated hydrothermal treatment, Selectivity, Cation Exchange Capacity, Regeneration
ADVISOR(S):
Dr. Sukalyan Sengupta, Dept of Civil & Environmental Engineering
(ssengupta@umassd.edu)
COMMITTEE MEMBERS:
Dr. Walaa Mogawer, Dept of Civil & Environmental Engineering
Dr. Jonathan Mellor, Dept of Civil & Environmental Engineering
Dr. Chen-Lu Yang, Center for Innovation & Entrepreneurship, UMass Dartmouth Dr. Sudipta Sarkar, Indian Institute of Technology, Roorkee, India
NOTE: All EAS Students are ENCOURAGED to attend.
Contact: Engineering and Applied Sciences
Topical Areas: Faculty, Students, Students, Graduate, Students, Undergraduate, Bioengineering, Civil and Environmental Engineering, College of Engineering, Computer and Information Science, Co-op Program, Electrical and Computer Engineering, Mechanical Engineering, Physics