Grantee Research Project Results
2024 Progress Report: Optimized biochar/hydrochar for disinfection byproduct removal in water
EPA Grant Number: SU840574Title: Optimized biochar/hydrochar for disinfection byproduct removal in water
Investigators: Marti, Erica , Moon, Jaeyun , Abduraheem, Ismail , Ung-Watson, Kers , Kim, Dong-Yong , Khatamgooya, Ahmadreza , Mussio-Marquez, Ashley , Rouhani, Donna , Hatfield, Jesse , Rhoimer-Agdeppa, Rexxor , Nelson, Scarlet
Institution: University of Nevada - Las Vegas
EPA Project Officer: Spatz, Kyle
Phase: I
Project Period: September 1, 2023 through August 31, 2024 (Extended to February 28, 2025)
Project Period Covered by this Report: September 1, 2023 through August 31,2024
Project Amount: $24,994
RFA: 19th Annual P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet Request for Applications (RFA) (2022) RFA Text | Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
The proposed project is the synthesis, characterization, and optimization of biochar and hydrochar adsorbents produced from agricultural waste biomass, which would ultimately be used as a drinking water filter media for disinfection byproduct removal in US households for standard use or during emergency situations or temporary water treatment, which disproportionately affect vulnerable populations. Especially in emergency situations and temporary water treatment systems, disinfection byproducts may exceed the regulated concentrations for drinking water. Removal of disinfection byproducts through a simple and low-cost process, like adsorption, is important because disinfection byproducts are harmful to human health as they are linked to cancer.
The research project has three main goals or tasks. The first task is to synthesize and characterize biochar and hydrochar adsorbents from agricultural waste biomass. In this task, both biochar (BC) and hydrochar (HC) will be generated using pyrolysis and hydrothermal carbonization, respectively at different temperatures. The adsorbents will be characterized by nitrogen adsorption/desorption (i.e., Brunauer-Emmett-Teller or BET) for investigating the pore size distribution and surface area, scanning electron microscopy (SEM) for investigating the surface morphology, Fourier transform infrared spectroscopy (FTIR) for investigating the surface functional groups associated with hydrophobicity/hydrophilicity, and water droplet contact angle for assessing hydrophobicity/hydrophilicity. The second task is enhancement of the adsorption properties of BC and HC through modification with physical (i.e., steam) or chemical (i.e., acid, base, thiol) approaches. The BC and HC will be characterized and compared to the unmodified forms. The most promising BC and HC will be brought forward task three, which is an assessment of BC and HC adsorption capacity for removal of regulated and unregulated disinfection byproducts in drinking water. Adsorption batch tests will involve varying the initial concentration of disinfection byproducts, varying the amount of adsorbent, and varying the contact time for adsorption to occur. Using standard isotherm and kinetic experiments, the capacity for disinfection byproduct adsorption will be determined. Development of a filter device using the best BC/HC or combination of BC and HC, as well as an economic analysis of the product, would be part of Phase II funding—if awarded. The project relates to P3 in the following ways: (1) improved drinking water, especially for vulnerable populations, to improve people's health; (2) development of a lowcost adsorbent that any person could afford to use; and (3) use of agricultural waste that would otherwise be discarded and the replacement of fossil fuel derived adsorbents that exacerbate climate change.
Undergraduate and graduate students on the Research Team will present at local research symposia, publish the results, and present to students in the PI's sustainability course.
Progress Summary:
For task 1, we successfully prepared and characterized biochar and hydrochar under varying conditions. Walnut biochar was created at three temperatures (700, 800 and 900 °C), and 900 °C was selected due to higher surface area and greater hydrophilicity on the biochar surface. Walnut hydrochar was created at three temperatures (200, 230, 250 °C) and at three reaction times (2, 3, 4 hours). 250 °C hydrochar heated for 4 hours was selected due to higher surface area and greater presence of carbon-oxygen bonds. For task 2, we successfully used chemical modification to prepare two biochars: base intercalation with acid exfoliation (BIAE) and sulfur-doped. Characterization showed substantially higher surface area for BIAE modified biochar. The bulk of the work was completed under task 3 with adsorption testing and a desorption study. BIAE modified biochar outperformed the unmodified biochar and hydrochar by removing most disinfection byproducts. Sample analysis from the desorption study is ongoing.
Future Activities:
Preliminary results indicate that walnut biochar modified through base intercalation with acid exfoliation was superior for adsorption of disinfection byproducts as compared to unmodified walnut biochar or hydrochar. Hydrochar exhibited poor removal for all DBPs and unmodified biochar removed less than half of the tested DBPs. On the other hand, BIAE modified biochar effectively removed 11 of 13 DBPs. Adsorption results for the sulfur-doped biochar and results from the desorption study are not available yet.
By the end of the no-cost extension, we expect to have complete results for all four classes of disinfection byproducts. We met the dissemination objectives through six poster presentations with involvement from multiple graduate and undergraduate students. A manuscript for a peerreviewed journal is in progress and is expected to be finished by May 2025.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
Water purification, drinking water, agricultural waste minimization, biochar, hydrochar, adsorption, disinfection byproducts, trihalomethanes, haloacetic acids, haloacetonitriles, nitrosamines, environmental engineering, materials synthesisProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.